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Since patients with chronic inflammatory rheumatic joint diseases may be more prone to infections, we wished to investigate the incidence of COVID-19 in this group, and explore the possible significance of factors related to the rheumatic disease, the patient or the treatment.Altogether 27 907 patients registered in the Norwegian Arthritis Registry (NorArthritis) were linked to the Norwegian Surveillance System for Communicable Diseases and the Norwegian Intensive Care and Pandemic Registry in order to find the incidence of COVID-19 in 2020, and the proportion of patients who were hospitalised. A standardised incidence ratio (SIR) was calculated by comparing with sex and age-specific incidence in the general population. Logistic regression analysis was used to investigate whether diagnosis, age, sex, disease activity, comorbidity or drug therapy had any bearing on the incidence.A total of 185 of the patients in NorArthritis tested positive for COVID-19, of whom 10 % were hospitalised. The incidence was lower than in the general population (SIR 0.84; 95 % confidence interval (CI): 0.72-0.97, P = 0.02). Young age and low disease activity were associated with higher incidence of infection. The other factors had no significant effect.The fact that the incidence of COVID-19 was lower than in the general population, and that within the group it was lower in those with moderate/high disease activity and greater age, is most likely attributable to patients of advanced age with chronic active disease having protected themselves against infection to a greater degree.

Background: Our objective was to determine the survival and causes of death in a large and well-characterized cohort of patients with giant cell arteritis (GCA). Methods: This is a hospital-based, retrospective, observational cohort study including patients diagnosed with GCA in Western Norway during 1972–2012. Patients were identified through computerized hospital records using the International Classification of Diseases (ICD)-coding system. Medical records were reviewed. Patients were randomly assigned population controls matched on age, sex, and geography from the Central Population Registry of Norway (CPRN). Date and cause of death were obtained from the Norwegian Cause of Death Registry (NCoDR). The survival was analyzed using Kaplan-Meier methods with the Gehan-Breslow test and the causes of death using cumulative incidence and Cox models for competing risks. Results: We identified 881 cases with a clinical diagnosis of GCA of which 792 fulfilled the American College of Rheumatology (ACR) 1990 classification criteria. Among those fulfilling the ACR criteria, 528 were also biopsy-verified. Cases were matched with 2577 population controls. A total of 490 (56%) GCA patients and 1517 (59%) controls died during the study period. We found no difference in the overall survival of GCA patients compared to controls, p = 0.413. The most frequent underlying causes of death in both groups were diseases of the circulatory system followed by cancer. GCA patients had increased risk of dying of circulatory disease (HR 1.31, 95% CI 1.13–1.51, p

BACKGROUND AND OBJECTIVES: The 52-week, randomized, double-blind, noninferiority, government-funded NOR-SWITCH trial demonstrated that switching from infliximab originator to less expensive biosimilar CT-P13 was not inferior to continued treatment with infliximab originator. The NOR-SWITCH extension trial aimed to assess efficacy, safety and immunogenicity in patients on CT-P13 throughout the 78-week study period (maintenance group) versus patients switched to CT-P13 at week 52 (switch group). The primary outcome was disease worsening during follow-up based on disease-specific composite measures. METHODS: Patients were recruited from 24 Norwegian hospitals, 380 of 438 patients who completed the main study: 197 in the maintenance group and 183 in the switch group. In the full analysis set, 127 (33%) had Crohn's disease, 80 (21%) ulcerative colitis, 67 (18%) spondyloarthritis, 55 (15%) rheumatoid arthritis, 20 (5%) psoriatic arthritis and 31 (8%) chronic plaque psoriasis. RESULTS: Baseline characteristics were similar in the two groups at the time of switching (week 52). Disease worsening occurred in 32 (16.8%) patients in the maintenance group vs. 20 (11.6%) in the switch group (per-protocol set). Adjusted risk difference was 5.9% (95% CI -1.1 to 12.9). Frequency of adverse events, anti-drug antibodies, changes in generic disease variables and disease-specific composite measures were comparable between arms. The study was inadequately powered to detect noninferiority within individual diseases. CONCLUSION: The NOR-SWITCH extension showed no difference in safety and efficacy between patients who maintained CT-P13 and patients who switched from originator infliximab to CT-P13, supporting that switching from originator infliximab to CT-P13 is safe and efficacious. Ministry of Health and Care services, Norway

Background The aim of this study was to examine the association between systemic lupus erythematosus (SLE) and periodontitis in Norway during a 10-year period from 2008 through 2017. Methods In this population-based study, 1,990 patients were included in the SLE-cohort based on diagnostic codes registered in the Norwegian Patient Registry. The control group (n = 170,332) comprised patients registered with diagnostic codes for non-osteoporotic fractures or hip or knee replacement because of osteoarthritis. The outcome was periodontitis, defined by procedure codes registered in the Control and Payment of Health Refunds database. Logistic regression analyses were performed to estimate odds ratio for periodontitis in patients versus controls adjusted for potential covariates. Results Periodontitis was significantly more common in SLE patients compared to controls (OR 1.78, 95% CI 1.47-2.14) and the difference was highest in SLE-patients 20 to 30 years of age (OR 3.24, 95% CI 1.23 – 8.52). The periodontitis rate in SLE patients was in the same range as for patients with diabetes mellitus type 2. Conclusions Patients with SLE had an almost doubled risk of periodontitis compared with the control population, and the difference was most accentuated in the young patients. These findings warrant an increased focus on dental health in SLE-patients. publishedVersion

BACKGROUND: Since patients with chronic inflammatory rheumatic joint diseases may be more prone to infections, we wished to investigate the incidence of COVID-19 in this group, and explore the possible significance of factors related to the rheumatic disease, the patient or the treatment. MATERIAL AND METHOD: Altogether 27 907 patients registered in the Norwegian Arthritis Registry (NorArthritis) were linked to the Norwegian Surveillance System for Communicable Diseases and the Norwegian Intensive Care and Pandemic Registry in order to find the incidence of COVID-19 in 2020, and the proportion of patients who were hospitalised. A standardised incidence ratio (SIR) was calculated by comparing with sex and age-specific incidence in the general population. Logistic regression analysis was used to investigate whether diagnosis, age, sex, disease activity, comorbidity or drug therapy had any bearing on the incidence. RESULTS: A total of 185 of the patients in NorArthritis tested positive for COVID-19, of whom 10 % were hospitalised. The incidence was lower than in the general population (SIR 0.84; 95 % confidence interval (CI): 0.72-0.97, P = 0.02). Young age and low disease activity were associated with higher incidence of infection. The other factors had no significant effect. INTERPRETATION: The fact that the incidence of COVID-19 was lower than in the general population, and that within the group it was lower in those with moderate/high disease activity and greater age, is most likely attributable to patients of advanced age with chronic active disease having protected themselves against infection to a greater degree.

Objective.To investigate the incidence of orthopedic procedures in patients with psoriatic arthritis (PsA), and how patient characteristics, time of diagnosis, and treatment affect the need for surgery.Methods.We reviewed the medical history of 1432 patients with possible PsA at Haukeland University Hospital in Bergen, Norway. There were 590 patients (mean age 49 yrs, 52% women) who had sufficient journal information and a confirmed diagnosis of PsA, and who were included in the present study. Relevant orthopedic procedures were obtained from the hospital’s administrative patient records. Survival analyses were completed to evaluate the effect of different factors such as year of diagnosis, age, sex, radiographic changes, disease activity, and treatment, on the risk of surgery.Results.There were 171 procedures (25% synovectomies, 15% arthrodesis, and 53% prostheses) performed on 117 patients. These factors all increased the risk of surgery: female sex [relative risk (RR) 1.9, p = 0.001], age ≥ 70 years at diagnosis (RR 2.4, p = 0.001), arthritis in initial radiographs (RR 2.2, p = 0.006), and maximum erythrocyte sedimentation rate 30–59 mm/h (RR 1.6, p = 0.026). Time period of diagnosis had no effect on the outcome. In a subanalysis of surgery exclusive of hip and knee arthroplasty, diagnosis in earlier years (1954–1985 vs 1999–2011) was a risk factor (RR 2.1, p = 0.042). Antirheumatic treatment changed significantly over time.Conclusion.There were 20% of patients with PsA who needed surgery. We found that the prognosis of patients with PsA did not change regarding the risk of orthopedic surgery, despite the change in treatment. A possible explanation is the increase in large joint replacements in the general population.

To investigate how patient characteristics, time of diagnosis, and treatment affect the need for orthopaedic surgery in patients with rheumatoid arthritis (RA).We reviewed the medical history of 1544 patients diagnosed with RA at Haukeland University Hospital in Bergen, Norway, from 1972 to 2009, of whom 1010 (mean age 57 years, 69% women) were included in the present study. Relevant orthopaedic procedures were obtained from the Norwegian Arthoplasty Register and the hospital's administrative patient records. In total, 693 procedures (joint synovectomies 22%, arthrodeses 21%, prostheses 41%, and forefoot procedures 12%) were performed in 315 patients. Survival analyses were completed to evaluate the impact of different factors such as age, gender, radiographic changes, and year of diagnosis, on the risk of undergoing surgery.Patients diagnosed in 1972-1985 and 1986-1998 had a relative risk of undergoing surgery of 2.4 and 2.2 (p 0.001), respectively, compared to patients diagnosed in 1999-2009. Radiographic changes at diagnosis and female gender were also significant risk factors. Anti-rheumatic medication was significantly different in the three time periods.Patients with a diagnosis in the early years had a greatly increased risk of having orthopaedic surgery performed. This is probably due to the year of diagnosis being a proxy for the type and intensity of medical treatment.

Pharmacological treatment and follow-up of gout is often inadequate.The patients risk repeated, painful arthritis flares and some develop chronic tophaceous gout and joint damage.Since 1 March 2017, a structured care pathway has been established for patients with gout at the Department of Rheumatology, Haukeland University Hospital. Patients were placed on preventive medication, the majority on allopurinol, and were regularly monitored. Patient education is key to the care pathway. The treatment goal is to lower the concentration of serum urate to a level below a defined threshold value (360 µmol/l for non-tophaceous gout or 300 µmol/l for tophaceous gout). Patient data were collected on a continuous basis and recorded in a research database. The care pathway is assessed after 18 months.A total of 103 patients have been included, of whom 93 (90 %) are men, with an average age of 63 years and large variations in duration of the disease (min.-max. 0-36 years). Eight patients left the care pathway during the project. The average level of serum urate at inclusion was 446 µmol/l (min.-max. 144-751 µmol/l). The average maximum dose of allopurinol was 333 mg (min.-max. 100-700 mg). Survival analysis showed that three months after the start of urate-lowering therapy, 49 % of the patients had achieved their analytical treatment goal. Altogether 83 % achieved the goal within six months. The majority (70 %) were free of flares after achieving the treatment goal.A standardised care pathway for gout enables adaptation of preventive treatment through regular monitoring. The care pathway helps the vast majority of patients to achieve treatment goals, which is crucial to avoid arthritis flares.

Background Pharmacological treatment and follow-up of gout is often inadequate.The patients risk repeated, painful arthritis flares and some develop chronic tophaceous gout and joint damage. Material and method Since 1 March 2017, a structured care pathway has been established for patients with gout at the Department of Rheumatology, Haukeland University Hospital. Patients were placed on preventive medication, the majority on allopurinol, and were regularly monitored. Patient education is key to the care pathway. The treatment goal is to lower the concentration of serum urate to a level below a defined threshold value (360 µmol/l for non-tophaceous gout or 300 µmol/l for tophaceous gout). Patient data were collected on a continuous basis and recorded in a research database. The care pathway is assessed after 18 months. Results A total of 103 patients have been included, of whom 93 (90 %) are men, with an average age of 63 years and large variations in duration of the disease (min.-max. 0-36 years). Eight patients left the care pathway during the project. The average level of serum urate at inclusion was 446 µmol/l (min.-max. 144-751 µmol/l). The average maximum dose of allopurinol was 333 mg (min.-max. 100-700 mg). Survival analysis showed that three months after the start of urate-lowering therapy, 49 % of the patients had achieved their analytical treatment goal. Altogether 83 % achieved the goal within six months. The majority (70 %) were free of flares after achieving the treatment goal. Interpretation A standardised care pathway for gout enables adaptation of preventive treatment through regular monitoring. The care pathway helps the vast majority of patients to achieve treatment goals, which is crucial to avoid arthritis flares.

Objective.To determine the risk of cancer in a large Norwegian cohort of patients with giant cell arteritis (GCA).Methods.This is a hospital-based, retrospective, observational cohort study including patients diagnosed with GCA in the Bergen Health Area during 1972–2012. Patients were identified through computerized hospital records using the International Classification of Diseases coding system. Medical records were reviewed. Each patient was randomly assigned population controls matched on age, sex, and geography from the Central Population Registry of Norway. Data on the occurrence of cancer were obtained from the Cancer Registry of Norway. The cumulative risk of malignancy was estimated using Kaplan-Meier methods and potential differences were analyzed using the Gehan-Breslow and log-rank tests.Results.We identified 881 cases with a clinical diagnosis of GCA, of which 792 fulfilled the American College of Rheumatology (ACR) 1990 classification criteria and 528 were biopsy-verified. Cases with no registered cancer prior to GCA diagnosis were included in a time-to-event analysis, with first cancer as the event (n = 767 with clinical GCA diagnosis, 686 fulfilling ACR criteria for GCA, 463 biopsy-verified). These cases were matched with previously cancer-free population controls (n = 1437, 1284, 895, respectively). We found no significant difference in the risk of malignancy after time of diagnosis/matching for GCA patients compared to population controls (p > 0.05).Conclusion.In this study of a large and well-characterized cohort of patients with GCA, there was no difference in the risk of malignancy in patients with GCA compared to matched population controls.

Background: In Norway encouraged by the health authorities non-medical switch from reference drug to biosimilar drug has been performed in most patients on biologic reference drugs with biosimilar drugs available, including etanercept. There is a need for real life data understanding the effect of biosimilar drugs when these drugs are introduced in clinical practice. Objectives: To explore drug survival for biosimilar SB4 etanercept in RA patients, both etanercept naive and non-medical switch patients, and compare with the etanercept reference drug. Methods: Preliminary 2 years drug survival data from one center in a 5 center study in Norway exploring drug survival for etanercept reference drug and biosimilar etanercept SB4 is presented. At this outpatient clinic RA patients as part of standard clinical care has been monitored systematically since 2003. Drug survival for SB4 etanercept, both the etanercept naive and the non-medical SB4 switch group, was compared with patients treated with the etanercept reference drug in the period 2003-2018. Baseline demographic, clinical and treatment data were retrieved and analyzed. Kaplan-Meier survival curves were used to explore 2 years drug survival. Survival differences between groups were tested using Breslow statistics. Results: At the outpatient clinic the number of RA patients treated with etanercept reference drug was 356, the number of patients treated with SB4 with no previous etanercept was 36 and the patients with a non-medical switch from reference etanercept to etanercept SB4 was 84. In the table below baseline demographics and disease measures are shown for the etanercept reference group, the non-medical SB4 switch group and the SB4 naive to etanercept group. Data in table are presented as percentage for group variables and as mean with standard deviation (SD) for continuous variables. Mean (95%CI) drug survival for the non-medical SB4 switch group was1.53 (1.38-1.68) years, for the SB4 group with no previous etanercept 1.23 (0.95-1.51) years and for etanercept reference group 1.38 (1.31-1.46) years. A statistically significant difference (p In the figure below Kaplan-Meier drug survival curves are shown. Conclusion: To the best of our knowledge this is the first data showing that drug survival of an etanercept biosimilar drug after a non-medical switch is higher than a historical cohort of etanercept reference drug. This is expected, since it is a selected group of etanercept responders. The interpretation of the results should be cautious, since only few patients are included in this first analysis. A larger number of patients from other participating out-patient clinics is planned to be included. Disclosure of Interests: Glenn Haugeberg Grant/research support from: For this study grant from Biogen, Consultant for: Medical Advisory boards for several companies, Paid instructor for: I have been paid for giving lectures for pharmaceutical companies and their employees, Speakers bureau: I have been paid for giving lectures in meetings organized by pharmaceutical companies, Bjorg Tilde Svanes Fevang: None declared, Gunnstein Bakland: None declared, Erik Rodevand: None declared, Andreas Diamantopoulos: None declared

Background: In the new millennium biologic therapies e.g. tumor necrosis factor inhibitors (TNFi) have played a major role improving clinical outcomes in rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (ax-SpA). A major limitation in many countries for prescribing these drugs has been the high drug costs. The patent period for several of these TNFis e.g. infliximab, etanercept and adalimumab has ended and as a consequence biosimilar TNFis are now reaching the market. This has a cost saving potential for payers. In Norway, encouraged by the health authorities, non-medical switch from originator to biosimilar has been performed in most patients on biologic originator drugs with biosimilar drugs available, including etanercept. To the best of our knowledge no longer than one year real life experienced real life evidence data for non-medical switch from originator etanercept to biosimilar etanercept SB4 exist (ref.1). Objectives: To explore three-year drug survival for biosimilar SB4-etanercept in RA, PsA and ax-SpA patients with a non-medical switch from etanercept originator to SB4. Methods: At the participating outpatient clinics patients with RA, PsA and ax-SpA are monitored using a clinical computer system, as standard clinical care. Demographic, clinical and treatment data were retrieved from the computer system for patients who started treatment with biosimilar etanercept SB4 between January 2016 and January 2019. Kaplan-Meier survival curves were used to explore drug survival. Survival differences between groups were tested using Breslow statistics. Results: At the participating outpatient clinics since 2016 a total of 474 RA, 249 PsA and 320 ax-SpA patients had a non-medical switch from etanercept originator to biosimilar etanercept SB4. In RA, PsA and ax-SpA patients the percentage of women was 68.2%, 42.6% and 30.3%, the percentage of current smokers 17.0%, 12.8% and 19.6%, mean (SD) age was 63.0 (13.1), 58.2 (11.3), 53.1 (12.1) years and disease duration 16.8 (9.8), 16.1 (9.7), 17.7 (11.0) years, respectively. In RA 80.0% were anti-CCP positive and in PsA and ax-SpA 34.4% and 90.8% were HLAB27 positive. In the table selected disease measures at baseline are shown. No significant difference (p=0.97) in drug survival for SB4 was seen between RA, PsA and ax-SpA patients. Mean (95% CI) SB4 drug survival time (years) was for RA 2.3 (2.2-2.4), for PsA 2.3 (2.2-2.4) and for ax-SpA 2.4 (2.3-2.5). In the figure below Kaplan-Meier drug survival curves are shown. Men had a statistically significant longer mean drug survival than women (2.5 (2.4-2.6) vs 2.2 (2.1-2.3), p=0.001). Conclusion: Our long term real life data show that the majority of patients with a non-medical switch from originator etanercept to biosimilar etanercept SB4 remained on the drug. No significant difference in drug survival was seen between RA, PsA and ax-Spa patients. Men however had a significantly longer drug survival than women. Further analyses are needed to explore reasons for cessation across gender and patient groups. Reference: [1] Glintborg B et al. Ann Rheum Dis 2018;0:1-9 Disclosure of Interests: Glenn Haugeberg Grant/research support from: For this study grant from Biogen, Consultant for: Medical Advisory boards for several companies, Paid instructor for: I have been paid for giving lectures for pharmaceutical companies and their employees, Speakers bureau: I have been paid for giving lectures in meetings organized by pharmaceutical companies, Bjorg Tilde Svanes Fevang: None declared, Gunnstein Bakland: None declared, Erik Rodevand: None declared, Andreas Diamantopoulos: None declared

Background Norwegian rheumatologists are encouraged to prescribe the lowest-priced biologic DMARDs according to the national tender system. Thus, non-medical switch from the originator drug to its biosimilar is extensively performed. There is a need for more real life data to clarify the clinical outcomes, dropout rates and reasons for these dropouts after a non-medical switch from the originator to biosimilar ETN. Objectives To explore drug survival and clinical outcomes in rheumatoid arthritis (RA) patients after a non-medical switch from the originator to biosimilar ETN (SB4) in ordinary outpatient clinics across Norway. Methods Herein we present preliminary data collected at one participating centre. Patients were monitored and data were collected by the use of a hospital clinical computer system GoTreatIT Rheuma. The computer system is also used for data collection for the Norwegian national arthritis registry, NorArtritt. Demographic, clinical and treatment data were retrieved (21st of January 2018) from the computer system for the time point of non-medical switch of ETN and the last follow up. Wilcoxon matched-pair signed rank test was used for comparison between the two-time points. Results Since April 2016 191 RA patients (mean age 60.8 years, 67% females) underwent a non-medical switch from originator to biosimilar ETN. Mean (SD) observation time for the 163 patients (85.3%) still on biosimilar ETN was 1.23 (0.46) yrs. 28 patients (14.7%) stopped treatment. Among them mean (SD) observation time for the 7 patients (3.7%) in remission was 0.53 (0.33) yrs, for the 10 patients (5.2%) reporting adverse events 0.44 (0.32) yrs and for the 11 patients (5.8%) reporting lack or loss of efficacy 0.44 (0.35) yrs. The adverse events reported was: 1 chest pain, 1 neuropathy, 1 GI reaction, 1 visual impairment, 1 infection, 2 joint stiffness (1 patient went back on ETN SB4) and 3 skin reactions. For all 191 patients no significant change (median [IQR]) from baseline to last observation was seen for DAS28 (2.1 [1.5–2.8] vs 1.9 [1.5–2.5], p=0.33), MHAQ (0.3 [0.0–0.7] vs 0.4 [0.1–0.6], p=0.62) and patient VAS global (20.0 [10.0–43.0] vs 25.0 [10.0–43.3] mm, p=0.73), whereas CRP improved significantly during follow up (2.0 [1.0–5.0] vs 1.0 [1.0–5.5] mg/dl, p=0.02). For the subgroup of RA patients who stopped treatment because of lack of efficacy a minor non-significant impairment was observed for DAS28 (2.0 [1.4–2.5] vs 2.6 [1.2–4.0], p=0.32), CRP (0.0 [0.0–6.0] vs 3.5 [0.8–13.3] mg/dl, p=0.66), MHAQ (0.1 [0.0–0.1] vs 0.5 [0.3–0.5], p=0.66) and patient VAS global (20.0 [10.0–30.0] vs 29.0 [17.0–58.5] mm, p=0.66). Conclusions Our preliminary data indicate that for the majority of patients, a non-medical switch from originator to biosimilar ETN (SB4) was well tolerated with no impairment in disease measures. Whether the reported adverse events were associated to the switch needs to be further studied. In patients who stopped the biosimilar because of lack of effect only a minor numerically increase in disease measures was seen. Our promising preliminary results need to be confirmed in a large scale study. Disclosure of Interest G. Haugeberg Shareholder of: DiaGraphIT AS, G. Bakland: None declared, E. Rodevand: None declared, B. T. Fevang: None declared, I. J. Hansen: None declared, A. Diamantopoulos: None declared

Patients with inflammatory joint diseases (IJD) have an increased risk of cardiovascular disease (CVD). Our goal was to examine indications for, and use of, lipid-lowering therapy (LLT) and antihypertensive treatment (AntiHT) in patients with IJD. Furthermore, to investigate the frequency of low-density lipoprotein cholesterol (LDL-c) and blood pressure (BP) goal attainment among IJD patients.The cohort was derived from the NOrwegian Collaboration on Atherosclerosis in patients with Rheumatic joint diseases (NOCAR). Indications for AntiHT were: systolic/diastolic BP ≥ 140/90 mm Hg, self-reported hypertension or AntiHT. CVD risk was estimated by the systematic coronary risk evaluation (SCORE) algorithm. LDL-c goals were2.6 mmol/L in case of diabetes, total cholesterol 8 mmol/L or a SCORE estimate ≥ 5%, and1.8 mmol/L for those with established CVD or SCORE ≥ 10%. Comparisons across IJD entities were performed using age and sex adjusted logistic regression.In total, 2277 patients (rheumatoid arthritis: 1376, axial spondyloarthritis: 474, psoriatic arthritis: 427) were included. LLT and AntiHT were indicated in 36.1% and 52.6% of the patients, of whom 37.6% and 47.0% were untreated, respectively. LDL-c and BP targets were obtained in 26.2% and 26.3%, respectively. Guideline recommended treatment and/or corresponding treatment targets were not initiated or obtained in approximately 50%. Rheumatoid arthritis patients were particularly likely to be undertreated with LLT, whereas hypertension undertreatment was most common in psoriatic arthritis.Inadequate CVD prevention encompasses all the three major IJD entities. The unmet need for CVD preventive measures is not only prevalent in RA, but exists across all the major IJD entities.

ObjectivesCalprotectin is an inflammatory marker of interest in rheumatoid arthritis (RA). We evaluated whether the level of calprotectin was associated with disease activity, and if it was predictive of treatment response and radiographic progression in patients with early RA.MethodsPlasma from disease-modifying antirheumatic drug (DMARD)-naïve patients with RA fulfilling 2010 American College of Rheumatology/European League Against Rheumatism classification criteria with symptom duration Results215 patients were included: 61% female, 82% anti-citrullinated peptide antibody positive, mean (SD) age 50.9 (13.7) years and median (25, 75 percentile) symptom duration 5.8 (2.8, 10.5) months. Calprotectin was significantly correlated with Clinical Disease Activity Index (r=0.32), ESR (r=0.50) and ultrasonography power Doppler (r=0.42) before treatment onset. After 12 months of treatment, calprotectin, but not ESR and CRP, was significantly correlated with power Doppler (r=0.27). Baseline levels of calprotectin, ESR and CRP were not predictive of treatment response, but high levels of calprotectin were associated with radiographic progression in multivariate models.ConclusionsCalprotectin was correlated with inflammation assessed by ultrasound before and during DMARD treatment, and was also associated with radiographic progression. The data support that calprotectin may be of interest as an inflammatory marker when assessing disease activity in different stages of RA.Trial registration numberNCT01205854; Post-results.

Background Individuals with inflammatory joint diseases (IJD) [rheumatoid arthritis (RA), axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA)] have increased risk of cardiovascular disease (CVD). In the European guidelines for CVD prevention, calculation of relative risk and risk age is advised in patients with low absolute risk of fatal CVD events the next 10 years estimated by the systematic coronary risk evaluation [SCORE] algorithm; the rational being that low absolute risk may conceal high relative risk and risk ages far beyond chronological age. Thus, more patients needing intensive CVD prevention may be identified. Relative risk is a ratio comparing absolute CVD risk in a specific patient to the risk given optimal CVD risk factor levels (CVDRFs). Risk age denotes the age with similar CVD risk and optimal CVDRFs. To this date, no studies have evaluated relative risk and risk age across IJD entities, neither has the agreement between different risk age models been investigated. Objectives 1) Estimate relative risk and risk age across IJD entities. 2) Investigate agreement between different risk age models. Methods RA/axSpA/PsA patients aged 40≤65 years with low/moderate 10-year risk of fatal CVD were included from a nationwide quality assurance project implementing CVD risk assessment. Relative risk and cardiovascular risk age was calculated in accordance with risk charts published by the European Society of Cardiology (2016) and Cooney et al (2012), respectively. Vascular age was calculated by matching SCORE to estimated risk ages in accordance with Cuende et al (2010). Four different vascular age estimations were calculated, depending on whether the EULAR 1.5 multiplication factor in RA was applied (mSCORE) and if SCORE version with HDL-c (SCORE-HDL-c) was used: SCORE, SCORE-HDL-c, mSCORE and mSCORE-HDL-c. Risk years beyond chronologic age, were calculated. Linear regression models were used to investigate agreement between risk age estimations. Results Relative risk was increased in 53% of all patients and 20% had three times the risk or higher compared to individuals with optimal CVDRF levels. In total, 42% and 20% had a risk age ≥5 years higher than their chronologic age, according to the cardiovascular risk age model and the vascular age model derived from SCORE, respectively. There were minor differences between RA, axSpA and PsA patients in terms of relative risk and risk age. Agreement between cardiovascular risk age and various vascular age models varied (Figure). Discrepancies ≥5 years in estimated risk age were observed in 14–43% of estimations. The largest observed difference in calculated risk age was 24 years. Similarly, linear regression models yielded a R2 of 0.81–0.96. Across all models, median difference between risk age and age increased with advancing relative risk. Moreover, several patients had high relative risk despite a risk age close to their chronologic age. Conclusions Relative risk and risk age may identify several patients at high need of intensive CVD preventive efforts despite low estimated absolute risk. However, there are considerable discrepancies between risk age models. Disclosure of Interest None declared

Background The aim was to review the funding, organization, data handling, outcome measurements, and findings from existing national shoulder and elbow joint replacement registries; to consider the possibility of pooling data between registries; and to consider wether a pan european registry might be feasible. Materials and methods Web sites, annual reports, and publications from ongoing national registries were searched using Google, PubMed, and links from other registries. Representatives from each registry were contacted. Results Between 1994 and 2004, 6 shoulder registries and 5 elbow registries were established, and by the end of 2009, the shoulder registries included between 2498 and 7113 replacements and the elbow registries between 267 and 1457 replacements. The registries were initiated by orthopedic societies and funded by the government or by levies on implant manufacturers. In some countries, data reporting and patient consent are required. Completeness is assessed by comparing data with the national health authority. All registries use implant survival as the primary outcome. Some registries use patient-reported outcomes as a secondary outcome. Conclusions A registry offers many advantages; however, adequate long-term funding and completeness remain a challenge. It is unlikely that large-scale international registries can be implemented, but more countries should be encouraged to establish registries and, by adopting compatible processes, data could be pooled between national registries, adding considerably to their power and usefulness.

Functional results of reversed total prostheses (RTP) have-to a very limited degree-been compared with those of other shoulder prosthesis types. The aim of our study was to compare results of four different types of shoulder prostheses in terms of function, pain, and quality of life (QoL).Questionnaires were completed by 859 patients with shoulder prostheses registered in the Norwegian Arthroplasty Register. Patients with osteoarthritis (OA), rheumatoid arthritis (RA), or fracture sequela (FS) were included. Symptoms and function were assessed using the Oxford Shoulder Score (OSS, scale 0-48), and the EuroQoL-5D (EQ-5D) was used to assess QoL.Best functional results were obtained using conventional total prostheses (TPs) and RTPs -mean OSS improvement 18 and 16 units, respectively, vs 11 with hemiprostheses (HPs). For patients with OA, TPs performed best; for those with RA and FS, RTPs performed best; and those with HPs had the worst results in all diagnostic groups. The greatest improvement in QoL was seen in patients with TPs and RTPs.Conventional TPs provide the best improvement in pain, function and QoL in OA patients; RTPs are superior in patients with RA and FS.

Background and purpose Different results after shoulder arthroplasty have been found for different diagnostic groups. We evaluated function, pain, and quality of life after shoulder arthroplasty in 4 diagnostic groups. Patients and methods Patients with shoulder arthroplasties registered in the Norwegian Arthroplasty Register from 1994 through 2008 were posted a questionnaire in 2010. 1,107 patients with rheumatoid arthritis (RA), osteoarthritis (OA), acute fracture (AF), or fracture sequela (FS) returned completed forms (65% response rate). The primary outcome measure was the Oxford shoulder score (OSS), which assesses symptoms and function experienced by the patient on a scale from 0 to 48. A secondary outcome measure was the EQ-5D, which assesses life quality. The patients completed a questionnaire concerning symptoms 1 month before surgery, and another concerning the month before they received the questionnaire. Results Patients with RA and OA had the best results with a mean improvement in OSS of 16 ...

Background and purpose Over the past 20 years, several changes in treatment policy and treatment options have taken place regarding hip replacement. For this reason, we wanted to investigate the results after hip replacement in terms of revision rate, during a 21-year period among hip replacements reported to the Norwegian Arthroplasty Register.Methods 110,882 primary total hip replacements were reported to the Norwegian Arthroplasty Register from 1987 through 2007. Risk of revision during the time periods 1993–1997, 1998–2002, and 2003–2007 was compared to that of the reference period 1987–1992. Adjusted Cox regression analyses were performed to compare the risk of revision in different time periods and extended analyses were done to investigate revision within the first postoperative year and after the first year.Results There was an overall reduced risk of revision in the time periods 1993–1997, 1998–2002, and 2003–2007 compared to the reference period: RR = 0.81 (95% CI 0.77–0.86), 0.51 (CI 0.47–0.55)...

Background and purpose Previous studies on shoulder arthroplasty have usually described small patient populations, and few articles have addressed the survival of shoulder implants. We describe the results of shoulder replacement in the Norwegian population (of 4.7 million) during a 12-year period. Trends in the use of shoulder arthroplasty during the study period were also investigated. Patients and methods 1,531 hemiprostheses (HPs), 69 total shoulder replacements (Neer type TSR), and 225 reversed total shoulder replacement (reversed TSR) operations were reported to the Norwegian Arthroplasty Register between 1994 and 2005. Kaplan-Meier failure curves were drawn up for particular subgroups of patients, and revision rates were calculated using Cox regression analysis. Results The 5- and 10-year failure rates of hemiprostheses were 6% (95% CI: 5–7) and 8% (95% CI: 6–10), and for reversed total shoulder replacements they were 10% (95% CI: 5–15) and 22% (95% CI: 10–33), respectively. For hemiprostheses, the risk of revision for patients who were 70 years or older was half that of those who were younger (RR = 0.47, CI: 0.28–0.77), while the risk of revision was highest for patients with sequelae after fracture compared to those with acute fractures (RR = 3.3, CI: 1.5–7.2). No differences in prosthesis survival were found between the different hemiprosthesis brands. The main reasons for revision of hemiprostheses were pain and luxation. For reversed total prostheses, the risk of revision was less for women than for men (RR = 0.26, CI: 0.11–0.63), and the main cause of revision was aseptic loosening of the glenoid component. During the study period, the incidence of shoulder arthroplasty increased for all diagnostic groups except inflammatory arthritis, for which a decrease was seen. Interpretation We found good results in terms of 5-year prosthesis failure rate, with the use of hemiarthroplasty for patients with inflammatory arthritis, osteoarthritis, and acute fractures. Reversed total shoulder replacement was associated with a rather poor prognosis.

Background and Aims: Delay in operative treatment for small bowel obstruction (SBO) has been shown to affect outcome adversely. The objective of this study was to detect time trends in treatment delay for patients with SBO during the study period 1961 to 1995 and to investigate factors influencing and factors affected by delay. Materials and Methods: The records of 815 patients with 921 operations for SBO from 1961–1995 were studied. Patients with large bowel obstruction, paralytic ileus and SBO caused by abdominal cancer or intussusception were excluded. Data were analysed with descriptive statistics and multiple linear regression analyses. Results: Old age and female sex were associated with increased treatment delay. Delay in hospital increased from 5 hours (median) in the 1960'ies to 16 hours (median) in the 1990'ies. Treatment delay correlated significantly with postoperative morbidity and hospital stay. Mortality increased after prolonged treatment delay in SBO caused by hernias whereas no significant increase in mortality was observed among adhesive obstructions. Conclusions: Hospital delay increased throughout the study period. Old patients and women had a longer median treatment delay than did young ones and men. Treatment delay led to an increase in postoperative morbidity and hospital stay after surgery for SBO.

Although TNF-α inhibitors' striking effect on clinical symptoms have revolutionised the treatment of ankylosing spondylitis (AS), no certain influence on the development of spinal ankylosis and joint destruction has been documented. We wished to investigate whether improved treatment has affected the use of hip arthroplasty surgery.Using the Norwegian Arthroplasty Register, we selected hip prosthesis procedures performed in patients with AS in 1988-2010 (n=534), and compared the trend in the number of procedures being performed annually in 1988-2002 versus 2003-2010. Patients with osteoarthritis (OA) (n=95094) were used as a control group.The frequency of hip prosthesis surgery increased significantly in both groups up until 2002. In 2003-2010, although not statistically significant (p=0.087), there was a trend towards a reduced frequency in the AS group when compared with the expected continued increase as was seen among patients with OA. Mean age at surgery increased significantly (p0.001) from 49.9 years to 56.4 years when comparing patients with AS up until and after 2002.TNF-α inhibitors were introduced to patients with AS in Norway in 2000-2003, and our findings suggest that they may have altered the prognosis by inhibiting or slowing large joint arthritis and thus reducing the need for hip replacement surgery.

Background Patients with rheumatoid arthritis (RA) has been shown to be at increased risk for other diseases, in particular for osteoporosis, infections, cardiovascular diseases and malignancy. There are limited data on prevalence of comorbidities in unselected RA patient outpatient cohorts reflecting the magnitude of comorbidities in RA patients. Objectives To explore the prevalence of comorbidities in RA patients followed at outpatient clinics in Norway. Methods The RA patients were recruited from two outpatient clinics in Norway, one located in the southern and one in the western part of Norway. As part of clinical routine the RA patients at these two centers were monitored at ordinary visits by the use of the computer software tool GoTreatIT® Rheuma. Standardized data collection for disease activity measures, patient reported outcome measures (PROM) and treatment was registered as part of clinical routine. Patients also self-reported their comorbidities using the computer system. Patients with at least one visit in 2015 at the outpatient clinics were included. Results A total of 2437 RA patients were assessed, 1065 from the southern and 1372 from the western located center. Only minor differences were found between the two centers, for demographic, disease and treatment variables. Patient demographic and disease characteristics: mean age 62.7 (SD 14.1) years, BMI 25.9 (4.5) kg/m 2 , education 11.8 (3.6) years, 70% females, current smoker 16.0% and 66.8% were RF+ and 73.5% were anti-CCP+. Measures reflecting disease activity: mean ESR 18.2 (14.4) mm/hr, CRP 7.0 (13.8) mg/dl, DAS28 2.4 (1.2) and CDAI 6.6 (7.0). Mean values for PROMs: Pain 32.7 (25.3) mm, fatigue 37.8 (29.8) mm. MHAQ 0.18 (0.42). Current user of mono synthetic disease modifying anti-rheumatic drugs (sDMARDs) 45.5%, mono biologic DMARDSs (bDMARDs) 10.4% and combination sDMARDs and bDMARDs 25.5%. Prednisolone was used by 40.8% of the patients. Self-reported comorbidity data was available in 1616 of the 2437 (66.3%) patients. The percentage of patients reporting to have myocardial infarction was 3.9%, arterial hypertension16.5%, heart failure 1.2%, peripheral artery disease 1.7%, cerebrovascular disease 1.8%, osteoporosis 12.8%, chronic infections 3.7%, lymphoma 0.7%, melanoma 0.9%, other skin cancer 0.5%, other cancers 5.8%. Among the 123 patients who reported to have cancer 6.5% reported to have metastasis and 58.1% reported to have had ca treatment the last 5 years. Thyroid gland disease was reported by 8.0%, diabetes mellitus by 4.4% and peptic ulcer disease by 5.0%. Conclusions Our data gives an estimate of the prevalence of the most frequent comorbidities in RA patients seen in Norwegian outpatient rheumatology clinics. Osteoporosis and cardiovascular disease was the most frequent comorbidities. Both of these comorbidities have been shown to be more frequent in RA patients compared with the background population. Data on prevalence of comorbidities may contribute to an increased awareness improving overall patient care in RA. Disclosure of Interest G. Haugeberg Shareholder of: Founder of and shareholder in the company DiaGraphIT AS, B.-T. Fevang: None declared, D. Soldal: None declared, C. Gjesdal: None declared

High rates of Staphylococcus aureus are reported in prosthetic joint infection (PJI) in rheumatoid arthritis (RA). RA patients are considered to have a high risk of infection with bacteria of potentially oral or dental origin. One thousand four hundred forty-three revisions for infection were reported to the Norwegian Arthroplasty Register (NAR) from 1987 to 2007. For this study 269 infection episodes in 255 OA patients served as control group. In the NAR we identified 49 infection episodes in 37 RA patients from 1987 to 2009. The RA patients were, on average, 10 years younger than the OA patients and there were more females (70% versus 54%). We found no differences in the bacterial findings in RA and OA. A tendency towards a higher frequency of Staphylococcus aureus (18% versus 11%) causing PJI was found in the RA patients compared to OA. There were no bacteria of potential odontogenic origin found in the RA patients, while we found 4% in OA. The bacteria identified in revisions for infection in THRs in patients with RA did not significantly differ from those in OA. Bacteria of oral or dental origin were not found in infected hip joint replacements in RA.

We read with interest the paper by Sadoghi and colleagues in the August issue of the journal [1]. Since the article uses data from the Norwegian Arthroplasty Register as a source for their analyses, we would like to comment some flaws in the article. To our surprise, the article at first glance gives an impression of having raw data available from the Norwegian Arthroplasty Register. However, in the statistical paragraph of the article it is stated that the data were obtained from the 2008 annual report (available from the register’s internet pages). This should have been clarified earlier and preferably in the abstract and title of the article. We do not disagree in the use of the data but are additionally surprised that not later data (e.g. the 2013 report) were applied. The article focuses on the causes for revision reported by the Norwegian registry. The statistical analysis is hence on the average annual number of revisions for the reported reasons for revision. The authors then analysed the annual numbers using analysis of variance. Since the authors observed that the data were not normally distributed, they used a transformation to correct this. However, as found in any basic statistical textbook, counting data is in nature not normally distributed but follows a Poisson distribution. The Poisson distribution would explain several of the surprising findings, including the heteroscedasticity, observed by the authors. The Poisson distribution would also include reasons for revision with zero observations (instead of using n/a). Another flaw in directly using the observed numbers for revision is that these numbers do not take into account the duration from the insertion of the primary prosthesis to the revision operation. Since the risk for revision (and the causes) changes during the follow-up for the primary prosthesis, the present analyses evidently have little or no value! This also includes the analyses of the annual increase in the number of revisions, since these numbers rely directly on the previous annual rates of primary operations, and the increase in these. Tukey and Kramer correct neither of the issues mentioned, and we are sorry that this letter contributes to increase the citation index for this article. For a more thorough analysis of ankle prostheses reported to the Norwegian Arthroplasty Register, including risks for revision and trends, study the article by Fevang et al. [2]. Neglecting to cite the paper by Fevang et al. [2] further demonstrates the lack of scientific precision in the article by Sadoghi and authors.

Objective To compare differences in the risk of revision for infection and changes in risk over time and in time from primary surgery to revision for infection after total hip replacement (THR) and total knee replacement (TKR) in rheumatoid arthritis (RA) and osteoarthritis (OA) patients. Methods In the Norwegian Arthroplasty Register, 6,629 and 102,157 primary total joint replacements in patients with RA and OA, respectively, were identified from 1987 (1994 for knees) until 2008. Survival analyses with revision due to infection as the end point were performed using Kaplan-Meier methods for constructing survival curves and multiple Cox regression to calculate relative risk (RR) estimates for diagnosis, age, sex, and year of primary surgery. An extended Cox model was used to estimate RR within different followup intervals. Results RA patients with TKR had a 1.6 times higher risk of revision for infection than OA patients, whereas there was no difference in the THRs. In the THRs, we found a higher risk of revision for infection from 2001 onward, whereas the development for TKRs was the opposite. These time effects affected the RA and OA groups equally. The risk of revision for infection from 6 years postoperatively on was higher in RA patients. Conclusion The overall risk of revision for infection after TKR was higher in RA patients. The risk of late infection leading to revision of the TKR and THR was higher in RA patients than in OA patients. After the year 2000, the RR of revision for infection in RA compared with OA remained unchanged.

Background: The aim of this study was to give results of elbow arthroplasty for a relatively large population and compare different prosthesis brands and different patient subgroups. Methods: Between 1994 and 2006, 562 total elbow replacement operations were reported to the Norwegian Arthroplasty Register. Revisions of prostheses were shown using Kaplan-Meier failure curves, and risk of revision was calculated using Cox regression analysis. Results: The overall 5- and 10-year failure rates were 8% and 15%, respectively. There were only minor differences between the different implants. Patients who developed traumatic arthritis after fracture had the worst prognosis compared with inflammatory arthritis (P ¼ .005). Risk of revision was also increased when the ulnar component was inserted without cement (P ¼ .02.) Conclusions: Good results in terms of prosthesis survival were obtained with total elbow arthroplasty, although results were worse than for knee- and hip arthroplasties. The best results were achieved in patients with inflammatory arthritis. Level of evidence: Level 2; prospective cohort study. 2009 Journal of Shoulder and Elbow Surgery Board of Trustees.

There have been few reports on the long-term outcome of ankle replacements. The Norwegian Arthroplasty Register has been registering ankle replacements since 1994, but no analysis of these data has been published to date. Here we report data on the use of total ankle replacements and the revision rate in the Norwegian population over a 12-year period.We used the Norwegian Arthroplasty Register to find ankle arthroplasties performed between 1994 and 2005. Patient demographics, diagnoses, brands of prosthesis, revisions, and time trends were investigated.There were 257 primary ankle replacements, 32 of which were cemented TPR prostheses and 212 of which were cementless STAR prostheses. The overall 5- year and 10-year survival was 89% and 76%, respectively. Prosthesis survival was the same for the cementless STAR prosthesis and the cemented TPR prosthesis. There was no significant influence of age, sex, type of prosthesis, diagnosis, or year of operation on the risk of revision. The incidence of ankle replacements due to osteoarthritis, but not due to inflammatory arthritis, increased over the years.The revision rate was acceptable compared to other studies of ankle arthroplasties, but high compared to total knee and hip arthroplasties. The overall incidence of ankle replacements increased during the study period.

Introduction Chronic inflammatory joint diseases are associated with joint destruction and subsequent marked disability and the need for orthopedic surgery. Relieving pain, correcting deformities, and replacing destroyed joints to achieve a better function are major indications for surgical treatment. In a long-term followup study of 1,600 patients with rheumatoid arthritis (RA), 25% underwent total joint arthroplasty within 22 years after disease onset (1). In general, the incidence of joint replacement procedures has increased during recent years (2). It has been suggested that a major reason for this trend is an increase in the prevalence of osteoarthritis (OA) due to an increased number of elderly persons in the population (2) and an increasing number of individuals who are overweight (3). Findings from some published studies suggest the opposite trend in the incidence of surgical procedures, including joint replacement procedures, due to RA (4–6). The major goal of the present study was to assess the use of orthopedic surgery among patients with chronic inflammatory joint disease in Norway during the period 1994– 2004. The incidence in the Norwegian population of total joint replacement procedures, synovectomies, and arthrodesis operations in patients with chronic inflammatory joint disease was investigated.

Aim of Study: The objective of this study was to determine the pattern of recurrence after one or more episodes of adhesive small bowel obstruction (ASBO) during a follow-up period of up to 40 years. Furthermore, we wanted to analyze possible factors with an influence on the recurrence rate and to study the magnitude of “everyday” abdominal pain among these patients. Patients and Methods: Hospital records of 500 patients operated on for adhesive obstruction at Haukeland University Hospital from 1961 to 1995 were studied. The patients were followed until death, loss to follow-up, or end of study (February 2002), with a median follow-up of 10 years and a maximum follow-up time of 40 years. A questionnaire was sent to all living patients to obtain information on recurrences and abdominal complaints. Results: The cumulative recurrence rate for patients operated once for ASBO was 18% after 10 years and 29% at 30 years. For patients admitted several times for ASBO, the relative risk of recurrent ASBO increased with increasing number of prior ASBO episodes. The cumulative recurrence rate reached 81% for patients with 4 or more ASBO admissions. Other factors influencing the recurrence rate were the method of treatment of the last previous ASBO episode (conservative versus surgical) and the number of abdominal operations prior to the initial ASBO operation. Compared to results from the general populations, more ASBO patients suffer from abdominal pain at home. Women and patients having matted adhesions have significantly more complaints about abdominal pain than men and patients with band adhesions. Conclusion: The risk of recurrence increased with increasing number of ASBO episodes. Most recurrent ASBO episodes occur within 5 years after the previous one, but a considerable risk is still present 10 to 20 years after an ASBO episode. Surgical treatment decreased the risk of future admissions for ASBO, but the risk of new surgically treated ASBO episodes was the same regardless of the method of treatment. People treated for ASBO seem to be more prone to experiencing abdominal pain than the normal population, especially those having matted adhesions. (Ann Surg 2004;240: 193‐201)

To study factors influencing complications and death after operations for small bowel obstruction (SBO) using multifactorial statistical methods.Death after surgery for SBO is believed to be influenced by factors such as old age, comorbidities, bowel gangrene, and delay in treatment. No studies have been reported in which adverse factors related to death and complications have been systematically investigated with modern statistical methods.The authors studied retrospectively 877 patients who underwent 1,007 operations for SBO from 1961 to 1995. Patients with paralytic ileus, intussusception, and abdominal cancer were excluded. Odds ratios for death, complications, postoperative hospital stay, and strangulation were calculated by means of logistic regression analyses.Death and complication rates decreased during the study period. Old age, comorbidity, nonviable strangulation, and a treatment delay of more than 24 hours were significantly associated with an increased death rate. The rate of nonviable strangulation increased markedly with patient age. Major factors increasing the complication rate were old age, comorbidity, a treatment delay of more than 24 hours, and the need for repeat surgery.Death and complication rates after SBO decreased from 1961 to 1995. Major factors influencing the rates were age, comorbidity, nonviable strangulation, and treatment delay. Nonviable strangulation was more common in old patients.

Background Although TNF-alpha inhibitors by easing pain and restoring function have revolutionized the treatment of patients with ankylosing spondylitis (AS), so far no certain influence on the development of spinal ankylosis has been documented, and it remains to be shown whether TNF-alpha inhibition influences joint destruction and subsequent need for arthroplasty surgery. Consequently, the aim of treatment in AS is still to reduce clinical symptoms. Objectives We wished to investigate whether improved treatment has resulted in a diminishing use of arthroplasty surgery. Methods Nearly all patients (98%) having undergone an arthroplasty of the hip later than 1987 are registered in the Norwegian Arthroplasty Register (NAR). Data concerning the identity of the patient, diagnosis and date of surgery are among the information recorded. We selected the group of patients having received a hip prosthesis on the basis of AS in the years 1988-2010 (n=534, 73.8% men), and compared the trend in number of procedures being performed annually with the time trend of the same procedure in patients with osteoarthritis (OA) (n=95094, 31.6% men). For statistical analysis we used Poisson regression models to test for the trend, and change in trend over the years. A random effect was included in the model to account for overdispersion in the data. Results The frequency of hip prosthesis surgery in both groups increased steadily up until 2002, with a coefficient of 0.028 per year for OA patients (p Conclusions The present study’s major finding was a trend of reduced frequency of hip replacement procedures in patients with AS during the time span 2003-2010 which contrasts the continued increase for OA patients. Up until 2002 the frequency increased significantly in accordance with the general increase in joint replacement surgery. TNF-alpha inhibition was introduced in the treatment of Norwegian AS patients in 2000, and our findings suggest that this medication may alter the prognosis of these patients by reducing large joint arthritis and thus reducing the need for hip replacement surgery. Disclosure of Interest None Declared