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ObjectivesChronic Obstructive Pulmonary Disease (COPD) is a progressive disease. Preventing deterioration of health status is therefore an important therapy goal. (Minimal) Clinically Important Differences ((M)CIDs) are used to interpret changes observed. It remains unclear whether (M)CIDs are similar for both deterioration and improvement in health status. This study investigates and compares these clinical thresholds for three widely-used questionnaires.Design and settingData were retrospectively analysed from an inhouse 3-week pulmonary rehabilitation (PR) randomised controlled trial in the German Klinik Bad Reichenhall (study 1), and observational research in Dutch primary and secondary routine clinical practice (RCP) (study 2).ParticipantsPatients with COPD aged ≥18 years (study 1) and aged ≥40 years (study 2) without respiratory comorbidities were included for analysis.Primary outcomesThe COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) and St George’s Respiratory Questionnaire (SGRQ) were completed at baseline and at 3, 6 and 12 months. A Global Rating of Change scale was added at follow-up. Anchor-based and distribution-based methods were used to determine clinically relevant thresholds.ResultsIn total, 451 patients were included from PR and 207 from RCP. MCIDs for deterioration ranged from 1.30 to 4.21 (CAT), from 0.19 to 0.66 (CCQ), and from 2.75 to 7.53 (SGRQ). MCIDs for improvement ranged from −3.78 to −1.53 (CAT), from −0.50 to −0.19 (CCQ), and from −9.20 to −2.76 (SGRQ). Thresholds for moderate improvement versus deterioration ranged from −5.02 to −3.29 vs 3.89 to 8.14 (CAT), from −0.90 to −0.72 vs 0.42 to 1.23 (CCQ), and from −15.85 to −13.63 vs 7.46 to 9.30 (SGRQ).ConclusionsMCID ranges for improvement and deterioration on the CAT, CCQ and SGRQ were somewhat similar. However, estimates for moderate and large change varied and were inconsistent. Thresholds differed between study settings.Trial registration numberRoutine Inspiratory Muscle Training within COPD Rehabilitation trial: #DRKS00004609; MCID study: #UMCG201500447.

Objectives Minimal clinically important differences (MCIDs) are used as fixed numbers in the interpretation of clinical trials. Little is known about its dynamics. This study aims to explore the impact of baseline score, study setting, and patient characteristics on health status MCIDs in chronic obstructive pulmonary disease (COPD). Study Design and Setting Baseline and follow-up data on the COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ), and St. George's Respiratory Questionnaire (SGRQ) were retrospectively analyzed from pulmonary rehabilitation (PR) and routine clinical practice (RCP). Anchor- and distribution-based MCID estimates were calculated and tested between settings, gender, age, Global initiative for Obstructive Lung Disease (GOLD) classification, comorbidities, and baseline health status. Results In total, 658 patients were included with 2,299 change score measurements. MCID estimates for improvement and deterioration ranged for all subgroups 0.50–6.30 (CAT), 0.10–0.84 (CCQ), and 0.33–12.86 (SGRQ). Larger MCID estimates for improvement and smaller ones for deterioration were noted in patients with worse baseline health status, females, elderly, GOLD I/II patients, and patients with less comorbidities. Estimates from PR were larger. Conclusion Baseline health status and setting affected MCID estimates of COPD health status questionnaires. Patterns were observed for gender, age, spirometry classification, and comorbidity levels. These outcomes would advocate the need for tailored MCIDs.

The minimal clinically important difference (MCID) quantifies when measured differences can be considered clinically relevant. This study aims to review and triangulate MCIDs of chronic obstructive pulmonary disease (COPD) health status tools.A systematic search in PubMed, EMBASE and Cochrane Library was conducted (Prospero #CRD42015023221). Study details, patient characteristics, MCID methodology and estimates were assessed and extracted by two authors. A triangulated mean was obtained for each tool's MCID, with two-thirds weighting for anchor-based and one-third for distribution-based results. This was then multiplied by a weighted factor based upon the study size and quality rating.Overall, 785 records were reviewed of which 21 studies were included for analysis. MCIDs of 12 tools were presented. General quality and risk of bias were average to good. Triangulated MCIDs for the COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) and St. George's Respiratory Questionnaire (SGRQ) were −2.54, −0.43 and −7.43 for improvement. Too few and/or too diverse studies were present to triangulate MCIDs of other tools.Evidence for the MCID of the CAT and CCQ was strong and triangulation was valid. Currently used MCIDs in clinical practice for the SGRQ (4) and Chronic Respiratory Questionnaire (0.5) did not match the reviewed content, for which the MCIDs were much higher. Using too low MCIDs may lead to an overestimation of the interpretation of treatment effects. MCIDs for deterioration were scarce, which highlights the need for more research.

Background The Minimal Clinically Important Difference (MCID) assesses what change on a measurement tool can be considered minimal clinically relevant. Although the recall period can influence questionnaire scores, it is unclear if it influences the MCID. This study is the first to examine longitudinally the impact of the recall period of an anchor question and its design on the MCID of COPD health status tools using the COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ) and the St. George’s Respiratory Questionnaire (SGRQ). Methods Moderate to very severe COPD patients without respiratory co-morbidities were recruited during 3-week Pulmonary Rehabilitation (PR). CAT, CCQ and SGRQ were completed at baseline, discharge, 3, 6, 9 and 12 months. A 15-point Global Rating of Change scale (GRC) was completed at each follow-up. A five-point GRC was used as second anchor at 12 months. Mean change scores of a subset of patients indicating a minimal improvement on each of the anchor questions were considered the MCID. The MCID estimates over different time periods were compared with one another by evaluating the degree of overlap of Confidence Intervals (CI) adjusted for dependency. Results In total 451 patients were included (57.9 ± 6.6 years, 65% male, 50/39/11% GOLD II/III/IV), of which 309 completed follow-up. Baseline health status scores were 20.2 ± 7.3 (CAT), 2.9 ± 1.2 (CCQ) and 50.7 ± 17.3 (SGRQ). MCID estimates for improvement ranged − 3.1 to − 1.4 for CAT, − 0.6 to − 0.3 for CCQ, and − 10.3 to − 7.6 for SGRQ. Absolute higher – though not significant – MCIDs were observed for CAT and CCQ directly after PR. Significantly absolute lower MCID estimates were observed for CAT (difference − 1.4: CI -2.3 to − 0.5) and CCQ (difference − 0.2: CI -0.3 to −0.1) using a five-point GRC. Conclusions The recall period of a 15-point anchor question seemed to have limited impact on the MCID for improvement of CAT, CCQ and SGRQ during PR; although a 3-week MCID estimate directly after PR might lead to absolute higher values. However, the design of the anchor question was likely to influence the MCID of CAT and CCQ. Trial registration RIMTCORE trial #DRKS00004609 and #12107 (Ethik-Kommission der Bayerischen Landesärztekammer). Electronic supplementary material The online version of this article (10.1186/s12955-018-0950-7) contains supplementary material, which is available to authorized users.

The value of inspiratory muscle training (IMT) in pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD) is unclear. The RIMTCORE (Routine Inspiratory Muscle Training within COPD Rehabilitation) randomised controlled trial examined the effectiveness of IMT added to pulmonary rehabilitation.In total, 611 COPD patients (Global Initiative for Chronic Obstructive Lung Disease stage II–IV) received a 3-week inpatient pulmonary rehabilitation, of which 602 patients were included in the intention-to-treat analyses. The intervention group (n=300) received highly intensive IMT and the control group (n=302) received sham IMT. The primary outcome was maximal inspiratory pressure (PImax). The secondary outcomes were 6-min walk distance, dyspnoea, quality of life and lung function. Outcomes were assessed pre- and post-pulmonary rehabilitation. ANCOVA was used.The intervention group showed higher effects in PImax (pIMT as an add-on to a 3-week pulmonary rehabilitation improves inspiratory muscle strength, but does not provide additional benefits in terms of exercise capacity, quality of life or dyspnoea. A general recommendation for COPD patients to add IMT to a 3-week pulmonary rehabilitation cannot be made.

Background: Various factors may influence health status of patients with Chronic Obstructive Pulmonary Disease (COPD). Aim: This study investigated the relation between personality traits and health status scores of COPD patients. Methods: COPD GOLD I-IV patients aged ≥40 years were included from primary and secondary care in the Netherlands. Exclusion criteria: respiratory co-morbidities and inability to understand Dutch questionnaires. Participants scored the Clinical COPD Questionnaire (CCQ), COPD Assessment Test (CAT), St. George9s Respiratory Questionnaire (SGRQ) and Eysenck Personality Questionnaire (EPQ-RSS) at home. The EPQ-RSS measures Psychoticism, Extraversion and Neuroticism (min: 0, max: 12). Pearson/Spearman correlation coefficients were calculated. Results: In total 185 participants had complete baseline data (67yrs, 57.3% male, GOLD I-IV 11/27/21/8%). Baseline health status was 2.13±1.04 (CCQ), 18.22±7.25 (CAT), and 43.26±19.58 (SGRQ). Correlations are demonstrated in table 1. Conclusion: Weak to moderate correlations exist between neuroticism and health status, with higher personality trait scores associated with worse health status scores. Extraversion has a weak negative correlation with health status. Personality traits seem of weak to moderate influence on health status.

The minimal clinically important difference (MCID) defines to what extent change on a health status instrument is clinically relevant, which aids scientists and physicians in measuring therapy effects. This is the first study that aimed to establish the MCID of the Clinical chronic obstructive pulmonary disease (COPD) Questionnaire (CCQ), the COPD Assessment Test (CAT) and the St George’s Respiratory Questionnaire (SGRQ) in the same pulmonary rehabilitation population using multiple approaches. In total, 451 COPD patients participated in a 3-week Pulmonary Rehabilitation (PR) programme (58 years, 65% male, 43 pack-years, GOLD stage II/III/IV 50/39/11%). Techniques used to assess the MCID were anchor-based approaches, including patient-referencing, criterion-referencing and questionnaire-referencing, and the distribution-based methods standard error of measurement (SEM), 1.96SEM and half standard deviation (0.5s.d.). Patient- and criterion-referencing led to MCID estimates of 0.56 and 0.62 (CCQ); 3.12 and 2.96 (CAT); and 8.40 and 9.28 (SGRQ). Questionnaire-referencing suggested MCID ranges of 0.28–0.61 (CCQ), 1.46–3.08 (CAT) and 6.86–9.47 (SGRQ). The SEM, 1.96SEM and 0.5s.d. were 0.29, 0.56 and 0.46 (CCQ); 3.28, 6.43 and 2.80 (CAT); 5.20, 10.19 and 6.06 (SGRQ). Pooled estimates were 0.52 (CCQ), 3.29 (CAT) and 7.91 (SGRQ) for improvement. MCID estimates differed depending on the method used. Pooled estimates suggest clinically relevant improvements needing to exceed 0.40 on the CCQ, 3.00 on the CAT and 7.00 on the SGRQ for moderate to very severe COPD patients. The MCIDs of the CAT and SGRQ in the literature might be too low, leading to overestimation of treatment effects for patients with COPD.

Ioanna G Tsiligianni,1,2 Harma J Alma,1,2 Corina de Jong,1,2 Danijel Jelusic,3 Michael Wittmann,3 Michael Schuler,4 Konrad Schultz,3 Boudewijn J Kollen,1 Thys van der Molen,1,2 Janwillem WH Kocks1,2 1Department of General Practice, 2GRIAC Research Institute, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands; 3Klinik Bad Reichenhall, Center for Rehabilitation, Pulmonology and Orthopedics, Bad Reichenhall, 4Department of Medical Psychology, Psychotherapy and Rehabilitation Sciences, University ofWürzburg, Würzburg, Germany Background: In the GOLD (Global initiative for chronic Obstructive Lung Disease) strategy document, the Clinical COPD Questionnaire (CCQ), COPD Assessment Test (CAT), or modified Medical Research Council (mMRC) scale are recommended for the assessment of symptoms using the cutoff points of CCQ ≥1, CAT ≥10, and mMRC scale ≥2 to indicate symptomatic patients. The current study investigates the criterion validity of the CCQ, CAT and mMRC scale based on a reference cutoff point of St George’s Respiratory Questionnaire (SGRQ) ≥25, as suggested by GOLD, following sensitivity and specificity analysis. In addition, areas under the curve (AUCs) of the CCQ, CAT, and mMRC scale were compared using two SGRQ cutoff points (≥25 and ≥20).Materials and methods: Two data sets were used: study A, 238 patients from a pulmonary rehabilitation program; and study B, 101 patients from primary care. Receiver-operating characteristic (ROC) curves were used to assess the correspondence between the recommended cutoff points of the questionnaires.Results: Sensitivity, specificity, and AUC scores for cutoff point SGRQ ≥25 were: study A, 0.99, 0.43, and 0.96 for CCQ ≥1, 0.92, 0.48, and 0.89 for CAT ≥10, and 0.68, 0.91, and 0.91 for mMRC ≥2; study B, 0.87, 0.77, and 0.9 for CCQ ≥1, 0.76, 0.73, and 0.82 for CAT ≥10, and 0.21, 1, and 0.81 for mMRC ≥2. Sensitivity, specificity, and AUC scores for cutoff point SGRQ ≥20 were: study A, 0.99, 0.73, and 0.99 for CCQ ≥1, 0.91, 0.73, and 0.94 for CAT≥10, and 0.66, 0.95, and 0.94 for mMRC ≥2; study B, 0.8, 0.89, and 0.89 for CCQ ≥1, 0.69, 0.78, and 0.8 for CAT ≥10, and 0.18, 1, and 0.81 for mMRC ≥2.Conclusion: Based on data from these two different samples, this study showed that the suggested cutoff point for the SGRQ (≥25) did not seem to correspond well with the established cutoff points of the CCQ or CAT scales, resulting in low specificity levels. The correspondence with the mMRC scale seemed satisfactory, though not optimal. The SGRQ threshold of ≥20 corresponded slightly better than SGRQ ≥25, recently suggested by GOLD 2015, with the established cutoff points for the CCQ, CAT, and mMRC scale. Keywords: pulmonary disease, chronic obstructive, health status

Op het spreekuur komt een COPD-patient die een longrevalidatieprogramma heeft gevolgd. Hierbij werd de Clinical COPD Questionnaire (CCQ) afgenomen om te bepalen of zijn gezondheidsstatus is verbeterd. Vergeleken met het begin van het traject toonde de CCQ een verbetering van de totaalscore met een punt. Hoe moeten we dit interpreteren? Was het revalidatieprogramma succesvol? Is hier sprake van klinisch relevante verbetering?

Hintergrund: In den 2013 aktualisierten GOLD-Empfehlungen wurde der CCQ neben dem CAT (COPD Assessment Test) und der MMRC-Dyspnoe-Skala als Symptom-Parameter aufgenommen und ist damit Grundlage der Einteilung in die Gruppen A-D. Bisher liegen aber keine Daten aus Deutschland vor, in wie weit sich der CCQ-Score nach einer dreiwochigen stationaren pneumologischer Rehabilitation bei COPD-Patienten andert und wie anderungssensitiv der CCQ im Vergleich mit dem CAT und der MMRC-Dyspnoe-Skala ist. Methode: Bei 201 konsekutiven COPD-Rehabilitanden (63,5% ♂, GOLD-Schweregrad 2 41,1%, GOLD 3 36%, GOLD 4 22,8%, mittleres Alter 57,4J., FEV1 51%SW) wurden zu Reha-Beginn (T0) und zu Reha-Ende (T1) MMRC, CAT und CCQ erfasst. Zur Abschatzung der Veranderungssensitivitat wurden die Effektstarken (SRM) verglichen. Ergebnisse: Zu T1 finden sich signifikante Verbesserungen aller 3 Scores, wobei die SRM bzgl. CCQ und CAT als mittelgradiger, die bzgl. MMRC als schwacher Effekt zu werten sind. Diskussion: CCQ und CAT verbessern sich am Ende der Rehabilitation mit einer Effektstarke (SRM) von 0,67. Beide weisen somit eine vergleichbare Anderungssensitivitat bzgl. der Rehabilitation auf. Demgegenuber erscheint die Anderungssensitivitat der MMRC-Dyspnoe-Skala deutlich geringer.