Search

Background: An increasing number of studies are using health administrative databases for tuberculosis (TB) research. However, there are limitations to using such databases for identifying patients with TB., Objective: To summarise validated methods for identifying TB in health administrative databases., Methods: We conducted a systematic literature search in two databases (Ovid Medline and Embase, January 1980-January 2016). We limited the search to diagnostic accuracy studies assessing algorithms derived from drug prescription, International Classification of Diseases (ICD) diagnostic code and/or laboratory data for identifying patients with TB in health administrative databases., Results: The search identified 2413 unique citations. Of the 40 full-text articles reviewed, we included 14 in our review. Algorithms and diagnostic accuracy outcomes to identify TB varied widely across studies, with positive predictive value ranging from 1.3% to 100% and sensitivity ranging from 20% to 100%., Conclusions: Diagnostic accuracy measures of algorithms using out-patient, in-patient and/or laboratory data to identify patients with TB in health administrative databases vary widely across studies. Use solely of ICD diagnostic codes to identify TB, particularly when using out-patient records, is likely to lead to incorrect estimates of case numbers, given the current limitations of ICD systems in coding TB.

Setting: Twenty-eight public hospitals in the Free State Province, South Africa., Objective: To examine the association between tuberculosis (TB) infection control (IC) scores in Free State hospitals and the incidence of TB disease among health care workers (HCWs) in 2012., Design: A cross-sectional survey and mixed-methods analysis of TB IC policies, practices and infrastructure using a comprehensive, 83-item IC audit and observation tool., Results: As the total IC score increased, the probability of TB in an HCW at that hospital decreased. When adjusted for other covariates in multivariate analysis, if the total score of a hospital increased by one unit, the odds of an HCW having TB decreased by 4.9% (95%CI 0.9-8.8). Significant associations were also seen for the personal protective equipment (PPE) score, where odds decreased by 11.5% (95%CI 1.8-20.1) for each unit increase in score. Administrative score, environmental score and miscellaneous score were not statistically significant in the multivariate model., Conclusions: These findings reaffirm that overall IC and PPE are essential to protect HCWs from acquiring TB. More attention to TB IC is required to protect the health care workforce and to stop the South African TB epidemic.

Background: Hospitalization is the most costly health system component of tuberculosis (TB) control programs. Our objectives were to identify how frequently patients are hospitalized, and the factors associated with hospitalizations and length-of-stay (LOS) of TB patients in a large Canadian city., Methods: We extracted data from the Montreal TB Resource database, a retrospective cohort of all active TB cases reported to the Montreal Public Health Department between January 1996 and May 2007. Data included patient demographics, clinical characteristics, and dates of treatment and hospitalization. Predictors of hospitalization and LOS were estimated using logistic regression and Cox proportional hazards regression, respectively., Results: There were 1852 active TB patients. Of these, 51% were hospitalized initially during the period of diagnosis and/or treatment initiation (median LOS 17.5 days), and 9.0% hospitalized later during treatment (median LOS 13 days). In adjusted models, patients were more likely to be hospitalized initially if they were children, had co-morbidities, smear-positive symptomatic pulmonary TB, cavitary or miliary TB, and multi- or poly-TB drug resistance. Factors predictive of longer initial LOS included having HIV, renal disease, symptomatic pulmonary smear-positive TB, multi- or poly-TB drug resistance, and being in a teaching hospital., Conclusions: We found a high hospitalization rate during diagnosis and treatment of patients with TB. Diagnostic delay due to low index of suspicion may result in patients presenting with more severe disease at the time of diagnosis. Earlier identification and treatment, through interventions to increase TB awareness and more targeted prevention programs, might reduce costly TB-related hospital use.

Objective: Healthcare workers (HCWs) in South Africa are at a high risk of developing active tuberculosis (TB) due to their occupational exposures. This study aimed to systematically quantify and compare the preferred attributes of an active TB case finding program for HCWs in South Africa., Methods: A Best-Worst Scaling choice experiment estimated HCW's preferences using a random-effects conditional logit model. Latent class analysis (LCA) was used to explore heterogeneity in preferences., Results: "No cost", "the assurance of confidentiality", "no wait" and testing at the occupational health unit at one's hospital were the most preferred attributes. LCA identified a four class model with consistent differences in preference strength. Sex, occupation, and the time since a previous TB test were statistically significant predictors of class membership., Conclusions: The findings support the strengthening of occupational health units in South Africa to offer free and confidential active TB case finding programs for HCWs with minimal wait times. There is considerable variation in active TB case finding preferences amongst HCWs of different gender, occupation, and testing history. Attention to heterogeneity in preferences should optimize screening utilization of target HCW populations.

Setting: Tuberculosis (TB) in-patient treatment unit in Vancouver, Canada., Objective: To examine the results of therapeutic drug monitoring (TDM) in anti-tuberculosis treatment., Design: We performed a retrospective analysis of TDM data from 2000 to 2010. All in-patients treated for TB with TDM performed during their treatment course were included., Results: TDM was performed on 52 patients in 76 treatment episodes from 2000 to 2010. Overall, 103/213 (48.4%) drug levels measured were low, and 5/213 (2.3%) were high. At least one drug level was low in 47/52 (90.3%) patients. Initial serum levels were low in respectively 76.6% and 68.4% of isoniazid (INH) and rifampicin (RMP) levels. In contrast, only 2.9% of initial pyrazinamide levels were low. Five patients with a susceptible strain on initial presentation later developed drug-resistant disease, with all five patients demonstrating at least one low drug level and two demonstrating multiple low levels. Dose adjustments were made in response to 26 INH and RMP levels, with variable serum responses., Conclusion: In this population with high rates of treatment failure and acquired resistance, we demonstrate that most patients had low drug levels. Prospective studies are required to examine the relationship between drug levels and clinical outcomes.

Background: Many risk factors for the development of tuberculosis (TB) have been reported but have not been simultaneously assessed., Objective: To determine the risk of developing TB associated with each risk factor, after adjusting for all others., Methods: We performed a population-based, retrospective cohort study of the contacts of TB cases recorded in British Columbia, Canada. Known risk factors for the development of TB were assessed over a 12-year period; Cox regression was used to estimate the hazard ratios (HRs) of TB, adjusting for the other factors., Results: Among 33 146 TB contacts, 228 developed TB during the study period (TB rate 668 per 100,000 population, 95%CI 604-783). The main risk factors for TB development were malnutrition (HR 37.5), no treatment of latent TB infection (HR 25) or <6 months of treatment (HR 5.38), age 0-10 years (HR 7.87), being a household contact (HR 8.47) and having a tuberculin skin test induration of >or=5 mm (HR >or=4.99). Bacille Calmette-Guérin vaccination significantly reduced the risk of TB development (HR 0.32, 95%CI 0.20-0.50)., Conclusions: Among contacts of TB cases, we have identified the few factors that carry a very high risk for developing TB. These factors identify populations at highest risk and permit more effective TB control.

Background: Recent approval of interferon-gamma release assays that are more specific for Mycobacterium tuberculosis has given new options for the diagnosis of latent tuberculosis infection (LTBI)., Objective: To assess the cost-effectiveness of Quanti-FERON-TB Gold (QFT-G) vs. the tuberculin skin test (TST) in diagnosing LTBI in contacts of active TB cases using a decision analytic Markov model., Methods: Three screening strategies--TST alone, QFT-G alone and sequential screening of TST then QFT-G--were evaluated. The model was further stratified according to ethnicity and bacille Calmette-Guérin (BCG) vaccination status. Data sources included published studies and empirical data. Results were reported in terms of the incremental net monetary benefit (INMB) of each strategy compared with the baseline strategy of TST-based screening in all contacts., Results: The most economically attractive strategy was to administer QFT-G in BCG-vaccinated contacts, and to reserve TST for all others (INMB CA$3.70/contact). The least cost-effective strategy was QFT-G for all contacts, which resulted in an INMB of CA$-11.50 per contact. Assuming a higher prevalence of recent infection, faster conversion of QFT-G, a higher rate of TB reactivation, reduction in utility or greater adherence to preventive treatment resulted in QFT-G becoming cost-effective in more subgroups., Conclusions: Selected use of QFT-G appears to be cost-effective if used in a targeted fashion.

Setting: Contacts of tuberculosis (TB) cases identified from eight Provincial databases in British Columbia, Canada, between 1990 and 2000., Objective: To assess the risk of developing TB based on tuberculin skin test (TST) sizes in contacts of TB cases who did not receive treatment for latent TB infection., Design: Retrospective, population-based cohort study with a 12-year follow-up., Results: Among 26,542 contacts, 180 individuals developed TB (TB rate 678/100,000). Household contacts with a TST size 0-4 mm had a TB rate of 1014/100,000, those with 5-9 mm a TB rate of 2162/100,000 and those with 10-14 mm a rate of 4478/100,000. Children aged 0-10 years with 0-4 mm had a TB rate of 806/100,000, those with 5-9 mm a TB rate of 5556/100,000 and those with 10-14 mm a rate of 42,424/100,000. Immunosuppressed contacts with TST sizes 0-4 mm had a TB rate of 630/100,000, those with 5-9 mm a TB rate of 1923/100,000, and those with 10-14 mm a rate of 1770/100,000., Conclusions: TB rates were high for all TST sizes in household contacts, 0-10 year old contacts and immunosuppressed contacts. These contacts may benefit from treatment for latent TB infection, regardless of the size of their TST.

Background: Standard treatment of active tuberculosis (TB) consists of isoniazid (INH), rifampin (RMP), pyrazinamide (PZA) and ethambutol (EMB). Although this regimen is effective in treating active TB, it is associated with many adverse drug reactions (ADRs) and poses a significant challenge to completion of treatment., Objectives: To examine the incidence of major ADRs and risk factors associated with first-line anti-tuberculosis medications., Methods: This study evaluated patients receiving treatment for active TB from a population-based database (2000-2005). The nature of the ADRs, likelihood of association with the study medications and severity were evaluated., Results: A total of 1061 patients received treatment, of whom 318 (30%) had at least one major ADR. The overall incidence of all major ADRs was 7.3 events per 100 person-months (95%CI 7.2-7.5): 23.3 (95%CI 23.0-23.7) when on all four first-line drugs, 13.6 (95%CI 13.3-14.0) when on RMP, INH and PZA, and 2.4 (95%CI 2.3-2.6) when on INH and RMP. Adjusted hazard ratio (HR) revealed that combination regimens containing PZA, females, subjects aged 35-59 and >or=60 years, baseline aspartate aminotransferase >or=80 U/l and drug resistance were associated with any major event., Conclusions: First-line anti-tuberculosis drugs are associated with significant ADRs. There are several risk factors associated with the development of ADRs, including exposure to regimens containing PZA.

Background: Fluoroquinolones are commonly used in the treatment of tuberculosis (TB) for drug-sensitive patients who are intolerant to first-line antituberculous agents or who are infected with drug-resistant organisms. Despite increasing use of these agents, there is little information on their tolerance outside of clinical trial settings., Objectives: To compare overall rate of major adverse events associated with levofloxacin-containing regimen to standard therapy., Methods: Cases (levofloxacin-containing regimen) were matched by age and sex to their control subjects (standard first-line TB drugs). Eligible patients were identified from the provincial TB database from 2001 to 2004. Drug safety was assessed by evaluation of the nature of the adverse event, the likelihood of association with the study medications, and severity. Only major side effects, that is, those who had a severe or moderate adverse event that was categorized to be definitely, probably, or possibly related to the TB medications, were considered for the analysis., Results: During the 3-year study period, 102 patients received levofloxacin, and 358 patients received first-line agents for treatment of active TB. There were no significant differences between the two groups except for indication (82% of patients in the levofloxacin group had an antecedent adverse event to first-line TB drugs, whereas 18% received levofloxacin because of resistance) and concurrent use of first-line drugs (majority of patients in the levofloxacin arm were not receiving concurrent isoniazid or rifampin). The rate of any major adverse event was almost half among those using levofloxacin as among those on standard therapies (rate ratio, 0.60; 95% confidence interval [CI], 0.44 to 0.82). After adjustment for the differences in exposure of concomitant medications, the rate of any major adverse event was similar between the levofloxacin and control arms (adjusted rate ratio, 0.83; 95% CI, 0.66 to 1.03). Furthermore, there was no difference between the levofloxacin and control arms with respect to CNS (adjusted rate ratio, 0.94; 95% CI, 0.61 to 1.43), GI tract (adjusted rate ratio, 0.81; 95% CI, 0.58 to 1.13), skin (adjusted rate ratio, 0.65; 95% CI, 0.38 to 1.10), or musculoskeletal (MSK) [adjusted rate ratio, 0.87; 95% CI, 0.48 to 1.60] related adverse events when adjusted for concomitant drugs. The results of the secondary analysis for the rate of major adverse events within the first 100 days were similar to the primary analysis. The time to the first major adverse event was similar between the levofloxacin group and the control group (adjusted hazards ratio, 1.01; 95% CI, 0.76 to 1.34)., Conclusions: Concomitant use of a levofloxacin-containing regimen resulted in a similar rate of adverse events compared with conventional first-line regimens when used for treatment of active TB, despite a history of adverse events.

Background: Tuberculosis (TB) remains a major health problem for Aboriginal people in Canada, with high rates of clustering of active TB cases. Bacille Calmette-Guerin (BCG) vaccination has been used as a preventive measure against TB in this high-risk population., Objectives: The study was designed to determine if BCG vaccination in Aboriginal people influenced recent TB transmission through an analysis of the clustering of TB cases., Methods: A retrospective analysis of all culture-positive Mycobacterium tuberculosis cases in Aboriginal people in western Canada (1995 to 1997) was performed. Isolates were analyzed using standard methodology for restriction fragment length polymorphism and spoligotyping., Results: Of 256 culture-positive Aboriginal TB cases, BCG status was confirmed in 216 (84%) cases; 34% had been vaccinated with BCG, 57% were male and 56% were living on-reserve. Patients who had been vaccinated with BCG were younger than unvaccinated individuals (mean age 32.4+/-1.65 years versus 45.0+/-1.8 years, P<0.0001). Clustering was found in 62% of cases: 59% of non-BCG vaccinated cases were clustered versus 68% of those vaccinated with BCG (P=0.16). Younger patients (younger than 60 years of age) were more likely to be clustered in the univariate analysis (P<0.01). When age, sex, province, and HIV and reserve status were controlled for, BCG vaccination was not associated with clustering (OR 1.3, 95% CI 0.7 to 2.6)., Conclusions: BCG vaccinated Aboriginal people were no less likely to have active TB from recently transmitted disease. BCG vaccination appears to have limited value in preventing clustering of TB cases within this high-risk community.

Background: With effective treatment strategies, the focus of tuberculosis (TB) management has shifted from the prevention of mortality to the avoidance of morbidity. As such, there should be an increased focus on quality of life (QoL) experienced by individuals being treated for TB. The objective of our study was to identify areas of QoL that are affected by active TB using focus groups and individual interviews., Methods: English, Cantonese, and Punjabi-speaking subjects with active TB who were receiving treatment were eligible for recruitment into the study. Gender-based focus group sessions were conducted for the inner city participants but individual interviews were conducted for those who came to the main TB clinic or were hospitalized. Facilitators used open-ended questions and participants were asked to discuss their experiences of being diagnosed with tuberculosis, what impact it had on their lives, issues around adherence to anti-TB medications and information pertaining to their experience with side effects to these medications. All data were audio-recorded, transcribed verbatim, and analyzed using constant comparative analysis., Results: 39 patients with active TB participated. The mean age was 46.2 years (SD 18.4) and 62% were male. Most were Canadian-born being either Caucasian or Aboriginal. Four themes emerged from the focus groups and interviews. The first describes issues related to the diagnosis of tuberculosis and sub-themes were identified as 'symptoms', 'health care provision', and 'emotional impact'. The second theme discusses TB medication factors and the sub-themes identified were 'adverse effects', 'ease of administration', and 'adherence'. The third theme describes social support and functioning issues for the individuals with TB. The fourth theme describes health behavior issues for the individuals with TB and the identified sub-themes were "behavior modification" and "TB knowledge.", Conclusion: Despite the ability to cure TB, there remains a significant impact on QOL. Since much attention is spent on preventative or curative mechanisms, the impact of this condition on QoL is often not considered. Attention to the issues experienced by patients being treated for TB may optimize adherence and treatment success.

Background: While smear positive patients with tuberculosis (TB) are considered more infectious than smear negative patients, the latter can also transmit TB., Methods: In a molecular epidemiology study of 791 patients in the Greater Vancouver regional district, the number of episodes of TB transmission from two groups of smear negative clustered patients by RFLP (assumed to be involved in recent transmission) was estimated after assessing for potential bias. Group 1 (n = 79) included patients with pulmonary TB or pulmonary + extrapulmonary disease (PTB or PTB+EPTB); group 2 (n = 129) included all patients in group 1 + extrapulmonary cases alone., Results: In the total sample the mean (SD) age was 51 (21) years, 54.3% were male, and 17.0% of patients were clustered. Compared with smear negative patients, smear positive patients were more likely to be in a cluster (OR = 2.0, 95% CI 1.1 to 3.6) and to have had a history of ethanol abuse (OR = 2.7, 95% CI 1.0 to 6.7), diabetes mellitus (OR = 2.8, 95% CI 1.1 to 7.0), injection drug use (OR = 3.1, 95% CI 1.1 to 8.3), and to have had a previous hospital admission (OR = 8.5, 95% CI 5.1 to 14.0). The proportion of episodes of transmission from smear negative clustered patients ranged from 17.3% to 22.2% in group 1 and from 25% to 41% in group 2., Conclusion: In Greater Vancouver, smear negative cases appear responsible for at least one sixth of culture positive episodes of TB transmission.

The risk of occupational tuberculosis (TB) infection and associated factors was estimated among all microbiology and pathology technicians and compared with a sample of nonclinical personnel in 17 Canadian acute care hospitals. Participants underwent tuberculin skin testing and completed questionnaires. Prior skin tests and vaccinations and all patients with TB hospitalized in the preceding 3 years were reviewed. Of the work areas where direction of air flow and air changes per hour were measured, only 51% were adequately ventilated. Among participating lab workers the average annual risk of tuberculin conversion was 1.0%. This was associated with lower hourly air exchange rates (16.7 versus 32.5 in workers with no conversion, p < 0.001) work in pathology (adjusted odds ratio [OR]: 5.4; [95% confidence interval: 1.3, 22], higher proportion of patients with missed diagnosis in the first 24 hours (per 20% increase-OR: 2.0; [1.3, 3.2], treatment delayed 1 week or more (per 20% increase-OR: 2.0; [3.2, 3.2]), and higher mortality (per 20% increase-OR: 2.5; [1.1, 5.6]). We conclude that laboratory workers, with no direct patient contact, have increased risk of tuberculin conversion in hospitals where a greater proportion of patients with TB die, or have delayed, or missed diagnosis, although this may be modified by workplace ventilation.

Objective: To define the molecular epidemiology of TB in western Canada, and in particular the risk factors for clustering., Measurements: We prospectively identified all positive cultures from newly diagnosed cases of TB diagnosed between February 1995 and January 1997 and carried out restriction fragment length polymorphism (RFLP) testing on all isolates., Results: Of 956 cases identified, 944 fulfilled the entry criteria. The mean age was 49.65 years (+/- 22.33), and 508 (53.6%) were males. Three hundred and three (32.1%) subjects were clustered; this varied from 20.2% of the foreign born, 48.4% of Canadian non-Aboriginal and 61.1% of all Aboriginal persons. Younger persons (P = 0.0001), males (P = 0.015), those with pulmonary disease (P < 0.001), living in a shelter in the past year (P < 0.001), drug-susceptible disease (P < 0.036), predisposing factors (P < 0.001), prior contact (P < 0.001), and prior skin test (P < 0.002) were more likely to cluster. Among specific risk factors, HIV infection, injection drug use, alcohol excess, and weight loss were all significant., Conclusions: In this description of the molecular epidemiology of TB in Western Canada, previous results have been confirmed and extended. These results highlight the importance of identifying specific high risk groups, especially in the context of renewed efforts to target persons for treatment of latent TB infection.

Background: The accurate diagnosis of latent tuberculosis infection (LTBI) is an important component of any tuberculosis control programme and depends largely on tuberculin skin testing. The appropriate interpretation of skin test results requires knowledge of the possible confounding factors such as previous BCG vaccination. Uncertainty about the effect of BCG vaccination on tuberculin skin testing and the strength with which recommendations are made to individual patients regarding treatment of LTBI have identified a need to analyse the available data on the effect of BCG on skin testing. A meta-analysis of the evidence for the effect of BCG vaccination on tuberculin skin testing in subjects without active tuberculosis was therefore performed., Methods: Medline was searched for English language articles published from 1966 to 1999 using the key words "BCG vaccine", "tuberculin test/PPD", and "skin testing". Bibliographies of relevant articles were reviewed for additional studies that may have been missed in the Medline search. Articles were considered for inclusion in the meta-analysis if they had recorded tuberculin skin test results in subjects who had received BCG vaccination more than 5 years previously and had a concurrent control group. Only prospective studies were considered. The geographical location, number of participants, type of BCG vaccine used, type of tuberculin skin test performed, and the results of the tuberculin skin test were extracted., Results: The abstracts and titles of 980 articles were identified, 370 full text articles were reviewed, and 26 articles were included in the final analysis. Patients who had received BCG vaccination were more likely to have a positive skin test (5 TU PPD: relative risk (RR) 2.12 (95% confidence interval (CI)1.50 to 3.00); 2 TU RT23: 2.65 [corrected] (95% CI 1.83 to 3.85). The effect of BCG vaccination on PPD skin test results was less after 15 years. Positive skin tests with indurations of >15 mm are more likely to be the result of tuberculous infection than of BCG vaccination., Conclusions: In subjects without active tuberculosis, immunisation with BCG significantly increases the likelihood of a positive tuberculin skin test. The interpretation of the skin test therefore needs to be made in the individual clinical context and with evaluation of other risk factors for infection. The size of the induration should also be considered when making recommendations for treatment of latent infection.

Background: The understanding of how tuberculosis is transmitted can be improved by combining DNA fingerprinting of Mycobacterium tuberculosis with conventional epidemiologic methods. We used such techniques to determine the predictors of clustering of identical isolates from tuberculosis patients in Vancouver., Methods: We used the restriction fragment length polymorphism (RFLP) technique and, if necessary, spoligotyping to determine DNA patterns of M. tuberculosis isolates from all patients with newly diagnosed tuberculosis in Greater Vancouver reported to the Division of Tuberculosis Control from January 1995 to March 1999. Isolates were considered to be part of a cluster if they had an identical DNA pattern. We also collected demographic and epidemiologic data. Predictors associated with being in a cluster were analyzed in a multivariate logistic regression model., Results: Isolates from 793 patients (430 men) were identified; 137 (17.3%) were considered to be in clusters. After adjustment for multiple potential predictors, we found that the following patients were more likely to be part of a cluster: Canadian-born Aboriginals (v. foreign-born patients) (adjusted odds ratio [OR] 6.0, 95% confidence interval [CI] 3.0-11.7), Canadian-born non-Aboriginals (v. foreign-born patients) (adjusted OR 3.6, 95% CI 2.1-6.3), and injection drug users (v. patients who did not inject drugs) (adjusted OR 3.9, 95% CI 1.9-8.1). Patients with a prior history of tuberculosis were less likely to be part of a cluster than were patients with no history of tuberculosis (adjusted OR 0.3, 95% CI 0.1-0.8)., Interpretation: Our findings indicate the need to target groups at high risk of tuberculosis more aggressively to prevent transmission and to treat latent infection. DNA fingerprinting may be a useful adjunct to conventional epidemiologic methods to monitor the transmission of tuberculosis in an inner-city setting.

Published reports appear to underestimate the true rate of adverse reactions to bacille Calmette-Guérin (BCG) vaccine. At a recent national conference on tuberculosis control among aboriginal populations, lack of awareness of what constitutes an adverse reaction was considered a possible contributing factor to underreporting. The following review defines a normal BCG response and discusses the management of complications when they occur.

Objective: To compare cases of tuberculosis (TB) diagnosed among aboriginal persons with a random sample of nonaboriginal persons diagnosed with TB, and evaluate the trends in rates of disease between both groups during the same period., Design: A case-control study., Setting: A provincial TB control program., Patients and Methods: All patients with TB diagnosed among aboriginal persons in British Columbia between 1992 and 1996 were compared with control patients diagnosed during the same period. For each patient a control patient was identified., Intervention: The demographic details, type of disease, bacteriology, risk factors for TB, therapy received as well as mode of administration were documented. The number of contacts identified for each patient as well as the number of patients completing chemoprophylaxis were identified. The rates of disease during the same period were also documented., Results: During the study, 202 patients with TB were diagnosed among aboriginal persons and 201 controls were chosen. Apart from age at diagnosis (35.1+/-20 years versus 45.7+/-19.7), differences in the prevalence of lymphadenopathy (5.9% versus 16.4%, P=0.0008) and pleural disease (21.3% versus 16.4%, P=0.00008), there were no differences in presentation between aboriginal and nonaboriginal people. Aboriginal people were more likely to have a history of contact with a patient with TB (53% versus 17.9%, P<0.05), to have received directly observed therapy (55% versus 33.8%, P=0.00002) and to have contacts who were purified protein derivative (PPD) positive (4+/-9 versus 2+/-3, P=0.002). These contacts were more likely to start isoniazid (2+/-3 versus 1+/-1, P=0.002). Overall, there was a significant decline in rates of TB among aboriginal persons compared with the general population, but there was a small increase in rates among all subjects in the final year of the study., Conclusions: In the present study, significant variations in rates of TB among different population groups in British Columbia were found. During the study period, there was a greater decline in the rates of TB among aboriginal persons. A greater use of directly observed therapy and greater use of chemoprophylaxis occurred among aboriginal persons, which may have contributed to this decline, or alternatively, it simply reflects the natural evolution of the TB epidemic.

Setting: Intravenous drug users (IDUs) represent a high risk group for dual human immunodeficiency virus (HIV) and tuberculosis (TB) infection. Screening with TB skin testing has therefore been suggested in this group. Subjects' compliance for returning to have TB skin test results read is a major problem. In the setting of a needle exchange program we evaluated the role of financial incentives to increase compliance., Methods: We evaluated the role of giving a small financial incentive of Can $5 to subjects if they returned to have their purified protein derivative (PPD) skin test read. IDUs who had previously been skin-tested were compared with IDUs drawn from a similar population who, prospectively, were offered a financial incentive., Results: During the initial period 558 subjects were evaluated and no incentive was offered. During the second phase of the study 549 IDUs were assessed but were also offered Can $5 if they returned to have their skin test read. Use of incentives increased compliance from 43% to 78% (P = 0.001). During the same period three active cases of TB were also diagnosed., Conclusions: We suggest that use of financial incentives can increase the return of IDUs to have their skin tests read. Further studies are required to assess the efficacy of follow-up interventions, especially the use of isoniazid chemoprophylaxis.

Objectives: To compare the clinical features and prevalence of active TB in British Columbia (BC) health-care workers (HCWs) with those of the general population, between 1991 and 1996., Methods: Comparison of 25 HCWs and 50 controls randomly selected from the Centres for Disease Control registry, with respect to demographics, prevention, diagnosis and management., Results: HCWs had fewer related risk factors, but more had initiated prior chemoprophylaxis (16% vs. 0%, P < 0.01) and knew their bacille Calmette-Guerin (BCG) (68% vs. 24%, P < 0.001) and purified protein derivative (PPD) status (60% vs 32%, P < 0.05). There were no differences in symptom duration (3.3+/-3.6 vs. 3.0+/-3.4 months), mycobacteriology and diagnostic features, treatment duration (264.9+/-69.9 vs. 239.0+/-78.7 days) and completion rates (84% for both). All HCWs used self-administered treatment (100% vs. 70%, P < 0.01), and fewer were hospitalized (8% vs. 28%, P < 0.05). Disease rates in nurses (3.6+/-4.4 per 100 000) were lower than the general population rates (9.0+/-0.8), but did not differ among physiotherapists (8.96+/-21.95), general practitioners (7.60+/-11.78) and medical residents (30.75+/-75.32);, Conclusions: Clinical features were similar in HCWs, but management strategies differed. BC HCWs are not at increased risk of tuberculosis, but the small sample size limited the power of our study to detect such an increase.

Adjunct therapy with corticosteroids, in conjunction with antituberculous drugs, may be appropriate in particular forms of tuberculosis. Prospective controlled trials have shown a benefit in tuberculous meningitis, pericardial and pleural disease. Although benefit has been shown in pleural disease, adjunct therapy is not routinely required unless there are significant systemic symptoms of fever or a particularly large effusion. It has been recommended in the past that corticosteroids should be used routinely in endobronchial TB, especially pediatric disease, but our recent experience has been that such therapy is not usually required. Although corticosteroid therapy is sometimes recommended in extensive pulmonary disease there are no controlled trials, in the modern drug era, to support such therapy. Where adrenal suppression is a concern supplemental corticosteroids are indicated. Fever, be it drug-related or from systemic disease, sometimes requires suppression with corticosteroids. The usual dose required is 40-60 mg of prednisone orally daily for 4-6 weeks depending on the system involved, with tapering doses of prednisone subsequent to this. Local corticosteroid therapy of BCG-related keloid reactions may also be useful. Anecdotal reports suggest immune suppression with corticosteroids predisposes to tuberculosis but retrospective studies on patients taking, in general, low doses of prednisone have not confirmed this risk. Corticosteroid interaction with the oral birth control pill and rifampin need also to be accounted for in prescribing these agents.

Tuberculosis is increasing in prevalence in North America, mainly due to HIV infection. We describe an unusual case of TB of the thymus in a HIV sero-negative Filipino immigrant who preoperatively was thought to have a thymoma. We describe the clinical, radiologic and pathologic findings and review the literature on TB of the thymus.