Patterns and characteristics of TB among key risk groups in Canada, 1993–2018

BACKGROUND: Canada has a low incidence of TB, although certain groups are disproportionately affected.OBJECTIVE: To describe and compare the epidemiology, trends and characteristics of TB in Quebec, Canada, among all patients reported during 1993–2018.METHODS: Demographics and risk factors were compared for the three groups accounting for most TB diagnoses reported in Quebec (foreign-born, Canadian-born non-Indigenous and Inuit). Average annual incidence and incidence rate ratios (IRRs) were estimated and compared using Poisson regression.RESULTS: Of 6,941 persons with a first episode of TB, 4,077 (59%) were foreign-born, 2,314 (33%) were Canadian-born non-Indigenous and 389 (6%) were Inuit. The average annual incidence for foreign-born, Canadian-born non-Indigenous and Inuit was respectively 17.0, 1.4 and 137.1 per 100,000 population. Compared to Canadian-born non-Indigenous, the IRR for foreign-born and Inuit was respectively 12.3 (95% CI 11.6–12.9) and 98.7 (95% CI 88.6–109.9). There was evidence of community transmission among the Inuit, with more than 80% of patients having a TB contact (2012–2018 data) and 65% (251/389) of diagnoses in those aged <25 years.CONCLUSION: Although TB rates among the Canadian-born non-Indigenous are extremely low, there are persistent and distinct TB epidemics among the foreign-born and Inuit. Tailored approaches to TB prevention and care are needed to address TB among high-risk populations in low TB incidence settings.

WHO target product profiles for TB preventive treatment

BACKGROUND: The WHO has developed target product profiles (TPPs) describing the most appropriate qualities for future TPT regimens to assist developers in aligning the characteristics of new treatments with programmatic requirements.METHODS: A technical consultation group was convened by the WHO to determine regimen attributes with greatest potential impact for patients (i.e., improved risk/benefit profile) and populations (i.e., reduction in transmission and TB prevalence). The group categorised regimen attributes as 'priority´ or 'desirable´; and defined for each attribute the minimum requirements and optimal targets.RESULTS: Nine priority attributes were defined, including efficacy, treatment duration, safety, drug-drug interactions, barrier to emergence of drug resistance, target population, formulation, dosage, frequency and route of administration, stability and shelf life. Regimens meeting optimal targets were characterised, for example, as having superior efficacy, treatment duration of ≤2 weeks, and improved tolerability and safety profile compared with current regimens. The four desirable attributes included regimen cost, safety in special populations, treatment adherence and need for drug susceptibility testing in the index patient.DISCUSSION: It may be difficult for a single regimen to satisfy all characteristics so regimen developers may have to consider trade-offs. Additional operational aspects may be relevant to the feasibility and public health impact of new TPT regimens.

Resource implications of the latent tuberculosis cascade of care: a time and motion study in five countries

BACKGROUND

The End TB Strategy calls for global scale-up of preventive treatment for latent tuberculosis infection (LTBI), but little information is available about the associated human resource requirements. Our study aimed to quantify the healthcare worker (HCW) time needed to perform the tasks associated with each step along the LTBI cascade of care for household contacts of TB patients.

METHODS

We conducted a time and motion (TAM) study between January 2018 and March 2019, in which consenting HCWs were observed throughout a typical workday. The precise time spent was recorded in pre-specified categories of work activities for each step along the cascade. A linear mixed model was fit to estimate the time at each step.

RESULTS

A total of 173 HCWs in Benin, Canada, Ghana, Indonesia, and Vietnam participated. The greatest amount of time was spent for the medical evaluation (median: 11 min; IQR: 6-16), while the least time was spent on reading a tuberculin skin test (TST) (median: 4 min; IQR: 2-9). The greatest variability was seen in the time spent for each medical evaluation, while TST placement and reading showed the least variability. The total time required to complete all steps along the LTBI cascade, from identification of household contacts (HHC) through to treatment initiation ranged from 1.8 h per index TB patient in Vietnam to 5.2 h in Ghana.

CONCLUSIONS

Our findings suggest that the time requirements are very modest to perform each step in the latent TB cascade of care, but to achieve full identification and management of all household contacts will require additional human resources in many settings.

Validated methods for identifying tuberculosis patients in health administrative databases: systematic review

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.

Three months of weekly rifapentine plus isoniazid is less hepatotoxic than nine months of daily isoniazid for LTBI

SETTING

Nine months of daily isoniazid (9H) and 3 months of once-weekly rifapentine plus isoniazid (3HP) are recommended treatments for latent tuberculous infection (LTBI). The risk profile for 3HP and the contribution of hepatitis C virus (HCV) infection to hepatotoxicity are unclear.

OBJECTIVES

To evaluate the hepatotoxicity risk associated with 3HP compared to 9H, and factors associated with hepatotoxicity.

DESIGN

Hepatotoxicity was defined as aspartate aminotransferase (AST) >3 times the upper limit of normal (ULN) with symptoms (nausea, vomiting, jaundice, or fatigue), or AST >5 x ULN. We analyzed risk factors among adults who took at least 1 dose of their assigned treatment. A nested case-control study assessed the role of HCV.

RESULTS

Of 6862 participants, 77 (1.1%) developed hepatotoxicity; 52 (0.8%) were symptomatic; 1.8% (61/3317) were on 9H and 0.4% (15/3545) were on 3HP (P < 0.0001). Risk factors for hepatotoxicity were age, female sex, white race, non-Hispanic ethnicity, decreased body mass index, elevated baseline AST, and 9H. In the case-control study, HCV infection was associated with hepatotoxicity when controlling for other factors.

CONCLUSION

The risk of hepatotoxicity during LTBI treatment with 3HP was lower than the risk with 9H. HCV and elevated baseline AST were risk factors for hepatotoxicity. For persons with these risk factors, 3HP may be preferred.

Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus-the 'D-shuttle' project

Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter 'D-shuttle' for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the terrestrial background radiation level of other regions/countries.

Sputum induction for tuberculosis diagnosis in an Arctic setting: a cost comparison

SETTING

Tuberculosis (TB) incidence was 234 per 100 000 in Nunavut, Canada, in 2012. Until recently, some individuals seen in local clinics for presumed TB required costly air evacuation to Southern Canada (Ottawa) for investigation if they were unable to produce sputum spontaneously.

OBJECTIVE

To estimate the cost per individual evaluated for TB, associated with the establishment of a sputum induction programme in Iqaluit, Nunavut, Canada.

DESIGN

A decision analysis model compared the total cost per individual for two strategies: 1) initial investigation in Iqaluit, with transport to Ottawa for those requiring sputum induction; and 2) sputum induction at the hospital in Iqaluit, with further investigation in Ottawa only if needed. The model simulated diagnostic and treatment paths from the initial clinic visit to completion of TB investigation or treatment (when applicable).

RESULTS

The estimated cost per person evaluated for TB with sputum induction in 1) Ottawa vs. 2) Iqaluit was CAD4798 (95% uncertainty range 2923-6650) vs. CAD2479 (1206-4256), respectively. Total costs were influenced by underlying TB prevalence, but local sputum induction consistently yielded cost savings.

CONCLUSION

Providing sputum induction in a high-incidence Arctic community such as Iqaluit is projected to generate substantial cost savings in the investigation and management of individuals with presumed TB.

A systematic review and meta-analysis of the impact of tuberculosis on health-related quality of life

PURPOSE

To summarize the impact of tuberculosis (TB) on quantitative measures on self-reported health-related quality of life (HRQOL).

METHODS

We searched eight databases to retrieve all peer-reviewed publications reporting original HRQOL data for persons with TB. All retrieved abstracts were considered for full-text review if HRQOL was quantitatively assessed among subjects with TB. Full-text articles were reviewed by two independent reviewers using a standardized abstraction form to collect data on socio-demographic characteristics, questionnaire administration, and mean HRQOL scores. Meta-analyses were performed for standardized mean differences in HRQOL scores, comparing subjects treated for active TB with subjects treated for latent TB infection (LTBI), or with healthy controls, at similar time points with respect to diagnosis and/or treatment.

RESULTS

From over 15,000 abstracts retrieved, 76 full-text articles were reviewed, which represented 28 unique cohorts (6,028 subjects) reporting HRQOL among subjects with active TB; 42 % were women and mean age was 42 years. Data on key social and behavioral determinants were limited. Within individual studies and in meta-analyses, subjects with active TB disease consistently reported worse HRQOL than concurrently evaluated subjects treated for LTBI. However, meaningful improvements in HRQOL throughout active TB treatment were reported by longitudinal studies.

CONCLUSIONS

In a variety of studies, in different settings and using different instruments, subjects with active TB consistently reported poorer HRQOL than persons treated for LTBI. Future research on HRQOL and TB should better address social and behavioral health determinants which may also affect HRQOL.

Potential cost-effectiveness of rifampin vs. isoniazid for latent tuberculosis: implications for future clinical trials

SETTING

Standard treatment for latent tuberculosis infection (LTBI) is 9 months daily isoniazid (9INH). An alternative is 4 months daily rifampin (4RMP), associated with better completion and less toxicity; however, its efficacy remains uncertain.

OBJECTIVES

To assess the cost-effectiveness of these regimens for treating LTBI in human immunodeficiency virus negative persons, using results from a recent clinical trial, plus different scenarios for 4RMP efficacy, and to estimate the costs of an adequately powered noninferiority trial and resulting savings from substitution with 4RMP.

DESIGN

A decision-analysis model tracked TB contacts and lower-risk tuberculin reactors receiving 9INH, 4RMP or no treatment. For different 4RMP efficacy scenarios, we estimated the cost-effectiveness, sample size and cost of non-inferiority trials, and potential cost savings substituting 4RMP for 9INH for 10 years in Canada.

RESULTS

With an assumed 4RMP efficacy of 60%, 9INH was more effective but slightly more expensive. Above a threshold efficacy of 69%, 4RMP was cheaper and more effective than 9INH. If the true efficacy of 4RMP is ≥75%, a trial powered to detect non-inferiority with a lower limit of 60% estimated efficacy (~20 000 subjects) may lead to cost savings within 10 years, even with the extreme assumption that Canada bears the entire cost.

CONCLUSION

4RMP may be a reasonable alternative to 9INH. Costs of a large-scale non-inferiority trial may be offset by subsequent savings.

Tuberculosis may be underestimated in Rwandan women

BACKGROUND AND HYPOTHESIS

The majority of adult tuberculosis (TB) cases reported to the surveillance system in Rwanda are male. If this results from detection mechanisms that are less sensitive to TB in women, notified cases should be more severe in women than in men.

METHODS

We analysed the 2006 series of TB cases among persons aged ≥ 15 years in Huye District and Kigali. Severe TB was defined as disease leading to death, or extra-pulmonary or disseminated TB.

RESULTS

Of 1673 cases identified, 40% involved women, who were younger than men (65% vs. 54% aged <35 years). Overall severity was similar in both sexes. Considering age <35 years, women were at higher risk of severe TB than men, although the difference was not statistically significant. Smear-negative pulmonary TB (SNPTB), and human immunodeficiency virus (HIV) infection were more frequent in women than in men (59% vs. 42%, P < 0.001). For women with smear-positive pulmonary TB (SPPTB), the risk of death was twice that among men (adjusted hazard ratio 1.8; 95%CI 1.0-3.2).

CONCLUSIONS

Among female TB patients, the higher risk of death with SPPTB, the higher frequency of SNPTB and the higher prevalence of HIV infection suggest that the passive system of case detection may underestimate the burden of TB in Rwandan women.

Obstructive sleep apnea is associated with fatigue in multiple sclerosis

Background:

Multiple sclerosis (MS) patients often suffer from fatigue.

Objective:

We evaluated the relationship of obstructive sleep apnea (OSA) to fatigue and sleepiness in MS patients.

Methods:

Ambulatory MS patients without known sleep disorders and healthy controls underwent diagnostic polysomnography and a multiple sleep latency test (objective sleepiness measure). Fatigue was measured with the Fatigue Severity Scale (FSS) and the Multidimensional Fatigue Inventory (MFI), and subjective sleepiness by Epworth Sleepiness Scale. Covariates included age, sex, body mass index, Expanded Disability Status Scale (EDSS), depression, pain, nocturia, restless legs syndrome, and medication.

Results:

OSA (apnea–hypopnea index ≥15) was found in 36 of 62 MS subjects and 15 of 32 controls. After adjusting for confounders, severe fatigue (FSS ≥5) and MFI-mental fatigue (>group median) were associated with OSA and respiratory-related arousals in MS, but not control subjects. Subjective and objective sleepiness were not related to OSA in either group. In a multivariate model, variables independently associated with severe fatigue in MS were severe OSA [OR 17.33, 95% CI 2.53–199.84], EDSS [OR 1.88, 95% CI 1.21–3.25], and immunomodulating treatment [OR 0.14, 95% CI 0.023–0.65].

Conclusions:

OSA was frequent in MS and was associated with fatigue but not sleepiness, independent of MS-related disability and other covariates.

Sleep disorders and fatigue in multiple sclerosis: evidence for association and interaction

Fatigue is highly prevalent in multiple sclerosis (MS). It appears to be multifactorial, with "primary" or disease-related factors involved, as well as "secondary" factors, including comorbidities. Sleep disturbances are frequent in MS as well, and often result from disease-related factors. Subjective sleep disturbances in MS have been extensively studied and have been associated with fatigue. Sleep disorders in the general population have been associated with fatigue as well. However, data on objectively diagnosed sleep disorders in MS are less conclusive. Studies of sleep in MS have often suffered from low numbers of study subjects and suboptimal methodology. We review the current knowledge on sleep disturbances in MS and the relationship to fatigue. Data from neuroimaging studies and studies of molecular consequences of sleep disorders in the general population, with particular attention to sleep-disordered breathing (SDB), are briefly reviewed. Potential biologic interactions with MS are discussed in this context. We conclude that further studies of sleep disorders in MS are needed, to objectively establish their significance in this disease, and also to document any impact of treatment of sleep disorders on biologic and clinical outcomes such as fatigue.

Predicting outcomes and drug resistance with standardised treatment of active tuberculosis

New World Health Organization guidelines recommend initial treatment of active tuberculosis (TB) with a 6-month regimen utilising rifampin throughout. We have modelled expected treatment outcomes, including drug resistance, with this regimen, compared to an 8-month regimen with rifampin for the first 2 months only, followed by standardised retreatment. A deterministic model was used to predict treatment outcomes in hypothetical cohorts of 1,000 new smear-positive cases from seven countries with varying prevalence of initial drug resistance. Model inputs were taken from published systematic reviews. Predicted outcomes included number of deaths, failures and relapses, plus the proportion with drug resistance. Sensitivity analyses examined different risks of acquired drug resistance. Compared to use of the standardised 8-month regimen, for every 1,000 new TB cases treated with the 6-month regimen we predict that 48-86 fewer persons will require retreatment, and 3-12 deaths would be avoided. However, the proportion failing or relapsing after retreatment is predicted to be higher, because with the 6-month regimen 50-94% of failures and 3-56% of relapses will have multidrug-resistant TB. We predict substantial public health benefits from changing from the 8-month to the 6-month regimen. However in almost all settings the current standardised retreatment regimen will no longer be adequate.

Global tuberculosis trends: a reflection of changes in tuberculosis control or in population health?

BACKGROUND

Many international organizations are advocating for new funds for tuberculosis (TB) specific interventions. Although this approach should help reduce TB incidence, improvements in population health may also be important. We have analyzed the association between changes in population health and health service indicators, and concomitant changes in TB incidence between 1990 and 2005.

METHODS

Country level data on population health and health services, economic and epidemiologic indicators were obtained for 165 countries. Regression methods were used to estimate the association of changes in potential predictors with changes in TB incidence.

RESULTS

Improvements in population health and health services are associated with improvements in TB outcomes. In adjusted analyses, each 1 year increase in life expectancy was associated with a 7.8/100,000 decline in TB incidence. A 1/1000 decrease in mortality rate in children aged <5 years and a 1% increase in measles vaccination coverage (serving as a general health services indicator) was associated with approximately a 1/100,000 decrease in TB incidence. In countries with a lower prevalence of human immunodeficiency virus (HIV) infection, a 1% increase in TB treatment success rate was also associated with a 1/100,000 decrease in incidence.

CONCLUSION

Investment in improving population health and health services may be as important as targeted strategies for controlling TB.

Use of geographic and genotyping tools to characterise tuberculosis transmission in Montreal

SETTING

In Canada, tuberculosis (TB) is increasingly an urban health problem. Montreal is Canada's second-largest city and the second most frequent destination for new immigrants and refugees.

OBJECTIVES

To detect spatial aggregation of cases, areas of excess incidence and local 'hot spots' of transmission in Montreal.

DESIGN

We used residential addresses to geocode active TB cases reported on the Island of Montreal in 1996-2000. After a hot spot analysis suggested two areas of overconcentration, we conducted a spatial scan, with census tracts (population 2500-8000) as the primary unit of analysis and stratification by birthplace. We linked these analyses with genotyping of all available Mycobacterium tuberculosis isolates, using IS6110-RFLP and spoligotyping.

RESULTS

We identified four areas of excess incidence among the foreign-born (incidence rate ratios 1.3-4.1, relative to the entire Island) and one such area among the Canadian-born (incidence rate ratio 2.3). There was partial overlap with the two hot spots. Genotyping indicated ongoing transmission among the foreign-born within the largest high-incidence zone. While this zone overlapped the area of high incidence among Canadian-born, genotyping largely excluded transmission between the two groups.

CONCLUSIONS

In a city with low overall incidence, spatial and molecular analyses highlighted ongoing local transmission.

Interferon-gamma release assays and TB screening in high-income countries: a cost-effectiveness analysis

OBJECTIVE

Interferon-gamma release assays (IGRA) are now available alternatives to tuberculin skin testing (TST) for detection of latent tuberculosis infection (LTBI). We compared the cost-effectiveness of TST and IGRA in different populations and clinical situations, and with variation of a number of parameters.

METHODS

Markov modelling was used to compare expected TB cases and costs over 20 years following screening for TB with different strategies among hypothetical cohorts of foreign-born entrants to Canada, or contacts of TB cases. The less expensive commercial IGRA, Quanti-FERON-TB Gold (QFT), was examined. Model inputs were derived from published literature.

RESULTS

For entering immigrants, screening with chest radiograph (CXR) would be the most and QFT the least cost-effective. Sequential screening with TST then QFT was more cost-effective than QFT alone in all scenarios, and more cost-effective than TST alone in selected subgroups. Among close and casual contacts, screening with TST or QFT would be cost saving; savings with TST would be greater than with QFT, except in contacts who were bacille Calmette-Guérin (BCG) vaccinated after infancy.

CONCLUSIONS

Screening for LTBI, with TST or QFT, is cost-effective only if the risk of disease is high. The most cost-effective use of QFT is to test TST-positive persons.

Dyspnea as clinical indicator in patients with chronic obstructive pulmonary disease

The aim of this study was to evaluate the relationship between dyspnea and functional, psychosocial and quality of life parameters among persons with chronic obstructive pulmonary disease (COPD). We conducted a cross-sectional study of 90 stable COPD patients recruited from a specialized respiratory clinic. Dyspnea was measured using the ATS-DLD-78 questionnaire modified dyspnea scale (1-5 scale). Physical and functional evaluation included spirometry and six minute walking tests. Subjects then completed five psychological questionnaires: the Coping Inventory for Stressful Situations, the State/Trait Anxiety Inventory, the Beck Depression Index, the NEO-Five Factor Personality Inventory, and the Interpersonal Relationships Inventory. Patients also completed two disease-specific health-related quality of life (HRQL) questionnaires: St. George's Respiratory Questionnaire (SGRQ) and Chronic Respiratory Questionnaire (CRQ). Subjects were predominantly male (n = 65) with a mean age of 68 years (+/- standard deviation 7.6). Over half (54%) the patients reported severe dyspnea (grade 5), and a quarter (24%) reported moderate dyspnea (grade 3-4). Mean FEV1 was 37.8 +/- 14.8% predicted. The mean total SGRQ score was 49 +/- 16 and the CRQ total score was 4.2 +/- 0.9. Dyspnea severity was associated with poorer HRQL scores and decreased physical performance. Based on linear regression, dyspnea scores--but not spirometric values--also correlated with indices of anxiety, depression, and neuroticism. Dyspnea correlated more strongly with HRQL and with indices of anxiety and depression than spirometric values. Although spirometry is often used to evaluate disease severity, dyspnea which is a patient centered outcome better reflect overall disease impact among COPD patients.

The effect of cyclooxygenase-2 inhibitors on bone mineral density: results from the Canadian Multicentre Osteoporosis Study

INTRODUCTION

The use of cyclooxygenase-2 (COX-2) inhibitors has been demonstrated to not only impair load-induced bone formation but also prevent menopause-associated bone loss. We hypothesized that COX-2 inhibitor use would be associated with increased bone mineral density (BMD) in postmenopausal women not using estrogen therapy and, conversely, with decreased BMD in men.

METHODS

The Canadian Multicentre Osteoporosis Study is a longitudinal, randomly selected, population-based community cohort. We present data from men (n=2,004) and postmenopausal women age 65 and older (n=2,776) who underwent a BMD measurement and structured interview in the 5th year of the study. The outcome measure was percent difference in BMD (g/cm(2)).

RESULTS

Daily COX-2 inhibitor use was reported by 394 subjects. In men, daily use of COX-2 inhibitors was associated with a lower BMD at all hip sites, with a percent difference of -3.1% [95% confidence interval (CI), -6.0, -0.3] between users and nonusers at total hip. In postmenopausal women not using estrogen replacement therapy, daily COX-2 inhibitor use was associated with higher BMD at most sites [percent difference at total hip: +3.0% (95% CI, 0.3, 5.8)]. These effects appeared to be dose-dependent.

CONCLUSION

COX-2 inhibitor use was associated with a lower BMD in men and, on the other hand, with a higher BMD in postmenopausal women not using estrogen replacement therapy. Men who have used COX-2 inhibitors may wish to seek BMD measurement to assess their fracture risk. However, COX-2 inhibitors may have utility in postmenopausal women if bone-selective analogs can be developed.

In closely monitored patients, adherence in the first month predicts completion of therapy for latent tuberculosis infection

BACKGROUND

Current therapy for latent TB infection (LTBI) is long, and requires close follow-up. This results in sub-optimal adherence-the major reason for failure of therapy.

METHODS

In an open label randomised trial comparing 4 months of rifampicin with 9 months of isoniazid, the proportion and regularity of doses taken, measured with an electronic monitoring system (MEMS), and provider estimates of adherence in the first month of therapy, were assessed as predictors of treatment completion.

RESULTS

Of 104 patients analysed, 86 took more than 80% of doses within the expected interval, 11 took more than 80% of doses but over a longer time interval than usually allowed, and seven did not complete treatment. Treatment completion was associated with the number of doses taken, and the variability of intervals between doses during the first month of treatment.

CONCLUSIONS

Adherence in the first month, based on the number of doses and variability of times when taken, could be useful to predict completion of LTBI therapy. Interventions could be targeted to patients with suboptimal adherence in the first month.

Self-management reduces both short- and long-term hospitalisation in COPD

The aim of the present study was to assess the long-term impact on hospitalisation of a self-management programme for chronic obstructive pulmonary disease (COPD) patients. A multicentre, randomised clinical trial was carried out involving 191 COPD patients from seven hospitals. Patients who had one or more hospitalisations in the year preceding study enrolment were assigned to a self-management programme "Living Well with COPD(TM)" or to standard care. Hospitalisations from all causes were the primary outcome and were documented from the provincial hospitalisation database; emergency visits were recorded from the provincial health insurance database. Most patients were elderly, not highly educated, had advanced COPD (reflected by a mean forced expiratory volume in one second of 1 L), and almost half reported a dyspnoea score of 5/5 (modified Medical Research Council). At 2 years, there was a statistically significant and clinically relevant reduction in all-cause hospitalisations of 26.9% and in all-cause emergency visits of 21.1% in the intervention group as compared to the standard-care group. After adjustment for the self-management intervention effect, the predictive factors for reduced hospitalisations included younger age, sex (female), higher education, increased health status and exercise capacity. In conclusion, in this study, patients with chronic obstructive pulmonary disease who received educational intervention with supervision and support based on disease-specific self-management maintained a significant reduction in hospitalisations after a 2-year period.

Tuberculosis surveillance among new immigrants in Montreal

SETTING

Foreign-born persons account for over 60% of Canadian tuberculosis (TB) incidence; immigrants with TB-related lung scarring ('inactive TB') are at particularly high risk, and represent an important target for preventive efforts.

OBJECTIVE

To document the performance of the immigrant surveillance programme for inactive TB in Montreal.

DESIGN

All immigrants arriving with inactive TB are referred by the public health department to the Montreal Chest Institute. We prospectively recorded clinical and radiographic data for those evaluated in 1999 and 2000. We examined physicians' adherence to Canadian guidelines. We also evaluated concordance of chest radiographic interpretation.

RESULTS

Of 1444 immigrants notified, 792 (55%) were sent referral letters. Most of the others lacked valid addresses. Of the 654 (45%) who were examined, 322 (22%) were diagnosed with untreated latent TB, 215 (15%) were recommended therapy, and 156 (11%) completed it. Of 388 potential candidates for treatment of latent TB, 274 (71%) underwent tuberculin tests. Treatment decisions followed guidelines for 87% of patients with full testing. Agreement between clinicians and chest radiologists as to TB-related radiographic abnormalities was frequent (K 0.63). Six 'high volume' clinicians performed better than others with respect to management and radiographic interpretation.

CONCLUSION

Centralised post-immigration surveillance requires more accurate referrals, and more consistent provider performance.

Yield of tuberculin screening among injection drug users

BACKGROUND

Regardless of their HIV status, injection drug users (IDUs) are at increased risk of developing active tuberculosis (TB) if they have latent TB infection (LTBI). We quantified the prevalence and predictors of LTBI and level of adherence to medical evaluation in a population of IDUs in Montreal.

METHODS

Participants were recruited from an ongoing dynamic cohort of IDUs followed for HIV seroconversion risk behaviour. Subjects with a tuberculin skin test (TST) of > or =5 mm were referred to designated TB clinics for medical evaluation. A financial incentive was provided for TST readings.

RESULTS

Of the 262 subjects tested, 246 (94%) returned for TST reading. The overall prevalence of positive TSTs was 22% (5% in HIV-positive, 28% in HIV-negative participants). Older age at first injection drug use (OR per 10 year increase in age 1.4, 95%CI 1.2-1.8), duration of injection drug use (OR per 10 year increase 1.6, 9.5%CI 1.5-2.2) and negative HIV status (OR 11.2, 95%CI 3.2-4.0) were independent predictors of a positive TST. Nine per cent of all TST-positive participants completed LTBI treatment.

CONCLUSION

TB screening activities with incentives can be successful in detecting TST-positive individuals, but better strategies are needed for medical follow-up in this high-risk group.

Feasibility and reliability of health-related quality of life measurements among tuberculosis patients

The dramatic global impact of tuberculosis on mortality has been well documented, but its impact on morbidity has not been well described. The emphasis on treatment of latent tuberculosis (TB) infection highlights the tradeoff between short-term decrements in health status from 'preventive' therapy, and long-term gains related to fewer cases of active TB. However, these changes in health status have not been characterized. As a first step, we examined the feasibility and reliability of administering two health status questionnaires, in a multicultural TB clinic setting. The Medical Outcomes Study SF-36 and the EuroQOL EQ-5D were self-administered during 3 weekly interviews. One hundred and eighty-six potentially eligible patients were identified, of whom 112 could be evaluated; 106 (57%) were confirmed eligible. Sixty-seven (63%) agreed to participate; 24 (36%) were women. Fifty-three participants (79%) were foreign-born, with median residence in Canada of 3.5 years. Fifty (75%) of the participants completed all study measurements: 25 were treated for latent TB, 17 for active TB, and eight had previous active TB. Cronbach's alpha coefficients ranged from 0.73 to 0.94 for the SF-36 domain scores. Intraclass correlation coefficients were 0.66 for the SF-36 physical component summary, 0.79 for the mental component summary, and 0.73 for the EQ-5D. These instruments appeared reliable in a highly selected group of TB patients.

Respiratory day hospital: a novel approach to acute respiratory care

In 1996 we established a day hospital dedicated to acute respiratory care, as an alternative to emergency department and inpatient treatment. The unit is staffed by respirologists, family physicians and specialized nurses; patients have access to all standard inpatient treatments and services. Between 1996/97 and 1998/99 the annual number of admissions to the day hospital increased from 658 to 922. By 1998/99 more than 75% of patients were referred for acute treatment, with a mean stay of 2.3 days. The most common diagnoses were asthma and chronic obstructive pulmonary disease, which accounted for 58% and 32% respectively of treatment-related admissions. Treatment most often involved intravenous corticosteroid therapy and inhaled bronchodilator therapy. Between 1996/97 and 1998/9 the proportion of patients requiring transfer to overnight care decreased from 22% to 14%; complications and unscheduled return visits were rare. We believe that a respiratory day hospital provides a useful alternative to emergency department and inpatient care.

Strategies incorporating spiral CT for the diagnosis of acute pulmonary embolism: a cost-effectiveness analysis

OBJECTIVE

To assess the cost-effectiveness of spiral CT for the diagnosis of acute pulmonary embolism.

DESIGN

Computer-based cost-effectiveness analysis.

PATIENTS

Simulated cohort of 1,000 patients with suspected acute pulmonary embolism (PE), with a prevalence of 28.4%, as in the Prospective Investigation of Pulmonary Embolism Diagnosis study.

INTERVENTIONS

Using a decision-analysis model, seven diagnostic strategies were compared, which incorporated combinations of ventilation-perfusion (V/Q) scans, duplex ultrasound of the legs, spiral CT, and conventional pulmonary angiography.

MEASUREMENTS AND RESULTS

Expected survival and cost (in Canadian dollars) at 3 months were estimated. Four of the strategies yielded poorer survival at higher cost. The three remaining strategies were as follows: (1) V/Q +/- leg ultrasound +/- spiral CT, with an expected survival of 953.4 per 1,000 patients and a cost of $1,391 per patient; (2) V/Q +/- leg ultrasound +/- pulmonary angiography (the "traditional" algorithm), with an expected survival of 953.7 per 1,000 patients and a cost of $1,416 per patient; and (3) spiral CT +/- leg ultrasound, with an expected survival of 958.2 per 1,000 patients and a cost of $1,751 per patient. The traditional algorithm was then excluded by extended dominance. The cost per additional life saved was $70,833 for spiral CT +/- leg ultrasound relative to V/Q +/- leg ultrasound +/- spiral CT.

CONCLUSIONS

Spiral CT can replace pulmonary angiography in patients with nondiagnostic V/Q scan and negative leg ultrasound findings. This approach is likely as effective as-and possibly less expensive than-the current algorithm for diagnosis of acute PE. When spiral CT is the initial diagnostic test, followed by leg ultrasound, expected survival improves but costs are also considerably higher. These findings were robust to variations in the assumed sensitivity and specificity of spiral CT.

Comparison of cost-effectiveness of tuberculosis screening of close contacts and foreign-born populations

Although tuberculosis (TB) screening of immigrants has been conducted for over 50 yr in many industrialized countries, its cost- effectiveness has never been evaluated. We prospectively compared the yield and cost-effectiveness of two immigrant TB screening programs, using close-contact investigation and passive case detection. Study subjects included all immigration applicants undergoing radiographic screening, already arrived immigrants requiring surveillance for inactive TB, and close contacts of active cases resident in Montreal, Quebec, Canada, who were referred from June 1996 to June 1997 to the Montreal Chest Institute (MCI), a referral center specializing in respiratory diseases. For all subjects seen, demographic data, investigations, diagnoses, and therapy were abstracted from administrative data bases and medical charts. Estimated costs of detecting and treating each prevalent active case and preventing future active cases, based on federal and provincial health reimbursement schedules, were compared with the costs for passively diagnosed cases of active TB. Over a period of 1 yr, the three programs detected 27 cases of prevalent active TB and prevented 14 future cases. As compared with passive case detection, close-contact investigation resulted in net savings of $815 for each prevalent active case detected and treated and of $2,186 for each future active case prevented. The incremental cost to treat each case of prevalent active TB was $39,409 for applicant screening and $24,225 for surveillance, and the cost of preventing each case was $33,275 for applicants and $65,126 for surveillance. Close-contact investigation was highly cost effective and resulted in net savings. Immigrant applicant screening and surveillance programs had a significant impact but were much less cost effective, in large part because of substantial operational problems.

Tuberculosis screening of immigrants to low-prevalence countries. A cost-effectiveness analysis

All adult immigrant applicants to Canada undergo chest radiographic screening for tuberculosis (TB). Tuberculin skin testing could reduce the number of chest X-rays, and identify more candidates for prophylaxis. We modeled the cost-effectiveness of chest radiography and tuberculin skin testing for TB prevention over a 20-yr time frame, among three simulated cohorts of 20-yr-old immigrants. Compared with no screening, radiographic screening prevented 4.3% of expected active TB cases in the highest risk cohort (50% TB-infected, 10% human immunodeficiency virus [HIV] seroprevalence), and 8.0% in the lowest risk cohort (5% TB-infected, 1% HIV seroprevalence). Tuberculin skin testing further reduced the expected incidence 8.0% and 4.0%, respectively. Compared with no screening, radiographic screening cost $3,943 Canadian per active TB case prevented in the highest risk cohort, and $236,496 per case prevented in the lowest risk group. Compared with radiographic screening, mass tuberculin skin testing cost $32,601 per additional case prevented in the highest risk group, and $68,799 per additional case prevented in the lowest risk group. Chest radiographic screening of young immigrants from countries with a high prevalence of TB is a relatively inexpensive means of TB prevention. Tuberculin skin testing is considerably less cost-effective. For immigrants from low-prevalence countries, both interventions are extremely costly with negligible impact. The cost-effectiveness of either strategy would be greatly enhanced by increased adherence to chemoprophylaxis recommendations. Radiographic screening of groups with a high prevalence of tuberculous infection will then likely save money.

Local determinants of response to endobronchial high-dose rate brachytherapy in bronchogenic carcinoma

STUDY OBJECTIVE

We evaluated bronchoscopic tumor appearance and tumor location as determinants of response to high-dose rate brachytherapy (HDR-BT) in patients with symptomatic unresectable bronchogenic carcinoma previously treated with external-beam irradiation.

PATIENTS AND METHODS

Thirty patients with symptomatic endobronchial bronchogenic carcinoma who had previously completed external irradiation were divided into two groups based on whether the initial bronchoscopic appearance showed an endoluminal mass or submucosal infiltration/extrinsic compression. Furthermore, patients were also classified based on tumor location: central (trachea or mainstem bronchi) and peripheral (lobar or segmental bronchi). Patients underwent three treatments of 800 cGy intraluminal irradiation at 2-week intervals, with follow-up evaluation 4 weeks later. We evaluated response in tumor extent based on bronchoscopic and chest radiograph appearance, as well as symptoms with standardized scales.

RESULTS

Fifteen of 24 patients who underwent follow-up bronchoscopy had reductions in the degree of endobronchial obstruction. Seven of 24 patients had radiographic improvement in the extent of atelectasis. Patients with both tumor appearances (endoluminal and submucosal/extrinsic compression) had significant improvements following HDR-BT with regard to hemoptysis. Patients with submucosal disease also had improvement in cough. Patients with peripheral tumors had better rates of response for hemoptysis and cough than did those with central tumors.

CONCLUSION

HDR-BT may result in symptomatic improvement in patients with bronchogenic carcinoma, whether characterized endoscopically as endoluminal projection or submucosal infiltration/extrinsic compression. Peripheral tumors have better rates of response than central tumors, possibly on the basis of less extensive disease.

Tuberculosis infection among health care workers in Montreal

We conducted a cross-sectional survey to estimate the prevalence of tuberculosis infection among health care workers at two downtown Montreal hospitals. Participants completed questionnaires, then underwent two-step tuberculin testing. Records of previous tuberculin tests and BCG vaccinations were reviewed. Charts of all tuberculosis patients admitted in 1992-93 were also reviewed. Air changes and direction of air flow in patient care areas were measured using tracer gas techniques and smoke tubes. Of 619 eligible workers, 522 participated (84%). 196 (38%) were tuberculin reactors; 23 (4%) had documented conversions. Inadequate ventilation and delays in diagnosis were identified at both hospitals. Comparing clinical with nonclinical personnel, the adjusted odds of a significant initial tuberculin reaction were 2.6 (95% confidence interval 1.3, 5.2), of a documented conversion 13.6 (1.4, 132), and of a booster reaction 0.9 (0.2, 3.6). Initial tuberculin reactivity was associated with male gender (p = 0.008), BCG vaccination (p = 0.0001), foreign birth (p = 0.007), age (p < 0.0001), and occupation (p = 0.02); conversion with male gender (p = 0.001) and occupation (p = 0.01); and boosting with older age (p = 0.02) and BCG vaccination (p = 0.001). Among clinical personnel at two hospitals, the prevalence of significant tuberculin reactions and of documented conversions was unexpectedly high.

High dose rate brachytherapy for the local control of endobronchial carcinoma following external irradiation

BACKGROUND

External irradiation is an established palliative treatment for patients with inoperable lung cancer. However, persistent or recurrent symptoms due to local disase are common following external irradiation. The impact of high dose rate (HDR) brachytherapy in the palliative management of patients with local sequelae of residual or recurrent endobronchial lung carcinoma following external irradiation was investigated.

METHODS

A prospective cohort of 29 patients (19 men, mean age 65 years) underwent HDR brachytherapy for inoperable lung cancer. All patients had completed external irradiation at least one month before entry into the study (mean (SD) dose 4400 (1481) cGy, completed 12.9 (21.3) months previously). Patients underwent outpatient bronchoscopic placement of 1-3 HDR brachytherapy catheters for delivery of 750-1000 cGy of intraluminal irradiation every two weeks on 1-3 occasions. Prospective evaluation before and four weeks after completion of HDR brachytherapy included assessment of indices of level of function, symptoms, extent of atelectasis (chest radiography), and bronchoscopic determination of degree of endobronchial obstruction.

RESULTS

One hundred and eighteen catheters were placed in 81 treatments. Eleven of the 26 patients who underwent repeat bronchoscopy showed a reduction in the degree of endobronchial obstruction; five of 18 patients had radiographic improvement in the extent of atelectasis. Positive response rates ranged from 25% for signs and symptoms related to pneumonitis to 69% for haemoptysis. Performance status improved in 24% of patients. Two patients died before completion of the study protocol. Short term complications included one episode of non-fatal, massive haemoptysis, five of minor haemoptysis, and one pneumothorax.

CONCLUSIONS

HDR brachytherapy may improve the degree of endobronchial obstruction, atelectasis, symptoms, and level of function with minimal short term complications in patients with recurrent or residual symptomatic disease following external irradiation.

Measuring ventilation of patient care areas in hospitals. Description of a new protocol

It has been recommended that ventilation of health care facilities should be monitored regularly to reduce the risk of nosocomial transmission of tuberculosis. We developed a simple method to measure air-change rates and direction of airflow in patient care areas. Pure carbon dioxide (CO2) was released at 13.5 L/min for 5 min, then measured for 30 min within the room and outside in the hallway. Smoke tubes were also used to measure direction of airflow. Doors and windows (if openable) were manipulated. This protocol, when conducted in five offices in 30 patients care areas in two hospitals, provided good mixing and reproducible decay curves, with less than 15% coefficient of variation for repeated measures over a wide range of air-change rates. Manipulation of door and/or window produced significant changes in air-change rates and airflow direction, although calculated air-change rates were more variable. Smoke tube measurements were inconsistent, agreed poorly with evidence of CO2 movement from room to hall, and were strongly affected by room to hallway temperature differentials. CO2 release and measurement proved to be a simple, yet reliable, method to measure air-change rates and the effect of door or window manipulation. Smoke tube measurements were not reliable to characterize direction of airflow.

In vino veritas? Alcoholics and liver transplantation

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