Sustainability and impact of an intervention to improve initiation of tuberculosis preventive treatment: results from a follow-up study of the ACT4 randomized trial.

Background: In a cluster randomized trial (clinicaltrials.gov: NCT02810678) a flexible but comprehensive health system intervention significantly increased the number of household contacts (HHC) identified and started on tuberculosis preventive treatment (TPT). A follow-up study was conducted one year later to test the hypotheses that these effects were sustained, and were reproducible with a simplified intervention. Methods: We conducted a follow-up study from May 1, 2018 until April 30, 2019, as part of a multinational cluster randomized trial. Eight sites in 4 countries that had received the intervention in the original trial received no further intervention; eight other sites in the same countries that had not received the intervention (control sites in the original trial) now received a simplified version of the intervention. This consisted of repeated local evaluation of the Cascade of care for TB infection, and stakeholder decision making. The number of HHC identified and starting TPT were repeatedly measured at all 16 sites and expressed as rates per 100 newly diagnosed index TB patients. The sustained effect of the original intervention was estimated by comparing these rates after the intervention in the original trial with the last 6 months of the follow-up study. The reproducibility was estimated by comparing the pre-post intervention changes in rates at sites receiving the original intervention with the pre-post changes in rates at sites receiving the later, simplified intervention. Findings: With regard to the sustained impact of the original intervention, compared to the original post-intervention period, the number of HHC identified and treated per 100 newly diagnosed TB patients was 10 more (95% confidence interval: 84 fewer to 105 more), and 1 fewer (95% CI: 22 fewer to 20 more) respectively up to 14 months after the end of the original intervention. With regard to the reproducibility of the simplified intervention, at sites that had initially served as control sites, the number of HHC identified and treated per 100 TB patients increased by 33 (95% CI: -32, 97), and 16 (-69, 100) from 3 months before, to up to 6 months after receiving a streamlined intervention, although differences were larger, and significant if the post-intervention results were compared to all pre-intervention periods. Interpretation: Up to one year after it ended, a health system intervention resulted in sustained increases in the number of HHC identified and starting TPT. A simplified version of the intervention was associated with non-significant increases in the identification and treatment of HHC. Inferences are limited by potential bias due to other temporal effects, and the small number of study sites. Funding: Funded by the Canadian Institutes of Health Research (Grant number 143350).

High-dose, short-duration versus standard rifampicin for tuberculosis preventive treatment: a partially blinded, three-arm, non-inferiority, randomised, controlled trial.

BACKGROUND: Tuberculosis preventive treatment (TPT) is a key component of tuberculosis elimination. To improve completion and reduce the burden for people and health systems, short, safe, and effective TPT regimens are needed. We aimed to compare safety and treatment completion of various doses and durations of rifampicin in people who were recommended to receive TPT. METHODS: This partially blinded, parallel-arm, non-inferiority, randomised, controlled, phase 2b trial was done at seven university-affiliated clinics in Canada, Indonesia, and Viet Nam. Participants aged 10 years or older were included if they had an indication for TPT according to WHO guidelines for Indonesia and Viet Nam, or Canadian guidelines for Canadian sites, and a positive tuberculin skin test or interferon-γ release assay. Participants were randomly assigned (1:1:1) to receive oral rifampicin at 10 mg/kg once daily for 4 months (standard-dose group), 20 mg/kg daily for 2 months (20 mg/kg group), or 30 mg/kg daily for 2 months (30 mg/kg group). The randomisation sequence was computer generated with blocks of variable size (three, six, and nine) and stratified by country for Indonesia and Viet Nam, and by city within Canada. Participants and investigators were masked to dose in high-dose groups, but unmasked to duration in all groups. The two co-primary outcomes were safety (in the safety population, in which participants received at least one dose of the study drug) and treatment completion (in the modified intention-to-treat [mITT] population, excluding those ineligible after randomisation). Protocol-defined adverse events were defined as grade 3 or worse, or rash or allergy of any grade, judged by an independent and masked panel as possibly or probably related to the study. A margin of 4% was used to assess non-inferiority. This study is registered with ClinicalTrials.gov, NCT03988933 (active). RESULTS: Between Sept 1, 2019, and Sept 30, 2022, 1692 people were assessed for eligibility, 1376 were randomly assigned, and eight were excluded after randomisation. 1368 participants were included in the mITT population (454 in the standard group, 461 in the 20 mg/kg group, and 453 in the 30 mg/kg group). 589 (43%) participants were male and 779 (57%) were female. 372 (82%) in the standard-dose group, 329 (71%) in the 20 mg/kg group, and 293 (65%) in the 30 mg/kg group completed treatment. No participants in the standard-dose group, one (<1%) of 441 participants in the 20 mg/kg group, and four (1%) of 423 in the 30 mg/kg group developed grade 3 hepatotoxicity. Risk of protocol-defined adverse events was higher in the 30 mg/kg group than in the standard-dose group (adjusted risk difference 4·6% [95% CI 1·8 to 7·4]) or the 20 mg/kg group (5·1% [2·3 to 7·8]). There was no difference in the risk of adverse events between the 20 mg/kg and standard-dose groups (-0·5% [95% CI -2·4 to 1·5]; non-inferiority met). Completion was lower in the 20 mg/kg group (-7·8% [95% CI -13·6 to -2·0]) and the 30 mg/kg group (-15·4% [-21·4 to -9·4]) than in the standard-dose group. INTERPRETATION: In this trial, 2 months of 30 mg/kg daily rifampicin had significantly worse safety and completion than 4 months of 10 mg/kg daily and 2 months of 20 mg/kg daily (the latter, a fully blinded comparison); we do not consider 30 mg/kg to be a good option for TPT. Rifampicin at 20 mg/kg daily for 2 months was as safe as standard treatment, but with lower completion. This difference remains unexplained. FUNDING: Canadian Institutes of Health Research.

The association between phylogenetic lineage and the subclinical phenotype of pulmonary tuberculosis: A retrospective 2-cohort study.

BACKGROUND: Subclinical pulmonary tuberculosis (PTB) is an asymptomatic disease state between established TB infection and symptomatic (clinical) TB disease. It is present in 20-25% of PTB patients in high-income countries. Mycobacterium tuberculosis complex (MTBC) genetic heterogeneity, and differential host immunological responses, have been implicated in its pathogenesis. METHODS: To determine the association between MTBC lineage and PTB disease phenotype, we used two retrospective cohorts of PTB patients in Canada and two independent lineage attribution methods (DNA fingerprinting and genome sequencing). The first cohort, Cohort 1, consisted of consecutively diagnosed PTB patients between 2014 and 2020. The second, Cohort 2, consisted of newly-arrived foreign-born PTB patients who either were or were not referred for post-landing medical surveillance between 2004 and 2017. Univariable and multivariable logistic regression models were sequentially fitted to both cohorts, adjusting for age, sex, disease type, drug resistance and HIV. Evolution of radiographic features was correlated to lineage in Cohort 2. FINDINGS: Cohort 1 and 2 included 874 (209 subclinical) and 111 (44 subclinical) patients, respectively. In both cohorts, subclinical patients were more likely than clinical patients to have relapse/retreatment disease, be smear-negative, have longer times-to-culture positivity and to harbor an ancestral MTBC lineage (Indo-Oceanic or Mycobacterium africanum). Relapse/retreatment disease and ancestral MTBC lineage were independent predictors of subclinical disease (ORs and 95% CIs in Cohort 1, 1.85 [1.07,3.28], p < 0.029 and 2.30 [1.66,3.18], p < 0.001, respectively, and Cohort 2, 5.74 [1.37-24.06], p < 0.017 and 3.21 (1.29,7.97], p < 0.012, respectively). The geographic distribution of Indo-Oceanic strains causing subclinical disease was uneven. Non-progressive lung disease was more common in patients infected with ancestral than modern lineages in Cohort 2, 56.0% vs 25.4%, p < 0.005. INTERPRETATION: MTBC lineage is a strong predictor of PTB disease phenotype. The genetic drivers of this association, and the relative contribution of other explanatory variables, are unknown.

The state of tuberculosis surveillance in Canada.

Tuberculosis incidence in Canada has remained essentially unchanged over the past decade. A strategic plan to reduce the burden of disease, underpinned by high-quality surveillance data, is sorely needed. However, tuberculosis surveillance data are lacking in Canada for multiple reasons. There is no single entity responsible for coordinating a tuberculosis response, including strategies for surveillance, thus inhibiting effective solutions. This in turn affects the timeliness and comprehensiveness of national tuberculosis surveillance reporting: between 2000 and 2020, there was an average 25-month delay to publication of annual surveillance data and the comprehensiveness of reports has precipitously fallen over time. Compounding these issues are case report forms for tuberculosis surveillance data which have not been updated since 2011, failing to keep up with the changing tuberculosis epidemiology and to provide information required for strategic planning. Common-sense steps can be taken to vastly improve the utility of collected tuberculosis surveillance data, and the development of a strategic plan for tuberculosis elimination. These include initiating a country-wide consultation on surveillance needs; allocating resources for data collection and analysis and data sharing; setting precise, measurable goals; and, importantly, establishing an oversight committee with representation from all provincial/territorial tuberculosis program leads who are held to account for performance.

RéSUMé: L'incidence de la tuberculose au Canada est demeurée essentiellement inchangée au cours de la dernière décennie. Un plan stratégique visant à réduire le fardeau de la maladie, étayé par des données de surveillance de haute qualité, est grandement nécessaire. Cependant, les données de surveillance de la tuberculose font défaut au Canada pour de multiples raisons. Il n'existe pas d'entité unique chargée de coordonner la réponse à la tuberculose, y compris les stratégies de surveillance, ce qui empêche de trouver des solutions efficaces. Cette situation a une incidence sur la rapidité et l'exhaustivité des rapports nationaux de surveillance de la tuberculose : entre 2000 et 2020, la publication des données annuelles de surveillance a été retardée de 25 mois en moyenne, et l'exhaustivité des rapports a chuté de façon vertigineuse au fil du temps. Ces problèmes sont aggravés par le fait que les formulaires de déclaration des cas pour les données de surveillance de la tuberculose n'ont pas été mis à jour depuis 2011, ce qui entrave leur capacité à suivre l'évolution de l'épidémiologie de la tuberculose et à fournir les informations nécessaires à la planification stratégique. Des mesures de bon sens peuvent être prises pour améliorer considérablement l'utilité des données de surveillance de la tuberculose collectées et le développement d'un plan stratégique pour l'élimination de la tuberculose. Il s'agit notamment de lancer une consultation à l'échelle du pays sur les besoins en matière de surveillance, d'allouer des ressources pour la collecte et l'analyse des données et leur partage, de fixer des objectifs précis et mesurables et, surtout, d'établir un comité de surveillance composé de représentants de tous les responsables provinciaux/territoriaux du programme de lutte contre la tuberculose qui sont tenus de rendre compte des performances.

The prevalence, risk factors, and public health consequences of peripheral lymph node-associated clinical and subclinical pulmonary tuberculosis.

OBJECTIVES: Relatively little is known about the prevalence, risk factors, and public health consequences of peripheral lymph node (PLN)-associated pulmonary tuberculosis (PTB). METHODS: We developed a 10-year (2010-2019) population-based cohort of PLNTB patients in Canada. We used systematically collected primary source data and expert reader chest radiograph interpretations in a multivariable logistic regression to determine associations between sputum culture positivity and demographic, clinical, and radiographic features. Public health risks were estimated among contacts of PLNTB patients. RESULTS: There were 306 patients with PLNTB, among whom 283 (92.5%) were 15-64 years of age, 159 (52.0%) were female, and 293 (95.8%) were foreign-born. Respiratory symptoms were present in 21.6%, and abnormal chest radiograph in 23.2%. Sputum culture positivity ranged from 12.9% in patients with no symptoms and normal lung parenchyma to 66.7% in patients with both. Respiratory symptoms, abnormal lung parenchyma, and HIV-coinfection (borderline) were independent predictors of sputum culture positivity (odds ratio [OR] 2.24 [95% confidence interval [CI] 1.15-4.39], P = 0.01, OR 4.78 [95% CI 2.41-9.48], P < 0.001, and OR 2.54 [95% CI 0.99-6.52], P = 0.05), respectively. Among contacts of sputum culture-positive PLNTB patients, one secondary case and 16 new infections were identified. CONCLUSION: Isochronous PTB is common in PLNTB patients. Routine screening of PLNTB patients for PTB is strongly recommended.

A comparison of the chest radiographic and computed tomographic features of subclinical pulmonary tuberculosis.

Subclinical pulmonary tuberculosis (PTB) is a recently described intermediate state of great interest, but about which little is known. This study sought to describe and compare the frequency of key radiologic features of subclinical PTB on chest radiograph (CXR) versus computed tomographic scan (CT), and to interpret the clinical and public health relevance of the differences. Diagnostic CXRs and CT scans of the thorax and neck in a 16-year cohort of subclinical PTB patients in Canada were re-acquired and read by two independent readers and arbitrated by a third reader. Logistic regression models were fit to determine how likely CXR features can be detected by CT scan versus CXR after adjustment for age and sex. Among 296 subclinical patients, CXRs were available in 286 (96.6%) and CT scans in 94 (32.9%). CXR features in patients with and without CT scans were comparable. Lung cavitation was 4.77 times (95% CI 1.95-11.66), endobronchial spread 19.36 times (95% CI 8.05-46.52), and moderate/far-advanced parenchymal disease 3.23 times (95% CI 1.66-6.30), more common on CT scan than CXR. We conclude that the extent to which CXRs under-detect key radiologic features in subclinical PTB is substantial. This may have public health and treatment implications.

The Radiographic and Mycobacteriologic Correlates of Subclinical Pulmonary TB in Canada: A Retrospective Cohort Study.

BACKGROUND: Very little is known about subclinical pulmonary TB (PTB), a recently described intermediate state, in high-income countries. RESEARCH QUESTION: What is the prevalence of subclinical PTB in Canada? What are its diagnostic chest radiography features? What is the relationship between those features and time to culture positivity, and what is the association between DNA fingerprint clustering, a measure of local transmission, and radiographic or other features in the foreign-born? STUDY DESIGN AND METHODS: We used primary source data to identify a 16-year retrospective cohort of patients with PTB. Demographic and mycobacteriologic features in patients with subclinical and clinical disease were compared, and the reason for assessment of patients with subclinical disease was described. Diagnostic chest radiographs in patients with subclinical disease were read by two independent readers and were arbitrated by a third reader. Linear regression was used to compute time to culture positivity (in days) in relationship to the change in chest radiograph findings from normal or minimally abnormal to moderately or far advanced, adjusted for age and sex and stratified by reason for assessment. Multivariate logistic regression was used in foreign-born patients with subclinical disease to determine associations between DNA fingerprint clustering of Mycobacterium TB isolates and age, sex, chest radiograph features, and time since arrival. RESULTS: We identified 1,656 patients with PTB, 347 of whom (21%) were subclinical. Compared with patients with clinical disease, patients with subclinical disease were more likely to be foreign-born (90.2% vs 79.6%) and to demonstrate negative smear results (88.2% vs 43.5%). The median time to culture-positivity was 18 days (interquartile range [IQR], 14-25 days) vs 12 days (IQR, 7-17 days). Most patients with PTB (75.2%) were identified during active case finding. Parenchymal disease was absent or minimal on chest radiography in 86.4% of patients. More advanced disease on chest radiography was associated with shorter times to culture positivity in nonstratified (by 3.3 days) and stratified (by 4.5-5.8 days) analysis (active case-finding groups). DNA fingerprint clustering was associated with male sex and a longer time between arrival and diagnosis. INTERPRETATION: Subclinical patients with PTB constitute a substantial and heterogeneous minority of patients with PTB in high-income countries. DNA fingerprint clustering is consistent with some, albeit limited, local transmission.

How much do smear-negative patients really contribute to tuberculosis transmissions? Re-examining an old question with new tools.

BACKGROUND: Sputum smear microscopy is a common surrogate for tuberculosis infectiousness. Previous estimates that smear-negative patients contribute 13-20% of transmissions and are, on average, 20 to 25% as infectious as smear-positive cases are understood to be high. Herein, we use an ideal real-world setting, a comprehensive dataset, and new high-resolution techniques to more accurately estimate the true transmission risk of smear-negative cases. METHODS: We treated all adult culture-positive pulmonary TB patients diagnosed in the province of Alberta, Canada from 2003 to 2016 as potential transmitters. The primary data sources were the Alberta TB Registry and the Provincial Laboratory for Public Health. We measured, as primary outcomes, the proportion of transmissions attributable to smear-negative sources and the relative transmission rate. First, we replicated previous studies by using molecular (DNA) fingerprint clustering. Then, using a prospectively collected registry of TB contacts, we defined transmission events as active TB amongst identified contacts who either had a 100% DNA fingerprint match to the source case or a clinical diagnosis. We supplemented our analysis with genome sequencing on temporally and geographically linked DNA fingerprint clusters of cases not identified as contacts. FINDINGS: There were 1176 cases, 563 smear-negative and 613 smear-positive, and 23,131 contacts. Replicating previous studies, the proportion of transmissions attributable to smear-negative source cases was 16% (95% CI, 12-19%) and the relative transmission rate was 0.19 (95% CI, 0.14-0.26). With our combined approach, the proportion of transmission was 8% (95% CI, 3-14%) and the relative transmission rate became 0.10 (95% CI, 0.05-0.19). INTERPRETATION: When we examined the same outcomes as in previous studies but refined transmission ascertainment with the addition of conventional epidemiology and genomics, we found that smear-negative cases were ∼50% less infectious than previously thought. FUNDING: Alberta Innovates Health Solutions.

Individual and public health consequences associated with a missed diagnosis of pulmonary tuberculosis in the emergency department: A retrospective cohort study.

OBJECTIVES: To determine: i) the emergency department (ED) utilization history of pulmonary tuberculosis (PTB) patients, and ii) the potential individual and public health consequences of a missed diagnosis of PTB in this setting. DESIGN: Retrospective observational cohort study. PARTICIPANTS: Patients with PTB aged >16 years diagnosed between April 1, 2010 and December 31, 2016 in the Province of Alberta, Canada. METHODS: We identified valid new cases of PTB from a provincial registry and linked them to ED attendees in administrative databases. Visits are considered 'PTB', pulmonary 'other', and non-pulmonary based on the most responsible discharge diagnosis. Individual consequences of a missed diagnosis included health system delay and PTB-related death; public health consequences included nosocomial ED exposure time and secondary cases. RESULTS: Of 711 PTB patients, 378 (53%) made 845 ED visits in the six months immediately preceding the date of diagnosis. The most responsible ED discharge diagnosis was PTB in 92 (10.9%), pulmonary 'other' in 273 (32%) and non-pulmonary in 480 (56.8%). ED attendees had a median (IQR) health system delay of 27 (7,180) days and, compared to non-ED attendees were more likely to die a TB-related death 5.9% vs 1.2%, p = 0.001. Emergency attendees generated 3812 hours of ED nosocomial exposure time, and 31 secondary cases (60.8% of all secondary cases reported). Mycobacterium tuberculosis isolates from ED-attendees were more likely than non-attendees to be clustered-i.e., have an identical DNA fingerprint with another isolate (27% vs. 21%, p = 0.037). CONCLUSIONS: ED utilization by PTB patients, and related consequences, are substantial. EDs are a potential resource for earlier PTB diagnosis.

Local Transmission Plays No Important Role in the Occurrence of Multidrug-Resistant Tuberculosis in Immigrants to Canada: An In-depth Epidemiologic Analysis.

BACKGROUND: Multidrug-resistant (MDR) tuberculosis has increased among migrants in Canada. The cause(s) of this increase is unknown. METHODS: We performed a retrospective cohort study in a Canadian province with substantially increased immigration between 1982-2001 and 2002-2019. The proportion of MDR tuberculosis among migrants arriving from high MDR (HMDR) tuberculosis burden countries during these 2 periods was used to estimate the proportion of cases due to immigration versus change in proportion in the country of birth. Epidemiologic, spatiotemporal, and drug resistance pattern data were used to confirm local transmission. RESULTS: Fifty-two of 3514 (1.48%) foreign-born culture-positive tuberculosis patients had MDR tuberculosis: 8 (0.6%) in 1982-2001 and 44 (2.0%) in 2002-2019. Between time periods, the proportion of MDR tuberculosis among migrants with tuberculosis from HMDR tuberculosis countries increased from 1.11% to 3.62%, P = .003; 31.6% attributable to recent immigration and 68.4% to a higher proportion of MDR tuberculosis in cases arrived from HMDR tuberculosis countries. No cases of MDR tuberculosis were attributable to local transmission. CONCLUSIONS: In stark contrast to HMDR tuberculosis countries, local transmission plays no important role in the occurrence of MDR tuberculosis in Canada. Improved tuberculosis programming in HMDR tuberculosis countries is urgently needed.

Prompt recognition of infectious pulmonary tuberculosis is critical to achieving elimination goals: a retrospective cohort study.

INTRODUCTION: All pulmonary tuberculosis (PTB) cases are presumed to be infectious to some degree. This spectrum of infectiousness is independently described by both the acid-fast bacilli smear and radiographic findings. Smear-positive patients with chest radiographic findings that are typical for adult-type PTB are believed to be most infectious. HYPOTHESIS: Characterisation of the presumed most infectious PTB case is possible by reference to readily available clinical features and laboratory results. METHODS: Retrospective cohort study of adult, culture-positive PTB cases (151 smear-positive; 162 smear-negative) diagnosed between 1 January 2013 and 30 April 2017 in Canada. We describe cases according to demographic, clinical and laboratory features. We use multivariable multinomial logistic regression to estimate the relative risk ratio (RRR) with 95% CI of features associated with an outcome of smear-positive PTB, characterised by 'typical' chest radiograph findings. RESULTS: Being Canadian-born, symptomatic, having a subacute duration of symptoms and broad-spectrum antibiotic prescriptions were all more commonly associated with smear-positive than smear-negative disease (36% vs 20%; 95% vs 63%; 88% vs 54%; and 59% vs 28%, respectively). After combining smear status and radiographic features, we show that smear-positive patients with typical chest radiographs were younger, had a longer duration of symptoms (RRR 2.41; 95% CI 1.01 to 5.74 and 2.93; 95% CI 1.20 to 7.11, respectively) and were less likely to be foreign-born, or have a moderate to high-risk factor for reactivation (RRR 0.40; 95% CI 0.17 to 0.92 and 0.18; 95% CI 0.04 to 0.71, respectively) compared with smear-negative patients with atypical chest radiograph findings. CONCLUSION: A clear picture of the presumed most infectious PTB case emerges from available historical and laboratory information; vigilance for this presentation by front-line providers will support elimination strategies aimed at reducing transmission.

Is there a fundamental flaw in Canada's post-arrival immigrant surveillance system for tuberculosis?

BACKGROUND: New immigrants to Canada with a history of tuberculosis or evidence of old healed tuberculosis on chest radiograph are referred to public health authorities for medical surveillance. This ostensible public health protection measure identifies a subgroup of patients (referrals) who are at very low risk (compared to non-referrals) of transmission. METHODS: To assess whether earlier diagnosis or a different phenotypic expression of disease explains this difference, we systematically reconstructed the immigration and transmission histories from a well-defined cohort of recently-arrived referral and non-referral pulmonary tuberculosis cases in Canada. Incident case chest radiographs in all cases and sequential past radiographs in referrals were re-read by three experts. Change in disease severity from pre-immigration radiograph to incident radiograph was the primary, and transmission of tuberculosis, the secondary, outcome. RESULTS: There were 174 cohort cases; 61 (35.1%) referrals and 113 (64.9%) non-referrals. Compared to non-referrals, referrals were less likely to be symptomatic (26% vs. 80%), smear-positive (15% vs. 50%), or to have cavitation (0% vs. 35%) or extensive disease (15% vs. 59%) on chest radiograph. After adjustment for referral status, time between films, country-of-birth, age and co-morbidities, referrals were less likely to have substantial changes on chest radiograph; OR 0.058 (95% CI 0.018-0.199). All secondary cases and 82% of tuberculin skin test conversions occurred in contacts of non-referrals. CONCLUSIONS: Phenotypically different disease, and not earlier diagnosis, explains the difference in transmission risk between referrals and non-referrals. Screening, and treating high-risk non-referrals for latent tuberculosis is necessary to eliminate tuberculosis in Canada.

Tuberculosis transmission in the Indigenous peoples of the Canadian prairies.

SETTING: The prairie provinces of Canada. OBJECTIVE: To characterize tuberculosis (TB) transmission among the Indigenous and non-Indigenous Canadian-born peoples of the prairie provinces of Canada. DESIGN: A prospective epidemiologic study of consecutively diagnosed adult (age ≥ 14 years) Canadian-born culture-positive pulmonary TB cases on the prairies, hereafter termed "potential transmitters," and the transmission events generated by them. "Transmission events" included new positive tuberculin skin tests (TSTs), TST conversions, and secondary cases among contacts. RESULTS: In the years 2007 and 2008, 222 potential transmitters were diagnosed on the prairies. Of these, the vast majority (198; 89.2%) were Indigenous peoples who resided in either an Indigenous community (135; 68.2%) or a major metropolitan area (44; 22.2%). Over the 4.5-year period between July 1st, 2006 and December 31st 2010, 1085 transmission events occurred in connection with these potential transmitters. Most of these transmission events were attributable to potential transmitters who identified as Indigenous (94.5%). With a few notable exceptions most transmitters and their infected contacts resided in the same community type. In multivariate models positive smear status and a higher number of close contacts were associated with increased transmission; adjusted odds ratios (ORs) and 95% confidence intervals (CIs), 4.30 [1.88, 9.84] and 2.88 [1.31, 6.34], respectively. Among infected contacts, being Indigenous was associated with disease progression; OR and 95% CI, 3.59 [1.27, 10.14] and 6.89 [2.04, 23.25] depending upon Indigenous group, while being an infected casual contact was less likely than being a close contact to be associated with disease progression, 0.66 [0.44, 1.00]. CONCLUSION: In the prairie provinces of Canada and among Canadian-born persons, Indigenous peoples account for the vast majority of cases with the potential to transmit as well as the vast majority of infected contacts. Active case finding and preventative therapy measures need to focus on high-incidence Indigenous communities.

Patient Perception of Speech Outcomes: The Relationship Between Clinical Measures and Self-Perception of Speech Function Following Surgical Treatment for Oral Cancer.

PURPOSE: Treatment for oral cancer can result in speech impairments that can have varying impacts on patient quality of life. This study explored the relationship between clinical measures of speech impairment and the perception that patients had of this change in the early stage of recovery. METHOD: This was a quasi-experimental 1-group pre-post study design carried out on 10 patients with surgical intervention for oral cancer. Two clinical measures (word intelligibility and consonant phoneme error) and 2 patient-perception measures (Speech Handicap Index total score and Speech Handicap Index patient criteria score) were collected at preoperative and 1-month postoperative appointments. RESULTS: Qualitative analysis revealed discordance between clinical and patient-perceived measures in 4 of 10 patients. Change in consonant phoneme error and change in word intelligibility were significantly correlated (r = .827). Furthermore, on average, statistically significant relationships were not found between clinical and patient-perceived measures or between the 2 patient-perception measures. CONCLUSIONS: Discordance between clinical and patient-perceived measures was observed in almost half of the sample, indicating that clinical tests did not fully explain the extent of impairment perceived by patients. Speech outcomes should focus on both types of measures, and patient perception outcomes should be carefully considered when recommending speech therapy.