Tuberculosis in the Circumpolar Region, 2006-2012.

SETTING: The northern circumpolar jurisdictions Canada (Northwest Territories, Nunavik, Nunavut, Yukon), Finland, Greenland, Norway, Russian Federation (Arkhangelsk), Sweden and the United States (Alaska). OBJECTIVE: To describe and compare demographic, clinical and laboratory characteristics, including drug resistance and treatment completion, of tuberculosis (TB) cases in the northern circumpolar populations. DESIGN: Descriptive analysis of all active TB cases reported from 2006 to 2012 for incidence rate (IR), age and sex distribution, sputum smear and diagnostic site characteristics, drug resistance and treatment completion rates. RESULTS: The annual IR of TB disease ranged from a low of 4.3 per 100 000 population in Northern Sweden to a high of 199.5/100 000 in Nunavik, QC, Canada. For all jurisdictions, IR was higher for males than for females. Yukon had the highest proportion of new cases compared with retreatment cases (96.6%). Alaska reported the highest percentage of laboratory-confirmed cases (87.4%). Smear-positive pulmonary cases ranged from 25.8% to 65.2%. Multidrug-resistant cases ranged from 0% (Northern Canada) to 46.3% (Arkhangelsk). Treatment outcome data, available up to 2011, demonstrated >80% treatment completion for four of the 10 jurisdictions. CONCLUSION: TB remains a serious public health issue in the circumpolar regions. Surveillance data contribute toward a better understanding and improved control of TB in the north.

Advancing surveillance of antimicrobial resistance: Summary of the 2015 CIDSC Report.

BACKGROUND: Antimicrobials are essential for the treatment and control of infectious diseases and therefore, the development and spread of antimicrobial resistance (AMR) is a global health concern. It is recognized that robust AMR surveillance is necessary; however, current gaps in national surveillance programs need to be addressed to enable better evidence-informed program and policy decisions. OBJECTIVE: To describe how an AMR Surveillance Task Group prioritized national AMR surveillance data requirements for high priority AMR organisms for human health in Canada and made recommendations on addressing the current data gaps. METHODS: The 2015 AMR Surveillance Task Group examined the data requirements for previously identified first priority organisms and assessed whether the current system met, partially met or did not meet these requirements. Information was summarized into synopsis tables and a ranking process was used to prioritize the data requirements and develop specific recommendations to address the gaps. RESULTS: First priority organisms identified for AMR surveillance are: Clostridium difficile, Extended-spectrum ß-lactamase-producing organisms, Carbapenem-resistant organisms (Acinetobacter + Enterobacteriaceae species), Enterococcus species, Neisseria gonorrhoeae, Streptococcus pyogenes and S. pneumonaea, Salmonella species, Staphylococcus aureus, Mycobacterium tuberculosis and Campylobacter species. For these organisms, there were 19 high priority data requirements identified: 10 of these requirements were met by the current surveillance systems, seven were partially met and two were unmet. For the two high priority data metrics in the community setting, the Task Group recommended conducting a point-prevalence community-based study (i.e., every five years) to follow infection rates of C. difficile infection, and community level antibiogram data on an annual basis for susceptibility data for Enterobacteriaceae species (E. coli and Klebsiella) causing genito-urinary infections. There were eight medium priority data requirements identified: one requirement was met by the current surveillance system, five were partially met and two were unmet. The medium priority unmet data requirements included susceptibility of infection isolates for C. difficile (diarrheal disease) and infection rates for Enterobacteriaceae species causing genito-urinary tract infections in community settings. It was noted that the feasibility of obtaining this medium priority in data in the community setting was low. The Task Group identified bloodstream infections as the top priority site of infection for AMR surveillance in the health care setting given the high morbidity and mortality associated with bloodstream infections. The importance of collecting susceptibility data on N. gonorrhoeae in the community was underscored given the rise in resistance and that the current surveillance system only partially collects this data. The Task Group recommended that a review of the national AMR surveillance data requirement priorities should occur on an ongoing basis and when new issues emerge. CONCLUSION: While current national surveillance programs either capture or partially capture many of the identified data requirements for first priority organisms, several gaps still remain, especially in community settings. A national review of the recommendations of the Task Group is underway.

Antimicrobial resistance surveillance in Canadian hospitals, 2007-2012.

BACKGROUND: The Canadian Nosocomial Infection Surveillance Program (CNISP) is a collaborative effort of the Public Health Agency of Canada's Centre for Communicable Diseases and Infection Control, the National Microbiology Laboratory, and 54 largely university-affiliated tertiary care sentinel hospitals in 10 provinces across Canada. OBJECTIVE: To provide a summary of antibiotic resistance rates of four key antibiotic resistant organisms in major hospitals across Canada from January 1, 2007, to December 31, 2012. METHODS: Patients' clinical and demographic data and associated results of laboratory analyses were submitted to the Agency by participating hospitals. The infection rates were summarized per 1,000 patient admissions at national and regional levels. RESULTS: In Canada, the overall health care-associated Clostridium difficile infection (HA-CDI), HA-CDI rates peaked in 2008 at 5.8 HA-CDI infections per 1,000 patient admissions then remained stable between 2009 and 2012 at approximately 5 HA-CDI infections per 1,000 admissions; the West and Central regions had higher rates than the Eastern region. The rates of methicillin-resistant Staphylococcus aureus (MRSA) peaked in 2009 at 9.5 MRSA infections per 1,000 patient admissions then decreased to 8.8 MRSA infections per 1,000 admissions in 2012, with the Central region having higher rates than the Western and Eastern regions. The rates of vancomycin-resistant Enterococci (VRE), have been low but rising with 0.08 VRE infections per 1,000 patient admissions in 2007, gradually rising to 0.5 VRE infections per 1,000 admissions in 2012, with consistently higher rates in the Western region, slightly lower rates in the Central region and the lowest rates in the Eastern region. The rates of carbapenem-resistant Enterobacteriaceae (CRE) have been measured since 2010 and have been low and stable, with 0.11 CRE infections per 1,000 patient admissions in 2010 and 0.14 CRE infections per 1,000 admissions in 2012, with higher rates in the Western and Central regions and lower rates in the Eastern region. CONCLUSION: In Canada, of the four antibiotic resistant organisms under surveillance, HA-CDI and MRSA have been gradually decreasing, VRE is low but rising, and CRE remains low with Western and Central rates consistently higher than Eastern rates.

Characterizing viral subtypes to assess patterns of HIV transmission.

We characterized HIV-1 subtypes among 204 persons newly diagnosed with HIV in Ontario from 2003 to 2005 using samples from the Canadian HIV Strain and Drug Resistance Surveillance Program. We examined HIV-1 subtype by demographic characteristics and exposure category, and determined independent predictors of infection with a non-B HIV subtype using multivariate logistic regression. The distribution of HIV subtypes was: B 77.0%, C 10.3%, AG 4.9%, A 2.5%, AE 2.5% and others 3.0%. Overall, 23.0% were non-B, greater in women than in men (62.8% versus 12.4%, P < 0.0001) and persons under 35 years (31.1% versus 18.5% in those ≥35, P = 0.04). Non-B subtype was predominant (78.9%) among persons from HIV-endemic regions and considerable (28.6%) among other persons infected heterosexually. In multivariate modelling adjusted for gender, non-B subtype was significantly associated with birth in an HIV-endemic region (adjusted odds ratio [aOR] 59.2, P < 0.0001) and heterosexual exposure (aOR 6.3, P = 0.02). Additionally, compared with men who had sex with men, non-B subtype was greater among heterosexual women (aOR 17.8, P < 0.001) and women who injected drugs (injection drug use, aOR 13.4, P = 0.01). We found a non-negligible proportion of non-B subtypes among women infected heterosexually not from HIV-endemic countries, providing interesting insights into HIV transmission patterns.

Update on World Health Organization HIV drug resistance prevention and assessment strategy: 2004-2011.

The HIV drug resistance (HIVDR) prevention and assessment strategy, developed by the World Health Organization (WHO) in partnership with HIVResNet, includes monitoring of HIVDR early warning indicators, surveys to assess acquired and transmitted HIVDR, and development of an accredited HIVDR genotyping laboratory network to support survey implementation in resource-limited settings. As of June 2011, 52 countries had implemented at least 1 element of the strategy, and 27 laboratories had been accredited. As access to antiretrovirals expands under the WHO/Joint United Nations Programme on HIV/AIDS Treatment 2.0 initiative, it is essential to strengthen HIVDR surveillance efforts in the face of increasing concern about HIVDR emergence and transmission.

Estimating the size of hard-to-reach populations: a novel method using HIV testing data compared to other methods.

OBJECTIVE: To estimate population size of hard-to-reach groups such as injecting drug users and men who have sex with men. DESIGN: Several different methods were used to estimate the size of these populations in Canada's three largest cities (Toronto, Montreal and Vancouver). METHODS: A novel method (referred to as the indirect method) was developed for use in Toronto and Vancouver that combines HIV serodiagnostic information with data on HIV testing behavior. Population size estimates were obtained by dividing the number of injecting drug users or men who have sex with men recorded in HIV serodiagnostic databases in a given year by the proportion of the corresponding group that reported being tested in a 1-year period. Results of this method were compared with four other methods: (1) population surveys; (2) capture-recapture (for injecting drug users only); (3) a modified Delphi technique; and (4) a method based on the proportion of never-married men aged 45 and over (for men who have sex with men only). Only these other methods were used in Montreal. RESULTS: The survey method gave the lowest estimates which are best viewed as minimum estimates given the relative inability of surveys to access these populations and the reluctance of participants to admit to sensitive behaviors. The indirect method produced results more closely comparable with those obtained by other methods, but they are probably slight overestimates, at least for injecting drug users, due to possible underestimation of the proportion tested for HIV. Point estimates using the indirect method were 17,700 and 17,500 for injecting drug users in Toronto and Vancouver, respectively, and 39,100 and 15,900 for men who have sex with men. In Toronto, results for the other methods ranged from 12,300-13,360 for injecting drug users and 18,800-35,000 for men who have sex with men. For Vancouver, these ranges were 6400-11,670 and 7000-26,500, respectively. In Montreal, ranges were 4300-12,500 for injecting drug users and 18,500-40,000 for men who have sex with men. CONCLUSIONS: This novel method provides estimates of population size of hard-to-reach groups such as injecting drug users and men who have sex with men that are comparable with results derived by other methods. These estimates may be useful for the purposes of planning, implementing and evaluating prevention and care services, especially when they are combined with the results of other estimation methods to improve the degree of confidence in the resulting estimates.

A qualitative investigation into an HIV outbreak among injection drug users in Vancouver, British Columbia.

The proportion of injection drug users (IDUs) testing positive for Human Immunodeficiency Virus (HIV) in British Columbia has increased from 3 to 7% since January 1993 (Patrick et al., 1997). We conducted a qualitative study as a first step in a case control investigation aimed at identifying risk factors associated with HIV seroconversion. Sixteen subjects participated in in-depth interviews which were transcribed and analysed using grounded theory methods. Three dominant themes emerged: Addiction, Prevention, and Social Determinants. The results suggest that prevention efforts such as the availability of clean needles and condoms are not adequate to combat the complex social determinants of addiction--be they causal or consequential--which in turn contribute to unsafe injection practices.

Factors associated with HIV testing among Canadians: results of a population-based survey.

The purpose of this study was to examine the HIV-testing behaviour of Canadians aged 15 years and older. Questions on HIV testing were asked as part of a Canada-wide random digit dialling telephone survey conducted in December 1995 to January 1996 on health practices and attitudes toward health care in Canada (n=3123). Including blood donation and insurance testing, 40.4% of men and 30.4% of women had been tested for HIV. Excluding blood donation and life-insurance testing (voluntary testing), 17.8% of men and 15.6% of women had been tested. In multivariate analyses, factors independently associated with voluntary testing among men were: having had sex with a man (OR=16.8), injection drug use (OR=5.8), having had a partner at high risk (OR=2.5), having received blood or clotting factor (OR=2.3), being younger than 45 years of age (OR=1.8), living in a city of over one million (OR=1.7), and making less than $30,000 a year (OR=1.6). For women, factors independently associated with voluntary testing were having received blood or clotting factor (OR=3.9), having had a high-risk partner (OR= 3.5), being younger than 45 years of age (OR=2.4), having had sex with a man (OR=2.3), and being unattached (OR=2.0). Results indicated that those at risk are more likely to be tested. It is of concern, however, that many of those reporting risk factors have not been tested. A better understanding of HIV testing behaviour is needed to improve the planning and evaluation of prevention and counselling services.

Factors associated with frequent needle exchange program attendance in injection drug users in Vancouver, Canada.

The objective of this study was to identify factors associated with frequent needle exchange program (NEP) attendance by injection drug users (IDUs) in Vancouver, Canada. Data were examined from a case control study of recent HIV infection. IDUs with documented HIV seroconversion after January 1, 1994 (n = 89) and seronegative controls with two documented HIV-negative test results in the same period (n = 192) were asked about demographic and social information, drug injection and sexual behavior, and NEP attendance. Logistic regression was used to examine the effect of multiple variables on NEP attendance while adjusting for HIV status and other potential confounders. Frequent (> 1 time/week) versus nonfrequent (< or = 1 time/week) NEP attenders did not differ with respect to gender, age, ethnicity, education, or HIV serostatus. For men, multivariate analysis showed that frequent cocaine injection was the only variable independently associated with NEP attendance (adjusted odds ratio [AOR] = 3.9; 95% confidence interval [CI] = 1.8-8.3); for women, independently associated variables were frequency of any drug injection (AOR = 5.5; 95% CI = 1.7-17), shooting gallery attendance (AOR = 11.5; 95% CI = 2.2-66), and having a nonlegal source of income (AOR = 3.4; 95% CI = 1.0-12). Borrowing used needles was associated with frequent NEP attendance in the univariate analysis. The NEP in Vancouver attracts IDUs who are frequent injectors (especially men using cocaine) and who have high-risk behaviors or an unstable lifestyle. This finding reinforces the role of NEPs as potential focal points for intervention in this hard-to-reach population.

Determinants of HIV seroconversion in injection drug users during a period of rising prevalence in Vancouver.

To identify determinants of HIV seroconversion among injection drug users (IDUs) during a period of rising prevalence, a case-control investigation was conducted. Cases were IDUs with a new positive test after 1 January 1994, and a negative test within the prior 18 months. Controls required 2 negative tests during the same period. Subjects completed a questionnaire on demographic, psychosocial, and behavioural factors. Eighty-nine cases and 192 controls were similar with respect to gender, age, ethnicity and inter-test interval. Multivariate analyses of events during the inter-test interval showed borrowing syringes (adj. OR = 2.96; P < 0.006), unstable housing (adj. OR = 2.01; P = 0.03) and injecting > or = 4 times daily (adj. OR = 1.71; P = 0.06) to be independently associated with seroconversion. Protective associations were demonstrated for sex with opposite gender (adj. OR = 0.36; P = 0.001) and tetrahydrocannabinol use (adj. OR = 0.41; P = 0.001). There is a need to evaluate programmes dealing with addiction, housing and the social underpinnings of risk behaviours in this population.

Social determinants predict needle-sharing behaviour among injection drug users in Vancouver, Canada.

Despite the fact that needle exchange was introduced in Vancouver as early as 1988, needle sharing remains common. An analysis was conducted to identify determinants of borrowing used needles among subjects participating in a case-control study. IDUs had a documented HIV seroconversion after 1 January, 1994 (n = 89), or repeatedly tested HIV-seronegative after this date (n = 192). Interviewer-administered questionnaires focused on drug use, sexual behaviours, source of needles and depression. Subjects were asked if they had "ever been forced to have sex" as a child, youth or adult. Logistic regression identified determinants of borrowing needles. After controlling for HIV serostatus, factors independently associated with borrowing were injecting > 4 times/day, polydrug use, and ever experiencing non-consensual sex (AOR = 3.4, 95% CI: 1.8, 6.5). Depression was associated with borrowing, although not independently so. Homosexual activity was independently associated with borrowing among males, whereas living with a sexual partner was an independent predictor for females. Access or barriers to clean needle use were not associated with borrowing. Social determinants, particularly a history of sexual abuse, are among the most significant predictors of needle borrowing among Vancouver's IDUs. Early identification of these factors should be a component of HIV prevention programmes.

Smoking-associated mortality in a cohort of Singaporeans observed for 20 years.

Smoking is well established as a main cause of preventable mortality throughout the world, but little data are available on Asian populations and none on Singapore. This study is the first to provide data specific to Singapore on the increased mortality among smokers, and is one of the few such studies on Asians. In 1974, smoking history data were taken from a random sample of 3579 adults living in Singapore. Of these, 3361 (1522 men and 1839 women) were eligible for follow-up and vital status was determined as at 31 December 1993. Cox regression analysis was used to estimate the relative risks of variety of causes of death for smokers compared to non-smokers, adjusted for age and ethnicity. Smoking was categorized as ever or never and also as none, light or heavy. As at 31 December 1993, 330 (21.7%) of the men and 249 (13.5%) of the women had died. Relative risk values were clearly elevated for male and female smokers for all-cause mortality (1.42 and 1.52, respectively), lung cancer (13.2, 6.37) and death due to chronic obstructive pulmonary disease (COPD) (4.71, 8.50). Relative risk values for death from cancer of the larynx or oesophagus, ischaemic heart disease and cerebrovascular disease were elevated but not significantly different from 1.0. A trend of increasing risk with increasing smoking intensity was seen for all-cause mortality among men and for lung cancer and COPD mortality, among both sexes. Ethnicity was associated with ischaemic heart disease mortality among men, with elevated risks in both the Indians (2.55) and the Malays (1.66) relative to the Chinese. These results should serve to strengthen the anti-smoking campaigns in Singapore.

Sample size estimation for clinicians.

The purpose of this paper is to describe the importance of an adequate sample size in clinical research and to enable clinicians to estimate their own sample size requirements for the more common types of studies (comparison of two means or two proportions). Four pieces of information are required to determine sample size: the desired level of statistical power, the level of statistical significance, the variability of the data, and the smallest difference between the study groups that is considered to be of clinical significance. Worked examples from the literature are used to illustrate how clinicians may easily do their own sample size calculations using published tables or available computer software, or both. The consideration of sample size and power during the planning stages of clinical research is crucial to the subsequent interpretation of study results, especially if the study is negative, and yet this point is often neglected in the medical literature. Attention to these simple guidelines will help ensure that research results lead to valid conclusions.

Evaluation of a safe-sex intervention programme among sex workers in Singapore.

The purpose of this study was to evaluate the effects of a brief intervention programme on STD knowledge, condom use and gonorrhoea incidence among sex workers in Singapore. A controlled before-and-after study design with non-random assignment of sex workers was used, supplemented by multivariate analysis to adjust for baseline differences. Control (n = 221, denoted C1) and experimental (n = 221, denoted E1) groups were interviewed on 2 occasions 3 months apart. Two supplementary groups were interviewed once each at the end of the 3-month period (n = 145 who had received the intervention and n = 151 who had not). Basic knowledge of STD symptoms and HIV transmission was high in all groups. There were misconceptions about casual transmission of HIV which improved dramatically at the second interview for group E1 (from 37-56% correct responses to 82-90%). Overall condom use was high (about 75%) and did not change after the intervention. Gonorrhoea rates were correspondingly low (0.4 episodes/worker/year) and also did not change. This brief intervention improved the STD knowledge of sex workers. However, behaviour as measured by reported condom use and gonorrhoea incidence did not change. Implications for future intervention programmes are discussed.