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Biomedical subjects

Douglas G Manuel

Publications and source records attributed to Douglas G Manuel.

At least 19 recordsLinked to original sources

Toward a unified approach: Considerations for bioinformatic and sequencing activities & data in wastewater surveillance of biologic public health threats.

Genomic technologies such as PCR and next-generation sequencing (NGS) have greatly advanced public health surveillance, especially during COVID-19, by enabling detailed tracking of pathogen spread, origins, and variants. While PCR is vital for targeted detection, falling NGS costs have made large-scale, high-throughput sequencing more feasible, supporting broader pathogen monitoring-including the detection of vaccine escape variants and new strains. Applying NGS to wastewater offers valuable population-level insights but faces challenges such as variable sample complexity, the need for skilled staff, suitable platforms, and robust IT infrastructure. Although there are currently a lot of efforts towards defining guidelines for sampling, analysis, and integrating wastewater data into public health policy, such as the recently published International Cookbook for Wastewater Practitioners, they often lack universal applicability, emphasizing the analytical approaches in favour of the NGS-based approaches. However, standardising protocols for sampling, sequencing, and analysis is crucial to ensure reliable, comparable data across surveillance systems worldwide. Pilot studies and continuous refinement are recommended to overcome implementation hurdles and fully realise the benefits of NGS in wastewater surveillance. This work attempts to outline these challenges and opportunities across the entire wastewater surveillance workflow, from data generation to reporting, and provide some concrete suggestions and considerations across the spectrum of activities. We further highlight that the infrastructure, funding and government-policy context in which surveillance operates acts as an enabling condition for these activities, and that technical standardisation alone is unlikely to deliver durable, comparable surveillance in its absence.

considerations↗

Guillain-Barré syndrome after influenza vaccination in adults: a population-based study.

BACKGROUND: Whether influenza vaccination is associated with Guillain-Barré syndrome (GBS) remains uncertain. METHODS: We conducted 2 studies using population-based health care data from the province of Ontario, Canada. In the first study, we used the self-matched case-series method to explore the temporal association between probable influenza vaccination (adults vaccinated during October and November) and subsequent hospitalization because of GBS. In the second study, we used time-series analysis to determine whether the institution of a universal influenza immunization program in October 2000 was associated with a subsequent increase in hospital admissions because of GBS at the population level. RESULTS: From April 1, 1992, to March 31, 2004, we identified 1601 incident hospital admissions because of GBS in Ontario. In 269 patients, GBS was diagnosed within 43 weeks of vaccination against influenza. The estimated relative incidence of GBS during the primary risk interval (weeks 2 through 7) compared with the control interval (weeks 20 through 43) was 1.45 (95% confidence interval, 1.05-1.99; P = .02). This association persisted in several sensitivity analyses using risk and control intervals of different durations. However, a separate time-series analysis demonstrated no evidence of seasonality and revealed no statistically significant increase in hospital admissions because of GBS after the introduction of the universal influenza immunization program. CONCLUSION: Influenza vaccination is associated with a small but significantly increased risk for hospitalization because of GBS.

Adult↗

Using OHIP physician billing claims to ascertain individual influenza vaccination status.

The objective of this study was to validate physician billing claims against self-reported influenza vaccination to assess individual-level vaccination status. We compared responses to the Canadian Community Health Survey 1.1 (CCHS) and Ontario Health Insurance Plan (OHIP) physician billing claims and found moderate agreement. Using self-report as the gold standard, OHIP claims based on using both influenza-specific and general vaccination codes have high specificity and positive predictive value (PPV), reasonable negative predictive value (NPV), but only fair sensitivity. OHIP physician billing claims are suboptimal for ascertaining the vaccination status of individuals because many individuals receive their vaccinations outside doctor's offices, but may be used as the backbone for the creation of an immunization registry.

Adolescent↗

Appropriate measures of influenza immunization program effectiveness.

Groll and Thomson's evaluation of the effectiveness of Ontario's Universal Influenza Immunization Campaign used per capita cases of laboratory-confirmed influenza. We argue that these data are susceptible to various biases and should not be used as an outcome measure. Laboratory data are traditionally used to identify the presence of influenza activity rather than to identify levels of influenza activity. A better measure of viral activity is the proportion of influenza tests positive; whereas the weekly proportion of tests positive was relatively consistent, a marked increase over time in the numbers of laboratory-confirmed cases paralleled an increase in the number of tests performed. Regardless, for evaluating universal influenza immunization program effectiveness, other established and available measures employed in previous studies describing the epidemiology of influenza should be used instead of laboratory data.

Humans↗

Effectiveness and efficiency of different guidelines on statin treatment for preventing deaths from coronary heart disease: modelling study.

OBJECTIVE: To examine the potential effectiveness and efficiency of different guidelines for statin treatment to reduce deaths from coronary heart disease in the Canadian population. DESIGN: Modelled outcomes of screening and treatment recommendations of six national or international guidelines--from Canada, Australia, New Zealand, the United States, joint British societies, and European societies. SETTING: Canada. DATA SOURCES: Details for 6760 men and women aged 20-74 years from the Canadian Heart Health Survey (weighted sample of 12,300,000 people) that included physical measurements including a lipid profile. MAIN OUTCOME MEASURES: The number of people recommended for treatment with statins, the potential number of deaths from coronary heart disease avoided, and the number needed to treat to avoid one coronary heart disease death with five years of statin treatment if the recommendations from each guideline were fully implemented. RESULTS: When applied to the Canadian population, the Australian and British guidelines were the most effective, potentially avoiding the most deaths over five years (> 15,000 deaths). The New Zealand guideline was the most efficient, potentially avoiding almost as many deaths (14,700) while recommending treatment to the fewest number of people (12.9% of people v 17.3% with the Australian and British guidelines). If their "optional" recommendations are included, the US guidelines recommended treating about twice as many people as the New Zealand guidelines (24.5% of the population, an additional 1.4 million people) with almost no increase in the number of deaths avoided. CONCLUSIONS: By focusing recommendations on people with the highest risk of coronary heart disease, the Canadian, US, and European societies guidelines could improve either their effectiveness (in terms of hundreds of avoided deaths) or efficiency (in terms of thousands of fewer people recommended treatment) in the Canadian population.

Adult↗

The effect of universal influenza immunization on vaccination rates in Ontario.

OBJECTIVES: This article examines the association between introduction of Ontario's Universal Influenza Immunization Program and changes in vaccination rates over time in Ontario, compared with the other provinces combined. DATA SOURCES: The data are from the 1996/97 National Population Health Survey and the 2000/01 and 2003 Canadian Community Health Survey, both conducted by Statistics Canada. ANALYTICAL TECHNIQUES: Cross-tabulations were used to estimate vaccination rates for the total population aged 12 or older, for groups especially vulnerable to the effects of influenza, and by selected socio-demographic variables. Z tests and multiple logistic regression were used to examine differences between estimates. MAIN RESULTS: Between 1996/97 and 2000/01, the increase in the overall vaccination rate in Ontario was 10 percentage points greater than the increase in the other provinces combined. Increases in Ontario were particularly pronounced among people who were: younger than 65, more educated, and had a higher household income. Between 2000/01 and 2003, vaccination rates were stable in Ontario, while rates continued to rise in the other provinces. Even so, Ontario's 2003 rates exceeded those in the other provinces.

Adolescent↗

Improving population attributable fraction methods: examining smoking-attributable mortality for 87 geographic regions in Canada.

Smoking-attributable mortality (SAM) is the number of deaths in a population caused by smoking. In this study, the authors examined and empirically quantified the effects of methodological problems in the estimation of SAM through population attributable fraction methods. In addition to exploring common concerns regarding generalizability and residual confounding in relative risks, the authors considered errors in measuring estimates of risk exposure prevalence and mortality in target populations and estimates of relative risks from etiologic studies. They also considered errors resulting from combining these three sources of data. By modifying SAM estimates calculated using smoking prevalence obtained from the 2000-2001 Canadian Community Health Survey, a population-based survey of 131,535 Canadian households, the authors observed the following effects of potential errors on estimated national SAM (and the range of effects on 87 regional SAMs): 1) using a slightly biased, mismatched definition of former smoking: 5.3% (range, 1.8% to 11.6%); 2) using age-collapsed prevalence and relative risks: 6.9% (range, 1.1% to 15.5%) and -15.4% (range, -7.9% to -21.0%), respectively; 3) using relative risks derived from the same cohort but with a shorter follow-up period: 8.7% (range, 4.5% to 11.8%); 4) using relative risks for all diseases with age-collapsed prevalence: 49.7% (range, 24.1% to 82.2%); and 5) using prevalence estimates unadjusted for exposure-outcome lag: -14.5% (range, -20.8% to 42.6%) to -1.4% (range, -0.8% to -2.7%), depending on the method of adjustment. Applications of the SAM estimation method should consider these sources of potential error.

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Both clinical epidemiology and population health perspectives can define the role of health care in reducing health disparities.

OBJECTIVE: To compare and contrast clinical epidemiology and population health perspectives on the role of health care in reducing socioeconomic disparities in health. STUDY DESIGN AND SETTING: A review of concepts outlined in selected articles on population health and clinical epidemiology and a systematic literature search for randomized controlled trials (RCTs) of therapeutic interventions for cardiovascular disease that contained analysis of outcomes by socioeconomic status. RESULTS: Population health has a focus on health disparities, particularly disparities related to socioeconomic status, and many of its proponents have a pessimistic view of the degree to which health care can reduce these disparities. Clinical epidemiology has a focus on the production of valid evidence on the impact of health care interventions; however, RCTs rarely report the impact of interventions across socioeconomic strata. Both population health and clinical epidemiology share the view that efficacy, effectiveness, and cost-effectiveness are all important in defining the impact of health care on health disparities. CONCLUSION: Principles drawn from both population health and clinical epidemiology could be used to provide a clearer picture of the role that health care interventions can have on socioeconomic disparities in health and to identify implications for policy, research, and clinical practice.

Epidemiologic Methods↗

Potential gaps in congestive heart failure management in a rural hospital.

INTRODUCTION: Congestive heart failure (CHF) is increasingly recognized as an important cause of morbidity and mortality. Previous studies in urban settings have shown that patients frequently are not receiving recommended therapy. There is a paucity of studies that have evaluated CHF management in a rural setting. We therefore reviewed hospital and outpatient care in this setting as an initial step toward improving CHF care. METHOD: A retrospective chart review was used to examine the care of all 34 patients hospitalized for CHF from 2000-2001 in a small rural hospital, to assess the need for improved CHF management. RESULTS: The median age of the patients was 78 yr, and a number of them had many co-morbid cardiovascular risks. Similar to other studies, only 23% of patients were prescribed recommended doses of angiotensin-converting enzyme (ACE) inhibitors. Use of beta-blockers was far below expected rates. Although there was follow-up care for nearly all patients (97%), few patients had echocardiography performed (38%) or had their medications altered in the outpatient setting. CONCLUSION: There is a need for improved management of CHF in the rural setting. Approaches to improving CHF care should use the continuity of care advantage provided by primary care physicians to optimize outpatient medical treatment regimens and improve access to diagnostic services such as echocardiography.

Adult↗

Age, risk-benefit trade-offs, and the projected effects of evidence-based therapies.

BACKGROUND: Physicians underutilize evidence-based therapies in the elderly, perhaps because of concerns about the generalizability of clinical trial results in elderly patients given that the relative efficacy of therapies may vary with age. We compared the estimated effects of age and efficacy of treatment on survival among patients with acute coronary syndromes. METHODS: Baseline risk, defined as mortality in the year after hospitalization for acute coronary syndromes, was determined for different age strata among 81,584 patients who had been discharged between April 1, 1997, and March 31, 2000, in Ontario, Canada. We calculated the relative efficacy (relative risk reduction) needed to achieve a clinically meaningful absolute survival benefit, using a number needed to treat of 50 patients for the different age strata. We also evaluated risk-benefit trade-offs in the elderly versus the young by modeling different levels of the relative efficacy and rates of fatal complication by age. RESULTS: Baseline risk (1-year all-cause mortality) was 12-fold lower in the youngest patients (age <50 years) than in oldest patients (age > or = 75 years). Given this gradient, a therapy would have to have a relative efficacy of 88% (i.e., a relative risk of 0.12) in the youngest age group, and 7% (a relative risk of 0.93) in the oldest age group, to generate a number needed to treat 50 patients. For a therapy whose relative efficacy was 25%, the fatal complication rate would have to be sevenfold greater in the oldest compared with the youngest age group to outweigh the survival benefits associated with treatment. CONCLUSION: For acute coronary syndromes, baseline mortality is so much higher for elderly patients that neither sharp reductions in the relative efficacy of therapies nor increases in the rates of serious complications are likely to negate the benefits of therapy. More attention should be paid to overall trial results and less to age-specific subgroup data, unless the latter provide very clear evidence for substantial reductions in absolute efficacy or net harm.

Aged↗

Using linked data to calculate summary measures of population health: Health-adjusted life expectancy of people with Diabetes Mellitus.

OBJECTIVES: To estimate the health-adjusted life expectancy (HALE) from diabetes mellitus (DM) using a population health survey linked to a population-based DM registry. METHODS: The 1996/97 Ontario Health Survey (N = 35,517) was linked to the Ontario Diabetes Database (N = 487,576). The Health Utilities Index (HUI3) was used to estimate health-related quality of life. HALE was estimated using an adapted Sullivan method. RESULTS: Life expectancy at birth of people with DM was 64.7 and 70.7 years for men and women - 12.8 and 12.2 years less than for men and women without DM. The HUI3 was lower for physician-diagnosed DM compared to self-reported DM (0.799 versus 0.872). HALE at birth was 58.3 and 62.8 years for men and women - 11.9 and 10.7 years less than that of men and women without DM. CONCLUSIONS: The linked data approach demonstrates that DM is an important cause of disease burden. This approach reduces assumptions when estimating the prevalence and severity of disability from DM compared to methods that rely on self-reported disease status or indirect assessment of disability severity.

Journal Article↗

Health-related quality of life and health-adjusted life expectancy of people with diabetes in Ontario, Canada, 1996-1997.

OBJECTIVE: To estimate the burden of illness from diabetes using a population health survey linked to a population-based diabetes registry. RESEARCH DESIGN AND METHODS: Measures of health-related quality of life (HRQOL) from the 1996/97 Ontario Health Survey (n = 35,517) were combined with diabetes prevalence and mortality data from the Ontario Diabetes Database (n = 487,576) to estimate the impact of diabetes on life expectancy, health-adjusted life expectancy (HALE), and HRQOL. RESULTS: Life expectancy of people with diabetes was 64.7 and 70.7 years for men and women, respectively-12.8 and 12.2 years less than that for men and women without diabetes. Diabetes had a large impact on instrumental and basic activities of daily living, more so than on functional health. HALE was 58.3 and 62.7 years, respectively, for men and women-11.9 and 10.7 years less than that of men and women without diabetes. Eliminating diabetes would increase Ontario life expectancy by 2.8 years for men and 2.6 years for women; HALE would increase by 2.7 and 3.2 years for men and women, respectively. CONCLUSIONS: The burden of illness from diabetes in Ontario is considerable. Efforts to reduce diabetes would likely result in a "compression of morbidity." An approach of estimating diabetes burden using linked data sources provides a robust approach for the surveillance of diabetes.

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Burden of cardiovascular disease in Canada.

BACKGROUND: This report updates the death estimates for cardiovascular disease (CVD) in Canada and introduces a population-based perspective on disease prevalence and health-related quality of life (HRQOL) burden. METHODS: The Canadian Mortality Database was used to estimate the mortality of men and women in different age groups for the 139 Canadian health regions from 1950 to 1999. Heart disease prevalence and its impact on HRQOL were estimated using the 2000-2001 Canadian Community Health Survey (CCHS). Life table techniques were used to estimate the impact of heart disease on life and health expectancy. RESULTS: Although CVD remains the leading cause of death in Canada, between 1950 and 1999 the death rates from CVD dropped from 702 per 100,000 to 288 per 100,000 men, and from 562 per 100,000 to 175 per 100,000 women. Results from the CCHS indicated that 5.4% of men and 4.6% of women reported having heart disease as diagnosed by a medical professional. Of these individuals, 14% of men and 21% of women reported difficulty ambulating - about six times more than people without heart disease. In total, 4.5 years of life expectancy and 2.8 years of health expectancy were lost due to CVD. The study also found large differences in the burden of CVD among men and women and across the 139 Canadian health regions. CONCLUSIONS: CVD is a major disease burden in terms of both mortality and HRQOL and is an important source of health inequalities between populations in Canada. Any attempt to improve the health of Canadians or to reduce health inequalities should include interventions to reduce CVD mortality and morbidity. Given the present impact of CVD on HRQOL, reducing or eliminating heart disease may potentially result in an increase in life expectancy that will be larger than the gains in health expectancy.

Activities of Daily Living↗

Risk factors for cardiovascular disease in Canada.

BACKGROUND: This paper provides an update of the prevalence of important cardiovascular disease (CVD) risk factors in subgroups of the Canadian population. To improve awareness of the impact of CVD risk factor variations on disease burden, smoking-attributable mortality (SAM) has been estimated for the first time for each health region in Canada. METHODS: The 2000/01 Canadian Community Health Survey (CCHS) was used to estimate the prevalence of current smoking, obesity, physical inactivity, low income, diabetes and hypertension. Combining smoking prevalence data from the 2000/01 CCHS, mortality data from the 1995 to 1997 Canadian Mortality Database, and relative risk estimates (relating smoking and smoking-associated deaths) from the American Cancer Society's Cancer Prevention Study II, SAM values were generated using population-attributable risk techniques. RESULTS: Based on self-reported data, the 2000/01 CCHS shows that 26.0% of Canadians currently smoke, 14.9% are obese, 53.5% are physically inactive, 11.3% have low income, 13.0% have hypertension and 4.2% have diabetes. Cardiovascular and all-cause SAM were estimated at 18,209 and 44,271 annual deaths, and contributed to 23% and 22% of total CVD and all-cause mortality in Canada, respectively. There are large variations in the prevalence of CVD risk factors and in SAM estimates between sexes and across age groups and geographic regions. CONCLUSIONS: The high prevalence of potentially modifiable CVD risk factors and the large variation that exists between subgroups of the Canadian population suggest that the burden of CVD could be reduced through risk factor modification. While prevalence data for risk factors in a population give an initial understanding of some of the contributing causes of a disease, the actual burden of disease caused by a risk factor is also modified by the magnitude of the increased risk to mortality and morbidity, and is best represented by its estimated attributable mortality and morbidity.

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Cause-deleted health-adjusted life expectancy of Canadians with selected chronic conditions.

Health-adjusted life expectancy (HALE) is life expectancy weighted or adjusted for the level of health-related quality of life (HRQOL). Cause-deleted probabilities of dying were derived using the cause-eliminated life table technique and death data from vital statistics for Canada in 1998/99. Life expectancy for men and women in Canada was 76.0 and 81.5 years respectively; HALE was 67.9 years for men and 71.1 years for women. Cancer represented the greatest burden of disease in the population, and eliminating it would increase men's life expectancy to 79.6 years and women's to 85.1 years. HALE would rise to 70.7 years for men and 73.6 for women. The gain in life expectancy would be very small if osteoarthritis were eliminated, but there would be an overall gain in HALE of approximately 1.0 years for men and 2.5 years for women. HALE estimated for chronic conditions using a utility-based measure of HRQOL from population health surveys should be regarded as a valuable component of population health surveillance.

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