Center for Health Evaluation and Outcome science

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Meacock R.,University of Manchester | Sutton M.,University of Manchester | Kristensen So.R.,University of Manchester | Harrison M.,University of British Columbia | Harrison M.,Center for Health Evaluation and Outcome science
Medical Decision Making | Year: 2017

Background. Policy evaluations taking a lifetime horizon have converted estimated changes in short-term mortality to expected life year gains using general population life expectancy. However, the life expectancy of the affected patients may differ from the general population. In trials, survival models are commonly used to extrapolate life year gains. The objective was to demonstrate the feasibility and materiality of using parametric survival models to extrapolate future survival in health care policy evaluations. Methods. We used our previous cost-effectiveness analysis of a pay-for-performance program as a motivating example. We first used the cohort of patients admitted prior to the program to compare 3 methods for estimating remaining life expectancy. We then used a difference-in-differences framework to estimate the life year gains associated with the program using general population life expectancy and survival models. Patient-level data from Hospital Episode Statistics was utilized for patients admitted to hospitals in England for pneumonia between 1 April 2007 and 31 March 2008 and between 1 April 2009 and 31 March 2010, and linked to death records for the period from 1 April 2007 to 31 March 2011. Results. In our cohort of patients, using parametric survival models rather than general population life expectancy figures reduced the estimated mean life years remaining by 30% (9.19 v. 13.15 years, respectively). However, the estimated mean life year gains associated with the program are larger using survival models (0.380 years) compared to using general population life expectancy (0.154 years). Conclusions. Using general population life expectancy to estimate the impact of health care policies can overestimate life expectancy but underestimate the impact of policies on life year gains. Using a longer follow-up period improved the accuracy of estimated survival and program impact considerably. © The Author(s) 2015.

Gill J.S.,University of British Columbia | Gill J.S.,Center for Health Evaluation and Outcome science
Current Opinion in Infectious Diseases | Year: 2016

Purpose of review Despite improvements in posttransplant care, BK virus (BKV) remains one of the most challenging posttransplant infections in kidney transplant recipients with high rates of allograft failure. In the absence of well tolerated and efficacious viral specific therapeutics, treatment is primarily focused on reduction of immunosuppression, which poses a risk of rejection and fails to lead to viral clearance in a number of patients. Recent findings Recent work has turned toward preventive therapies analogous to those used for other infections like cytomegalovirus. These efforts have focused on the use of quinolone antibiotic prophylaxis to prevent BKV infection and pretransplant vaccination to boost humoral and cellular immunity. Summary Despite promising in-vitro and observational data, quinolone antibiotic prophylaxis has not been effective in preventing BKV infection in prospective studies. However, prophylaxis with newer less toxic viral specific agents such as brincidofovir-the lipid oral formulation of cidofovir-may yet prove effective. Strategies focused on eliciting a humoral immune response to recombinant virus-like particles or using adoptive transfer of BKV-specific T cells have also shown significant potential to prevent BKV infection in organ transplant recipients. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Torchalla I.,Center for Health Evaluation and Outcome science
Journal of Smoking Cessation | Year: 2011

This article reviews the literature to compare differential outcomes among men and women after smoking cessation, assess barriers they may face during cessation and provide recommendation to address gender-specific challenges in smoking cessation interventions. There is some evidence that women achieve lower abstinence rates than men after a quit attempt with nicotine replacement therapy, as well as without pharmacotherapy, and several underlying mechanisms were discussed to account for these findings. These include: (a) women have specific genetic variants that affect pharmacokinetics and pharmacodynamics of the medication, (b) hormonal influences increase nicotine metabolism and withdrawal symptoms, (c) women are more responsive to nonpharmacological aspects of smoking than men, (d) women are more vulnerable to depression and negative mood than men, (e) weight concerns are greater barriers for women than for men and (g) women receive less effective social support than men during a quit attempt. Gender-specific counselling that accounts for these factors and addresses the different needs of men and women may be a promising approach to improve long-term abstinence rates. However, more research is required to identify gender-related underlying mechanisms of differential smoking cessation outcomes, develop tailored interventions that account for gender differences and study the implementation and outcomes of gender-responsive treatment approaches. © Australian Academic Press 2011.

Nosyk B.,Center for Excellence in AIDS | Nosyk B.,University of California at Los Angeles | Sun H.,Center for Health Evaluation and Outcome science | Evans E.,University of California at Los Angeles | And 4 more authors.
Addiction | Year: 2012

Aims To identify dose-tapering strategies associated with sustained success following methadone maintenance treatment (MMT). Design Population-based retrospective cohort study. Setting Linked administrative medication dispensation data from British Columbia, Canada. Participants From 25545 completed MMT episodes, 14602 of which initiated a taper, 4183 individuals (accounting for 4917 MMT episodes) from 1996 to 2006 met study inclusion criteria. Measurements The primary outcome was sustained successful taper, defined as a daily dose ≤5mg per day in the final week of the treatment episode and no treatment re-entry, opioid-related hospitalization or mortality within 18 months following episode completion. Findings The overall rate of sustained success was 13% among episodes meeting inclusion criteria (646 of 4917), 4.4% (646 of 14602) among all episodes initiating a taper and 2.5% (646 of 25545) among all completed episodes in the data set. The results of our multivariate logistic regression analyses suggested that longer tapers had substantially higher odds of success [12-52 weeks versus <12 weeks: odds ratio (OR): 3.58; 95% confidence interval (CI): 2.76-4.65; >52 weeks versus <12 weeks: OR: 6.68; 95% CI: 5.13-8.70], regardless of how early in the treatment episode the taper was initiated, and a more gradual, stepped tapering schedule, with dose decreases scheduled in only 25-50% of the weeks of the taper, provided the highest odds of sustained success (versus <25%: OR: 1.61; 95% CI: 1.22-2.14). Conclusions The majority of patients attempting to taper from methadone maintenance treatment will not succeed. Success is enhanced by gradual dose reductions interspersed with periods of stabilization. These results can inform the development of a more refined guideline for future clinical practice. © 2012 Society for the Study of Addiction.

Strehlau V.,University of British Columbia | Torchalla I.,Center for Health Evaluation and Outcome science | Kathy L.,Center for Health Evaluation and Outcome science | Schuetz C.,University of British Columbia | Krausz M.,University of British Columbia
Journal of Psychiatric Practice | Year: 2012

Purpose. This study assessed lifetime and current prevalence rates of mental disorders and concurrent mental and substance use disorders in a sample of homeless women. Current suicide risk and recent health service utilization were also examined in order to understand the complex mental health issues of this population and to inform the development of new treatment strategies that better meet their specific needs. Methods. A cross-sectional survey of 196 adult homeless women in three different Canadian cities was done. Participants were assessed using DSM-IV-based structured clinical interviews. Current diagnoses were compared to available mental health prevalence rates in the Canadian female general population. Results. Current prevalence rates were 63% for any mental disorder, excluding substance use disorders; 17% for depressive episode; 10% for manic episode; 7% for psychotic disorder; 39% for anxiety disorders, 28% for posttraumatic stress disorder; and 19% for obsessive-compulsive disorder; 58% had concurrent substance dependence and mental disorders. Lifetime prevalence rates were notably higher. Current moderate or high suicide risk was found in 22% of the women. Participants used a variety of health services, especially emergency rooms, general practitioners, and walk-in clinics. Conclusion. Prevalence rates of mental disorders among homeless participants were substantially higher than among women from the general Canadian population. The percentage of participants with moderate or high suicide risk and concurrent disorders indicates a high severity of mental health symptomatology. Treatment and housing programs need to be accompanied by multidisciplinary, specialized interventions that account for high rates of complex mental health conditions. Copyright © 2012 Lippincott Williams & Wilkins Inc.

Gwadry-Sridhar F.H.,University of Western Ontario | Gwadry-Sridhar F.H.,Lawson Health Research Institute | Manias E.,University of Melbourne | Lal L.,Ingenix Consulting | And 6 more authors.
Value in Health | Year: 2013

Objectives To systematically review the evidence on the impact of interventions to improve medication adherence in adults prescribed antihypertensive medications. Methods An electronic search was undertaken of articles published between 1979 and 2009, without language restriction, that focused on interventions to improve antihypertensive medication adherence among patients (≥18 years) with essential hypertension. Studies must have measured adherence as an outcome of the intervention. We followed standard guidelines for the conduct and reporting of the review and conducted a narrative synthesis of reported data. Results Ninety-seven articles were identified for inclusion; 35 (35 of 97, 36.1%) examined interventions to directly improve medication adherence, and the majority (58 of 97, 59.8%) were randomized controlled trials. Thirty-four (34 of 97, 35.1%) studies reported a statistically significant improvement in medication adherence. Discussion/Conclusions Interventions aimed at improving patients' knowledge of medications possess the greatest potential clinical value in improving adherence with antihypertensive therapy. However, we identified several limitations of these studies, and advise future researchers to focus on using validated adherence measures, well-designed randomized controlled trials with relevant adherence and clinical outcomes, and guidelines on the appropriate design and analysis of adherence research. © 2013 International Society for Pharmacoeconomics and Outcomes Research (ISPOR).

Torchalla I.,Center for Health Evaluation and Outcome science | Strehlau V.,University of British Columbia | Li K.,Center for Health Evaluation and Outcome science | Krausz M.,Center for Health Evaluation and Outcome science | Krausz M.,University of British Columbia
Drug and Alcohol Dependence | Year: 2011

Objective:: To examine lifetime and current prevalence rates of substance use disorders and the demographic and clinical correlates of current drug dependence in a sample of homeless women. Methods:: A cross-sectional study of 196 homeless women in three Canadian cities was done. Each subject was assessed using structured clinical interviews. A multivariate regression model was applied to determine predictors of substance use. Results:: The mean age of the sample was 35.3 years, 54.4% identified as Aboriginal, 46.4% lived on the street Crack cocaine (58%) was the most common substance used, followed by alcohol (53%), cannabis (41%), and heroin (30%). Overall, 82.4% of the sample had at least one type of current substance use disorder, of which 70.5% had drug dependence and 37.8% had alcohol dependence. 58.3% had concurrent substance use and mental health disorders. 76.7% of those individuals with current alcohol dependence had concurrent drug dependence. Only 24.6% of those who had recovered from alcohol dependence had no current substance use disorder. Multivariate analyses showed that younger age, living on the street, engaging in sex work, and having ever attempted suicide were associated with current drug dependence. Conclusion:: Prevalence rates for alcohol and especially drug dependence were exceptionally high in this sample. Innovative programs need to be developed which are accessible and tailored to meet the needs of this specific population, accounting for high problem severity, polysubstance dependence, and high rates of psychiatric comorbidity. © 2011 Elsevier Ireland Ltd.

Kuyper L.M.,University of British Columbia | Khan N.A.,University of British Columbia | Khan N.A.,Center for Health Evaluation and Outcome science
Canadian Journal of Cardiology | Year: 2014

Background: Previous reviews have shown that β-blocker use for the treatment of hypertension without compelling indications was associated with increased risk of stroke in the elderly. It remains unclear whether this increased risk was driven by the type of β-blocker. We sought to compare the efficacy of atenolol vs nonatenolol β-blockers in clinical trials enrolling young (< 60 years) and older patients with hypertension. Methods: The Cochrane and MEDLINE databases were searched (January 2006-May 2013) for randomized trials evaluating stroke, myocardial infarction, death, or composite cardiovascular end points. Twenty-one hypertension trials with data on 145,811 participants were identified: 15 used atenolol, 7 were placebo-controlled trials, and 14 were active comparator trials. There were no trials of newer generation β-blockers identified. Results: Among the elderly, atenolol was associated with an increased risk of stroke (relative risk [RR], 1.17; 95% confidence interval [CI],1.05-1.30) compared with other antihypertensive agents. The risk of stroke for nonatenolol β-blockers compared with other agents (RR,1.22; 95% CI, 0.99-1.50) did not reach statistical significance in the elderly. In the young, atenolol was associated with reduced risk of stroke compared with other agents (RR, 0.78; 95% CI, 0.64-0.95), whereas nonatenolol β-blockers were associated with a lower risk of composite cardiac events (RR, 0.86; 95% CI, 0.75-0.996) compared with placebo, with no significant difference in events compared with active controls. Conclusions: In the young, both atenolol and nonatenolol β-blockers are effective in reducing cardiovascular end points for hypertension without compelling indications. Atenolol is associated with increased stroke in the elderly but whether this extends to nonatenolol β-blockers remains uncertain. © 2014 Canadian Cardiovascular Society.

Henrich N.,Center for Health Evaluation and Outcome science | Henrich N.,University of British Columbia | Holmes B.,University of British Columbia | Holmes B.,Michael Smith Foundation for Health Research
PLoS ONE | Year: 2011

During the 2009 H1N1 pandemic, a vaccine was made available to all Canadians. Despite efforts to promote vaccination, the public's intent to vaccinate remained low. In order to better understand the public's resistance to getting vaccinated, this study addressed factors that influenced the public's decision making about uptake. To do this, we used a relatively novel source of qualitative data - comments posted on-line in response to news articles on a particular topic. This study analysed 1,796 comments posted in response to 12 articles dealing with H1N1 vaccine on websites of three major Canadian news sources. Articles were selected based on topic and number of comments. A second objective was to assess the extent to which on-line comments can be used as a reliable data source to capture public attitudes during a health crisis. The following seven themes were mentioned in at least 5% of the comments (% indicates the percentage of comments that included the theme): fear of H1N1 (18.8%); responsibility of media (17.8%); government competency (17.7%); government trustworthiness (10.7%); fear of H1N1 vaccine (8.1%); pharmaceutical companies (7.6%); and personal protective measures (5.8%). It is assumed that the more frequently a theme was mentioned, the more that theme influenced decision making about vaccination. These key themes for the public were often not aligned with the issues and information officials perceived, and conveyed, as relevant in the decision making process. The main themes from the comments were consistent with results from surveys and focus groups addressing similar issues, which suggest that on-line comments do provide a reliable source of qualitative data on attitudes and perceptions of issues that emerge in a health crisis. The insights derived from the comments can contribute to improved communication and policy decisions about vaccination in health crises that incorporate the public's views. © 2011 Henrich, Holmes.

Lam M.C.W.,University of British Columbia | Lee T.,Center for Health Evaluation and Outcome science | Atkinson K.,University of British Columbia | Bressler B.,University of British Columbia
World Journal of Gastroenterology | Year: 2014

AIM: To determine if early initiation of anti-tumor necrosis factor therapy affects the need for dose escalation. METHODS: This was a retrospective review of patients receiving infliximab therapy for Crohn's disease (CD) at two outpatient gastroenterology clinics during July 2009 to October 2010. All patients included in the study were biologic agent naïve and had moderate to severe CD (Harvey Bradshaw index > 8). Patients were divided into groups based on length of time between diagnosis to therapy initiation and concurrent immunosuppressant therapy. Kaplan-Meier survival analysis was used to compare the time to dose escalation for the four groups. RESULTS: There were 68 patients, 51% female and 49% male, with an average age at diagnosis of 24.7 ± 11.9 years. The average age at infliximab initiation was 34.8 ± 14.8 years. Of the 68 patients, 19% initiated inflixiamb within 2 years of diagnosis, and 51% had concurrent immunosuppressant therapy at the time of therapy initiation. Fifty percent of patients required dose escalation and the median time from therapy initiation to dose escalation was 10 mo (interquartile range: 5.3-14.8). There was a statistically significant higher probability of requiring dose esclataion in patients who initiated biologic therapy within 2 years of diagnosis, without concurrent immunosuppressant therapy (P < 0.01). CONCLUSION: Those who receive infliximab within 2 years of CD diagnosis require more intense immunosuppressant therapy than those who received infliximab later. © 2014 Baishideng Publishing Group Co., Limited. All rights reserved.

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