Mohammed Ansari

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Evidence-based practice requires translating research findings into clinical and policy decision making. Clinical practice guidelines (CPGs) serve this purpose by evaluating evidence and making recommendations about therapeutic and diagnostic interventions and clinical management strategies. Systematic reviews are considered the best available evidence and(More)
BACKGROUND Systematic reviews are often advocated as the best source of evidence to guide clinical decisions and health care policy, yet we know little about the extent to which they require updating. OBJECTIVE To estimate the average time to changes in evidence that are sufficiently important to warrant updating systematic reviews. DESIGN Survival(More)
Comparative Effectiveness Reviews are systematic reviews of existing research on the effectiveness, comparative effectiveness, and harms of different health care interventions. They provide syntheses of relevant evidence to inform real-world health care decisions for patients, providers, and policymakers. Strong methodologic approaches to systematic review(More)
OBJECTIVES To assess inter-rater reliability and validity of the Newcastle Ottawa Scale (NOS) used for methodological quality assessment of cohort studies included in systematic reviews. STUDY DESIGN AND SETTING Two reviewers independently applied the NOS to 131 cohort studies included in eight meta-analyses. Inter-rater reliability was calculated using(More)
Jonathan AC Sterne,1 Miguel A Hernán,2 Barnaby C Reeves,3 Jelena Savović,1,4 Nancy D Berkman,5 Meera Viswanathan,6 David Henry,7 Douglas G Altman,8 Mohammed T Ansari,9 Isabelle Boutron,10 James R Carpenter,11 An-Wen Chan,12 Rachel Churchill,13 Jonathan J Deeks,14 Asbjørn Hróbjartsson,15 Jamie Kirkham,16 Peter Jüni,17 Yoon K Loke,18 Theresa D Pigott,19 Craig(More)
BACKGROUND Erectile dysfunction (ED) is a common male sexual disorder. The relative benefits and harms of pharmacologic therapies for ED, as well as the value of hormonal testing in men with ED, are uncertain. PURPOSE To evaluate the efficacy and harms of oral phosphodiesterase-5 (PDE-5) inhibitors and hormonal treatments for ED and assess the effect of(More)
OBJECTIVE To develop two checklists for the quality of observational studies of incidence or risk factors of diseases. STUDY DESIGN AND SETTING Initial development of the checklists was based on a systematic literature review. The checklists were refined after pilot trials of validity and reliability were conducted by seven experts, who tested the(More)
BACKGROUND The evidence for testing thiopurine S-methyltransferase (TPMT) enzymatic activity or genotype before starting therapy with thiopurine-based drugs is unclear. PURPOSE To examine the sensitivity and specificity of TPMT genotyping for TPMT enzymatic activity, reducing harm from thiopurine by pretesting, and the association of thiopurine toxicity(More)
OBJECTIVES To assess the reliability of the Cochrane Risk of Bias (ROB) tool between individual raters and across consensus agreements of pairs of reviewers and examine the impact of study-level factors on reliability. STUDY DESIGN AND SETTING Two reviewers assessed risk of bias for 154 randomized controlled trials (RCTs). For 30 RCTs, two reviewers from(More)
BACKGROUND Many of the 500,000 North American patients with chronic mitral regurgitation may be poor candidates for mitral valve surgery. OBJECTIVE The objective of this study was to investigate the comparative effectiveness, harms, and cost-effectiveness of percutaneous mitral valve repair using mitral valve clips in candidates at prohibitive risk for(More)