Online Program

Improved statistical methods for meta-analysis of rare events

Monday, November 4, 2013 : 2:50 p.m. - 3:10 p.m.

Yan Ma, PhD, Hospital for Special Surgery---Weill Medical College of Cornell University, New York, NY
Haitao Chu, MD, PhD, Division of Biostatistics, University of Minnesota, Minneapolis, MN
Madhu Mazumdar, PhD, Weill Medical College of Cornell Univeristy, New York, NY
Meta-analysis (M-A) of proportions, such as the incidence of clinical events among a cohort of patients or the response rate among patients receiving a certain treatment regimen, provides systematically synthesized evidence for medical and public health decisions. Our research is motivated by a recently published M-A, which evaluated the proportion of patients with preventable adverse drug reactions (PADRs). Data for the M-A were extracted from 16 studies conducted in 11 countries. Among 48797 emergency visits or hospitalizations, only 3% were identified to have PADRs. The conventional random effects model for M-A of proportions assumes within-study variation to be normally distributed. Due to failure in our ability to check this assumption, the estimation of rare events such as PADRs is expected to be biased under the conventional method and the exact methods based on binomial distributions is recommended for use. We compare the operating characteristics of two existing exact approaches---normal binomial (N-B) and beta-binomial (B-B) models ---through an extensive simulation study. In addition, we incorporate the empirical ("sandwich") estimator of variance into both models to improve the robustness of the statistical inference. The simulation study shows that B-B tends to have significantly smaller bias and mean squared error than N-B for truly rare events (<=5%) , while N-B outperforms B-B for relatively common events (> 5% but <=25%). Use of the sandwich estimator of variance improves the precision of estimation for both models. We illustrate the two approaches by applying them to our motivating example.

Learning Areas:

Biostatistics, economics
Conduct evaluation related to programs, research, and other areas of practice
Public health or related public policy

Learning Objectives:
Compare the operating characteristics of two existing exact likelihood approaches for meta-analysis of proportions. Evaluate the performance of sandwich variance estimator in the context of meta-analysis.

Keyword(s): Statistics, Drug Safety

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have been the principal investigator on the proposed study.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.