We carried out all estimates per Rao's method using Microsoft Excel (2007) and verified them using SAS Version 9.2 (SAS Institute, Cary, NC). We used the Comprehensive Meta-Analysis software version 2 (Biostat, Englewood, NJ) [18], which incorporates assumptions appropriate for synthesizing results from observational studies and clinical trials, to verify results and assess comparable patterns in the data. The estimates from these methods yielded identical results (data not shown).
