The nine-earliest studies included in this UNC2881 review were published between 1999 and 2004, with the ten remaining studies published from 2005 to 2009. However, no secular trends were observed for any of the validation statistics. Eleven of the studies included in this review were rated as high quality and seven as medium quality. Sensitivity ranged from 43% to 87% amongst the high quality studies, and from 58% to 87% amongst the medium quality. The PPV��s for these two categories were also similar, ranging from 36% to 99% amongst the high-quality studies, and from 34% to 100% amongst the medium quality. Any geographic comparisons were limited by the fact that 15 of the 19 studies were conducted in North America. The only difference observed was that the sensitivity values tended to be higher amongst the seven US studies than the five Canadian ones. Chart reviews, sometimes in conjunction with unspecified diagnostic criteria, formed the basis of the gold standard in nine studies, and patient self-report was used in one. Cardiac disease registries were used in two studies, while a specific set of diagnostic criteria were incorporated in the reference standards of the seven remaining studies. To our knowledge this is the first systematic review and meta analysis on the validity of HF diagnoses in administrative data. Findings from this review suggest that the sensitivity of these codes is suboptimal, as sensitivity was #69% in 8 of the 14 studies reporting this statistic. However, the specificity and PPV of these codes appears much better: specificity was at least 95% in the 13 studies where this statistic was reported, and, in the majority of studies, the PPV was at least 87%. Further support was provided by the results of the meta-analysis, as the pooled specificity of HF codes was 97%, and the pooled LR+ was 52. This means an Berbamine individual coded for HF is fifty-two-times more likely to actually have HF than someone not coded. However, the pooled sensitivity was modest, at just 75%, and the summary LR- value of 0.27 suggests that the absence of an HF code can rule out the diagnosis of HF only moderately. The PPV��s and NPV��s amongst the studies included in this review were generally good, being at least 87% in the majority of studies reporting these statistics.