Arrhythmias and conduction disturbance
Meta-Analysis of Cohort and Case–Control Studies of Type 2 Diabetes Mellitus and Risk of Atrial Fibrillation

https://doi.org/10.1016/j.amjcard.2011.03.004Get rights and content

Atrial fibrillation (AF) is 1 of the most clinically diagnosed cardiac disturbances but little is known about its risk factors. Previous epidemiologic studies have reported on the association between diabetes mellitus (DM) and subsequent risk of AF, with inconsistent results. The aim of this study was to conduct a meta-analysis of published studies to reliably determine the direction and magnitude of any association between DM and AF. A systematic review and meta-analysis was conducted. PubMed and EMBASE were searched to identify prospective cohort and case–control studies that had reported on the association between DM and other measurements of glucose homeostasis with incident AF by April 2010. Studies conducted in primarily high-risk populations and participants in randomized controlled trials were excluded. Seven prospective cohort studies and 4 case–control studies with information on 108,703 cases of AF in 1,686,097 subjects contributed to this analysis. The summary estimate indicated that patients with DM had an approximate 40% greater risk of AF compared to unaffected patients (relative risk [RR] 1.39, 95% confidence interval [CI] 1.10 to 1.75, p for heterogeneity <0.001). After correcting for publication bias, the RR was 1.34 (1.07 to 1.68). Studies that had adjusted for multiple risk factors reported a smaller effect estimate compared to age-adjusted studies (RR 1.24, 95% CI 1.06 to 1.44, vs 1.70, 1.29 to 2.22, p for heterogeneity = 0.053). The population-attributable fraction of AF owing to DM was 2.5% (95% CI 0.1 to 3.9). In conclusion, DM is associated with an increased risk of subsequent AF but the mechanisms that may underpin the relation between DM and AF remain speculative.

Section snippets

Methods

We performed a systematic review of the available literature according to Meta-Analysis Of Observational Studies in Epidemiology (MOOSE) guidelines for the conduct of meta-analyses of observational studies.6 Relevant studies were identified by computerized searches from the following data sources: MEDLINE via Ovid (from 1950 through April 2010) and EMBASE (from 1966 through May 2010) using relevant text words and medical subject headings that included all spellings of “type 2 diabetes” or

Results

Six prospective cohort studies relating DM to subsequent risk of AF involving 5,436 incident cases of AF in 801,837 patients were identified.1, 11, 12, 13, 14, 15 An additional cohort including 265 incident cases of AF in 28,449 patients reported on the association between impaired glucose tolerance and risk of AF16 (Table 1). Three of the 7 cohort studies provided gender-specific estimates adjusted at least for age of the association between DM and AF; thus, 10 separate estimates of the

Discussion

In this meta-analysis involving information on 108,703 cases of AF in 1,686,097 patients from 7 prospective cohort and 4 case–control studies, DM was associated with an overall 34% increase in risk of AF after correcting for presence of publication bias. Summary estimates for the cohort and case–control studies were broadly similar, although lack of a significant difference among study designs may have been caused by the meta-regression analysis being underpowered.

However, the overall summary

Acknowledgment

The authors are grateful to Aaron Folsom and Faye Lopez for their critical revision of this report. Dr. Huxley had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

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