Patients with bipolar disorder have high levels of cardiovascular disease risk factors. The presence of metabolic syndrome significantly influences future cardiovascular disease morbidity and mortality. The authors sought to clarify the prevalence and moderators of metabolic syndrome in bipolar patients, accounting for subgroup differences.
The authors searched MEDLINE, PsycINFO, EMBASE, and CINAHL through April 2012 for research reporting metabolic syndrome prevalence rates in bipolar patients. Medical subject headings “metabolic syndrome” and “bipolar” were used in the title, abstract, or index term fields. Manual searches were conducted using the reference lists from identified articles.
The search yielded 81 articles in 37 publications (N=6,983). The overall metabolic syndrome rate was 37.3% (95% confidence interval [CI]=36.1–39.0) using any standardized metabolic syndrome criteria. Compared with general population groups, bipolar patients had higher metabolic syndrome rates (odds ratio=1.98; 95% CI=1.74–2.25). In bipolar patients, older age had a modest effect on the metabolic syndrome rate. The strongest moderator was the region in which the study took place, with the highest rates observed in New Zealand and Australia (64.2% [95% CI=38.3–83.9]) and North America (49.3% [95% CI=29.7–69.3]). Metabolic syndrome was significantly more prevalent in patients currently treated with antipsychotics (45.3% [95% CI=39.6–50.9] than in patients who were antipsychotic free (32.4% [95% CI=27.5–37.4]; odds ratio=1.72 [95% CI=1.24–2.38]).
These findings strongly support the claim that patients with bipolar disorder are at high risk for metabolic syndrome and related cardiovascular morbidity and mortality and require regular monitoring and adequate preventive efforts and treatment for cardio-metabolic risk factors. These findings further suggest that the risk of metabolic syndrome is greater in bipolar patients taking prescribed antipsychotic medication.