Long-term use of valproic acid reduced mortality in bipolar disorder patients in a Taiwanese population: An association analysis using the national health insurance research database (NHIRD)

Abstract

ObjectiveValproic acid (VPA) is used for the treatment of epilepsy and bipolar disorder (BD). The aims of this study was to examine that long-term VPA use affects mortality in BD patients. MethodsAssociation analysis was conducted using the National Health Insurance Research Database (NHIRD) of Taiwan. The long-term VPA use group was selected as patients treated with VPA for BD who used VPA only. The control group consisted of BD patients who were not treated with VPA or lithium. The lithium use group consisted by BD patients used lithium only was also joined the analysis. The cofactors included age (>65 years), sex and the Charlson Comorbidity Index. ResultsThe hazard ratio (HR) of mortality for the VPA group was 0.83 (95% confidence interval (CI), (0.70–0.99); P = 0.04) and the result of lithium group did not reach statistical significance. Furthermore only the duration> 3 years subgroup had a significantly lower incidence of mortality than the control group, with an HR of 0.54 (95% CI, (0.42–0.70); P < 0.001) and 0.58 (95% CI, (0.38, 0.89); P = 0.013 in VPA and lithium groups, respectively. The effect of VPA treatment in terms of reducing the risk of mortality was evidenced only in the male population and the <65 years subgroup (HR: 0.75; 95% CI, (0.59–0.95), and 0.78; 95% CI, (0.64–0.96), respectively). The major limitation of this study was that the causes of death of the expired subjects were not available. ConclusionLong-term VPA use decreases the risk of mortality in BD patients, especially in the male population and those aged <65 years.