Mood stabilizers and risk of all-cause, natural, and suicide mortality in bipolar disorder: A nationwide cohort study

Objectives

People with bipolar disorder have an elevated risk of mortality. This study evaluated associations between the use of mood stabilizers and the risks of all-cause mortality, suicide, and natural mortality in a national cohort of people with bipolar disorder.

Methods

In this nationwide cohort study, we used data from January 1, 2000, to December 31, 2016, collected from Taiwan's National Health Insurance Research Database and included 25,787 patients with bipolar disorder. Of these patients, 4000 died during the study period (including 760 and 2947 from suicide and natural causes, respectively). Each standardized mortality ratio (SMR) was calculated as the ratio of observed mortality in the bipolar cohort to the number of expected deaths in the general population. Multivariable Cox proportional hazards regression with a time-dependent model was performed to estimate the hazard ratio (HR) of each mood stabilizer with each mortality outcome.

Results

The SMRs of all-cause mortality, suicide, and natural mortality in the bipolar disorder cohort were 5.26, 26.02, and 4.68, respectively. The use of mood stabilizers was significantly associated with decreased risks of all-cause mortality (adjusted HR [aHR] = 0.58, p< 0.001), suicide (aHR = 0.60, p < 0.001), and natural mortality (aHR = 0.55, p < 0.001) within a 5-year follow-up period after index admission. Among the individual mood stabilizers, lithium was associated with the lowest risks of all-cause mortality (aHR = 0.38, p < 0.001), suicide (aHR = 0.39, p < 0.001), and natural mortality (aHR = 0.37, p < 0.001).

Conclusion

In addition to having protective effects against suicide and all-cause mortality, mood stabilizers also exert a substantial protective effect against natural mortality, with lithium associated with the lowest risk of mortality.