Change in employment status in bipolar disorder: A longitudinal study using national claims data

Objective: To assess change in employment status in patients with bipolar disorder in comparison with non-mentally ill controls from 1 year before bipolar incidence to 10 years after. Sociodemographic factors of change in employment status were also examined for patients with bipolar disorder. Method: A cohort of 502 patients with ICD-9-CM bipolar disorder was identified using claims data from the National Health Insurance Research Database of Taiwan between 1998 and 2001 and compared to non-mentally ill controls through December 31, 2008. The primary outcome measure was the time from bipolar incidence to the time of change in employment status, ie, from earning income to not earning income. Results: The probability of changing to a non-income earner was significantly higher (P <.0001) in patients with bipolar disorder than in controls over time, even before the incidence of bipolar disorder (27% vs 14% for patients with bipolar disorder vs controls, respectively). Risks of occupational deterioration in patients with bipolar disorder were greater in the year before incidence and in the following year, with gradually decreasing risks over the subsequent 2 years, and comparable to controls from the third year onward. The adjusted hazard ratio of changing to a non-income earner was 2.06 (95% CI, 1.82-2.33) in patients with bipolar disorder. Male sex, ages 18 to 25 years, lower payroll bracket (<NT$50,001 [US $1,489]), and living in an urban area and insured area in the Northern region were associated with the risk of changing to a non-income earner in patients with bipolar disorder. Conclusions: Patients with bipolar disorder had poorer employment outcomes than the controls, with greater risks of occupational deterioration before and after the bipolar episodes. Employment status should be incorporated as a measure of functioning and of treatment and intervention effectiveness in clinical practices and research.