Population study of disease burden, management, and treatment of bipolar disorder in Sweden: a retrospective observational registry study

Abstract

Objectives: The aim of the study was to describe temporal changes in bipolar disorder during 20 years within the Swedish population and to investigate clinical and socioeconomic characteristics, drug treatment, and mortality among patients with bipolar disorder.

Methods: We conducted a retrospective, nationwide registry study (the Swedish Population Register) that included all patients diagnosed with bipolar disorder (1991-2010) and linked individual data from the Swedish National Patient Register, the National Prescribed Drug Register, and the Population Register (NCT01455961). A cross-sectional cohort analysis was performed for years 2006 versus 2009. Data were analyzed using descriptive statistics.

Results: During the study period, the annual incidence of diagnosed bipolar disorder increased 3.5-fold, and patients were diagnosed at a younger age. Mortality among patients with bipolar disorder was twice that of the general population. Compared to an age-standardized population, 30% fewer patients with bipolar disorder were available for work. Among the 40% employed, 64% reported sick leave (46% >100 days/year). Despite similar education levels, disposable income was lower compared to the general population. The most commonly preceding psychiatric diagnoses were depressive or anxiety disorders. Comparing the data for 2006 and 2009 demonstrated similar somatic comorbidity burdens and socioeconomic levels. There was also a decrease in dispensed antipsychotic medications and lithium, while antiepileptic prescriptions increased slightly. Antidepressant dispenses remained virtually unchanged.

Conclusions: In Sweden, the incidence and prevalence of diagnosed bipolar disorder have increased during the last 20 years. Compared to the general population, these patients had similar education levels, lower employment levels, less disposable income, more sick leave, and twice the mortality. A trend towards earlier diagnosis, more use of antidepressants, and less use of lithium was seen.

Keywords: bipolar disorder; incidence; mortality; prevalence; socioeconomic factors.