Sex differences in mortality among patients admitted with affective disorders in North Norway: A 33-year prospective register study
Methods: Based on a hospital case register covering all admissions to psychiatric hospital in the two northernmost counties in Norway from 1980 to 2012, 790 men and 866 women with major depressive disorder and 331 men and 514 women with bipolar disorder were included. The cohort was linked to the Norwegian Cause of Death Registry. The relative mortality in men compared to women was tested using Cox regression with attained age as the time variable. The standardized mortality ratio (SMR) of the patients when compared to the general population in Norway was calculated.
Results: Patients with aﬀective disorders had twice the mortality of the general Norwegian population [SMR = 2.1, 95% conﬁdence interval (CI): 1.9–2.3]. For major depressive disorder, the SMR for total mortality was higher among men (2.6, 95% CI: 2.2–3.0) than women (1.8, 95% CI: 1.5–2.1). For bipolar disorder, no diﬀerence was seen between men and women. The SMR for suicide among women showed an increasing trend throughout the period 1980–1990: 20.0 (95% CI: 10.4–38.4); 1991–2001: 27.0 (95% CI: 15.7–46.2); 2002–2012: 40.4 (95% CI: 23.0–71.2).
Conclusions: The substantially increased mortality in patients with aﬀective disorders in Norway has been persistent over a period of 33 years, despite extensive reforms in psychiatric health care. Indications of increasing SMR for suicide in women call for further research.