Sex differences in mortality of admitted patients with personality disorders in North Norway - a prospective register study

BACKGROUND: It is well established that patients with serious mental disorders have higher mortality than the general population, yet there are few studies on mortality of both natural and unnatural causes in patients with personality disorders. The aim of this study was to investigate the mortality of in-patients with personality disorder diagnosis in a 27-year follow-up cohort in North Norway, with a special focus on gender differences. METHOD: Based on a hospital case register covering 1980 to 2006, 284 female and 289 male patients were included. The cohort was linked to the Norwegian Cause of Death Registry for information concerning mortality. The mortality rates were adjusted for age by applying a Poisson regression model. The relative mortality in men compared to women was tested with Cox regression with attained age as the time variable. The number of deaths to be expected among the patients if the mortality rates of the general population in Norway had prevailed was estimated and excess mortality, expressed by the standardized mortality ratio (SMR), calculated. RESULTS: When compared to the mortality in the general population, men and women with personality disorder diagnoses had 4.3 (95% CI: 3.2 - 5.9) and 2.9 (95% CI: 1.9 - 4.5) times, respectively, increased total mortality. Patients with personality disorder diagnoses have particularly high mortality for unnatural deaths; 9.7 (95% confidence interval (CI): 6.3 - 15.1) times higher for men and 17.8 (95% CI: 10.1 - 30.3) for women, respectively, and even higher for suicides – 15 (95% CI: 9–27) for men and 38 (95% CI: 20–70) for women. The mortality due to natural causes was not statistically significantly increased in women, whereas men had 2.8 (95% CI: 1.8 - 4.4) times higher mortality of natural deaths than the general population. CONCLUSION: Compared to the general population, patients with a personality disorder have high mortality, particularly mortality from unnatural causes. The number of deaths caused by suicides is especially high for women. Men also have higher mortality of natural causes than the general population.