Gender differences in the relation between comorbidity and mortality of patients with Alzheimer's disease

Objective: To investigate whether differences in the number and type of com orbid conditions may help explain the gender gap in mortality among patient s with AD. Background: The prevalence and incidence of AD are higher among women, who also have more severe cognitive impairment and accelerated decli ne. However, men have an exceedingly higher mortality. Methods: The authors conducted a retrospective cohort study on 5,831 men and 17,918 women with a diagnosis of AD. Data were from the Systematic Assessment of Geriatric dr ug use via Epidemiology (SAGE) database, which includes information on resi dents of 1,492 nursing homes in five US states (1992-1995). Men and women w ere compared with respect to demographic characteristics, dementia severity , psychiatric and behavioral symptoms, indicators of physical disability, a nd general health status. Also compared were age- and race-adjusted prevale nce of all comorbid conditions at each level of cognitive impairment. Id su rvival analyses, the risk of death and of hospitalization were determined b y gender and level of cognitive impairment. Finally, gender-related differe nces in the intensity of pharmacologic treatment were examined. Results: Wo men were older than men (83 +/- 7 versus 81 +/- 7 years) and were more like ly to exhibit severe cognitive deterioration (27% versus 19% among men). Ov erall, there were no significant gender-related differences on several meas ures of physical disability (activities of daily living performance, gait a nd history of falls, incontinence, pressure sores), but significantly more women were underweight (45% versus 37% among men). However, the age- and ra ce-adjusted 1-year mortality rate was 17% for women and 31% for men. The mo rtality rate of women at the highest degree of dementia severity was lower than the rate for men with minimal cognitive impairment. At any level of co gnitive impairment, the prevalence of arrhythmia, chronic obstructive pulmo nary disease, PD, and cancer was higher among men. Women were also less lik ely to be hospitalized, and they received fewer medications for each given disease. Conclusions: The survival advantage of women with AD relative to m en may occur as a result of fewer comorbid clinical conditions associated w ith the diagnosis of dementia.