Asthma in the elderly: mortality rate and associated risk factors for mortality.

BACKGROUND: There is a distinct lack of information on the prognosis of asthma in the elderly.
METHODS: In order to compare mortality rates of elderly people with and without asthma and to identify mortality risk factors in those with asthma, 1,233 ambulatory patients aged > or = 65 years with a diagnosis of asthma (n = 210) or chronic nonrespiratory conditions (n = 1,023) were enrolled in a multicentric study. Patients underwent baseline spirometry and multidimensional assessment and were then followed up for a mean of 57.9 months (SD 16.9). We compared mortality rates in the two groups and identified predictors of death using multivariable survival analysis.
RESULTS: The 5-year mortality rate in people with asthma was 24.3%, compared to 16.3% in control subjects (p < 0.01), but asthma per se did not explain the excess risk of death. The main causes of death among people with and without asthma were cardiovascular diseases (36.4% and 21.3%, respectively), nonneoplastic lung diseases (28.8% vs 5.4%), and neoplasms (7.6% vs 22.6%). In people without asthma, death was associated with age, gender, smoking, cardiovascular diseases, worse performance on a 6-min walking test, cognitive impairment, depression, and worse respiratory function. In people with asthma, only the association between death and age, smoking, and depression was confirmed. At variance with control subjects, in asthmatics we found an inverse correlation between being overweight and death (hazard ratio [HR], 0.35; 95% confidence interval [CI], 0.13 to 0.94) and a trend toward a higher mortality rate in people with a body mass index < 22 kg/m(2) (HR, 2.21; 95% CI, 0.94 to 5.18).
CONCLUSIONS: Asthma in the elderly was associated with higher mortality rate, although this condition was not an independent risk factor. Causes of death and factors associated with death were somewhat different between people with and without asthma.