Stroke in an elderly population: incidence and impact on survival and daily function. The Italian Longitudinal Study on Aging

BACKGROUND: Epidemiological data are essential to estimate the burden of stroke. We evaluated stroke incidence in older Italians and the effect of first-ever stroke on survival and activities of daily living (ADL). METHODS: The analysis was performed in the Italian Longitudinal Study on Aging (ILSA) sample, consisting of 5,632 individuals aged 65-84. The ILSA aims at major cardiovascular and neurological age-associated diseases. The baseline survey was performed in 1992 to detect prevalent diseases. The longitudinal examination started on September 1995 aiming at incidence, function and survival. RESULTS: Complete follow-up data were achieved for 77% of the baseline stroke-free cohort (4,164 persons; 50.9% males; mean age 74.5 +/- 5.7 years). Incidence for first-ever stroke was 9.51 (95% CI: 7.75-11.27) per 1,000 person years and 12.99 (95% CI: 10.99-14.98) including recurrent stroke (total incidence). Crude mortality was 49.2% among first stroke patients and 15% among persons without stroke. The first-ever stroke mortality risk ratio, adjusted for demographics and comorbidity, was 2.40 (95% CI: 1.62-3.54). In survivors, impairment of at least one ADL was present in 67.6% of first-ever stroke patients vs. 31.6% of individuals without stroke. The comorbidity-adjusted OR was 2.63 (95% CI: 1.20-5.78) in the total cohort, and 4.00 (95% CI: 1.39-11.46) in individuals without disability at baseline. CONCLUSIONS: The ILSA provides the first data on stroke incidence in Italy on a national basis. Overall, 153,000 new cases can be expected annually in the Italian elderly population. First-ever stroke still has a strong effect on survival and function of older persons.