Long term postischemic stroke mortality in diabetes: a veteran cohort analysis

Recent data on stroke mortality in diabetics in the United States is lacking. We investigated trends in diabetes prevalence and stroke morality among diabetics in a large veteran cohort.

The Patient Treatment File was used to identify all patients discharged from any Veterans hospital between October 1990 and September 1997 with a diagnosis of ischemic stroke (ICD-9-CM codes 434, 436) listed as primary diagnosis. Demographic, morbidity, and mortality data were recorded. Chi-square tests were used to examine differences between diabetics and nondiabetics, and t tests were used for continuous variables. Cox proportional hazards regression was used to examine the effects of diabetes (DM) on the survival times controlling for multiple covariates.

Of 48 733 ischemic stroke patients identified, 98% were male and 13 925 (25%) had DM. Mean age was similar between DM and non-DM (67.2 versus 67.5, P=NS). Prevalence of DM among stroke subjects increased from 25% to 31%. Charlson index >2 was much higher in DM (68.2% versus 47.9%, P<0.001). Mortality at 60 days and 1 year was similar in both groups (2.9 versus 2.7%, P=NS; 12.6 versus 13.1, P=NS). Kaplan-Meier survival plot showed that DM had shorter long term survival time (log-rank, P<0.001). Multivariate Cox proportional hazards regression showed a higher risk of death for diabetics (HR=1.15, 95% CI 1.11 to 1.19, P<0.001).

Despite greater comorbidity, postacute ischemic stroke mortality at 60 days and 1 year is not different between subjects with and without DM. Long term mortality after stroke is much lower among DM than that reported in older studies.