Cognitive impairment better predictor of first stroke in the oldest old

Cognitive impairment appears to predict risk for first stroke in very elderly patients better than the Framingham stroke risk score, according to a recent study.

Researchers examined 480 patients from the Leiden 85-plus Study, an observational, prospective, population-based cohort study of elderly people in the Netherlands. Framingham stroke risk score and Mini-Mental State Examination (MMSE) score were obtained at baseline, and risk of first stroke was calculated in tertiles of each of these variables. Results were published online May 16 by Stroke.

All patients were 85 years of age at the start of the study. Fifty-six had a stroke during five years of follow-up, for an incidence rate of 30.3 per 1,000 person-years. Patients with high Framingham scores did not have a higher risk for stroke than those with low Framingham scores (hazard ratio, 0.77; 95% confidence interval [CI], 0.39 to 1.54), but those with high cognitive impairment did have higher risk than those with low cognitive impairment (hazard ratio, 2.85; 95% CI, 1.48 to 5.51). MMSE score had discriminative power for stroke prediction when compared with the Framingham risk score (area under the receiver-operating characteristic curve, 0.65; 95% CI, 0.57 to 0.72), and the two prediction tools differed significantly in area under the receiver-operating characteristic curves, with the MMSE curve being higher (P=0.006).

The authors pointed out that some of the study participants may have had silent strokes that went undetected and that MMSE was the only measure used to assess cognitive impairment. However, they concluded that cognitive impairment appears to be a better tool to determine risk for first stroke in very elderly patients than the Framingham stroke risk score. “Assessment of cognitive function can be considered as an easily accessible tool to identify very old subjects at risk for stroke,” they wrote. They noted that their results need to be validated in other elderly cohorts.