Cognitive performance of hypertensive elderly Nigerians: a case control study.

The importance and contribution of optimal blood pressure control to improvement in quality of life, cognitive abilities inclusive, have been established and accepted by all and sundry. In the elderly population, however, hypertension and cognitive dysfunction are commonly encountered disorders. The objective is to determine the role of blood pressure on the cognitive performances of Nigerian elderly hypertensive patients. A total of 327 randomly selected elderly subjects above 60 years of age comprising 153 hypertensive: 53 males (34.64%) and 100 females (65.36%) with a mean age of 66.65 +/- 6.64 years; and 174 normotensive healthy controls: 63 males (36.21%) and 111 females (63.79%) with a mean age of 67.29 +/- 6.45 years were studied. The mean blood pressure for the hypertensive was 160/110mmHg (range 150/94 - 190/130mmHg) while it was 120/74mmHg (range 110/50 - 139/89mmHg) for the normotensives. The cognitive testing was done with the Community Screening Instrument for Dementia (CSI'D'). The main outcome measures were cognitive test scores (CSI'D' scores) and blood pressure readings. The CSI'D' scores correlated significantly with higher educational level (P < 0.05; P = 0.0372) but the mean CSI'D' scores of hypertensives was not significantly different from that of normotensives (P>0.05). The diastolic blood pressure was the strongest predictor of the presence of cognitive impairment with a statistically significant linear relationship (P = 0.013). This study assessed the effect of blood pressure on cognitive performance. The evidence from the study showed that blood pressure has no effect on cognitive performance of subjects generally but among hypertensive subjects, diastolic blood pressure negatively correlates with cognitive performance.