Risk factors for stroke among patients with hypertension: a case-control study

In some African countries, more than half of the adult population are estimated to be hypertensive leading to an escalated burden of stroke in the continent. We conducted the first study to unravel the major risk factors for stroke among hypertensive patients (Nigerian-Africans) using a case-control design while also exploring the relative contributions of carotid intima medial thickness (CIMT) and carotid diameter as risk markers for stroke.

Using conventional techniques, stroke-related demographic, clinical and laboratory data were obtained from 135 consecutive volunteering hypertensive stroke patients and compared with 117 age and gender-matched hypertensive patients with no clinical evidence of stroke, TIA or coronary artery disease. Common carotid IMT and diameters were measured in all participants. Univariate and multivariate analyses were conducted at p=0.05.

13.2% of the stroke patients were first diagnosed as hypertensive at presentation with stroke. Among hypertensive patients, the modifiable factors significantly (p<0.00001 to p<0.037) associated with stroke occurrence included higher maximum and minimum blood pressures in the preceding 3months, higher fasting plasma glucose, greater alcohol consumption, lesser physical activity and increased CIMT. Using a multivariate model which predicted 84.6% of stroke occurrence, only fasting total cholesterol of >150mg/dl (p=0.021) and common carotid diameter of ≥5.9mm (p=0.008) independently multiplied the risk of stroke.

Particularly in resource-limited settings, aside from BP control, stroke prevention efforts should be targeted towards these identified risk factors for stroke among hypertensive patients. Carotid diameter should be further explored as an intermediate risk marker for stroke.