Coronary and cardiovascular risk estimation in uncomplicated mild hypertension. A comparison of risk assessment methods.

Objective To compare the accuracy of five risk assessment methods in identifying patients with uncomplicated mild hypertension at high coronary heart disease (CHD) and cardiovascular disease (CVD) risk. Design Comparison of risk estimates using each risk assessment method with CHD risk ≥ 15% and CVD risk ≥ 20% over 10 years calculated using the Framingham risk functions. Setting British population. Subjects People aged 35-64 years with uncomplicated mild systolic hypertension (systolic blood pressure (SBP) 140-159 mmHg, n = 202) from the 1995 Scottish Health Survey. Main outcome measures Sensitivity, specificity, positive and negative predictive values. Results Compared with CHD risk ≥ 15% over 10 years, the Sheffield table and Joint British Societies (JBS) Chart had good sensitivity and specificity (> 90%). The New Zealand (NZ) Chart had sensitivity 83% and specificity 89%. Compared with CVD risk ≥ 20% over 10 years the Sheffield table had sensitivity 81%, the JBS Chart had sensitivity 63%, and the NZ Chart had sensitivity 75%. All had good specificity (> 90%). For CHD risk and CVD risk the World Health Organization/International Society of Hypertension (WHO-ISH) and United States Joint National Committee VI (JNC-VI) methods had high sensitivity at the cost of very poor specificity (< 50%). Conclusion In patients with uncomplicated mild hypertension, the Sheffield table and JBS Chart both identified CHD risk ≥ 15% over 10 years with acceptable accuracy, while the NZ Chart was less accurate. Compared with CVD risk ≥ 20% over 10 years, these three risk assessment methods were all less accurate, but the Sheffield table retained the highest sensitivity (P < 0.05 versus JBS Chart, P= NS versus NZ Chart). The WHO-ISH and JNC-VI methods had unacceptably low specificities compared with both measures of risk and failed to differentiate between those at high and low risk.