Is coronary risk an accurate surrogate for cardiovascular risk for treatment decisions in mild hypertension? A population validation

Objective To examine the relationship between coronary (CHD) and cardiovasc ular (CVD) risk in patients with uncomplicated mild hypertension and to det ermine the accuracy of using CHD risk greater than or equal to 15% over 10 years to identify for antihypertensive treatment those patients with CVD ri sk greater than or equal to 20% over 10 years as advised in recent British guidelines. Design Comparison of decisions made using CHD risk greater than or equal to 15% over in years calculated by the Framingham risk function and estimated using a simple table with CVD risk greater than or equal to 20% over 10 ye ars. Setting British population. Subjects People aged 35-64 years with uncomplicated mild systolic hypertens ion (SBP 140-159 mmHg, n = 624) from the 1995 Scottish Health Survey. Main outcome measures Relationship between CHD and CVD risk. Sensitivity, s pecificity, positive and negative predictive values (PPV and NPV), Results CHD risk 15% over 10 years was equivalent to CVD risk 21% over 10 y ears. Exact CHD risk greater than or equal to 15% over 10 years had sensiti vity 79%, specificity 98%, PPV 94% and NPV 93% in detecting CVD risk greate r than or equal to 20% over 10 years. Use of the table to estimate CHD risk greater than or equal to 15% over 10 years gave sensitivity 88%, specifici ty 90%, PPV 76% and NPV 95%. Conclusion CHD risk appears acceptably accurate for targeting treatment in mild hypertension. The risk assessment table, which slightly overestimates CHD risk, was more sensitive in identifying patients with CVD risk greater than or equal to 20% over in years and may be preferable to using exact CHD risk. European guidelines which suggest targeting treatment for mild hyper tension at CHD risk greater than or equal to 20% over 10 years are over-con servative compared with British guidelines. (C) 2001 Lippincott Williams & Wilkins.