Treatment and blood pressure control in isolated systolic hypertension vs diastolic hypertension in primary care

Cross-sectional surveys on prevalence, treatment and control of hypertension could not satisfactorily distinguish between diastolic hypertension and isolated systolic hypertension because the definition of hypertension included patients under pharmacological treatment. We assessed the situation in the two types of hypertension in general practice in Belgium, based on current blood pressure ( BP) measurements and on BP prior to the initiation of drug therapy. Participating physicians enrolled the first 15 at least 55-year-old men visiting the surgery, measured their BP and recorded data on medical history including pretreatment BP, drug utilization, cardiovascular risk factors and target organ damage. Diastolic hypertension was defined as diastolic BPgreater than or equal to90 mmHg, irrespective of systolic BP, and isolated systolic hypertension as systolic BPgreater than or equal to140 mmHg and diastolic BP<90mmHg. Among 3761 evaluable patients, 74% were hypertensive. Among the 1533 hypertensive patients in whom blood pressure was known prior to treatment (n = 965) or who were untreated at the study visit (n = 568), 1164 had diastolic hypertension and 369 isolated systolic hypertension. The prevalence of antihypertensive treatment was, respectively, 75 and 25% (P<0.001) in these two types of hypertension. The odds of being treated were independently determined by type of hypertension, severity of hypertension and level of risk (P<0.001). BP was controlled in 25% of all patients with diastolic hypertension and in 13% of all patients with isolated systolic hypertension (P<0.001). About half of the treated patients with systolic hypertension were on a diuretic and/or a calcium-channel blocker. In conclusion, isolated systolic hypertension is less frequently treated than diastolic hypertension, overall BP control is poor and actual drug therapy diverges from recommendations based on placebo-controlled intervention trials.