Treatment of isolated systolic hypertension: The SHELL study results

Objective: Our aim was to compare the effect of lacidipine and chlorthalidone on cardiovascular outcome as a primary parameter and blood pressure as a secondary in elderly patients with isolated systolic hypertension in a prospective study with an open design. Methods: 1882 males and females outpatients greater than or equal to60 years were randomly assigned to the administration of chlorthalidone 12.5.mg o.d. or lacidipine 4 mg o.d. Patients were recruited if sitting systolic blood pressure was greater than or equal to160 mmHg with a diastolic blood pressure equal or lower than 95 mmHg. Primary endpoint was a composite of cardiovascular and cerebrovascular events. Results: At randomization mean systolic blood pressure was 178.1 mmHg in the lacidipine and 178.2 mmHg in the chlorthalidone group, the corresponding mean diastolic values being 86.9 and 86.8 mmHg. In both lacidipine and chlorthalidone groups treatment caused a significant (p<0.001) and marked systolic blood pressure reduction which was maintained throughout the treatment period with a significant (p<0.001) and steady although less marked reduction in diastolic blood pressure as well. At the end of treatment period (median 32 months), the reduction was 36.8/8.1 mmHg (systolic/diastolic) in the chlorthalidone and 38.4/7.9 mmHg in the lacidipine group, the final on treatment blood pressures being 142.0/79.2 and 143.2/79.5 mmHg, respectively. Treatments were similarly effective in males and females and in age groups between 60 and 69 years (n=763), 70 and 79 years (n=744) and greater than or equal to80 years (n=375). Similar reductions were obtained in a subgroup of patients (n=209) followed in double-blind fashion for 1 year. The overall incidence of the primary endpoints was 9.3% with no significant between-group difference. Total mortality was also similar between groups. Conclusions: In elderly patients with isolated systolic hypertension, administration of lacidipine or chlorthalidone markedly reduced systolic blood pressure with no difference in the incidence of cardiovascular events and total mortality.