To compare in head-to-head trials the effect of first-line diuretic drugs versus other classes of antihypertensive drugs on morbidity, mortality and drop-outs due to adverse drug effects in patients with hypertension.

To compare the percentage of patients requiring dose titration, addition of a second or third drug, and switching to other therapy in the same trials.

To compare the blood pressure lowering efficacy in the two groups in the same trials.