This study aims to compare the effects of prescribing indapamide, a thiazide-like diuretic, with bendroflumethiazide, a thiazide diuretic, as the first-line choice of diuretic in the treatment of hypertension. The outcome measure will be a composite of non-fatal myocardial infarction, acute coronary syndrome, stroke, acute decompensated heart failure or death from cardiovascular causes. We will identify in CPRD all patients aged 18 years and over with first diagnosis of hypertension after 1987. Among them, we will form two groups with first ever prescription of indapamide or bendroflumethiazide. We will follow the groups either to the date of last prescription, date of medication switch, date of additional medication for hypertension (such as beta-blockers, calcium channel blockers, ACE inhibitors, alpha-blockers, ARBs or other antihypertensive medication), date of outcome, date of de-registration with the medical practice or the date of last practice data collection. We will also extract information on patient age, sex, medical practice, co-morbidities, co-prescribed medication, smoking, weight and alcohol consumption. Incidence of event rates will be calculated in each group. Descriptive analysis, and univariate and multivariate Cox regression survival models will be used as appropriate. Subgroup analyses will be implemented for known risk factors. This large population-based study may provide new evidence on the potential benefit of treating hypertensive patients with indapamide or bendroflumethiazide and may inform future clinical trials.