Hydrochlorothiazide vs chlorthalidone, indapamide, and potassium-sparing/hydrochlorothiazide diuretics for reducing left ventricular hypertrophy: A systematic review and meta-analysis

Left ventricular hypertrophy develops in 36%-41% of hypertensive patients and independently predicts cardiovascular events and total mortality. Moreover, drug-induced reduction in left ventricular mass (LVM) correlates with improved prognosis. The optimal thiazide-type diuretic for reducing LVM is unknown. Evidence regarding potency, cardiovascular events, sodium, and potassium suggested the hypothesis that "CHIP" diuretics (CHlorthalidone, Indapamide, and Potassium-sparing diuretic/hydrochlorothiazide [PSD/HCTZ]) would reduce LVM more than HCTZ. Systematic searches of five databases were conducted. Among the 38 randomized trials, a 1% reduction in systolic blood pressure (SBP) predicted a 1% reduction in LVM, P = 0.00001. CHIP-HCTZ differences in reducing LVM differed across trials (ie, heterogeneity), making interpretation uncertain. However, among the 28 double-blind trials, heterogeneity was undetectable, and HCTZ reduced LVM (percent reduction [95% CI]) by -7.3 (-10.4, -4.2), P < 0.0001. CHIP diuretics surpassed HCTZ in reducing LVM: chlorthalidone -8.2 (-14.7, -1.6), P = 0.015; indapamide -7.5 (-12.7, -2.3), P = 0.005; and all CHIP diuretics combined -7.7 (-12.2, -3.1), P < 0.001. The comparison of PSD/HCTZ with HCTZ had low statistical power but favored PSD/HCTZ: -6.0 (-14.1, +2.1), P = 0.149. Thus, compared to HCTZ, CHIP diuretics had twice the effect on LVM. CHIP diuretics did not surpass HCTZ in reducing systolic or diastolic blood pressure: -0.3 (-5.0, +4.3) and -1.6 (-5.6, +2.4), respectively. The strength of evidence that CHIP diuretics surpass HCTZ for reducing LVM was high (GRADE criteria). In conclusion, these novel results have demonstrated that CHIP diuretics reduce LVM 2-fold more than HCTZ among hypertensive patients. Although generally related to LVM, blood pressure fails to explain the superiority of CHIP diuretics for reducing LVM.