TRH and hydrops fetalis: Spironolactone 25–50 mg/day vs control reduced systolic BP by 10.3 mmHg over 9 months, and patients with lower renin had a greater BP reduction with spironolactone than those with higher renin (P for interaction = .041).124 Further explanatory analysis or trials consistently showed antihypertensive effects of spironolactone in patients with TRH who had underlying diseases such as primary aldosteronism, HF with preserved ejection fraction (HFpEF), and dialysis.108–113