Abnormal nocturnal blood pressure (BP) patterns, including non-dipping and reverse dipping, are associated with elevated cardiovascular risk. A randomized, single-blind, multicenter Indian trial evaluated the prevalence of nocturnal dipping patterns and the effect of SPC therapy on restoring physiological dipping in adults with hypertension.

The TOPSPIN trial enrolled 1,981 adults who received one of three SPC regimens: amlodipine–perindopril, perindopril–indapamide, or amlodipine–indapamide. Ambulatory BP monitoring (ABPM) assessed dipping status at baseline (n = 1,980) and at six months (n = 1,624). Dipping categories were defined by percent nocturnal systolic BP fall.

At baseline, 53.1% of participants were non-dippers, including 15.8% with reverse dipping. Compared with dippers, non-dippers were older (53.2 vs 50.8 years; p < 0.001), more often female (46.2% vs 37.4%; p < 0.001), had a higher prevalence of diabetes (20.8% vs 16.3%; p = 0.010), and had lower estimated glomerular filtration rate (eGFR) (92.5 vs 96.1 mL/min; p < 0.001). Logistic regression showed independent associations with age >55 years (OR 1.42; 95% CI 1.17–1.72), female sex (OR 1.44; 95% CI 1.19–1.74), diabetes (OR 1.40; 95% CI 1.10–1.79), current smoking (OR 1.66; 95% CI 1.12–2.46), and serum sodium >140 mmol/L (OR 1.24; 95% CI 1.02–1.52).

Among participants with complete follow-up data, non-dipping prevalence declined modestly from 53.1% to 49.5% (p = 0.024). At six months, non-dipping rates were 51.4% with amlodipine–perindopril, 47.8% with perindopril–indapamide, and 49.1% with amlodipine–indapamide, with no significant between-group differences (p = 0.49).

These findings demonstrate that non-dipping is highly prevalent in Indian adults with hypertension and that six months of SPC therapy produces only limited improvement in nocturnal dipping status.