Abstract 4368589: Impact of Single-Pill Combination Therapy on Nocturnal Blood Pressure Dipping in Indian Patients: A Subanalysis from the TOPSPIN Trial

Background: Non-dipping and reverse-dipping of nocturnal blood pressure (BP) are associated with increased cardiovascular risk. Data on dipping status and its modulation by Single-Pill Combination (SPC) therapy in Indian or South Asian populations is sparse. Objectives: To evaluate the prevalence and predictors of nocturnal BP dipping patterns in Indian hypertensive patients and the efficacy of three SPCs on restoring dipping status. Methods: TOPSPIN was a multicenter, randomized, single-blind trial of 1981 Indian adults with hypertension, treated with three SPCs: amlodipine–perindopril, perindopril–indapamide, and amlodipine–indapamide. Ambulatory BP monitoring (ABPM) was performed at baseline (n=1980) and 6 months (n=1624). Dipping was defined by percent nocturnal systolic BP fall: extreme dipper (≥20%), dipper (10 - 20%), non-dipper (<10%), and reverse dipper (no fall or a paradoxical rise). Logistic regression identified predictors of non-dipping. Results: Among the 1980 participants with baseline ABPM data, 53.1% were classified as non-dippers, including 15.8% with a reverse-dipping pattern. Compared to dippers, non-dippers were older (53.2 vs. 50.8 years, p<0.001), more likely to be female (46.2% vs. 37.4%, p<0.001), have diabetes (20.8% vs. 16.3%, p=0.010) and have lower eGFR (92.5 vs 96.1 ml/min, p<0.001). Non-dippers had significantly higher mean 24-hr ambulatory SBP, DBP, mean night-time SBP and DBP. Multivariable logistic regression showed that non-dipping was independently associated 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). For the patients (n = 1624) with complete baseline and 6-month ABPM data, the prevalence of non-dippers (non and reverse dippers) modestly declined from 53.1% to 49.5% (p=0.024). However, when stratified by treatment arm, the proportion of non-dippers at 6 months was 51.4% in the amlodipine–perindopril group, 47.8% in the perindopril–indapamide group, and 49.1% in the amlodipine–indapamide group with no significant between-group difference (p = 0.49). Conclusions: Non-dipping is highly prevalent among Indian hypertensive patients. Six months of SPC reduced overall BP but had a clinically minimal impact on restoring nocturnal dipping, with no significant differences across treatment arms.