P275 Uncontrolled post-clinic blood pressure readings can identify nocturnal non-dipping blood pressure pattern

Abstract Funding Acknowledgements Aga Khan University Faculty of Health Sciences Research Committee (#80096) On Behalf PC BP (Post Clinic Blood Pressure) Study Group Background Nocturnal non-dipping increases cardiovascular morbidity and mortality in both hypertensive and normotensive subjects. Ambulatory blood pressure monitoring(ABPM) can identify nocturnal blood pressure(BP) dipping patterns but clinic BP cannot. We previously showed that 15-minute post-clinic BP correlates well with 24- hour ABPM. Purpose We aimed to determine if 15-minute post-clinic BP reading helped to identify patients with nocturnal non-dipping pattern. Methods A cross-sectional study involving 150 participants, as part of the Post Clinic-Ambulatory Blood Pressure(PC-ABP) study, was conducted in cardiology clinics. Participants aged ≥18 years, with hypertension or those referred for its assessment, were included. Pregnant females were excluded. Post-clinic BP was taken 15 minutes after the patient-physician encounter in the clinic using an automated, validated BP device by a research assistant. All the participants were then referred for 24-hour ABPM. Patterns of nocturnal dipping were studied amongst groups of controlled(<140 mmHg) and uncontrolled(≥140mmHg) post-clinic systolic BP(SBP). Fischer exact test was used to determine the difference in dipping patterns amongst the two groups. Results The mean age of participants was 60.3 ± 11.9 years. Of 150 participants, 49% were male and of all, 76% were hypertensive. Mean nighttime SBP(±SD) was 121.9(±18) mmHg(p-value <0.001). Mean nighttime DBP(±SD) was 68.7(± 8.7) mmHg(p < 0.001). Patterns of nocturnal dipping amongst patients with mean post-clinic SBP <140mmHg versus ≥140mmHg has been shown in Table 1. The difference in nocturnal dipping patterns between the two groups was statistically insignificant(p-value 0.071). Pearson correlation coefficient between post-clinic SBP and nighttime SBP for patients with loss of dip was higher (0.64; p < 0.001) whereas it was 0.56(p-value <0.001) for those with preserved dip.  Conclusion Uncontrolled post-clinic BP can help in identifying patients with nocturnal non-dipping. Larger studies can help determine the prognostic value of post-clinic BP amongst patients with nocturnal non-dipping. Nocturnal Dipping Amongst The Two Groups Controlled PC SBP <140mmHg (n = 80) Uncontrolled PC SBP ≥140mmHg (n = 70) Preserved Nocturnal Dipping (10 to 20% nocturnal drop in SBP) 61.2% (n = 49) 47.1% (n = 33) Loss of Dip (>0% to <10% of nocturnal drop in SBP) 33.8% (n = 27) 48.6% (n = 34) Reversed Dip (≤0% drop in SBP) 5% (n = 4) 1.4%(n = 1) Excessive Dip (>20% drop in SBP) 0 2.9% (n = 2) Table 1 shows the patterns of nocturnal dipping amongst patients with controlled (<140mmHg) and uncontrolled (≥140mmHg) 15-minute post-clinic systolic blood pressure (PC SBP).