Background: Circadian variation in blood pressure (BP) has been shown to determine cardiovascular events in people with chronic kidney diseases (CKDs). Studies aimed at elucidating the relationship between diurnal variation in BP and cardiovascular disease have yielded conflicting results, and very few of these studies have been conducted on CKD patients in Sub-Saharan Africa, hence the need for this study.
Subjects and methods: Eighty-five adult participants comprising 54 patients with CKD (36 males and 18 females) and 31 hypertensive patients (16 males and 15 females) free of CKD were recruited for 24 h ambulatory BP monitoring and cardiovascular risk factor assessment.
Results: Patients with CKD had a higher mean clinic systolic BP (159.8 ± 28.6 vs. 147.9 ± 19.0 mmHg, P = 0.049) and reduced estimated glomerular filtration rate (19.2 ± 18.6 vs. 106.2 ± 30.6, P < 0.0001) when compared with hypertensives free of CKD. The mean 24 h ambulatory SBP (135.9 ± 28.5 vs. 120.3 ± 11.8 mmHg, P = 0.007), diastolic BP (82.6 ± 18.1 vs. 74.8 ± 9.0 mmHg, P = 0.034) and mean arterial pressure (100.9 ± 21.2 vs. 90.6 ± 10.2 mmHg, P = 0.018) were higher amongst CKD patients. Compared with hypertensive without CKD, daytime hypertension (58.9% vs. 21.4, P = 0.001), nocturnal hypertension (80.4% vs. 50.0%, P = 0.004) and non-dippers (92.0% vs. 73.1%, P = 0.026) were commoner in people with CKD. White coat effect was more common amongst hypertensives without CKD (74.2% vs. 38.0%, P = 0.002). The mean left atrial diameter and left ventricular mass index were higher in CKD group.
Conclusion: This study highlights the high prevalence of varied phenotypes in circadian rhythm amongst CKD patients. Ambulatory blood pressure monitoring may be useful for early risk stratification of CKD patients. Large longitudinal study is needed to assess the prognostic implication of the findings.