Prevalence of ambulatory hypotension in elderly patients with CKD stages 3 and 4

Background. Recent understanding of the incidence of chronic kidney disease (CKD) has led us to the introduction of national blood pressure (BP) targets aimed at reducing the incidence of end-stage renal failure. The target clinic BP is <140/90 mm Hg and <130/80 in patients with significant proteinuria according to UK NICE guidelines. However, the relationship between clinic BP and ambulatory hypotension has not been studied. Methods. We prospectively collected data regarding cardiovascular risk factors, clinic and 24-h ambulatory blood pressure monitoring (24-h ABPM) in 98 treated patients with CKD stages 3 and 4. Results. The mean percentage of systolic blood pressure (SBP) recordings <100 mmHg was 21.2 +/- 16.2% and of diastolic blood pressure (DBP) recordings <60 mmHg was 19.8 +/- 16.9%. The patients were divided into two groups above and below the median age. The older group had a higher percentage of cardiovascular disease than younger patients (57.1 versus 34.7, P = 0.03) and a lower percentage of primary renal disease (18.4 versus 55.1, P < 0.01). Clinic SBP was higher in the older group (158.4 +/- 20.1 versus 147.2 +/- 17.8 mmHg, P < 0.01) but 24-h ABPM SBP was not different (117.3 +/- 14.7 versus 121.0 +/- 12.8 mmHg, P = 0.19). DBP was lower in the older group for both clinic BP (80.3 +/- 10.2 versus 85.5 +/- 12.3 mmHg, P = 0.03) and 24-h ABPM (69.1 +/- 8.2 versus 76.7 +/- 8.8 mmHg, P = < 0.01). There were a higher percentage of systolic (SBP < 100 mmHg) and diastolic (DBP < 60 mmHg) hypotensive episodes in the older group (21.3 +/- 18.9 versus 13.2 +/- 13.6% P = 0.02 and 21.6 +/- 17.9 versus 8.1 +/- 13.3%, P < 0.01, respectively). Conclusions. Hypotension was common among treated CKD patients and despite similar clinic SBP, older CKD patients had lower 24-hABPMDBP and more frequent systolic and diastolic hypotensive episodes. Further research is underway into how this relates to antihypertensive therapy and future outcomes.