An investigation of the effect of advancing uraemia, renal replacement therapy and renal transplantation on blood pressure diurnal variability

phenomenon is not modulated by successful renal transplantation. Background. Ambulatory blood pressure recordings have been shown to correlate better with target organ damage than have isolated clinic blood pressure readhypertensives; uraemia ings. There have been some small studies demonstrating that abnormal blood pressure diurnal rhythm is common in uraemia and in patients on renal replacement therapy. Abnormal blood pressure diurnal rhythm itself may be a risk factor for accelerated target Introduction organ damage. Methods. We retrospectively studied 480 ambulatory Ambulatory blood pressure monitoring (ABPM ) has blood pressure recordings in 380 patients with essential become an increasingly reliable and useful tool for the hypertension, secondary hypertension, and on renal accurate measurement of both daytime ambulatory replacement therapy. We examined diurnal blood pres- blood pressure and night-time (sleeping) blood pressure rhythm in each group. sure, when in normal individuals there is a decline in Results. Abnormal blood pressure diurnal rhythm blood pressure. Data from population studies have (non-dipping) is significantly more prevalent in patients given diVerent values for the ‘normal’ nocturnal decline with underlying renal disease, even with normal excret- of blood pressure in healthy individuals [1,2]. This ory renal function ( 53%) than in age-, sex-, and race- change in blood pressure is approximately a 15% matched controls with essential hypertension ((30%), reduction in systolic and 20% reduction in diastolic P 600 mmol/l (75%), and in renal transplant pressure load, specifically allowing identification of recipients (74%). subjects whose sleep-related fall in BP is blunted, or Conclusions. Abnormal blood pressure diurnal rhythm reversed, itself representing an additional end-organ (‘non-dipping’) is significantly more common in sec- risk factor. ondary than in primary hypertension, even with normal Blood pressure control is an important modifiable renal function. Abnormal blood pressure diurnal risk factor for cardiovascular disease which is significrhythm becomes increasingly common with advancing antly more prevalent with uraemia, as well as an uraemia. Once the plasma creatinine is greater than important factor determining the rate of renal func600 mmol/l the prevalence of non-dipping is the same tional decline in renal impairment [6,7]. The aim of as that seen with renal replacement therapy. This our study was to examine the prevalence of abnormal