Hypertension is the most common modifiable risk factor for cardiovascular disease. It is also the fastest growing reason for renal replacement therapy. Ambulatory blood pressure (ABP) has consistently been shown to be a superior predictor of cardiovascular risk to that measured in the clinic setting. There is however limited data in its use to risk stratify patients with renal dysfunction We studied the relationship between ABP and renal disease in a in a cohort of non-diabetic hypertensive patients.Design and method:
At baseline, when not on antihypertensive medication, 3,760 non-diabetic patients (1,789 male, mean age 51.88 (SD 13.9) years) underwent ABP and baseline assessment including phlebotomy. Using the Cockcroft-Gault Equation we calculated an estimated creatinine clearance. All statistic were performed using SAS 9.0.Results:
Nighttime blood pressure was more closely correlated with creatine clearance that daytime blood pressure (- 0.194 vs −0.106, p, 0.0001). A similar pattern was seen for systolic blood pressure (SBP) when compared to diastolic blood pressure. Using multiple logistic regression when those with normal renal function (N = 2,050) were compared to those with significant renal impairment (N = 441) nighttime blood pressure was stronger predictor of renal function Each 10mmHg increase in nighttime SBP was associated with an odd ratio of 1.29 (1.18–1.40; p < 0.0001). This was after adjustment for daytime SBP, age, gender, smoking history, BMI and cardiovascular history.Conclusions:
Nighttime SBP has a significant association with renal dysfunction independent of other risk factors including of daytime blood pressure. ABP should be used in the assessment of patients with renal disease. Future research into the benefits of treating elevated nighttime blood pressure is needed to clarify this association.