Davidson Michael B, Hix John K, Vidt Donald G, Brotman Daniel J
Department of General Internal Medicine, Cleveland Clinic Foundation, Cleveland, Ohio, USA.
Arch Intern Med. 2006 Apr 24;166(8):846-52. doi: 10.1001/archinte.166.8.846.
Most healthy people exhibit a decrease in systolic blood pressure (SBP) at night. A drop of less than 10% from mean daytime values (nondipping) is associated with chronic kidney disease, insulin resistance, and cardiovascular events. Whether nondipping precedes a decline in renal function remains unclear. We hypothesized that nondipping would predict a decline in the glomerular filtration rate (GFR) over time.
Consecutive patients referred for ambulatory blood pressure monitoring were included in our retrospective cohort if they had a serum creatinine level noted at the time of their ambulatory blood pressure recording and a follow-up creatinine level recorded at least 1 year later. Mean day and night SBPs were compared (nighttime SBP-daytime [corrected] SBP ratio). We defined nondipping as a nighttime [corrected] SBP-daytime [corrected] SBP ratio higher than 0.90. The GFR was calculated using the Modification of Diet in Renal Disease 4-variable equation.
Of 322 patients included, 137 were dippers and 185 were nondippers; their mean baseline GFRs were 80.5 mL/min per 1.73 m(2) and 76.4 mL/min per 1.73 m(2), respectively. During a median follow-up of 3.2 years, the GFRs remained stable among dippers (mean change, 1.3%) but declined among nondippers (mean change, -15.9%) (P<.001). The creatinine levels increased by more than 50% in 2 dippers (1.5%) and in 32 nondippers (17.3%) (P<.001). These findings persisted after adjustment for other predictors of GFR decline.
Blunted diurnal blood pressure variation is associated with a subsequent deterioration in renal function that is independent of SBP load and other risk factors for renal impairment.
大多数健康人夜间收缩压（SBP）会下降。夜间收缩压较日间平均水平下降不足10%（非勺型血压）与慢性肾病、胰岛素抵抗及心血管事件相关。非勺型血压是否先于肾功能下降尚不清楚。我们推测非勺型血压可预测肾小球滤过率（GFR）随时间下降。
连续入选行动态血压监测的患者，若其在行动态血压记录时记录了血清肌酐水平且至少1年后记录了随访肌酐水平，则纳入我们的回顾性队列研究。比较日间和夜间平均收缩压（夜间收缩压-日间[校正后]收缩压比值）。我们将非勺型血压定义为夜间[校正后]收缩压-日间[校正后]收缩压比值高于0.90。使用肾脏病饮食改良4变量方程计算GFR。
纳入的322例患者中，137例为勺型血压者，185例为非勺型血压者；其平均基线GFR分别为每1.73 m²80.5 mL/min和每1.73 m²76.4 mL/min。在中位随访3.2年期间，勺型血压者的GFR保持稳定（平均变化1.3%），而非勺型血压者的GFR下降（平均变化-15.9%）（P<0.001）。2例勺型血压者（1.5%）和32例非勺型血压者（17.3%）的肌酐水平升高超过50%（P<0.001）。在对GFR下降的其他预测因素进行校正后，这些结果仍然存在。
昼夜血压变化减弱与随后的肾功能恶化相关，且独立于收缩压负荷及其他肾功能损害风险因素。
