Night-time blood pressure is associated with the development of chronic kidney disease in a general population: the Ohasama Study.

OBJECTIVE

Ambulatory blood pressure (BP) is reportedly associated with target organ damage. However, whether ambulatory BP carries prognostic significance for the development of chronic kidney disease (CKD) has not been confirmed.

METHOD: We measured ambulatory BP in 843 participants without CKD at baseline from a general Japanese population and examined the incidence of CKD defined as positive proteinuria or an estimated glomerular filtration rate (eGFR) less than 60 ml/min per 1.73 m at health checks. The association between baseline ambulatory BP and CKD incidence was examined using the Cox proportional hazard regression model adjusted for sex, age, BMI, habitual smoking, habitual alcohol consumption, diabetes mellitus, hypercholesterolemia, a history of cardiovascular disease, antihypertensive medication, eGFR at baseline, the number of follow-up examinations, and the year of the baseline examination.

RESULTS

The mean age of the participants averaged 62.9 ± 8.1 years, 71.3% were women and 23.7% were under antihypertensive medication. During a median follow-up of 8.3 years, 220 participants developed CKD events. The adjusted hazard ratios for CKD in a 1-standard deviation increase in daytime and night-time SBP were 1.13 [95% confidence interval (CI) 0.97-1.30] and 1.21 (95% CI 1.04-1.39), respectively. When night-time and daytime BP was mutually adjusted into the same model, only night-time BP persisted as an independent predictor of CKD.

CONCLUSION

Night-time BP is a better predictor of CKD development than daytime BP in the general population. Ambulatory BP measurement is considered useful for evaluating the risk of progression to CKD.