Relationship between prehypertension and incidence of chronic kidney disease in a general population: a prospective analysis in central south China.

Objective: The objective of the study was to investigate whether prehypertension is associated with progression to chronic kidney disease (CKD) in the general population in central south China.

Methods: A prospective cohort study was carried out in 1,703 white-collar workers without preexisting CKD in Changsha in 2006 at baseline. The cohort population was followed for an average of 54 months by annual examinations. The glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease study equation modified by the Chinese coefficient. CKD was defined as positive albuminuria or an estimated GFR <60 mL/min/1.73 m(2). Blood pressure (BP) categories were defined by the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. The association of blood pressure and CKD incidence was examined using a Cox regression model adjusted for relevant factors.

Results: During the follow-up of cohort, 194 incidences of CKD were recorded. Compared with normotension group, the hazard ratios (95 % confidential intervals) for CKD were 1.25 (1.02-1.85) in prehypertension group, 1.62 (1.07-2.79) in undiagnosed hypertension group, and 1.98 (1.15-3.96) in diagnosed hypertension group. Kaplan-Meier curves showed there was a significant difference in the cumulative incidence of CKD between the different blood pressure categories (log-rank test, P < 0.001). The independent risk factors of CKD were age, estimated glomerular filtration rate (eGFR), systolic blood pressure, and diastolic blood pressure according to the Cox proportional hazard analysis. It was found that 2.4 % in participants with CKD incidences could be described as excessive incidence attributable to prehypertension.

Conclusion: Prehypertension is significantly associated with CKD in a Chinese urban population.