[Association between hypertension duration and chronic kidney disease in residents in China]

Objective: To evaluate the association between hypertension duration and risk for chronic kidney disease in residents in China. Methods: Participants aged 18-74 years from the sixth round of China Chronic Disease and Risk Factor Surveillance in 2018 were included. The age/date at hypertension diagnosis was reported by them, and hypertension duration was calculated based on the age at diagnosis and the age at survey. The hypertension duration was calculated as 0 year (i.e., normotensive participants), 0.1- year, 5.0- years, 10.0- years, and ≥15.0 years. Serum creatinine, urinary albumin, and urinary creatinine levels were measured, and chronic kidney disease was diagnosed when glomerular filtration rate was <60 ml·min^-1·(1.73 m²)^-1 and/or urine albumin-to-creatinine ratio was ≥30 mg/g. Multivariable logistic regression analysis, which took intra-group correlation into account, was used to evaluate the association of hypertension duration with chronic kidney disease. Results: A total of 140 662 residents were finally included in the analysis. After adjusting the confounders, including blood pressure, the odds ratio of chronic kidney disease was 1.16 (95%CI: 1.09-1.23), 1.33 (95%CI: 1.20-1.48), 1.33 (95%CI: 1.18-1.49), and 1.43 (95%CI: 1.29-1.60) in study subjects with hypertension durations of 0.1-4.9 years, 5.0-9.9 years, 10.0-14.9 years, and ≥15.0 years, respectively, in comparison with normotensive people. This result was further supported by the positive association between hypertension duration and chronic kidney disease in people with previously diagnosed hypertension. The results of restricted cubic spline suggested that the risk for chronic kidney disease showed a steep increase within 0.1- 4.9 years after hypertension diagnosis, then showed neither increase nor decrease. The above association seemed to be stronger in those with hypertension diagnosed age <45 years. Compared with those with hypertension duration of 0.1-4.9 years, the odds ratio was 1.38 (95%CI: 1.04-1.84), 1.22 (95%CI: 0.91-1.65), and 1.47 (95%CI: 1.04-2.07) in those with hypertension durations of 5.0-9.9 years, 10.0-14.9 years, and ≥15.0 year, respectively. In those with hypertension diagnosis at ≥45 years, the corresponding odds ratio was 1.08 (95%CI: 0.98-1.19), 1.08 (95%CI: 0.97-1.21), and 1.16 (95%CI: 1.02-1.32), respectively. Conclusions: Hypertension duration is positively associated with the risk for chronic kidney disease in residents in China, and this association is independent of blood pressure level. Early diagnosis of hypertension and long-term control of blood pressure are effective strategies for secondary prevention of hypertension-related chronic kidney disease.