The impact of orthostatic hypertension on renal damage in patients with hypertension：a bidirectional cohort study

Objective To investigate the association between orthostatic hypertension (OHT) and worsening of renal function in hypertensive patients.

Methods From January 2016 to May 2024, a bidirectional cohort was established based on data from the hypertension clinic of the Affiliated Hospital of Zunyi Medical University. The study endpoints included:① Rapid decline in renal function (RKFD), defined as during the follow-up period, the estimated glomerular filtration rate (eGFR) decreased by more than 5 mL/ (min·1.73 m²) per year compared with the baseline. ② New-onset chronic kidney disease (CKD), defined as eGFR＜60 mL/(min·1.73 m²) or urinary microalbumin/creatinine ratio (ACR) ≥ 3.0 mg/mmol during follow-up for more than 3 months in a subject who did not have chronic kidney disease at baseline. ③ A composite renal endpoint event, defined as a rapid decline in renal function or a new episode of CKD during follow-up. The deadline for the endpoint event was December 31, 2024. Cumulative blood pressure and inter-visit blood pressure variability used as indicators to evaluate the blood pressure control of patients during the follow-up period. Kaplan-Meier curve and multivariate Cox regression analysis were used to investigate the effect of OHT on renal damage in hypertensive patients.

Results A total of 856 hypertensive patients 45.91% (393 cases) were male and 15.80% (135 cases) had OHT were included in the final cohort, with a mean age of (50.0±10.5) years. During a median follow-up of 3.75 years, a total of 210 (24.53%) patients experienced composite renal endpoint events, 171 (19.98%) patients experienced rapid decline in renal function, and 62 (7.24%) patients developed new CKD. Multivariate Cox regression analysis showed that compared with patients with orthostatic normal blood pressure (ONT), the risks of RKFD and new-onset CKD in OHT patients were increased HR (95%CI) was 3.03 (2.16–4.25), 3.16 (1.78–5.62), respectively, and the risk of composite renal endpoint events also increased (HR=2.81, 95%CI 2.06–3.84). Subgroup analysis showed that the association between OHT and renal endpoint events remained stable across age, gender, normalized cumulative systolic blood pressure, and baseline eGFR levels.

Conclusion OHT is an independent risk factor for worsening renal function in hypertensive patients.