Hypothetical intervention of targeted systolic blood pressure control of < 120 mmHg on renal prognosis for persons with stage 3-4 chronic kidney disease: an application of parametric g-formula using health checkup data in Japan

Background: The revised KDIGO guidelines recommend maintaining systolic blood pressure (sBP) < 120 mmHg in patients with chronic kidney disease (CKD), based on cardiovascular and survival benefits. However, the renal benefit of this strategy remains less clear.

Methods: We used data of routine health checkups in Japan. Persons whose estimated glomerular filtration rate (eGFR) was < 60 mL/min/1.73 m² in 2015 without end-stage disease were followed until 2020. We estimated the 5-year benefit of hypothetical targeted sBP control using parametric g-formula modeling, accounting for both time-fixed and time-varying confounding variables. Four sensitivity analyses, including analysis using a marginal structural model (MSM) and positive control outcome analysis, were also done.

Results: We enrolled 28,972 persons with CKD (median age: 54 years, male: 69%, baseline eGFR [median]: 56 mL/min/1.73m²). As compared with the natural course without a targeted intervention, there was no renoprotective effect of targeted sBP control, with a 5-year difference in eGFR of 0.65 mL/min/1.73 m² (95% confidence interval - 0.42 to 1.65 mL/min/1.73 m²). MSM analysis found a similar result. In contrast, the positive control analysis using the cardiovascular outcome showed that targeted sBP control would reduce the cardiovascular disease incidence by 6.0% over 5 years.

Conclusions: A targeted sBP control strategy maintaining < 120 mmHg may not yield a renoprotective effect for patients with stage 3-4 CKD, although it was expected to offer a cardiovascular benefit. Future research may be warranted in higher-risk populations, such as elderly people or those with more advanced kidney disease.