Intensive blood pressure control and the progression of IgA nephropathy: a cohort study using marginal structural models.

Abstract

In chronic kidney disease, current guidelines recommend systolic blood pressure (SBP) below 120mmHg. However, the renoprotective effect of intensive blood-pressure (BP) lowering on immunoglobulin A nephropathy (IgAN) remains undetermined. We aimed to determine the effect of intensive BP control on the progression of IgAN. At Peking University First Hospital, 1530 patients with IgAN were enrolled. An examination of the relationship between baseline and time-updated BP and composite kidney outcomes, defined as development of end-stage kidney disease (ESKD) or a 30% decline in estimated glomerular filtration rate (eGFR), was conducted. Baseline and time-updated BPs were modeled using multivariate causal hazards models and marginal structural models (MSMs). In a median follow-up of 43.5 (interquartile range 27.2, 72.7) months, 367 (24.0%) patients experienced the composite kidney outcomes. No significant associations were found between baseline BP and the composite outcomes. Using MSMs with time-updated SBP for analysis, a U-shaped association was found. In reference to SBP 110-119mmHg, hazard ratios (95% confidence intervals) for the SBP categories <110, 120-129, 130-139 and ≥140mmHg were 1.48 (1.02-2.17), 1.13 (0.80-1.60), 2.21 (1.54-3.16) and 2.91 (1.94-4.35), respectively. The trend was more prominent in patients with proteinuria ≥1g/day and eGFR ≥60mL/min/1.73 m2. After analyzing time-updated diastolic BP, no similar trend was observed. In patients with IgAN, intensive BP control during the treatment period may retard the kidney disease progression, but the potential risk of hypotension still needs to be considered.