Early changes in renal function during rapid up‐titration of guideline‐directed medical therapy following an admission for acute heart failure

Aim In this subgroup analysis of STRONG‐HF, we explored the association between changes in renal function and efficacy of rapid up‐titration of guideline‐directed medical therapy (GDMT) according to a high‐intensity care (HIC) strategy. Methods and results In patients randomized to the HIC arm (n = 542), renal function was assessed at baseline and during follow‐up visits. We studied the association with clinical characteristics and outcomes of a decrease in estimated glomerular filtration rate (eGFR) at week 1, defined as ≥15% decrease from baseline. Patients in the usual care group (n = 536) were seen at day 90. The treatment effect of HIC versus usual care was independent of baseline eGFR (p‐interaction = 0.4809). A decrease in eGFR within 1 week occurred in 77 (15.5%) patients and was associated with more rales on examination (p = 0.004), and a higher New York Heart Association class at the corresponding visit. Following the decrease in eGFR at 1 week, lower average optimal doses of GDMT were prescribed during follow‐up (p = 0.0210) and smaller reductions in N‐terminal pro‐B‐type natriuretic peptide occurred (geometrical mean 0.81 in no eGFR decrease vs 1.12 in GFR decrease, p = 0.0003). The rate of heart failure (HF) readmission or death at 180 days was 12.3% in no eGFR decrease versus 18.5% in eGFR decrease (p = 0.2274) and HF readmissions were 7.8% versus 16.6% (p = 0.0496). Conclusions In the STRONG‐HF study, HIC reduced 180‐day HF readmission or death regardless of baseline eGFR. An early decrease in eGFR during rapid up‐titration of GDMT was associated with more evidence of congestion, yet lower doses of GDMT during follow‐up.