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Kidney Week

Abstract: TH-PO198

Early Decline in GFR Predicts Long-Term Renal Events in Hypertensive CKD Patients Using Renin-Angiotensin System (RAS) Blockers

Session Information

Category: Hypertension and CVD

  • 1602 Hypertension and CVD: Clinical

Authors

  • Yun, Giae, Seoul National University Bundang Hospital Department of Internal Medicine, Seongnam, Gyeonggi-do, Korea (the Republic of)
  • Chin, Ho Jun, Seoul National University Bundang Hospital Department of Internal Medicine, Seongnam, Korea (the Republic of)
Background

Renin-angiotensin-aldosterone inhibitors (RASIs) are essential in treating chronic kidney disease (CKD), but their initiation can lead to a decline in glomerular filtration rate (GFR). Limited research exists on the impact of RASI-induced GFR changes on long-term GFR variations and albuminuria.

Methods

This observational cohort study extends an open-label, case-controlled randomized clinical trial (NCT01552954) with hypertensive CKD patients(estimated GFR (eGFR) ≥30ml/min/1.73m2, random urine albumin-to-creatinine ratio (UACR) ≥30mg/g creatinine). After an 8-week screening phase (0-week) after discontinuing RASIs, participants were prescribed an angiotensin receptor blocker (ARB: Olmesartan 40mg/day) and underwent a second visit at 8 weeks with randomization into intensive or conventional low-salt diet education. Third visit was conducted at 16 weeks. We recruited participants for cohort observation and completed at 38 months(29-48) after a 0-week visit. Patients were grouped into tertiles based on percent change in initial GFR during the first 8 weeks (pcGFRi).

Results

We analyzed data from 174 people finished 38-month observation among 235 participants enrolled for the trial phase. Groups 1, 2, and 3 (first, second, and third tertiles) showed percent changes in GFR of -16.0(-41.5~-8.1), -2.8(-7.3~-1.6), and 8.3(1.8~28.4)%, respectively. At the 0-week visit, there were no differences in the tertile groups' age, gender, GFR, 24hr UACR, or 24hr sodium excretion. These factors positively correlated with the percent change in GFR during the study period (factor B=8.180, p<0.001 for the group; factor B=0.801, p<0.001 for pcGFRi). The GFR slopes during a study peroid were, in order, -2.9(-4.0~-1.8), -1.3(-2.4~-0.3), and 0.1(-1.0~1.2)ml/min/1.73 m2/year (p=0.001 by the ANCOVA test). The relative risks to eGFR decrease ≥30% in groups 2 and 3 compared to 1 were 0.237 (0.07~0.798, p=0.020) and 0.035 (0.004~0.302, p=0.035). The pcGFRi's AUC to eGFR decrease ≥30% was 0.787 (0.685–0.889, p0.001). The cut-off value for pcGFRi eGFR decline ≥30% is 7.25% (71.4 % sensitivity, 70.9% specificity).

Conclusion

The decline of GFR by initiation of RASI predicts long-term renal event of GFR decline ≥30% in users of RASI, strongly. Further research comparing renal outcomes between RASI users with initial decrease in GFR and non-users is needed to guide RASI usage based on initial change in GFR.