Association of long-term aspirin use with kidney disease progression.

BACKGROUND: Chronic microinflammation contributes to the progression of chronic kidney disease (CKD). Aspirin (ASA) has been used to treat inflammation for centuries. The effects of long-term low-dose ASA on CKD progression are unclear.

METHODS: We examined the association of long-term use of newly initiated low-dose ASA (50-200 mg/day) with all-cause mortality using Cox proportional hazard models; with cardiovascular/cerebrovascular (CV) mortality and with end stage kidney disease (ESKD) using Fine and Gray competing risk regression models; with progression of CKD defined as patients' eGFR slopes steeper than -5 mL/min/1.73m2 /year using logistic regression models in a nationwide cohort of US Veterans with incident CKD. Among 831,963 patients, we identified 385,457 who either initiated ASA ( N  = 21,228) within 1 year of CKD diagnosis or never received ASA ( N  = 364,229). We used propensity score matching to account for differences in key characteristics, yielding 29,480 patients (14,740 in each group).

RESULTS: In the matched cohort, over a 4.9-year median follow-up period, 11,846 (40.2%) patients (6,017 vs. 5,829 ASA users vs. non-users) died with 25.8% CV deaths, and 934 (3.2%) patients (476 vs. 458) reached ESKD. ASA users had a higher risk of faster decline of kidney functions, i.e., steeper slopes (OR 1.30 [95%CI: 1.18, 1.44], p  < 0.01), but did not have apparent benefits on mortality (HR 0.97 [95%CI: 0.94, 1.01], p  = 0.17), CV mortality (Sub-Hazard Ratio [SHR]1.06 [95%CI: 0.99-1.14], p  = 0.11), or ESKD (SHR1.00 [95%CI: 0.88, 1.13], p  = 0.95).

CONCLUSION: Chronic low-dose ASA use was associated with faster kidney function deterioration, and no association was observed with mortality or risk of ESKD.