Comparison of the effectiveness and safety of two aspirin doses in secondary prevention of cardiovascular outcomes in patients with chronic kidney disease: a subgroup analysis of ADAPTABLE.

BACKGROUND: Among patients with established cardiovascular disease, the ADAPTABLE trial found no significant differences in cardiovascular events and bleeding rates between 81 mg and 325 mg of aspirin (ASA) daily. In this secondary analysis from the ADAPTABLE trial, we studied the effectiveness and safety of ASA dosing in patients with a history of chronic kidney disease (CKD).

METHODS: ADAPTABLE participants were stratified based on the presence or absence of CKD, defined using ICD-9/10-CM codes. Within the CKD group, we compared outcomes between patients taking ASA 81 mg and 325 mg. The primary effectiveness outcome was defined as a composite of all cause death, myocardial infarction, or stroke and the primary safety outcome was hospitalization for major bleeding. Adjusted Cox proportional hazard models were utilized to report differences between the groups.

RESULTS: After excluding 414 (2.7%) patients due to missing medical history, a total of 14,662 patients were included from the ADAPTABLE cohort, of whom 2648 (18%) patients had CKD. Patients with CKD were older (median age 69.4 vs. 67.1 years; p<0.0001) and less likely to be white (71.5% vs. 81.7%; p<0.0001) when compared to those without CKD. At a median follow-up of 26.2 months, CKD was associated with an increased risk of both the primary effectiveness outcome (adjusted HR 1.79 (1.57, 2.05) P<0.001 and the primary safety outcome (adjusted HR 4.64 (2.98, 7.21), p<0.001 and p<0.05, respectively) regardless of ASA dose. There was no significant difference in effectiveness (adjusted HR 1.01 95% CI 0.82, 1.23; p=0.95) or safety (adjusted HR 0.93; 95% CI 0.52, 1.64; P=0.79) between ASA groups.

CONCLUSION: Patients with CKD were more likely than those without CKD to have adverse cardiovascular events or death and were also more likely to have major bleeding requiring hospitalization. However, there was no association between ASA dose and study outcomes among these patients with CKD.