Treatment Effect of Percutaneous Coronary Intervention in Dialysis Patients With ST-Elevation Myocardial Infarction

Rationale & Objective: Patients receiving maintenance dialysis have higher mortality after primary percutaneous coronary intervention (pPCI) than patients not receiving dialysis. Whether pPCI confers a benefit to patients receiving dialysis that is similar to that which occurs in lower-risk groups remains unknown. We compared the effect of pPCI on in-hospital outcomes among patients hospitalized for ST-elevation myocardial infarction (STEMI) and receiving maintenance dialysis with the effect among patients hospitalized for STEMI but not receiving dialysis. Study Design: Retrospective cohort study. Setting & Participants: We used the National Inpatient Sample (2016-2018) and included all adult hospitalizations with a primary diagnosis of STEMI. Predictors: Primary exposure was PCI. Confounders included dialysis status, demographics, insurance, household income, comorbidities, and the elective nature of the admission. Outcome: In-hospital mortality, stroke, acute kidney injury, new dialysis requirement, vascular complications, gastrointestinal bleeding, blood transfusion, mechanical ventilation, palliative care, and discharge destination. Analytical Approach: The average treatment effect (ATE) of pPCI was estimated using propensity score matching independently within the group receiving dialysis and the group not receiving dialysis to explore whether the effect is modified by dialysis status. Additionally, the average marginal effect (AME) was calculated accounting for the clustering within hospitals. Results: Among hospitalizations, 4,220 (1.07%) out of 413,500 were for patients receiving dialysis. The dialysis cohort was older (65.2 +/- 12.2 vs 63.4 +/- 13.1, P < 0.001), had a higher proportion of women (42.4% vs 30.6%, P < 0.001) and more comorbidities, and had a lower proportion of White patients (41.1% vs 71.7%, P < 0.001). Patients receiving dialysis were less likely to undergo angiography (73.1% vs 85.4%, P < 0.001) or pPCI (57.5% vs 79.8%, P < 0.001). Primary PCI was associated with lower mortality in patients receiving dialysis (15.7% vs 27.1%, P < 0.001) as well as in those who were not (5.0% vs 17.4%, P < 0.001). The ATE on mortality did not differ significantly (P interaction = 0.9) between patients receiving dialysis (-8.6% [95% CI, -15.6% to -1.6%], P = 0.02) and those who were not (-8.2% [95% CI, -8.8% to -7.5%], P < 0.001). The AME method showed similar results among patients receiving dialysis (-9.4% [95% CI, -14.8% to -4.0%], P < 0.001) and those who were not (-7.9% [95% CI, -8.5% to -7.4%], P < 0.001) (P interaction = 0.6). Both the ATE and AME were comparable for other in-hospital outcomes in both groups. Limitations: Administrative data, lack of pharmacotherapy and long-term outcome data, and residual confounding. Conclusions: Compared with conservative management, pPCI for STEMI was associated with comparable reductions in short-term mortality among patients irrespective of their receipt of maintenance dialysis.