Abstract Aims Underrepresentation of migrants, women, and older adults in cardiovascular disease (CVD) trials may contribute to disparate care and survival. Among patients who underwent percutaneous coronary intervention (PCI), we aimed to investigate the associations of (i) underrepresented groups with major adverse cardiac events (MACE), CVD mortality, and non-CVD mortality, (ii) underrepresented groups with cardiac rehabilitation (CR) uptake, and (iii) CR uptake with outcomes. Methods and results We included 15 211 consecutive patients from the CARDIOBASE Bern PCI registry (2009–18). In multi-state models comparing transition probabilities of events, sex was not associated with increased risk of any event. For each year increase in age, the increased risk of non-CVD and CVD mortality was 8% [95% confidence interval (CI) 6–9%]. Being migrant was associated with a lower risk of non-CVD mortality [hazard ratio (HR) (95% CI) 0.49 (0.27–0.90)] but not with CVD mortality. In logistic regression analysis, CR uptake was lower among women [odds ratio (95% CI) = 0.72 (0.57–0.86)] and older adults [0.32 (0.27–0.38)], but not among migrants. In cox regression, CR was independently associated with lower all-cause [HR (95% CI) = 0.12 (0.03–0.37)] and CVD mortality [0.1 (0.02–0.7)], but not with MACE [1.08 (0.8–1.4)]. Conclusion Among underrepresented groups undergoing PCI, age, but not migration status nor sex, contributed to disparities in mortality. Migrant status did not result in lower attendance of CR. Considering the protective associations of CR on CVD mortality independent of age, sex, and migration status, the lower uptake in women and older adults is noteworthy.