Meta-Analysis Identifies Risk Factors for Adverse Outcomes in MINOCA Patients

This systematic review and meta-analysis investigated the association between common clinical risk factors and long-term outcomes in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA). The analysis included 12,081 patients from multiple studies, with a mean follow-up of 49.2 months. The primary outcomes were major adverse cardiac events (MACEs) and all-cause mortality.

The pooled incidence of MACEs was 17%, and all-cause mortality was 10%. For MACEs, older age was associated with increased risk (HR: 1.02, 95% CI: 1.01-1.04), while higher BMI was protective (HR: 0.92, 95% CI: 0.86-0.99). For all-cause mortality, significant predictors included age (HR: 1.04 per year), diabetes (HR: 1.33, 95% CI: 1.07-1.64), creatinine (HR: 1.01, 95% CI: 1.0009-1.02), and STEMI-pattern presentation (HR: 2.85, 95% CI: 1.09-7.44). Higher BMI (HR: 0.89, 95% CI: 0.82-0.98) and dyslipidemia (HR: 0.83, 95% CI: 0.76-0.90) were associated with lower mortality.

Safety and tolerability data were not reported in this meta-analysis, as it focused on risk factors rather than interventions. The study did not report adverse events, serious adverse events, or discontinuations.

Compared to prior studies in MINOCA, this meta-analysis confirms that traditional cardiovascular risk factors such as age and diabetes remain important, but also highlights the paradoxical protective effect of higher BMI and dyslipidemia, known as the obesity paradox and lipid paradox, which have been observed in other cardiovascular populations. However, the mechanisms behind these associations remain unclear.

Key methodological limitations include the observational nature of the included studies, which precludes causal inference. The analysis was restricted to select clinical variables, and many traditional MI risk factors were not predictive. The authors note that only select clinical variables predict outcomes in MINOCA, while many traditional MI risk factors do not. Additionally, the meta-analysis did not report on potential confounders or heterogeneity among studies.

Clinically, these findings highlight the need for MINOCA-specific risk models and targeted management strategies, as traditional risk stratification tools may not apply. The protective associations of higher BMI and dyslipidemia should be interpreted cautiously and not lead to changes in lifestyle recommendations.

Unanswered questions include the underlying mechanisms for the protective effects of higher BMI and dyslipidemia, the role of other potential risk factors not analyzed, and whether targeted interventions based on these risk factors can improve outcomes. Further prospective studies are needed to validate these findings and develop MINOCA-specific risk scores.