Objective:

To describe the association between CCI-defined comorbidity burden and long-term all-cause mortality in elderly patients with acute myocardial infarction (AMI).

Approach:

• Study Design: Retrospective cohort study of 350 elderly patients (age ≥65 years) admitted with AMI.
• Data Collection: CCI scores calculated from admission records; patients stratified into low, moderate, and high comorbidity groups.
• Statistical Analysis: Cox proportional hazards models used to assess the association between CCI and long-term all-cause mortality.

Key Findings:

• 28.0% of patients died during a median follow-up of 40.9 months (range: 1.4–57.5 months).
• All-cause mortality increased with higher CCI scores: 16.95% (low, CCI 1–2), 29.58% (moderate, CCI 3–4), 40.00% (high, CCI ≥5); Log-rank P < 0.001.
• Univariable analysis showed CCI score significantly associated with all-cause mortality (HR = 1.164, 95% CI 1.059–1.278, P = 0.002).
• In multivariable analysis, CCI did not reach statistical significance after adjustment for confounders (HR = 1.089, P = 0.125).
• Smoking history was independently associated with worse prognosis (HR = 1.862, P = 0.003), while PCI receipt was associated with lower mortality (HR = 0.497, P = 0.001).

Interpretation:

Higher CCI scores correlate with increased long-term all-cause mortality in univariable analyses, but CCI's independent predictive ability is not confirmed after multivariable adjustment.

Limitations:

• Observational study design may introduce biases and limit causal inferences.
• CCI was not independently associated with long-term mortality after adjustment.
• Subgroup analyses were exploratory and not intended to establish independent predictive ability.

Conclusion:

Routine CCI assessment may help characterize comorbidity burden, but individualized risk assessment should consider multiple clinical factors.