Risk Factors and Clinical Outcomes in Nonagenarians with Acute Coronary Syndrome: A Case-Control Study

<b>Objective:</b> With the growing number of individuals over the age of 90 (nonagenarians), understanding the risk factors and clinical outcomes associated with acute coronary syndrome (ACS) in this population has become increasingly important. This study aims to compare demographic, biochemical, and clinical parameters between nonagenarian ACS patients and a control group of healthy individuals within the same age bracket, as well as to analyze differences within the ACS group according to myocardial infarction type and evaluate the impact of percutaneous coronary intervention (PCI) on in-hospital mortality. <b>Methods:</b> 104 patients aged 90-100 years diagnosed with ACS for the first time between January 2022 and January 2024 were included in this retrospectively designed case-control study. The patients were categorized into ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) groups based on their electrocardiographic findings. The control group included 113 healthy individuals within the same age range with no prior history of coronary artery disease. Data on traditional risk factors, including lipid profiles and family history, were analyzed using logistic regression models. Additionally, differences in clinical outcomes, including the length of hospital stay and mortality rates, were evaluated based on the application of PCI. <b>Results:</b> The ACS group exhibited significantly higher glucose, white blood cell count, and total cholesterol levels, along with lower hemoglobin and mean corpuscular volume, compared to the control group (<i>p</i> < 0.05). While no significant difference was found in low-density lipoprotein (LDL) levels, high-density lipoprotein (HDL) levels were significantly lower in ACS patients (<i>p</i> < 0.001). Family history played a more substantial role in the STEMI group compared to the NSTEMI group (<i>p</i> = 0.049). Additionally, STEMI patients were more likely to undergo invasive procedures, which were associated with reduced in-hospital mortality (<i>p</i> = 0.042). In contrast, no significant difference in mortality was observed in the NSTEMI group based on PCI status. <b>Conclusions:</b> This study highlights the distinct risk profiles of elderly ACS patients, emphasizing the critical role of low HDL levels and family history, particularly in STEMI cases. Furthermore, PCI was shown to reduce in-hospital mortality rates in STEMI patients, suggesting that invasive treatment approaches may be beneficial even in this vulnerable population. Personalized and multidisciplinary management strategies are essential for this vulnerable population. Further prospective research is needed to validate these findings and guide clinical decision-making for nonagenarians.