Impact of body mass index on the clinical outcomes after percutaneous coronary intervention in patients ≥ 75 years old.

Background: The impact of body mass index (BMI) on the clinical outcomes after percutaneous coronary intervention (PCI) in patients ≥ 75 years old remained unclear.

Methods: A total of 1098 elderly patients undergoing PCI with stent implantation were recruited. Patients were divided into four groups by the value of BMI: Underweight (≤ 20.0 kg/m 2 ), normal weight (20.0-24.9 kg/m 2 ), overweight (25.0-29.9 kg/m 2 ) and obese (≥ 30.0 kg/m 2 ). Major clinical outcomes after PCI were compared between the groups. The primary endpoint was defined as in-hospital major adverse cardiovascular events (MACEs), which included death, myocardial infarction (MI) and target vessel revascularization. The secondary endpoint was defined as 1 year death. Logistic regression analysis was performed to adjust for the potential confounders.

Results: Totally, 1077 elderly patients with available BMIs were included in the analysis. Patients of underweight, normal weight, overweight and obese accounted for 5.6%, 45.4%, 41.5% and 7.5% of the population, respectively. Underweight patients were more likely to attract ST-segment elevation MI, and get accompanied with anemia or renal dysfunction. Meanwhile, they were less likely to achieve thrombolysis in MI 3 grade flow after PCI, and receive beta-blocker, angiotensin converting enzyme inhibitor or angiotensin receptor blocker after discharge. In underweight, normal weight, overweight and obese patients, in-hospital MACE were 1.7%, 2.7%, 3.8%, and 3.7% respectively (P = 0.68), and 1 year mortality rates were 5.0%, 3.9%, 5.1% and 3.7% (P = 0.80), without significant difference between the groups. Multivariate regression analysis showed that the value of BMI was not associated with in-hospital MACE in patients at 75 years old.

Conclusions: The BMI "obese paradox" was not found in patients ≥ 75 years old. It was suggested that BMI may not be a sensitive predictor of adverse cardiovascular events in elderly patients.