Body Mass Index and 10-Year Clinical Outcomes After Percutaneous Coronary Intervention—Interaction with Age, Sex, Diabetic Status and Clinical Presentation

<b>Background/Objective</b>: The association of body mass index (BMI) with long-term outcomes following percutaneous coronary intervention (PCI) remains poorly investigated. We undertook this study to assess the association between BMI and long-term outcomes after PCI. <b>Methods</b>: Overall, 5597 patients with coronary artery disease undergoing PCI were included in the study. Patients were categorized in groups according to the following BMI categories: underweight group (BMI <18.5 kg/m²), normal weight group (BMI 18.5 kg/m² to <25 kg/m²), overweight group (BMI 25 kg/m² to <30 kg/m²) and obesity group (BMI ≥30 kg/m²). The primary endpoint was all-cause mortality at 10 years. <b>Results:</b> At 10 years, all-cause deaths (primary endpoint) occurred in 1754 patients: 31 deaths (59.7%) in the underweight group, 582 deaths (39.1%) in the normal weight group, 710 deaths (31.1%) in the overweight group and 431 deaths (33.8%) in the obesity group (overall <i>p</i> < 0.001; <i>p</i> for nonlinearity <0.001). Nonsurvivors had a significantly lower BMI compared with survivors (26.5 [24.2-29.9] kg/m² vs. 27.2 [24.8-30.1] kg/m², <i>p</i> < 0.001). Interaction testing showed a BMI-by-age interaction denoting a stronger association between higher BMI (≥25 kg/m²) and reduced risk of all-cause mortality in patients ≥75 years of age (P_int = 0.009). The association of BMI with all-cause mortality was U-shaped (<i>p</i> for nonlinearity < 0.001). The C-statistic of the multivariable Cox proportional hazards model for mortality increased from 0.762 [0.751-0.773] with baseline variables only to 0.766 [0.756-0.777], <i>p</i> < 0.001) after the BMI inclusion in the model (baseline variables plus BMI). <b>Conclusions</b>: In patients with coronary artery disease undergoing PCI, BMI was associated with 10-year mortality with a U-shaped relationship.