December 11, 2013
View Full PaperAssociation of Body Mass Index and Long-Term Outcomes in Older Patients With Non–ST-Segment–Elevation Myocardial Infarction
Key Result
Among 34,465 older patients with NSTEMI, overweight and obese class I and II patients had lower long-term mortality compared to normal-weight patients, but similar or higher readmissions.
Study Design
Type
Cohort (n=34,465)
Multicenter
Yes
Structured PICO
Does higher body mass index improve long-term outcomes in older patients with non-ST-segment-elevation myocardial infarction?
P
Population
34,465 patients aged ≥65 years with non-ST-segment-elevation myocardial infarction, followed for 3 years after hospital discharge.
E
Exposure
Overweight (BMI 25.0-29.9), obese class I (BMI 30.0-34.9), obese class II (BMI 35.0-39.9), and obese class III (BMI ≥40.0)
C
Comparator
Normal-weight patients
O
Outcome
All-cause mortality for 3 years after hospital dischargehard clinical
In older patients with NSTEMI, being overweight or mildly to moderately obese is associated with lower long-term mortality compared to normal weight, demonstrating a long-term obesity paradox.
Abstract
BACKGROUND: Prior studies have found that obese patients have paradoxically lower in-hospital mortality after non-ST-segment-elevation myocardial infarction than their normal-weight counterparts, yet whether these associations persist long term is unknown. METHODS AND RESULTS: We linked detailed clinical data for patients with non-ST-segment-elevation myocardial infarction aged ≥65 years in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the American College of Cardiology/American Heart Association Guidelines (CRUSADE) Registry to Medicare claims data to obtain longitudinal outcomes. Using height and weight measured on admission, patients were categorized into 6 body mass index (BMI kilograms per meter squared) groups. Multivariable Cox proportional hazards models were used to estimate the association between BMI and (1) all-cause mortality, (2) all-cause readmission, (3) cardiovascular readmission, and (4) noncardiovascular readmission for 3 years after hospital discharge. Among older patients with non-ST-segment-elevation myocardial infarction (n=34,465), 36.3% were overweight and 27.7% were obese. Obese patients were younger and more likely to have hypertension, diabetes mellitus, and dyslipidemia than normal or underweight patients. Relative to normal-weight patients, long-term mortality was lower for patients classified as overweight (BMI, 25.0-29.9), obese class I (BMI, 30.0-34.9), and obese class II (BMI, 35.0-39.9), but not obese class III (BMI ≥40.0). In contrast, 3-year all-cause and cardiovascular readmission were similar across BMI categories. Relative to normal-weight patients, noncardiovascular readmissions were similar for obese class I but higher for obese class II and obese class III. CONCLUSIONS: All-cause long-term mortality was generally lower for overweight and obese older patients after non-ST-segment-elevation myocardial infarction relative to those with normal weight. Longitudinal readmissions were similar or higher with increasing BMI.