Body mass index and risk of adverse cardiac events in elderly patients with hip fracture: a population-based study.
OBJECTIVE
To determine whether obesity affects cardiac complications after hip fracture repair.


METHODS
A population-based historical study using data from the Rochester Epidemiology Project.


METHODS
Olmsted County, Minnesota.


METHODS
All urgent hip fracture repairs between 1988 and 2002.


METHODS
Body mass index (BMI) was categorized as underweight (<18.5 kg/m(2)), normal-weight (18.5-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), and obese (>or=30 kg/m(2)). Postoperative cardiac complications were defined as myocardial infarction, angina pectoris, congestive heart failure, or new-onset arrhythmias within 1-year of surgery. Incidence rates were estimated for each outcome, and overall cardiac complications were assessed using Cox proportional hazards models adjusted for age, sex, year of surgery, use of beta-blockers, and the Revised Cardiac Risk Index.


RESULTS
Hip fracture repairs were performed in 184 (15.6%) underweight, 640 (54.2%) normal-weight, 251 (21.3%) overweight, and 105 (8.9%) obese subjects (mean age 84.2 +/- 7.5; 80% female). Baseline American Society of Anesthesiologists (ASA) status was similar in all groups (ASA I/II vs III-V, P=.14). Underweight patients had a significantly higher risk of developing myocardial infarction (odds ratio (OR) 1.44, 95% confidence interval (CI)=1.0-2.1; P=.05) and arrhythmias (OR=1.59, 95% CI=1.0-2.4; P=.04) than normal-weight patients. Multivariate analysis demonstrated that underweight patients had a higher risk of developing an adverse cardiac event of any type (OR=1.56, 95% CI=1.22-1.98; P<.001). Overweight and obese patients with hip fracture had no excess risk of any cardiac complication.


CONCLUSIONS
The obesity paradox and low functional reserve in underweight patients may influence the development of postoperative cardiac events in elderly people with hip fracture.
Batsis
John A
JA
Section of General Internal Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA. John.batsis@gmail.com
Huddleston
Jeanne M
JM
Melton
L Joseph
LJ
Huddleston
Paul M
PM
Lopez-Jimenez
Francisco
F
Larson
Dirk R
DR
Gullerud
Rachel E
RE
McMahon
M Molly
MM
D000368:Aged; D000369:Aged, 80 and over; D000787:Angina Pectoris / Q000453:epidemiology / Q000209:etiology*; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000209:etiology*; D015992:Body Mass Index; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006333:Heart Failure / Q000453:epidemiology / Q000209:etiology*; D006620:Hip Fractures / Q000453:epidemiology / Q000601:surgery*; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008910:Minnesota; D009203:Myocardial Infarction / Q000453:epidemiology / Q000209:etiology*; D009765:Obesity / Q000150:complications* / Q000453:epidemiology; D050177:Overweight / Q000150:complications / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D013851:Thinness / Q000150:complications / Q000453:epidemiology