Session II - Geriatric

Fri., 10/11/13 Geriatric, PAPER #39, 8:00 am OTA 2013

Association Between Type of Surgery and Perioperative Acute Myocardial Infarction in Elderly Hip Fracture Patients

Nathalie H. Urrunaga, MD, MS1; Amelia C. Watkins, MD2; Robert S. Sterling, MD3;
Mary L. Forte, PhD, DC4;
1Department of Medicine, Division of Gastroenterology and Hepatology,
University of Maryland School of Medicine, Baltimore, Maryland, USA;
2Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA;
3Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA;
4Departments of Epidemiology and Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA

Background/Purpose: Recent noncardiac surgical research suggests that perioperative myocardial infarction (MI) is becoming a dominant complication after noncardiac surgery. However, the incidence of perioperative MI in surgically treated hip fracture patients is unknown. Moreover, the impact of the type of surgery on MI risk is unknown.The aims of this study were to determine the incidence of inpatient MI in surgically treated low-energy hip fracture patients, and whether the odds of MI differed by the type of surgery (internal fixation [IF], hemiarthroplasty [HA], or total hip arthroplasty [THA]) after controlling for other factors. We hypothesized that MI risk would be highest after arthroplasty.

Methods: We used a retrospective cohort of low-energy, surgically treated hip fracture patients (ICD-9 820.x, OA/OTA 31-A, 31-B) age 65 years or older from the 2000-2009 Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample. Patients with cancer, revisions, infection, or high-energy trauma were excluded. The primary outcome was acute MI; the secondary outcome was mortality. Multivariate logistic regression modeled the association between the type of surgery (IF, HA, THA) and MI, controlling for age, sex, type of fracture, and modified Charlson score without acute MI. Incidence estimates (inpatient MI and MI-associated mortality) and adjusted odds ratios (OR) from SAS survey procedures are reported.

Results: 2,275,944 discharges met inclusion criteria. The mean patient age was 83 years and most patients were female (75.6%). IF was used in 63.4% of patients; 34.0% received HA and 2.6% received THA. Nearly half of the fractures were intertrochanteric or subtrochanteric (50.9% combined) and 96.5% of these were treated with IF. Femoral neck (28.9%) and unspecified femoral neck fractures (20.2%; ICD-9 820.8, 820.9) comprised the remaining hip fractures of which 66.1% received HA and 4.8% THA. Perioperative acute MI occurred in 2.2% of patients overall. MI differed by procedure and was highest after HA (2.5%) and lowest after IF (2.0%). Multivariate analysis showed a similar pattern by procedure. The odds of acute MI were higher after HA (OR 1.46; 95%confidence interval [CI] 1.38, 1.56) and THA (OR 1.27; 95% CI 1.10, 1.46) compared with IF, after controlling for other factors. Overall, inpatient mortality after acute MI was eight times that of patients without MI (17.4% vs 2.2%) and MI-associated mortality was highest after THA (18.2%).

Conclusion: Arthroplasty was associated with higher odds of MI and higher MI-associated mortality than internal fixation in older hip fracture patients. Acute MI is a deadly perioperative condition after hip fracture. When considering arthroplasty for treatment of a hip fracture, the surgeon must weigh the additional MI risk and associated mortality of this procedure versus internal fixation. Routine screening for MI could improve survival since early intervention after MI improves outcomes.

Alphabetical Disclosure Listing

• The FDA has not cleared this drug and/or medical device for the use described in this presentation   (i.e., the drug or medical device is being discussed for an “off label” use).  ◆FDA information not available at time of printing. Δ OTA Grant.