Risk Factors for Poor Outcome, Mortality Following Hip Fracture Identified

A new study identifi ed predictors of complications and mortality following a hip fracture, including dialysis, cardiac disease, diabetes, and a longer time before surgery, the only modifiable risk factor when patients are hospitalized.

"This is the first study to postulate predictors of morbidity and mortality following hip fracture using a national model," according to Philip J. Belmont Jr, MD, Orthopaedic Surgeon, William Beaumont Army Medical Center in El Paso, Texas, and colleagues. "While many co-morbidities appear to be infl uential in predicting outcome, some of the more significant factors include the presence of shock, obesity, diabetes and time to surgery."

Each year, more than 340,000 Americans are hospitalized for hip fractures. According to AAOS data, 69% of hip fracture patients are women and 46% are between 65 and 84 years. Many hip fracture patients suffer complications with life-altering consequences. The estimated mortality rate within one year of a hip fracture ranges from 12% to 33%.

In this study, Belmont and colleagues used data from the 2008 National Sample Program (NSP) of the National Trauma Data Bank (NTDB) to identify a representative sample of 44,419 hip fractures. The study population had an average age 72.7 years and 62% of patients were women; patient demographics,
medical comorbidities, injury-specific factors, and outcomes were recorded and a national estimate model developed for analysis.

Primary outcomes included mortality and the development of at least one complication (4.5% and 12.5%), respectively. Secondary outcomes consisted of the development of a major complication and specific complications such as pulmonary/cardiac complications, venous thromboembolic disease, and infection.

Hypertension and diabetes were the most common medical comorbidities among patients. Dialysis, presenting in shock, cardiac disease, male sex, and a high Injury Severity Score (ISS) were signifi cant predictors of mortality. Dialysis, shock, obesity, cardiac disease, diabetes, and a greater time to surgery signifi cantly influenced the risk of developing one or more postoperative complications. Obesity, femoral neck fracture, cardiac disease, and diabetes signifi cantly increased the risk of developing major complications. The presence of shock following injury was the most important predictor of both cardiac and venous thromboembolic disease complications with an odds ratio exceeding 10 for the development of cardiac complications.

"Most of the predictors of complications and mortality are non-modifiable," including the presence of significant cardiac/respiratory disease, diabetes, dependence on dialysis, and presentation to the hospital in shock, explained Belmont. "Reduced time to surgical intervention appears to be the single greatest factor with which a surgeon might infl uence the risk of mortality or complications." A previous study has shown a 41% increase in mortality if surgery is delayed 48 hours or more. The majority of patients are taken into surgery within 24 hours.

In older hip fracture patients, the preoperative work-up, and/or the correction of major clinical abnormalities—important and frequent considerations—can sometimes take more than one day, said Belmont. The potential benefit of correcting major clinical abnormalities prior to hip fracture surgery can influence survival. This process often can be expedited when the orthopedic surgeon works directly with the internal medicine physician or hospitalist who is helping to manage the patient.

"With the rising incidence of hip fractures, patient treatment solutions directed toward this modifi able factor may reduce complications, and potentially, mortality," said Dr. Belmont.