Metabolic syndrome and hip fracture: Epidemiology and perioperative outcomes.

INTRODUCTION: Hip fractures and metabolic syndrome (MetS) are becoming major global healthcare burdens as populations age. This study sought to determine the impact of MetS in hip fracture patients on perioperative outcomes following operative fixation or arthroplasty.

METHODS: Data from the 2004-2014 Nationwide Inpatient Sample was used to select 3,348,207 discharges with hip fracture. MetS patients were identified by having at least 3 of 4 component comorbidities: hypertension, dyslipidemia, obesity, and diabetes. Logistic regression was used to estimate odds ratios for the association between MetS and perioperative outcomes adjusted for age, gender, race, payer status, and comorbidities.

RESULTS: Overall, 32% of hip fracture patients were treated with open reduction internal fixation (ORIF), 28% hemiarthroplasty (HA), 18% closed reduction with internal fixation (CRPP), and 3% primary total hip arthroplasty (THA). The remaining 19% of cases were either treated via unspecified procedure of hip repair (9%), managed non-operatively (2%), underwent multiple procedures during the hospital stay (6%), or the surgical procedure data was missing (2%) and were excluded from procedural analyses. The prevalence of MetS was 7.9% and increased among minorities, patients treated at urban hospitals, with comorbidities (heart failure, kidney disease, peripheral vascular disease), and with Medicare coverage. MetS was associated with increased odds of any adverse event (p < 0.0001), specifically: acute renal failure, myocardial infarction, acute posthemorrhagic anemia. MetS was also associated with increased LOS (p < 0.0001) and increased total charges (p < 0.0001). However, MetS was associated with reduced odds of postoperative pneumonia, deep vein thrombosis and pulmonary embolism, surgical site infection, septicemia, and in-hospital mortality (p < 0.0001). The above associations were maintained for MetS patients stratified according to their treatment groups: HA, CRPP, and ORIF.

CONCLUSIONS: MetS is associated with increased odds of complications in hip fracture patients but decreased odds of in-hospital mortality. This may be related to patients' nutritional status and catabolic states in the perioperative period.