Severe Obesity Linked to Worse Outcomes, Higher Costs of Lower Extremity Fracture Surgery

Obese female patient consulting with male doctor in white coat, looking at clipboard

Patients with severe obesity who undergo surgery for orthopedic trauma tend to have higher morbidity and mortality rates. Given the advent of value-based care and bundled reimbursements, there’s keen interest in characterizing how obesity affects healthcare costs and outcomes.

Christian A. Pean, MD, formerly a fellow in the Harvard Medical School Orthopedic Trauma Initiative, Michael J. Weaver, MD, chief of the Orthopaedic Trauma Service at Brigham and Women’s Hospital, and colleagues recently became the first to project the cost implications of severe obesity for treatment of lower extremity fractures, along with studying its effect on complications and healthcare utilization. In the Journal of Orthopaedic Trauma, they report associations between severe obesity and significantly longer operative times, worse 30-day outcomes, longer hospital stays, and substantially higher costs.


The researchers queried the National Surgical Quality Improvement Project (NSQIP) database of the American College of Surgeons, which prospectively collects more than 200 variables on surgical procedures at more than 600 participating hospitals.

For the years 2012 to 2019, they identified 10,436 adults who underwent femoral shaft and tibial shaft fracture fixation, excluding polytrauma cases, with 7% categorized as having severe obesity (body mass index >40 kg/m2).

The authors applied publicly available data from the Agency for Healthcare Research Quality (AHRQ) and the Centers for Medicare and Medicaid Services to the cohort’s rates of readmission and inpatient hospital stays.

They determined the cost of operative time to be $37/minute, using methods from an AHRQ study. They also estimated additional costs of certain complications attributable to severe obesity using a previous cost analysis of the NSQIP (published in The Joint Commission Journal on Quality and Patient Safety).

Clinical Outcomes and Healthcare Utilization

Compared with patients whose BMI was 18 to 30 kg/m2, patients with severe obesity had:

  • Significantly higher 30-day infectious complication rates—mean, 9.0% vs. 6.7% (OR, 1.36, P=0.013)
  • Significantly higher 30-day readmission rates—7.9% vs. 5.6% (OR, 1.44; P=0.008)
  • Significantly longer hospital stays—5.8 vs. 5.0 days (P=0.008)
  • Significantly longer operative times—115 vs. 103 minutes (P=0.001)


On average, severe obesity resulted in an estimated $4,258.07 in additional healthcare expenditures per patient compared with normal BMI. This represented annual projected expenses of $365,776.43 and $3.09 million in added costs for the cohort during the study period.

Policy Considerations

These results suggest orthopedic surgeons and hospitals that care for a disproportionate number of patients with obesity may face an undue cost and capacity burden, especially under bundled payment systems. This is particularly relevant in orthopedic trauma, where modification of risk factors before surgery is seldom feasible.

Applying quality-driven reimbursement in these populations could inadvertently avoid disincentivizing operating decisions and should be considered when patients with obesity present with lower extremity fractures. Because of the higher prevalence of obesity in Black patients and other U.S. racial/ethnic minority patients, this issue also has implications for health equity.

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