Class 3 Obesity is Not Associated with Same-day Admission in Obese Patients Undergoing Parathyroidectomy

Importance: Rising rates of obesity and outpatient performance of parathyroidectomies are making it increasingly crucial to investigate the association of obesity with post-operative complications.

Objective: To determine whether Class 3 obesity is associated with increased same-day admission compared to lower obesity classes following outpatient parathyroidectomy.

Design: Retrospective cohort study.

Setting: Outpatient surgery.

Patients: 12,973 patients ≥18 years old who underwent outpatient parathyroidectomy between 2014 and 2016, per the American College of Surgeons National Surgical Quality Improvement Program registry.

Interventions: Primary exposure variable: body mass index (BMI), with patients assigned to one of six cohorts.

Measurements: Primary outcome measure: same-day admission. Secondary outcome measure: 30-day readmission. Logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI).

Main Results: There was a final sample size of 12,973 adult patients who underwent parathyroidectomy from 2014 to 2016. The admission rate for BMI ≥30 and < 40 kg/m (reference cohort) was 42.6%. The admission rates for Class 3 obesity categories were 46.2%, 56.2%, and 52.6% for those in the BMI range of ≥40 kg/m and < 50 kg/m, ≥50 kg/m and < 60 kg/m, and ≥ 60 kg/m, respectively. On multivariable logistic regression, there were no difference in the odds of 30-day hospital admission or readmission rate with any of the BMI cohorts when compared to the reference group.

Conclusions: There is no significant difference in rates of same-day admission or 30-day readmission between any Class 3 (BMI ≥40 kg/m) obesity cohort and the Class 1 and 2 (BMI ≥30 and < 40 kg/m) reference cohort following outpatient parathyroidectomy. This corroborates the notion that BMI classes cannot be used in a vacuum to determine eligibility for outpatient parathyroidectomy - a concept that can guide safe and cost-effective institutional practices.