Impact of body mass index on utilization of selected hospital resources for four common surgical procedures

Background Evidence about the impact of obesity on surgical resource consumption in the Australian setting is equivocal. Our objectives were to quantify the prevalence of obesity in four frequently performed surgical procedures and explore the association between body mass index (BMI) and hospital resource utilization including procedural duration, length of stay (LOS) and costs. Methods A retrospective cohort study of patients undergoing four surgical procedures at a tertiary referral centre in New South Wales, between 1 January 2016 and 31 December 2016, was conducted. The four surgical procedures were total hip replacement, laparoscopic appendectomy, laparoscopic cholecystectomy and hysteroscopy with dilatation and curettage. Surgical groups were stratified according to BMI category. Results A total of 699 patients were included in the study. The prevalence of obesity was significantly higher than local and national population estimates for all procedures except appendectomy. BMI was not associated with increased hospital resource utilization (procedural, anaesthetic or intensive care stay duration) in any of the four surgical procedures examined after controlling for age, gender and complexity. For other outcomes of hospital resource utilization (LOS and cost), the relationship was inconsistent across the four procedures examined. A high BMI was positively associated with higher LOS, medical costs and allied health costs in those who underwent an appendectomy, and critical care costs in those who underwent laparoscopic cholecystectomy. Conclusion Obesity was common in patients undergoing four frequently performed surgical procedures. The relationship between BMI and hospital resource utilization appears to be complex and varies across the four procedures examined.