Purpose: We analyzed the impact of obesity on the costs of partial and radical nephrectomy.
Materials and methods: The charts of 237 patients who underwent open radical nephrectomy (48), laparoscopic radical nephrectomy (67), open partial nephrectomy (61) or laparoscopic partial nephrectomy (61) were retrospectively reviewed. Clinical data were collected, including age, American Society of Anesthesiologists score, body mass index, tumor size, complications and length of stay. Cost data comprised total direct costs and subcosts, including anesthesia, laboratory, operating room service, radiology, room and board, pharmacy and surgical supplies. Obese and nonobese patients were compared in each group using the Mann-Whitney U and chi-square tests for continuous and categorical variables, respectively. Univariate analysis was used to assess predictors of direct costs.
Results: Length of stay was longer in obese patients in the open partial nephrectomy group (p = 0.04). There were no differences between obese and nonobese patients in terms of complications and comorbidities. Costs were higher in obese patients in the open partial nephrectomy group ($10,187 vs $6,538, p = 0.02). There were no other differences in cost between obese and nonobese patients in the 3 other surgical groups. On univariate analysis length of stay robustly predicted the cost of each kind of operation (p <0.0001). Obesity status was almost a significant predictor of direct cost in the open partial nephrectomy group (p = 0.056).
Conclusions: Body mass index had an impact on costs only in the subset of patients who underwent open partial nephrectomy. Length of stay seems to be the main determinant of costs in renal surgery. Further studies are warranted.