Effect of Obesity and Overweight Status on Complications and Survival After Minimally Invasive Kidney Surgery in Patients with Clinical T2-4 Renal Masses.

Objective

To evaluate the effect of obesity and overweight on surgical, functional, and survival outcomes in patients with large kidney masses after minimally invasive surgery. Materials and

Methods

Within a multicenter multinational dataset, patients found to have ≥cT2 renal mass and treated with minimally invasive (laparoscopic or robotic) kidney surgery (radical or partial nephrectomy) during the period 2003 to 2017 were abstracted. They were stratified according to the body mass index classes as normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30.0 kg/m2). Mixed models and Cox proportional hazard regression tested differences in complication rates, estimated glomerular filtration rate (eGFR) change over time, overall mortality (OM), and disease recurrence (DR) rates.

Results

Of 812 patients, 30.6% were normal weight, 42.7% were overweight, and 26.7% obese. Overweight (odds ratio 0.82, 95% confidence interval [CI]: 0.51-1.31, p = 0.406) and obese patients (OR: 0.81, 95% CI: 0.44-1.47, p = 0.490) experienced similar complication rates than normal weight. Moreover, no statistically significant differences in eGFR were found for overweight (p = 0.129) or obese (p = 0.166) patients compared to normal weight. However, higher OM rates were recorded in overweight (hazard ratio [HR] 3.59, 95% CI: 1.03-12.51, p = 0.044), as well as in obese, patients (HR 7.83, 95% CI: 2.20-27.83, p = 0.002). Similarly, higher DR rates were recorded in obese (HR 2.76, 95% CI: 1.40-5.44, p = 0.003) patients.

Conclusions

Obese and overweight patients do not experience higher complication rates or worse eGFR after minimally invasive kidney surgery, which therefore can be deemed feasible and safe also in this subset of patients. Nevertheless, obese and overweight patients seem to carry a higher risk of OM, and therefore, they should undergo a strict follow-up after surgery.