Accuracy of the NSQIP risk calculator for predicting complications following adrenalectomy

Adrenalectomy is performed to treat functional pathology and remove tumors of malignant concern. The National Surgical Quality Improvement Program (NSQIP) risk calculator predicts 30-day complications and length of stay following index surgical procedures. We assess whether this tool accurately predicts complications following adrenalectomy procedures at a tertiary care academic medical center.

A retrospective review was performed for all adrenalectomies at a single institution from 2004 to 2016. 197 patients underwent adrenalectomy without concurrent resections. Predicted risk for NSQIP complications was calculated for each patient. The mean predicted and observed risks (%) at 30 days across all patients within each category were determined, and these were compared with two-sided one-sample t tests.

Of 197 adrenalectomies, 180 were laparoscopic and 17 were open. For laparoscopic adrenalectomy, ten (5.5%) complications were observed including nine (5%) graded Clavien III or greater. All observed complication rates were significantly different than predicted (p values for all < 0.005). Mean observed length of stay was also significantly less than predicted (1.6 versus 2.1 days, p < 0.001). In the open adrenalectomy subgroup, there were no observed complications with observed mean length of stay equivalent to predicted (5.8 versus 5.3, p = 0.08) without a higher readmission rate (5.9 versus 6.0%).

Statistical differences were noted between the actual complication rates of adrenalectomy versus those predicted by the NSQIP calculator. Certain observed differences may not necessarily have clinical significance. Urology procedure-specific calculators may better refine predictions for sub-specialty procedures with future work requisite to determine performance across all practice settings.