Postoperative 30-day Mortality Rates for Kidney Cancer Are Dependent on Hospital Surgical Volume: Results from a Norwegian Population-based Study

Abstract

Background: To improve cancer care in Norway, the government introduced surgical volume requirements for hospitals in 2015. To treat kidney cancer (KC) in Norway, the lower limit is 20 surgical procedures per year.

Objectives: To compare the impact of hospital volume on outcome with regard to 30-d mortality (TDM) following KC surgery.

Design, setting, and participants: We identified all KC patients from the Cancer Registry of Norway diagnosed during 2008-2013 whose surgical treatment involved partial or radical nephrectomy. Hospitals were divided into three volume groups: low (LVH), intermediate (IVH), and high (HVH) volume.

Outcome measurements and statistical analysis: Relationships with outcome were analysed using multivariate logistic regression.

Results and limitations: In total, 3273 patients were identified. The TDM rate was 0.89% overall, 0.73% for localised KC, and 2.6% for metastatic KC. The mean (median, interquartile range) numbers of procedures for LVH, IVH and HVH were 5.2 /yr (3, 1.3-8.7), 27 /yr (26, 23-30) and 53 /yr (53, 48-58), with TDM rates of 2.2%, 0.83%, and 0.39%, respectively (p=0.001). In a multivariate logistic regression model, tumour stage, age, and hospital volume remained independent TDM predictors. The odds ratio for TDM was 4.98 (confidence interval 1.72-14.4) for LVH compared to HVH (p=0.003). Study limitations include a lack of data for surgical complications and other possible confounders.

Conclusions: TDM is associated with age, stage, and hospital volume. The study supports the new regulation for hospital volume introduced in Norway.

Patient summary: The risk of dying within 30 d following kidney cancer surgery is low. Advanced disease and older age are risk factors for higher mortality. In this study, we also showed that more patients die within 30 d in hospitals performing fewer operations per year than in hospitals performing many operations.

Keywords: 30-d mortality; Hospital volume; Kidney cancer; Partial nephrectomy; Population-based study; Radical nephrectomy; Surgery.