Potential beneficial effects of bariatric surgery on the prevalence of kidney cancer: a national database study.

BACKGROUND

The incidence of obesity has been steadily increasing, especially in developed countries. Also, obesity is considered one of the modifiable risk factors of kidney cancer.

OBJECTIVES

This study aims to determine the impact of bariatric surgery-induced weight loss on the prevention of kidney cancer.

SETTING

Academic Hospital, United States.

METHODS

The National (Nationwide) Inpatient Sample (NIS) was queried for the period 2010 to 2015 for first-time kidney cancer-related hospitalization, used as a proxy for cancer incidence, in patients with a history of bariatric surgery (cases) and patients with obesity but no history of bariatric surgery (controls). Patients with a previous diagnosis of cancer were excluded from the analysis. In order to identify comparable patients, all controls had to have a body mass index ≥35 kg/m, as per the existing qualification criteria for bariatric surgery. The International Classification of Diseases-9 codes (ICD-9) was used to identify admissions for kidney cancer. A univariate analysis was conducted to compare demographics and co-morbidities between groups. A multivariate logistic regression model was performed to assess differences between surgical and control groups and adjust for independent variables such as smoking history and family history of malignancy. All percentages and means (with confidence intervals [CIs]) were weighted.

RESULTS

A total of 2,300,845 were included in the analysis, of which 2,004,804 controls-subjects, with a mean age of 54.4 ± .05 years, and 296,041 treatment-subjects, with a mean age of 51.9 ± .05 years. Demographics and co-morbidities, such as tobacco use, diabetes, and hypertension, were also measured. Patients with a history of bariatric surgery were significantly less likely to experience renal cancer than patients without a history of bariatric surgery, with 5935 cases in the control group and 684 in the case group (P < .0001). After a multivariate logistic regression was performed, the OR was 1.10 (95% CI: 1.02-1.22, P < .0224).

CONCLUSION

Our finding suggests that bariatric surgery-induced weight loss could significantly prevent first-time kidney cancer-related hospitalizations in patients with obesity. Prospective studies are needed to confirm our findings.