Impact of diabetes and modifiable risk factors on pancreatic cancer survival in a population-based study after adjusting for clinical factors

Purposes: Our study aimed to examine the impact of diabetes, smoking and BMI on pancreatic cancer survival in a population-based setting by adjusting both sociodemographic and clinical factors and measuring their attributable risk.

Methods: Data on pancreatic adenocarcinoma patients diagnosed in 2011-2017 were acquired from the Louisiana Tumor Registry. Diabetes, smoking, height, and weight were abstracted from medical records and linked with Hospital Inpatient Discharge Data to enhance the completeness of the diabetes data. The Cox regression model was used to assess effect sizes of diabetes, smoking, and BMI on cancer-specific survival and survival rate. The partial population attributable risk was employed to measure the attributable risk of these risk factors.

Results: Of the 3,200 eligible patients, 34.6% were diabetics, 23.9% were current smokers, and 52.3% had BMI ≥ 25 kg/m². After adjusting for sociodemographic and clinical factors, diabetic patients had an increased cancer-specific death risk of 15% (95% CI, 1.06-1.25), 36% (95% CI, 1.19-1.44) for current smokers, and 24% (95% CI, 1.00-1.54) for patients with a BMI ≥ 40 when compared to their counterparts. Diabetic current smokers had significantly lower 2- and 3-year adjusted cancer-specific survival rates, 13.1% and 10.5%, respectively. By eliminating diabetes and modifiable risk factors, an estimated 16.6% (95% CI, 6.9%-25.9%) of the cancer-specific deaths could be avoided during a nine-year observational period between 2011 and 2019.

Conclusions: Diabetes and smoking contributed substantially to the reduction of pancreatic cancer survival even after controlling for sociodemographic and clinical factors; however, BMI ≥ 35 was observed to increase risk of mortality among stage III-IV patients only.