Table 4. Multivariable survival analysis of overall survival—interaction of age and facility type.

Number of observations in the original data set = 1,861. Number of observations used = 1,861. Backward selection with an alpha level of removal of .05 was used. No variables were removed from the model.The estimated stratified treatment effect was controlled by American Joint Committee on Cancer analytic stage group, chemotherapy, diagnostic confirmation, facility location, pancreatic origin, primary payor, race group, radiation, radiation/surgery sequence, sex, surgery at primary site, systemic/surgery sequence, and year of diagnosis.

Bolded p values are statistically significant.

Abbreviations: —, not applicable; CI, confidence interval; HR, hazard ratio; REF, reference.