Purpose Long-standing diabetes is a risk factor for pancreatic cancer, and recent-onset diabetes in the several years before diagnosis is a consequence of subclinical pancreatic malignancy. However, the impact of diabetes on survival is largely unknown.
Patients and Methods We analyzed survival by diabetes status among 1,006 patients diagnosed from 1986 to 2010 from two prospective cohort studies: the Nurses’ Health Study (NHS) and Health Professionals Follow-Up Study (HPFS). We validated our results among 386 patients diagnosed from 2004 to 2013 from a clinic-based case series at Dana-Farber Cancer Institute (DFCI). We estimated hazard ratios (HRs) for death using Cox proportional hazards models, with adjustment for age, sex, race/ethnicity, smoking, diagnosis year, and cancer stage.
Results In NHS and HPFS, HR for death was 1.40 (95% CI, 1.15 to 1.69) for patients with long-term diabetes (> 4 years) compared with those without diabetes (P< .001), with median survival times of 3 months for long-term diabetics and 5 months for nondiabetics. Adjustment for a propensity score to reduce confounding by comorbidities did not change the results. Among DFCI patient cases, HR for death was 1.53 (95% CI, 1.07 to 2.20) for those with long-term diabetes compared with those without diabetes (P = .02), with median survival times of 9 months for long-term diabetics and 13 months for nondiabetics. Compared with nondiabetics, survival times were shorter for long-term diabetics who used oral hypoglycemics or insulin. We observed no statistically significant association of recent-onset diabetes (< 4 years) with survival.
Conclusion Long-standing diabetes was associated with statistically significantly decreased survival among patients with pancreatic cancer enrolled onto three longitudinal studies.