Effect of diabetes mellitus comorbidity on outcomes in stages II and III colorectal cancer

Aim The effects of diabetes mellitus (DM) on the outcomes of colorectal cancer (CRC) are controversial. This retrospective study evaluated the effects of DM on American Joint Committee on Cancer (AJCC, 7th) Stages II and III CRC patients who received curative surgery. Methods We reviewed the records of CRC patients who were treated from January 2008 to December 2014 and identified the presence of DM and hypertension prior to CRC diagnosis. Cox proportional hazards analyses were used for prognostic factor determination, and survival was analyzed using the Kaplan-Meier method with the log-rank test. Results Total of 1066 consecutive eligible patients with stage II/III CRC were enrolled. There were 326 (30.6%) patients diagnosed with DM, and 311 (29.2%) CRC patients had recurrence. Patients with DM did not have a higher recurrence risk (p = 0.183) but had higher mortality (adjusted hazard ratio [aHR] = 1.381; 95% conference interval [CI], 1.069-1.782). In addition, HbA1c (>= 7 vs. <7) was not associated with recurrence (p = 0.365). Patients with DM had more hypertension than patients without DM (69.1% vs. 37.6%, p < 0.001). A lower recurrence risk was noted in patients with hypertension (p = 0.002), but the overall survival (OS) did not reach statistical significance (aHR = 0.910; 95% CI, 0.707-1.169). Conclusion In our study, DM was a poor prognostic factor for survival in curative CRC patients. More studies are required to elucidate the effects that DM and other metabolic disorders, such as hypertension, have on the prognosis of patients with CRC.