AIMS/HYPOTHESIS Diabetes is associated with an increased incidence of colorectal cancer (CRC). There exists conflicting evidence regarding the impact of diabetes on CRC-specific mortality (herein also referred to as cancer-specific mortality). The objectives of this study were to determine whether diabetes is associated with a more advanced CRC stage at diagnosis and with higher all-cause and cancer-specific mortality. METHODS This retrospective cohort study used linked, population-based health databases from Ontario, Canada. Among individuals diagnosed with CRC from 2007 to 2015, we compared the likelihood of presenting with later- (III or IV) vs early- (I or II) stage CRC between patients with and without diabetes adjusting for relevant covariates. We then determined the association between diabetes and all-cause and CRC-specific mortality, after adjusting for CRC stage at diagnosis and other covariates. RESULTS Of the 44,178 individuals with CRC, 11,822 (26.7%) had diabetes. After adjustment for CRC screening and other covariates, individuals with diabetes were not more likely to present with later-stage CRC (adjusted OR 0.97, 95% CI 0.93, 1.01). Over a median follow-up of 2.63 (interquartile range [IQR] 0.97-5.10) years, diabetes was associated with higher all-cause mortality (adjusted HR 1.08, 95% CI 1.04, 1.12) but similar cancer-specific survival (adjusted HR 1.0, 95% CI 0.95, 1.06). CONCLUSIONS/INTERPRETATION Individuals with diabetes who develop CRC are not more likely to present with a later stage of CRC and have similar cancer-specific mortality compared with those without diabetes. Diabetes was associated with higher all-cause mortality in CRC patients, indicating that greater attention to non-cancer care is needed for CRC survivors with diabetes.

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糖尿病对大肠癌分期和死亡风险的影响：一项基于人群的队列研究。

目的/假设糖尿病与大肠癌（CRC）的发生率增加有关。关于糖尿病对CRC特异性死亡率（在本文中也称为癌症特异性死亡率）的影响，存在矛盾的证据。这项研究的目的是确定糖尿病是否与诊断时更高级的CRC分期以及更高的全因和特定癌症死亡率相关。方法这项回顾性队列研究使用了来自加拿大安大略省的基于人群的链接健康数据库。在2007年至2015年被诊断出患有CRC的个体中，我们比较了有无糖尿病患者调整相关协变量后出现晚期（III或IV）与早期（I或II）CRC的可能性。然后，我们确定了糖尿病与全因和CRC特异性死亡率之间的关联，在诊断时调整CRC阶段和其他协变量后。结果在44178名CRC患者中，有11822名（26.7％）患有糖尿病。在针对CRC筛查和其他协变量进行调整后，糖尿病患者不太可能出现晚期CRC（校正后的OR为0.97，95％CI为0.93，1.01）。在2.63（四分位间距[IQR] 0.97-5.10）年的中位随访期内，糖尿病与全因死亡率较高（校正后HR 1.08、95％CI 1.04、1.12）相关，但与癌症特异性生存率相似（校正HR） 1.0，95％CI 0.95，1.06）。结论/解释与没有糖尿病的人相比，患有CRC的糖尿病患者不太可能出现CRC晚期，并且具有相似的癌症特异性死亡率。糖尿病与CRC患者的全因死亡率较高相关，