Trends of colorectal cancer-related mortality among patients with comorbid type 2 diabetes in the United States, 1999–2020.

e15681 Background: Colorectal cancer (CRC) is a leading cause of cancer-related mortality in the United States. Type 2 diabetes (T2D), a prevalent comorbidity, has been shown to exacerbate CRC outcomes. Patients with T2D, especially those with complications, have been shown to have higher rates of CRC recurrence and lower overall survival rates compared to non-diabetic CRC patients. Understanding the temporal, demographic, and geographic disparities in CRC mortality with T2D as a contributing cause of death is essential for addressing health inequities and guiding public health interventions. Methods: This study utilized CDC WONDER data from 1999 to 2020 to analyze 18,119 deaths among individuals aged > 25 years, with CRC (ICD-10 codes C18–C20) as the underlying cause of death and T2D (ICD-10 code E11) as a contributing cause. Age-adjusted mortality rates (AAMRs) per 1,000,000 were calculated, and temporal trends were assessed using Joinpoint regression. Subgroup analyses were performed by sex, race, urban-rural status, and geographic region. Results: From 1999 to 2006, the AAMR for CRC with comorbid T2D increased from 3.0 (95% CI, 2.7–3.2) to 4.1 (95% CI, 3.8–4.4), with an annual percent change (APC) of 3.8% (p < 0.01). A significant decline was observed from 2006 to 2014 (APC = -2.1%, p < 0.01), followed by a marked increase from 2014 to 2020, rising from 3.4 (95% CI, 3.2–3.6) to 5.1 (95% CI, 4.8–5.4), with an APC of 6.4% (p < 0.01). Cumulative AAMRs were higher in males (4.8 [95% CI, 4.7–4.9]) compared to females (3.0 [95% CI, 3.0–3.1]). Among racial groups, AAMR was highest for American Indians (6.2 [95% CI, 5.3-7.1]) and African Americans (4.9 [95% CI, 4.7-5.1]), followed by White adults (3.7 [95% CI, 3.6-3.7]) and Asians (3.2 [95% CI, 2.9-3.4]). Noncore rural regions exhibited higher AAMRs compared to large central metropolitan areas (5.8 [95% CI, 5.5–6.0] vs. 3.3 [95% CI, 3.2–3.4]). Regionally, the Midwest had the highest AAMR (4.6 [95% CI, 4.5–4.8]), followed by the West (4.5 [95% CI, 4.4–4.6]), South (3.4 [95% CI, 3.3–3.4]), and Northeast (2.8 [95% CI, 2.7–2.9]). Conclusions: Colorectal cancer mortality with comorbid T2D has exhibited dynamic trends over the past two decades, with an alarming rise in recent years. Significant disparities persist across sex, race, and geographic regions, with males, American Indians, and rural populations experiencing the highest mortality rates. These findings underscore the urgent need for targeted public health interventions and equitable access to care for populations disproportionately impacted by CRC and T2D.