Trends in mortality with both lung cancer and diabetes mellitus listed on the death certificate in the United States, 1999–2023

Lung cancer and diabetes mellitus are both common, yet national trends in deaths with both recorded have not been described. We analyzed CDC WONDER multiple cause-of-death data for 1999–2023, identifying deaths in adults aged 25 years or older with lung cancer and diabetes mellitus (ICD-10 C34, E10–E14) both listed on the certificate. We calculated age-adjusted mortality rates (AAMRs) per 100,000 overall and by sex, race and Hispanic origin, region and (1999–2020) urbanization, estimated annual percent change (APC) with Joinpoint regression, compared groups with rate ratios and, for 2020–2023, excluded certificates also listing COVID-19. There were 174,422 deaths. The AAMR rose from 2.871 in 1999 to 3.425 in 2007, fell to 2.731 in 2018 (2007–2018 APC − 2.46%; 95% CI − 3.05 to − 1.88), rose to 3.262 in 2021 (2018–2021 APC 7.22%; 95% CI − 0.26 to 15.26; not significant) and was 2.990 in 2023. Excluding certificates also listing COVID-19 removed about 31% of the 2019–2021 increase. The male-to-female ratio fell from 2.22 to 1.74. In 2023 the Black-to-White ratio was 1.28 (95% CI 1.20 to 1.37) and the South-to-Northeast ratio 1.64 (95% CI 1.53 to 1.75). By point estimate, the South has had the highest regional rate since 2017. Non-metropolitan rates exceeded metropolitan rates in every year to 2020 (ratio 1.55 in 2020). Mortality with both conditions recorded differed persistently by sex, race, region and urbanization. These descriptive data cannot establish why rates changed or estimate risk among people with diabetes. Part of the 2019–2021 increase remains unexplained.