Trends and health inequalities in the global burden of kidney cancer from 1990 to 2021, with projections to 2040

A comprehensive assessment of kidney cancer (KC) that incorporated spatiotemporal, demographic, and socioeconomic dimensions was lacking. This study aimed to establish a comprehensive global assessment framework for KC burden spanning 1990 to 2021. Epidemiologic data on KC were sourced from the Global Burden of Disease 2021 study, generating KC incidence, prevalence, and disability-adjusted life-year (DALY) estimates. In 2021, there were 1,961,210.85 (95% uncertainty interval [UI]: 1,861,776.54–2,051,838.01) prevalent cases of KC, 387,828.72 (95% UI: 365,359.71–406,635.25) new KC cases, and 4,016,362.12 (95% UI: 3,806,832.21–4,246,783.03) KC DALYs. the high-socio-demographic index (SDI) group had the highest case age-standardized rates (ASRs) and number of the 3 indicators, middle-SDI regions showed the sharpest increase in incidence and prevalence ASRs, while the ASR of DALYs for low-middle-SDI regions demonstrated the most significant increase. The slope index of inequality recorded a near tripling (5–12) in incidence inequality between top- and bottom-ranking SDI countries spanning 1990 through 2021. Other indicators followed a similar profile. The numbers of the 3 indicators for KC are projected to increase globally between 2022 and 2040, while the corresponding ASRs will decrease annually. The global burden of KC has remained high for 32 years. High-SDI regions have borne a substantial disease burden, predominantly driven by aging populations, whereas low-middle- and middle-SDI regions have exhibited steeper increasing burden trends, representing critical targets for future prevention efforts. Projected increases in KC burden demand proactive scaling of healthcare resources, declining ASRs warrant vigilance against unequal burden distribution, effective strategies must prevent overall improvement from masking localized deterioration.