Examining Trends in Kidney Cancer Mortality by Gender and Race in the United States: A 20-Year Analysis
Authors: Jani Chinmay , Arora Shreya , Abdallah Nour , Mouchati Christian , Jani Ruchi , Singh Harpreet , Mckay Rana 
Published: August 2023

Abstract

Background
Kidney cancer (KC) is a significant contributor to cancer mortality worldwide, with gender, racial, and ethnic disparities impacting outcomes. While previous studies have investigated the outcomes of diverse patient populations, gaps in knowledge remain. The incidence of KC has been rising steadily, and it is essential to understand the patterns of mortality to identify and address disparities in healthcare. Therefore, this study aimed to investigate trends in age-adjusted mortality rates (ASMR) by gender, race, and ethnicity in the US at national levels.

Methods
The Center for Disease Control Wonder database was used to extract national KC mortality data (ICD-10 C64) from 1999-2020. ASMR and 95% confidence intervals (CI) were extracted based on gender and race reported per 100,000 population. Absolute percentage changes were calculated. Joinpoint Command Line Version 4.5.0.1 was used to apply a Joinpoint regression analysis and calculate Average Annual Percentage Change (AAPC). IRB approval was not needed as CDC is an open-source database with de-identified information.

Results
Over twenty years, 284,224 KC deaths were reported, with an overall decrease in ASMR in recent years. Males had significantly higher ASMR throughout the study period, with a lower decrease than females. Female mortality rates for all racial and ethnic groups declined over the study period, with the largest decrease observed in American Indian/Alaskan Native females (-34.3%). However, American Indian/Alaskan Native females still had the highest mortality rates in 2020. Asian females had the lowest mortality rates throughout the study period, but they only decreased slightly (-8.3%). African American and white females had similar mortality rates that decreased by 25% and 22.2%, respectively. Among males, there was a general decline in mortality rates across all racial and ethnic groups, with the largest decrease observed in American Indian/Alaskan Native males (-44.3%). Despite having lower mortality rates than most other groups, White males had the highest age-adjusted mortality rate (ASMR) of 5.7 in 2020 due to the lack of significant decline. When considering the average annual percentage change (AAPC) over the entire period, the decline in mortality rate was statistically significant for all groups except Asian females. The AAPC ranged from -2.1% for American Indian/Alaskan Native females to -0.4% for Asian females. The steepest decline was observed in American Indian/Alaskan Native males (-2.1%), followed by American Indian/Alaskan Native females (-1.8%) and African American females (-1.7%).

Conclusions
In conclusion, our study highlights significant gender, racial, and ethnic disparities in kidney cancer mortality rates in the US. Our study underscores the importance of targeted interventions to reduce mortality rates among American Indian/Alaskan Native populations, who consistently had the highest mortality rates in kidney cancer throughout the study period. Additionally, our findings highlight the need for continued attention to male mortality rates at the gender level. The results of this study can inform healthcare policies and practices that aim to address the disparities in kidney cancer mortality rates and ultimately improve the health outcomes of all populations.
CDMRP DOD Funding: no