BACKGROUND

Heart failure (HF) and kidney disease frequently co-occur, increasing mortality risk. The cardiorenal syndrome results from damage to either the heart or kidney impacting the other organ. The epidemiology of cardiorenal syndrome among the general population is incompletely characterized and despite shared risk factors with HF, differences in mortality risk across key demographics have not been well described. Thus, the primary goal of this study was to analyze annual trends in cardiorenal-related mortality, evaluate if these trends differed by age, sex, and race or ethnicity, and describe these trends against a backdrop of HF mortality.

METHODS AND FINDINGS

The Centers for Disease Control and Prevention Wide-ranging ONline Data for Epidemiologic Research database was used to examine cardiorenal- and HF-related mortality in the US between 2011and 2020. International Classification of Diseases, 10 Revision codes were used to classify cardiorenal-related deaths (I13.x) and HF-related deaths (I11.0, I13.0, I13.2, and I50.x), among decedents aged 15 years or older. Decedents were further stratified by age group, sex, race, or ethnicity. Crude and age-adjusted mortality rates (AAMR) per 100,000 persons were calculated. A total of 97,135 cardiorenal-related deaths and 3,453,655 HF-related deaths occurred. Cardiorenal-related mortality (AAMR, 3.26; 95% CI: 3.23-3.28) was significantly lower than HF-related mortality (AAMR, 115.7; 95% CI: 115.6-115.8). The annual percent change (APC) was greater and increased over time for cardiorenal-related mortality (2011-2015: APC, 7.1%; 95% CI: 0.7-13.9%; 2015-2020: APC, 19.7%, 95% CI: 16.3-23.2%), whereas HF-related mortality also increased over that time period, but at a consistently lower rate (2011-2020: APC, 2.4%; 95% CI: 1.7-3.1%). Mortality was highest among older and male decedents for both causes. Cardiorenal-related deaths were more common in non-Hispanic or Latino Blacks compared to Whites, but similar rates were observed for HF-related mortality. A larger proportion of cardiorenal-related deaths, compared to HF-related deaths, listed cardiorenal syndrome as the underlying cause of death (67.0% vs. 1.2%).

CONCLUSIONS

HF-related deaths substantially outnumber cardiorenal-related deaths; however, cardiorenal-related deaths are increasing at an alarming rate with the highest burden among non-Hispanic or Latino Blacks. Continued surveillance of cardiorenal-related mortality trends is critical and future studies that contain detailed biomarker and social determinants of health information are needed to identify mechanisms underlying differences in mortality trends.