Abstract
BACKGROUND: Multimorbidity, having two or more chronic conditions, is a growing public health concern associated with substantial health and societal burdens. However, evidence on its impact on health-related quality of life (HRQoL) among U.S. adults remains limited. This study fills a major research gap by examining the association between multimorbidity and HRQoL among U.S. adults, a population often overlooked in prior research and provides evidence to inform policies aligned with national and global health goals for reducing the chronic disease burden. METHODS: A cross-sectional study was conducted among adults aged 18 to 64 years. Data from the Medical Expenditure Panel Survey was used in this study for years 2019 to 2021. The primary study outcome was the HRQoL; it was evaluated using the 12-item Veterans RAND 12. Descriptive analysis was used to describe the characteristics of the study sample. The adjusted relationship between Multimorbidity and HRQoL was assessed using the multivariable linear regression after other factors were adjusted in the regression analysis. RESULTS: The study sample consists of 30,827 adults. Multimorbidity was prevalent among 23.4% of adults. It was higher among women, unemployed, poor, and physically inactive adults. Adults with multimorbidity had a lower mean HRQoL score than those without multimorbidity (Physical health = 46.06 vs. 53.29, Mental health = 47.62 vs. 52.37). Results from the adjusted linear regression model found that adults with multimorbidity have a significantly lower HRQoL in both the physical domain (β = -2.658, p-value<0.0001), and the mental domain (β = -3.119, p-value<0.0001). CONCLUSIONS: Multimorbidity has a substantial negative impact on both physical and mental aspects of HRQoL in U.S. adults. These findings highlight the need for targeted public health strategies and clinical interventions, such as promoting integrated chronic disease management to address the burden of multimorbidity. Future research should explore specific condition clusters most strongly associated with reduced HRQoL to better inform policy and care models.