Abstract
BACKGROUND: Human and economic burden of psychological distress (PD) are well known. However, how PD and its various classifications impact health-related quality of life (HRQoL) and its various domains such as physical function (PF), role physical (RP), mental health (MH) and role emotional (RE) is poorly understood. OBJECTIVES: To measure the longitudinal decline in HRQoL related to PD and its various dimensions, and to examine sociodemographic factors associated with HRQoL. METHODS: Data on SF-36 profiles, Kessler Psychological Distress (K10) scale scores and other sociodemographic characteristics of individuals with PD aged ≥ 15 were sourced from 8 waves (7, 11, 13, 15, 17, 19, 21, n = 41,545) of the Household, Income, and Labour Dynamics in Australia (HILDA) survey spanning the years 2007 to 2021. PD severity was classified as no (K10 score: 10-19), mild (K10: 20-24), moderate (K10: 25-29) and severe PD (K10: 30-50). HRQoL was measured as health state utilities (HSUs) via the SF-6D algorithm aligned with Australian population norms. Five separate linear mixed models were estimated, each with HSUs, PF, RP, MH, or RE as the outcome variable. RESULTS: The mean age of the respondents was 44.88 years (53% female), and the most common age group was 24-44 years (34%). HRQoL declined over time; however, the time coefficients became insignificant after accounting for other sources of variation, including age, sex, English proficiency, Indigenous status, region of residence, marital status, education, employment, physical activity, body mass index (BMI), club membership, smoking, drinking, and income. The adverse impact of PD on HSUs intensified with increasing severity, ranging from - 0.086 in mild PD to -0.177 in severe PD. HRQoL differed across age (from - 0.016 in 25-44 years to -0.059 in 65 + years) and sex groups (disutility difference - 0.012). Different domains of HRQoL were affected by PD disproportionally with the highest and lowest effect recorded in the domain of MH (-0.364) and PF (-0.114), respectively in the category of severe PD. Factors such as education, physical activity, being employed, drinking, and income were positively associated with PD while BMI level and smoking negatively affected HRQoL. CONCLUSIONS: Effective HRQoL management in individuals with PD requires tailored interventions that consider disease severity, age, and sex. The insights on the association of time and other sociodemographic determinants with HRQoL have potential applications in PD-related cost-effective analyses of health interventions.