Estimating the health-related quality of life burden attributable to illicit drug use in Australian adults.

Abstract

Background: Illicit drug use poses a significant global public health challenge, affecting health-related quality of life (HRQoL) and contributing to disease burden. Illicit drug use is also linked to substantial adverse health and social outcomes, including mental health disorders and chronic physical morbidities. This study addresses a critical research gap by examining the association between illicit drug use and HRQoL in Australian adults.

Methods: This study utilised data from two waves (wave 17 [2017] and wave 21 [2021]) of the Household, Income and Labour Dynamics in Australia (HILDA) Survey and analysed a pooled dataset comprising 29,811 person-year observations from 18,295 unique individuals. HRQoL was assessed using the Physical Component Summary (PCS), the Mental Component Summary (MCS), the Short-Form Six-Dimension utility index (SF-6D), and the eight dimensions of the SF-36 health survey. The study defined illicit drug use as self-reported use of any of the following six drug types in the past 12 months: marijuana/cannabis, methamphetamine/amphetamine, cocaine, ecstasy, hallucinogens, and any other illicit drug (e.g., heroin, GHB, ketamine, K2, and synthetics). A binary variable was created to indicate whether an individual used any of these drugs during the specified period. The random-effects generalised least squares (GLS) estimation technique was used to quantify the relationships between illicit drug use and HRQoL.

Results: After adjusting for a comprehensive set of covariates, the findings revealed a significant negative association between illicit drug use and mental health. Individuals who reported illicit drug use had markedly lower MCS scores (β = -2.29, 95% CI: -2.68, -1.89) compared to non-users. Furthermore, illicit drug use was associated with a significant reduction in SF-6D utility values (β = -0.022, 95% CI: -0.026, -0.018), highlighting the adverse impact on overall HRQoL among adults. Illicit drug use was associated with reduced MCS scores and SF-6D utility values across genders and age groups, with greater reduction among young adults aged 15-29 years [(MCS = -2.30, 95% CI: -2.92, -1.68) and (SF-6D = -0.021, 95% CI: -0.027, -0.015)], and male drug users [(MCS = -2.46, 95% CI: -2.93, -1.99), and (SF-6D = -0.021, 95% CI: -0.026, -0.016)].

Conclusion: The study findings confirmed that individuals who use illicit drugs experience significantly lower HRQoL than their peers. Additionally, the study provided a specific disutility value for illicit drug use, offering crucial data for future evaluations of the cost-effectiveness of drug harm reduction programs.