Tailoring opioid substitution therapy: Patient profiles, clinical outcomes, and preferences for new formulations

Introduction: Understanding patient experiences with opioid substitution treatment (OST) is critical to developing more personalized and responsive care strategies. This study employed latent class analysis (LCA) to: (1) identify subgroups of patients based on their perceptions and satisfaction with OST; (2) examine differences across subgroups in clinical outcomes and interest in novel formulations (methadone tablets, weekly/monthly buprenorphine depot, buprenorphine implant); (3) assess associations with individual and treatment-related factors; and (4) explore class-specific risk and protective factors. Methods: A total of 280 individuals (79 % male; mean age = 46.9 years) receiving OST (methadone syrup = 78 %; sublingual buprenorphine tablets = 22 %) at six public addiction services in Italy completed an anonymous questionnaire. The survey assessed sociodemographics, current OST type and adherence, treatment perceptions and overall satisfaction, treatment duration, recent substance use and OST misuse, interest in novel formulations, motives for switching, and recovery capital (BARC-10). Results: LCA identified three subgroups: Satisfied yet burdened, Satisfied and engaged, and Not experiencing benefit. The Not experiencing benefit class showed low satisfaction and limited perceived effectiveness with OST, high recent heroin and cocaine use, shorter treatment duration, and lowest recovery capital, with living alone emerging as a key risk factor. The Satisfied yet burdened class reported high satisfaction with OST but significant stigma and burden; recovery capital was positively linked to age and employment; living alone and higher education were associated with cocaine use; heroin use was higher among those receiving methadone syrup. The Satisfied and engaged class showed the highest satisfaction with OST, longer treatment, and appreciation for clinical contact; living alone remained the main risk factor, associated with heroin use. Methadone tablets were preferred by those on methadone syrup across all classes. Interest in monthly buprenorphine depot was highest in the Satisfied yet burdened class, especially among women and those on sublingual buprenorphine. The implant was favored in the Satisfied and engaged class by men with higher education. Individuals living alone in the Not experiencing benefit class showed the lowest interest in long-acting options. Conclusion: Findings highlight the importance of tailoring OST delivery to distinct patient profiles to enhance engagement, reduce unmet needs, and support long-term recovery.