Treatment non-adherence among methadone maintenance patients and associated factors: a multicenter, cross-sectional study in Vietnam.

Objective: This multicenter, cross-sectional study was conducted to investigate the prevalence of treatment non-adherence and its associated factors among methadone maintenance patients in Vietnam.

Methods: This secondary data analysis was conducted using the data from a previous study. Six hundred patients were interviewed face-to-face to collect data on their demographic characteristics and social support. Information about the treatment characteristics and patients' non-adherence was gathered from medical records and books monitoring their treatment process. Treatment non-adherence was defined as missing at least one methadone dose in the last three months.

Results: The overall prevalence of non-adherence was 45.7%. The average social support score of patients who completely adhered to treatment was significantly higher than that of those who did not (p < 0.001). In the multivariate logistic regression model, for each one-unit increase in social support (one score), treatment time (a year), and patient's monthly income (one million Vietnam dongs), the odds of non-adherence decreased by 28% (aOR = 0.72, 95%CI 0.59-0.88, p = 0.002), 15% (aOR = 0.85, 95%CI 0.80-0.91, p < 0.001) and 9% (aOR = 0.91, 95%CI 0.85-0.97, p = 0.004), respectively. Patients living in Son La (a mountainous province) were 1.72 times (95%CI 1.09-2.71) more likely to be non-adherent as compared to those in other areas (p = 0.020). As per univariate analyses, other associated factors could be age, education level, family monthly income, occupation, and opioid relapse (p < 0.001).

Conclusions: A high non-adherence rate was found among Vietnamese methadone maintenance patients. Interventions involving social support, occupation, income, and education are needed to improve their treatment adherence.