Dose-effect relationship between overdose mortality and prescribed methadone dosage in low-threshold maintenance...

Area of Science:

• Public Health
• Addiction Medicine
• Epidemiology

Background:

• Overdose mortality remains a significant public health concern among injecting drug users (IDU).
• Previous research highlighted the effectiveness of high-dose methadone maintenance and detoxification programs in reducing mortality.
• The efficacy of low-threshold methadone maintenance programs in preventing overdose deaths required further investigation.

Purpose of the Study:

• To evaluate the effectiveness of low-threshold methadone maintenance therapy in reducing overdose mortality among Dutch IDU.
• To identify predictors of overdose mortality within this population.

Main Methods:

• Prospective cohort study design.
• Involved 498 Dutch injecting drug users (IDU) with 1,969 person-years of follow-up from 1989 to 1995.
• Statistical analysis to compare overdose mortality rates between IDU receiving different methadone dosages and those not in maintenance, adjusting for covariates.

Main Results:

• A total of 44 IDU deaths occurred, with 15 attributed to illicit drug overdose.
• Compared to IDU not in maintenance, adjusted relative risks for overdose mortality were significantly reduced for those receiving methadone: 0.35 (5-50 mg), 0.13 (55-70 mg), and 0.11 (75+ mg).
• Current injection use and HIV-seropositivity were identified as independent predictors of overdose mortality.

Conclusions:

• Low-threshold methadone maintenance programs are effective in reducing overdose mortality among IDU.
• Higher methadone dosages (55-70 mg and 75+ mg) demonstrated the most significant protective effect.
• These findings support the implementation and expansion of accessible methadone maintenance programs to combat overdose deaths in this vulnerable population.