title: Methadone treatment for HIV prevention-feasibility, retention, and predictors of attrition in Dar es Salaam, Tanzania: a retrospective cohort study.
abstract: BACKGROUND
  People who inject drugs (PWID) in Dar es Salaam, Tanzania, have an estimated human immunodeficiency virus (HIV) prevalence of 42%-50% compared with 6.9% among the general population. Extensive evidence supports methadone maintenance to lower morbidity, mortality, and transmission of HIV and other infectious diseases among PWID. In 2011, the Tanzanian government launched the first publicly funded methadone clinic on the mainland of sub-Saharan Africa at Muhimbili National Hospital.
  
  
  METHODS
  We conducted a retrospective cohort study of methadone-naive patients enrolling into methadone maintenance treatment. Kaplan-Meier survival curves were constructed to assess retention probability. Proportional hazards regression models were used to evaluate the association of characteristics with attrition from the methadone program.
  
  
  RESULTS
  Overall, 629 PWID enrolled into methadone treatment during the study. At 12 months, the proportion of clients retained in care was 57% (95% confidence interval [CI], 53%-62%). Compared with those receiving a low dose (<40 mg), clients receiving a medium (40-85 mg) (adjusted hazard ratio [aHR], 0.50 [95% CI, .37-.68]) and high (>85 mg) (aHR, 0.41 [95% CI, .29-.59]) dose of methadone had a lower likelihood of attrition, adjusting for other characteristics. Older clients (aHR, 0.53 per 10 years [95% CI, .42-.69]) and female clients (aHR, 0.50 [95% CI, .28-.90]) had a significantly lower likelihood of attrition, whereas clients who reported a history of sexual abuse (aHR, 2.84 [95% CI, 1.24-6.51]) had a significantly higher likelihood of attrition.
  
  
  CONCLUSIONS
  Patient retention in methadone maintenance is comparable to estimates from programs in North America, Europe, and Asia. Future implementation strategies should focus on higher doses and flexible dosing strategies to optimize program retention and strengthened efforts for clients at higher risk of attrition.
authors.affiliation: Department of Global Health, University of Washington, Seattle Pangaea Global AIDS Foundation, Oakland, California.
authors.forename: Barrot H
authors.initials: BH
authors.lastname: Lambdin
authors.affiliation: Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
authors.forename: Frank
authors.initials: F
authors.lastname: Masao
authors.affiliation: Pangaea Global AIDS Foundation, Oakland, California.
authors.forename: Olivia
authors.initials: O
authors.lastname: Chang
authors.affiliation: Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
authors.forename: Pamela
authors.initials: P
authors.lastname: Kaduri
authors.affiliation: Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
authors.forename: Jessie
authors.initials: J
authors.lastname: Mbwambo
authors.affiliation: Ministry of Health and Social Welfare, Dar es Salaam, Tanzania.
authors.forename: Ayoub
authors.initials: A
authors.lastname: Magimba
authors.affiliation: Ministry of Health and Social Welfare, Dar es Salaam, Tanzania.
authors.forename: Norman
authors.initials: N
authors.lastname: Sabuni
authors.affiliation: Pangaea Global AIDS Foundation, Oakland, California School of Medicine, Yale University, New Haven, Connecticut.
authors.forename: R Douglas
authors.initials: RD
authors.lastname: Bruce
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D055118:Medication Adherence; D008691:Methadone / Q000627:therapeutic use*; D008875:Middle Aged; D058850:Opiate Substitution Treatment; D012189:Retrospective Studies; D013636:Tanzania / Q000453:epidemiology; D055815:Young Adult
chemical_list: D008691:Methadone
keywords: HIV; implementation science; methadone; people who inject drugs; sub-Saharan Africa