title: Retention and its predictors among methadone maintenance treatment clients in China: a six-year cohort study.
abstract: BACKGROUND
  To investigate factors associated with retention among the first cohort of drug users attending methadone maintenance treatment (MMT) clinics in China.
  
  
  METHODS
  A six-year cohort of 1511 drug users was enrolled in the first 8 MMT clinics in China in 2004 and followed between March, 2004 and December, 2010. Six-year retention rates were calculated and compared by methadone dosage, clinic location, and length of follow-up. Factors associated with retention were evaluated using Cox proportional hazard regression models.
  
  
  RESULTS
  The overall retention rate over 6-year was 35.7%. Highest drop-out occurred within the first 12 months of treatment. The retention rates for the 6-year by low (≤ 30 mg/day), medium (31-60 mg/day), and high (>60 mg/day) methadone dosage groups were 20.8%, 34.8% and 53.2%, respectively (p < 0.001). The highest 6-year retention rate among eight clinics was 43.8%, while the lowest one was 17.7% (p < 0.001). The results from Cox proportional hazard models indicate that clients having >30 mg daily methadone dosage (p < 0.001), having relatives receiving MMT (p = 0.027), and having >10% urine morphine positive result (p < 0.001) were more likely to be retained in MMT over the six-year period. It has also found that drug injection (p = 0.005) and needle sharing (p < 0.0001) were significantly associated with better retention.
  
  
  CONCLUSIONS
  Health workers should adjust individuals' methadone dosages as a method to prevent early treatment termination. Further studies are needed to explore the impact of severity of opiate addiction on long-term retention of MMT clients. Careful assessment of drug users upon MMT enrollment may be helpful for providing additional care to clients.
authors.affiliation: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Cao
authors.affiliation: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China. Electronic address: wuzunyou@chinaaids.cn.
authors.forename: Zunyou
authors.initials: Z
authors.lastname: Wu
authors.affiliation: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Keming
authors.initials: K
authors.lastname: Rou
authors.affiliation: Semel Institute Center for Community Health, University of California, Los Angeles, CA, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Semel Institute Center for Community Health, University of California, Los Angeles, CA, USA.
authors.forename: Chunqing
authors.initials: C
authors.lastname: Lin
authors.affiliation: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Changhe
authors.initials: C
authors.lastname: Wang
authors.affiliation: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.affiliation: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Pang
authors.affiliation: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Yin
authors.affiliation: Yunnan Institute of Drug Abuse, Kunming, Yunnan, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Li
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D055118:Medication Adherence / Q000523:psychology; D008691:Methadone / Q000008:administration & dosage*; D058850:Opiate Substitution Treatment / Q000379:methods* / Q000523:psychology / Q000639:trends; D009293:Opioid-Related Disorders / Q000188:drug therapy* / Q000453:epidemiology* / Q000523:psychology; D010352:Patient Dropouts / Q000523:psychology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016320:Substance Abuse Treatment Centers / Q000379:methods* / Q000639:trends; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D008691:Methadone
keywords: Cohort study; Methadone maintenance treatment; Retention; Risk factor