Methadone treatment as a determinant of HIV risk reduction among injecting drug users: a nested case-control study.
In order to evaluate the protective effect of methadone treatment on HIV infection, we performed a nested case-control study on seroconverters (cases) who were part of a cohort of HIV-negative injecting drug users (IDUs) (controls). Controls were matched with cases by sex, age, duration of drug use and follow-up time. Information on methadone treatment in the year prior to seroconversion was collected using clinical registries. Univariate and multivariate conditional logistic regression were used to identify variables related to HIV-seroconversion. The study included 40 cases and 40 controls. Univariate analysis showed the following variables to be associated to HIV seroconversion: number of cycles of treatment, daily dose and time out of treatment. After performing multivariate analysis, daily dose remained protective with a linear effect noted even at low doses and time out of treatment was the most important risk factor. The risk increased 1.5 times for every 3 months spent out of treatment. Long-term methadone treatment protects against HIV infection. Its effect may be attributable to a reduction in the frequency of injecting drug use or to an increased knowledge of risk factors following counselling in drug centres.
Serpelloni
G
G
Gruppo C, ULSS-25, Verona, Italy.
Carrieri
M P
MP
Rezza
G
G
Morganti
S
S
Gomma
M
M
Binkin
N
N
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000517:prevention & control* / Q000523:psychology / Q000635:transmission; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007558:Italy; D008137:Longitudinal Studies; D008297:Male; D008691:Methadone / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D009293:Opioid-Related Disorders / Q000150:complications / Q000523:psychology / Q000534:rehabilitation*; D010353:Patient Education as Topic; D011446:Prospective Studies; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000150:complications / Q000523:psychology / Q000534:rehabilitation*
D008691:Methadone