title: Loss to follow-up and bias assessment among a cohort of Thai men who have sex with men in Bangkok, Thailand.
abstract: Minimising loss to follow-up is essential to obtain unbiased results. This study aimed to assess factors associated with loss to follow-up and effects on biasing exposure-outcome associations in a cohort of men who have sex with men in Bangkok. We enrolled sexually-active Thai men who have sex with men, at least 18 years old, in a study with four-monthly follow-up visits. At each visit, men answered HIV risk behaviour questions using audio computer-assisted self-interview. Logistic regression was used to evaluate factors associated with loss to follow-up and bias between exposures and prevalent HIV infection were estimated using adjusted relative odds ratios. From 2006 to 2010, we enrolled 1744 men who have sex with men; as of April, 2014, 1256 (72%) had completed at least the month-36 visit; loss to follow-up was 9.6%. Factors independently associated with loss to follow-up were age (18-21 years), education (primary level or less, secondary or vocational education), living outside Bangkok and vicinity, sexual orientation (bisexual, heterosexual), previous HIV testing, HIV infection, and behaviour in the past 4 months (recreational drug use, reporting group sex). An effect of loss to follow-up on factors of prevalent HIV infection was found by sexual orientation (transgender) and unprotected anal intercourse (receptive/insertive). These findings highlight the need to strengthen post-HIV test counselling. Directed counselling for HIV care should be given to young men who have sex with men and recreational drug users.
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand vpv6@cdc.gov.
authors: Sarika
authors: S
authors: Pattanasin
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.
authors: Wipas
authors: W
authors: Wimonsate
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.
authors: Wannee
authors: W
authors: Chonwattana
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.
authors: Jaray
authors: J
authors: Tongtoyai
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.
authors: Supaporn
authors: S
authors: Chaikummao
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.
authors: Anuwat
authors: A
authors: Sriporn
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.
authors: Wichuda
authors: W
authors: Sukwicha
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand.
authors: Philip A
authors: PA
authors: Mock
authors: Thailand Ministry of Public Health - US Centers for Disease Control and Prevention Collaboration, Nonthaburi, Thailand Division of HIV/AIDS Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors: Timothy H
authors: TH
authors: Holtz
mesh_terms: D000293:Adolescent; D000328:Adult; D015982:Bias; D015331:Cohort Studies; D005500:Follow-Up Studies; D015658:HIV Infections / Q000453:epidemiology*; D018451:Homosexuality, Male / Q000208:ethnology / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D059012:Lost to Follow-Up; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D012309:Risk-Taking; D012747:Sexual Partners; D013785:Thailand / Q000453:epidemiology; D047568:Unsafe Sex / Q000706:statistics & numerical data; D055815:Young Adult
keywords: AIDS; Asia; Epidemiology; HIV; MSM; high-risk behaviour; homosexual; loss to follow-up; men; men who have sex with men; prospective studies