A partner study was conducted in northern Thailand between March 1992 and June 1996 which included data that allowed an assessment of the reliability of self-reports of sexual behavior and contraceptive use among heterosexual couples. The authors enrolled 529 couples among whom all male subjects were human immunodeficiency virus (HIV) seropositive voluntary blood donors and their female sexual partners were either HIV infected (n=246) or HIV seronegative (n=283). The levels of agreement within couples were assessed for recency of last sexual intercourse, sexual activity in the prior year, and contraceptive practices. For HIV discordant couples, a prospective study was conducted to examine risk factors for HIV transmission, the primary goal of the study. This allowed assessment of reliability of inter-partner reports over 6-12 months. Overall, agreement among couples was good for common sexual practices, especially vaginal intercourse and time since last intercourse, but was lower for condom use. Anal and oral sex were infrequently reported by these couples and there was greater disagreement for the occurrence of these practices. Partner agreement for contraceptive histories was good to excellent. Prospective data showed less frequent intercourse and more condom use but reliability remained good. Common sexual practices may be reliable for both HIV concordant and discordant couples in studies estimating prevalent infection. Estimates of incident heterosexually transmitted HIV may be made with greater reliability by studies which include assessment of reports of risk behavior by each member of a couple than studies of individuals.
PIP: A study conducted in northern Thailand in 1992-96 enabled assessment of the reliability of self-reports of sexual behavior and contraceptive use among heterosexual couples. Enrolled were 529 HIV-positive male voluntary blood donors and their female partners who were either HIV-infected (n = 246) or seronegative (n = 283). In addition, a prospective analysis was conducted among the HIV discordant couples to examine risk factors for HIV transmission and further assess the reliability of inter-partner reports. Among HIV discordant couples, women reported an average of 185 sexual events in the past 2 years while men reported 165 such events. In discordant couples, these averages were 206 and 186 events, respectively. Agreement of the time since last sex within 3 days was recorded for 63.2% of concordant and 65.0% of discordant couples. Positive agreement on use of any contraceptive method in the past year was 88% for concordant couples and 91% for discordant couples. The prospective analysis demonstrated similar levels of agreement; the frequency of sexual acts decreased by 50% after HIV was diagnosed and condom use increased. The high degree of overall concordance of reports of sexual activity and contraceptive use between partners in this analysis is encouraging in terms of the validity of research studies on HIV transmission. Estimates of incident heterosexually transmitted HIV may be made with greater reliability by studies that include assessment of reports of risk behavior by each member of a couple rather than studies of individuals.