Background

The conundrum of measuring condom use consistency, particularly with adolescents, has left researchers with a cacophony of strategies, thereby limiting comparability and interpretation.

Objective

The aim of this analysis was to compare and contrast two measures of condom use consistency, global versus partner-specific, and their relationships with key covariates, using trajectory groups differentiated by stability of condom use consistency over three time-points.

Method

Using self-report data from sexually-active girls (ages 13-17 years) in a clinic-based intervention study aimed at lowering risk for early pregnancy, this analysis compared two measures of self-reported condom use consistency: 1) a global measure: overall condom use consistency in the past 6 months, and 2) a partner-specific measure: condom use consistency with the most recent sex partner in the last 6 months. Using a subjective rule-based approach, the adolescent girls in the study (N=151) were classified into trajectory groups representing their condom use consistency at three time-points (baseline, 6, and 12 months). Then, using bivariate methods, trajectory groups were compared on four baseline covariates (age, treatment condition, hormonal use in the last 6 months, number of sex partners in the last 6 months) and three time-varying covariates measured at baseline, 6, and 12 months (hormonal use stability, stability of primary sex partner, stability of number of sex partners).

Results

For the trajectory groups formed using the global measure of condom use consistency, stability of the primary sex partner differed significantly between trajectory groups. For the partner-specific trajectory groups, two baseline and one time-varying covariate relationships were significant: hormonal use in 6 months prior to baseline, number of sex partners in past 6 months (baseline), and stability of the primary sex partner (time-varying) with hormone use stability (time-varying) trending toward significance.

Discussion

The larger number of significant covariate relationships with the partner-specific trajectory groups suggests greater utility in assessing partner-linked behavior rather than a global measure. Despite limitations of the analytic strategy, this study sheds light on a measurement conundrum that has been an obstacle to comparing and contrasting indicators of condom use consistency during adolescence.