Patient retention is critically important in the conduct of a successful clinical trial. The power in numbers in multicenter trials is dependent on the completion of follow-up for every patient randomized. If at the end of a clinical trial, a significant number of randomized patients are missing outcome data, there will not be enough pool for data analyses to conclude a study based on its primary and secondary objectives. When patients who are either lost to follow-up or who withdraw consent during the clinical trial are eliminated from the data pool, they subsequently affect the power and the validity of conclusions derived from the clinical study. This paper aims to present current guidance on data retention for patients who have withdrawn consent from clinical trials.
OBJECTIVE: This study examines whether men-who-have-sex-with-men (MSM) and transgender (TG) persons' attitudes, beliefs, and risk perceptions toward human immunodeficiency virus (HIV) vaccine research have been altered as a result of the negative findings from a phase 2B HIV vaccine study. DESIGN: We conducted a cross-sectional survey among MSM and TG persons (N = 176) recruited from community settings in Atlanta from 2007 to 2008. The first group was recruited during an active phase 2B HIV vaccine trial in which a candidate vaccine was being evaluated (the "Step Study"), and the second group was recruited after product futility was widely reported in the media. METHODS: Descriptive statistics, t tests, and chi-square tests were conducted to ascertain differences between the groups, and ordinal logistic regressions examined the influences of the above-mentioned factors on a critical outcome, future HIV vaccine study participation. The ordinal regression outcomes evaluated the influences on disinclination, neutrality, and inclination to study participation. RESULTS: Behavioral outcomes such as future recruitment, event attendance, study promotion, and community mobilization did not reveal any differences in participants' intentions between the groups. However, we observed greater interest in HIV vaccine study screening (t = 1.07, P < 0.05) and enrollment (t = 1.15, P < 0.05) following negative vaccine findings. Means on perceptions, attitudes, and beliefs did not differ between the groups. Before this development, only beliefs exhibited a strong relationship on the enrollment intention (β = 2.166, P = 0.002). However, the effect disappeared following negative trial results, with the positive assessment of the study-site perceptions being the only significant contributing factor on enrollment intentions (β = 1.369, P = 0.011). CONCLUSION: Findings show greater enrollment intention among this population in the wake of negative efficacy findings from the Step Study. The resolve of this community to find an HIV vaccine is evident. Moreover, any exposure to information disseminated in the public arena did not appear to negatively influence the potential for future participation in HIV vaccine studies among this population. The results suggest that subsequent studies testing candidate vaccines could be conducted in this population.