Retention and protocol adherence of Hispanic volunteers in a longitudinal trial.

Objectives: To compare Hispanic research volunteers with high and low levels of study retention and adherence.

Methods: Correlational analysis of demographics, recruitment strategies, knowledge, and attitudes of 470 households in a clinical trial.

Results: Within 12 months, 53 (11.3%) households dropped out; those less certain about some factual information were more likely to drop out (P < 0.05). Participants born outside the United States were more likely to adhere to protocols (P = 0.03). Flyers were effective for recruiting only 3% of participants.

Conclusions: In newly immigrated populations, written recruitment materials may be ineffective; knowledge and attitudes may be important for study retention and adherence.