Abstract
The report aims to review the literature and describe the methods used for retention of patients in a clinical study. The Enhanced Recovery in Coronary Heart Disease (ENRICHD) trial was a multicenter, randomized clinical trial designed to evaluate the effects of a psychosocial intervention on cardiovascular morbidity and mortality. A total of 2481 patients met the criteria for depression, low social support, or both after a myocardial infarction and needed to be followed. Follow-up evaluation consisted of telephone interviews 3, 9, 12, 24, 36, and 48 months after enrollment and clinic visits scheduled at 6, 18, 30, 42, and 54 months. Creative strategies used to achieve optimum retention of this complex patient population over a long follow-up period are presented. Strategies to enhance adherence throughout the course of the trial required adequate tracking of patients to ensure minimum dropout, follow-up evaluation optimized through multiple methods of contact to guarantee completeness of data collection; and development of procedures to address the needs of patients at risk for dropout. Patients in the group that completed the study participated for a mean of 28.3 months, and those lost to follow-up evaluation participated for a mean of 19 months. Retention was not substantially different by gender or minority status. The results of this project can assist investigators in planning studies that require patient follow-up evaluation, and can provide clinicians with specific strategies for maximizing retention-to-treatment recommendations. As a result of the retention strategies described in this report, 93.02% of the patients completed their study participation or died. This is a very high retention rate given the complexity of the study sample, protocol, and required duration of follow-up evaluation.
The purpose of the Enhancing Recovery in Coronary Heart Disease (ENRICHD) trial was to test the efficacy of a cognitive behavioral psychosocial intervention in a randomized clinical trial of patients with a diagnosis of depression or social isolation after acute myocardial infarction (MI). This multicenter trial involved diverse populations enrolled from eight clinical sites across the United States. An important goal was to ensure adequate representation of women and minorities.
The patients were randomized to one of two conditions: usual care alone or usual care plus a psychosocial intervention. Follow-up data collection consisted of telephone interviews 3, 9, 12, 24, 36, and 48 months after enrollment. Clinic visits were scheduled at 6, 18, 30, 42, and 54 months. Thus, the minimum follow-up period was 6 months, and maximum follow-up period was 54 months (average, 31 months). Details of the study design and methods are described elsewhere. 1,2
This report reviews the literature concerning retention strategies used in previous randomized controlled trials (RCTs) and describes the varied strategies and techniques used to promote full participation of patients enrolled in the ENRICHD trial. The results of this project may assist investigators in planning for studies that require patient follow-up evaluation, and may provide clinicians specific strategies for maximizing retention.