Much has been written about low retention rates in longitudinal studies of children (Bender, Ilke, DuHamel, & Tinkelman, 1997; Hartsough, Babinski, & Lambert, 1996). Although no reports on retention rates in studies of lead-exposed children were found, other clinical trial studies reported varied retention rates. In a review of clinical studies following children with ADHD into adulthood, Klein and Mannuzza (1991) reported retention rates of 51 percent to 88 percent. Other authors reported retention rates ranging from 75 percent (Tinkelman, Reed, Nelson, & Offord, 1993) to 81 percent (Hartsough et al., 1996). Reasons given for these retention rates include the length of the commitment required, participants' distrust of research programs, and family stresses (Bender et al., 1997). Loss of any subject can affect the statistical power of the findings, possibly leading to erroneous conclusions. Thus, it is important to retain as much of the original cohort as possible. The Treatment of Lead-Exposed Children (TLC) study, was a multiyear National Institute of Environmental Health Sciences contract carried out in four urban sites: Newark, NJ; Baltimore, MD; Philadelphia, PA; and Cincinnati, OH. Its purpose was to study the effects of oral chelation on the neurobehavioral sequelae of lead exposure in children with low to moderate lead levels (20-44ug/dl). The study enrolled 780 children ages 12 to 33 months. It consisted of a randomized, placebo-controlled, double-blind trial of up to three courses of treatment with succimer (a lead chelating agent) and required frequent visits over a period of three years. The Newark TLC site, located at the University of Medicine and Dentistry of New Jersey (UMDNJ), enrolled 208 children, of whom 71 percent were African American, and 22 percent were Latino/Hispanic. Of the enrolled children, 101 were girls and 107 were boys. Almost all were residents of urban areas with deteriorating housing. The Newark TLC site maintained a 97 percent retention rate (attrition rate of 3 percent) over a five-year period. Retention rates for the other three TLC sites ranged from 84 percent to 95 percent. This article describes the four primary factors that contributed to Newark TLC's high retention rate: program structure, social work resources, family care, and tangible supports. FACTORS IN HIGH RETENTION RATE Program Structure Staffing made a significant contribution to the low attrition rate at the Newark site. On the basis of decades of experience working with urban lead-exposed children, one of the principal investigators decided to hire personnel dedicated to the project rather than use staff from other hospital departments. Clinical staff consisted of one pediatric advanced practice nurse, one registered nurse, two pediatricians, a bilingual social worker, a bilingual social work aide, a supervising psychologist, and a bilingual psychologist. Using University Hospital in Newark as home base, TLC Newark also operated clinics in a nearby city's health department and at a satellite outpatient clinic 40 miles away. TLC Newark staff traveled to all three sites, so that families were assured that the same staff would always greet them, know their history, and care for their needs on each visit. All TLC staff were hired three to six months before recruitment of study participants. Regardless of prior experience and training in working with lead-exposed children, all staff received at least three months of training in the UMDNJ Pediatric Lead program. Social Work Resources The presence of a dedicated bilingual social worker was a key component of Newark's retention success and was unique to the Newark TLC site. The social worker provided a vital link between the study and the enrolled families. The most critical elements of this role were home visits, missed appointment follow-ups, referrals to ancillary services, hands-on assistance, and managing and providing transportation to and from clinic visits. …
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