title: Maximizing retention in long-term clinical trials of a weight loss agent: use of a dietitian support team.
abstract: High-attrition rates have been observed in long-term clinical trials of weight loss agents. We evaluated the impact of an innovative retention programme on 1-year retention.
  
  
  
  Three Phase 3 global multicentre clinical trials evaluated the efficacy and safety of a CB1 receptor antagonist in subjects with BMI ≥ or = 27 kg/m2. The impact of a multifaceted retention programme including a dietitian screening interview, a comprehensive culturally adapted lifestyle modification programme, and a dietitian support system to maximize lifestyle adherence, was evaluated in 4,410 subjects from four subpopulations (non-US English-speaking, non-English-speaking, US-without dietitian screening and US-with dietitian screening) comprising 208 centres from 15 countries.
  
  
  
  The median proportion retained over the first year among subjects in three protocols was 82%. Non-English-speaking countries showed higher retention rates (89%) compared with the USA (73%) and non-US English-speaking (81%) countries. Within the USA, behavioural screening was associated with 29% reduction in dropout rate; for every five monthly teleconferences attended above 11, there was a 32% decrease in dropout rate.
  
  
  
  This novel retention programme greatly improved upon reported retention rates of studies conducted with other weight loss agents in long-term clinical trials. Its effectiveness should be confirmed in future trials.
authors.affiliation: Massachusetts General Hospital Diabetes Center Boston MA USA; Harvard Medical School Boston MA USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Delahanty
authors.affiliation: Cato Research Durham NC USA.
authors.forename: M
authors.initials: M
authors.lastname: Riggs
authors.affiliation: Pfizer Global Research and Development Groton CT USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Klioze
authors.affiliation: Pfizer Global Research and Development Groton CT USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Chew
authors.affiliation: Pfizer Global Research and Development Groton CT USA.
authors.forename: R D
authors.initials: RD
authors.lastname: England
authors.affiliation: Akcea Therapeutics Cambridge MA USA.
authors.forename: A
authors.initials: A
authors.lastname: Digenio
keywords: clinical trial; obesity; retention; type 2 diabetes; weight management