Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE Phase 2) screening and recruitment: Methods and results

Abstract

The Comprehensive Assessment of the Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE) study is a systematic investigation of sustained 25% calorie restriction (CR) in non-obese humans. CALERIE is a multicenter (3 clinical sites, one coordinating center), parallel group, randomized controlled trial. Participants were recruited, screened, and randomized to the CR or control group with a 2:1 allocation. Inclusion criteria included ages 21–50 years for men and 21–47 years for women, and a body mass index (BMI) of 22.0 ≤ BMI < 28.0 kg/m2. Exclusion criteria included abnormal laboratory markers, significant medical conditions, psychiatric/behavioral problems, and an inability to adhere to the rigors of the evaluation/intervention schedule. A multi-stage screening process (telephone screen and 3 inclinic visits) was applied to identify eligible participants. Recruitment was effective and enrollment targets were met on time. 10,856 individuals contacted the clinical sites, of whom 9,787 (90%) failed one or more eligibility criteria. Of the 1,069 volunteers who started the inclinic screening, 831 (78%) were either ineligible or dropped. 238 volunteers were enrolled (i.e., initiated the baseline evaluations), 220 were randomized, and 218 started the assigned intervention (2% from the first screening step). This study offered lessons for future multi-center trials engaging non-disease populations. Recruitment strategies must be tailored to specific sites. A multi-disciplinary screening process should be applied to address medical, physical, and psychological/behavioral suitability of participants. Finally, a multi-step screening process with simple criteria first, followed by more elaborate procedures has the potential to reduce the use of study resources.

Persistence of weight loss and acquired behaviors 2 y after stopping a 2-y calorie restriction intervention

“…Of 65 completers, 39 subjects (60%) agreed to enroll in the follow-up study. An extensive presentation of the CALERIE 2 study design, methods, and main results has been previously reported (30)(31)(32). Only adherent participants were included within the current per protocol analyses.…”

“…The CALERIE phase 1 trial first showed that CR at an amount of 15-25% is safe and feasible in nonobese humans and results in weight loss with improvements in body composition, energy expenditure (EE), hormone concentrations, the lipid profile, and insulin sensitivity (5,(22)(23)(24)(25)(26)(27) without triggering eating-disorder symptoms, harmful psychological effects, a reduced quality of life (QOL), or decreased cognitive function (28,29). The CALERIE Phase 2 (CALERIE 2) multicenter trial randomly assigned 218 nonobese, healthy men and women to a 25% CR diet or an ad libitum (control) diet for 2 y (30). Although the 2-y trial resulted in substantially less CR than the targeted 25% CR (w12% CR), CR individuals lost on average .10% of weight from baseline to year 1 and basically maintained this weight loss over the second year period (31).…”

A Practical Do-It-Yourself Recruitment Framework for Concurrent eHealth Clinical Trials: Simple Architecture (Part 1) (Preprint)

“…In the two years following the launch, the center has used the system to recruit participants for eight research projects, including the successful completion of four NIH-funded projects, which recruited across the life span, from a project targeting youth ages [14][15][16][17][18][19], to a project targeting adults 65 years and older [23,24]. As of July 26, 2017, a total of 6,525 prospective participants had completed the pre-screening survey and there are currently 14,557 records entered into the Referral Tracking database.…”

“…Pre-screening optimizes recruitment procedures by reserving staff time for interactions with participants who are likely to be enrolled [14]. Dividing recruitment into a series of different examinations of increasing complexity has also been shown to be successful in the recruitment for large trials [15,16], though few studies describe their pre-screening methods and subsequent record keeping. There are few, if any, published descriptions on optimization of these processes for eHealth clinical trials.…”

Inflammatory Oxidative Aging: A New Theory of Aging

“…What does seem clear is that the lower caloric intake and dietcalled healthy compared to the so-called Western diet improves parameters of healthy aging, as demonstrated in a recent study [47]. Is currently developing a multi-center study to better design (phase 2 CALERIE) RC with 25% that measure aspects of medical, physical and psychological behavior that will bring more light on this in a future intervention Mediate [48].…”