Setting and overview of the PREDICTS trial
The Preventing Diabetes with Digital Health and Coaching for Translation and Scalability trial (PREDICTS) is a Type 1 Hybrid Effectiveness-Implementation trial (HEI) that was conducted to determine the clinical effectiveness of a technology-enabled and adapted DPP lifestyle intervention to reduce hemoglobin A1c (HbA1c) and body weight of patients with prediabetes in an integrated healthcare system. As a Type 1 HEI trial [29], secondary aims related to examining the dissemination and implementation context included the assessment of potential reach [30] recruitment costs, and potential for adoption and sustained implementation of digital diabetes prevention strategies within a typical healthcare setting. The PREDICTS trial recruited 599 overweight or obese adults with prediabetes, determined by the HbA1c range of 5.7%-6.4%. The study protocol and details about participant recruitment and intervention reach are presented in detail elsewhere [5, 30]. In brief, eight clinics within the Nebraska Medicine healthcare system in the Greater Omaha area participated in the trial, from which 22,642 patients aged 19 and older who were at risk of T2D and had a Body Mass Index ≥ 25 kg/m2 were identified via an electronic health record (EHR) system query. Partnering PCPs reviewed health records of 11,313 of the resulting patient pool, and those who were not excluded from participation after physician review were sent a recruitment packet inviting them to participate in the trial. Packets included an opt-out postcard for patients to return if not interested. Trained study staff members contacted potential participants who did not return the opt out postcard within 2 weeks by outreach phone call to determine interest and conduct a telephone screening to further assess eligibility. A total of 2,796 patients were telephone screened, 30% of which were found ineligible due to not meeting the inclusion criteria (see Wilson et al. [30], under review). In total, 1,412 patients who passed the telephone screening attended an in-person screening at which HbA1c was assessed to determine final eligibility. Of these, 630 were found eligible and 599 of them were enrolled in the trial.
Participants were randomly assigned to the digital DPP (the intervention arm, n = 299) or to the enhanced standard of care (n = 300). The digital DPP is a technology-based delivery of the DPP lifestyle intervention [3] that consists of small group support, personalized health coaching, digital tracking tools, and weekly behavior change curriculum approved by the CDC Diabetes Prevention Recognition Program (the Omada Health Program®) [11]. Using internet-enabled devices (laptop, tablet or smartphone), program participants can asynchronously complete weekly interactive curriculum lessons, privately message a health coach for individual counseling, track weight loss and physical activity using a wireless weight scale and pedometer, and monitor their engagement and weight loss progress. The program is inclusive of an initial 16-week intensive curriculum focusing on weight loss and a subsequent 36-week curriculum focusing on weight maintenance, with a total of 12 months of educational lessons. Participants in the control arm were provided with a one-time, two-hour diabetes prevention education class, consisting of detailed information on current recommended levels of physical activity and healthy food choices involving portion size, eating regular meals, and a well-balanced diet based on the CDC My Plate recommendations, and the development of a personal action plan. The recruitment phase of the PREDICTS trial occurred over the 15-month duration from November 2017, through March, 2019, when the last eligible participant was randomized.
Analytical framework
We designed the analytic approach to address two primary issues. First, we focused on determining the cost needed for a large HEI randomized controlled trial to accrue the proposed sample size over a finite period of time (e.g., 599 participants over 15 months). This reflects the actual costs of recruitment and enrollment for the HEI trial. Second, we focused on sensitivity analysis to determine the potential costs of our PHM approach if it were to be used by a healthcare system for recruitment and enrollment to a local program (not a clinical trial) that aligned with the CDC Diabetes Prevention Recognition Program requirements. The analytical approach followed the best practice guidelines for the costing of prevention interventions [31, 32] and the modified cost assessment procedure proposed by Ritzwoller et al. [26], consisting of five elements: 1) perspective of the analysis, 2) identifying costs components, 3) capturing relevant costs, 4) data analysis, and 5) sensitivity analysis.
The recruitment costs were assessed from the organizational (i.e. healthcare system) perspective given that organizations are making the decision of whether or not to integrate such programs into their practices and thus bear the costs of implementing such programs. All costs were categorized as labor and non-labor costs and expressed as 2018 US dollars. For the collection and analysis of costs, we utilized a micro-costing approach with activity-based costing strategy [33], a method that is widely adopted in healthcare, to explicitly identify, measure, and value all resources used to recruit participants for the study. Specifically, total labor costs were estimated by summing the costs of each recruitment activity, which was calculated by multiplying the total activity time (in hours) by the per-hour cost of resources.
Costing a PHM approach for participant recruitment and enrollment
Step 1: identify labor cost components by recruitment activities and associated labor hours
The diabetes prevention trial applied a PHM approach that holds the potential to be automated within existing healthcare systems to identify, screen, enroll, and engage potential participants. To better capture the recruitment costs, in which the majority are activity-based, we created a process map (Fig. 1) to illustrate the study recruitment process with each steps reflecting an activity in the participant recruitment process from initial identifying individuals at risk, ordering screening tests, conducting screening tests, managing screening test results, to the final enrollment in the preventive services. All the identified recruitment activities were further categorized into three sections: participant identification, participant eligibility screening, and eligible participant intake and enrollment. At the end of the recruitment phase, members of the research team estimated the average number of hours per weeks they spent on the specific task, supplemented by the regular documentation of average times spent on each subcategory by project management tracking of the recruitment progress and resource use. We further multiplied the average hours per week by the number of weeks dedicated to a recruitment activity to derive the total numbers of labor hours on a specific task in the entire recruitment process.
Participant Identification
A computer programmer applied pre-specified inclusion and exclusion criteria to identify potential eligible participants via EHR query [5]. Once a list of potential participants was generated, a physician champion engaged PCPs at each of the participating clinics for patient list review and clearance, or potential participant referral. A recruitment packet consisting of a physician invitation letter, a study description, and an opt-out postcard was prepared and mailed to potentially eligible patients. A total of 14 recruitment packet preparation sessions were conducted to prepare and send 10,770 invitation packets by postal mail.
Participant Eligibility Screening
Research assistants conducted a telephone screen call to assess specific inclusion and exclusion criteria for all patients who did not return the opt-out postcard. After initial eligibility was determined, a screening visit was scheduled and the initial screening packet, containing screening instruction, direction to the screening location, and a copy of the informed consent was prepared and sent by postal mail or email (based on participant preference). Research assistants and clinical staff (e.g., research nurse coordinators, medical assistants, or phlebotomists) conducted the screening assessment session, including HbA1c testing, blood pressure, weight, height, and resting heart rate measurements at eight different primary care clinics across the metropolitan area.[30]
Eligible Participant Intake and Enrollment
Participants found eligible by HbA1c screening completed an in-person baseline assessment prior to being randomized into one of the trial conditions. Research staff conducted all the assessment and data collection activities (survey questionnaires and waist circumference measurement) at the baseline visit.
Step 2: Determine hourly wage rates
Labor costs were estimated based on time spent on each recruitment activity (i.e., activity-based costing), outlined on the process map (Fig. 1), conducted by the staff members and a full-time project manager who oversaw all aspects of the study, including staff recruitment, orientation and training, meeting and planning, coordinating between clinics, IRB related tasks, and corresponding hourly wages. Number of hours worked was also tracked using bi-weekly timesheets of all research personnel. The per-hour salary rate for personnel who conducted the EHR query with computer programming and PCPs who reviewed the list of their potentially eligible patients to exclude any patients for reasons related to safety and appropriateness of the intervention were estimated at $44.29 and $124.87, respectively. These rates were calculated based on annual salaries plus fringe benefits at a standard rate of 28%. All the other recruitment activities were conducted by the non-clinical research staff and clinical research staff at an hourly rate of $16.35. Costs associated with the full-time project manager were estimated based on the actual 2017–2019 salaries.
Step 3: Determine non-labor costs
Non-labor costs for telecommunication service subscription, appointment reminder service subscription, equipment, and supplies were based on actual amounts spent and were tracked from receipts and payment invoices. The research team collected non-labor costs, further categorized each as fixed or variable. Variable costs were reported as unit costs and multiplied by the number of participants or the item purchased. These costs included point-of-care HbA1c fingerstick test and venipuncture HbA1c test, iPads and cases, scales, gulick tape, stadiometer, and safety box. Fixed costs included recruitment materials, the Appointment Reminder software subscription, and telephone and cellphone services. A detailed listing of the materials and services, and individual costs, grouped into operational services, operational supplies, and medical supplies, are provided in Table 1. Other non-labor costs include research staff travel costs for assessment sessions, which was accrued at a rate of $0.25 per mileage. We did not take into account the overhead or space costs, because the study-related screening and assessment sessions occurred outside of regular business hours (in the weekday evenings or Saturday morning).
Table 1
PREDICTS trial recruitment costs.
Activity/category | Time, hours | Number | Costs ($) |
Labor costs | | | |
A full-time project manager, including fringe benefits | | | $96187 |
Participant identification | | | |
EHR query | 472 | | $20906 |
PCP recruit & review | 132 | | $16482 |
Recruitment packet preparation | 236 | | $3850 |
Participant eligibility screening | | | |
Participant screening calls & schedule | 2984 | | $48791 |
Screening visit packet preparation | 132 | | $2158 |
Preparation for screening visits, non-clinical | 396 | | $6475 |
Ordering of HbA1c testing & PCP signed off | 24 | 1412 | $2939 |
Screening visit | 1476 | | $24133 |
Follow-up for screening visit | 230 | | $3752 |
Eligible participants intake & enrollment | | | |
Baseline visit packet preparation | 77 | | $1259 |
Preparation for baseline visits | 96 | | $1574 |
Baseline visit | 790 | | $12917 |
Follow-up for baseline visit | 66 | | $1071 |
Total labor costs | 7109 | | $242493 |
Non-labor costs | | | |
Operational Service | | | |
Mail/Postage | | | $7745 |
Telephone/cellphone, monthly fee, device, & data plan | | | $2895 |
Venipuncture HbA1c testb | | 837 | $78678 |
Operational/medical supplies | | | |
Incentives | | 1412 | $35300 |
iPad & iPad cases | | 15 | $6636 |
AppleCare | | | $869 |
Apple pencil | | 1 | $129 |
Safety box | | 2 | $71 |
Printing | | | $5447 |
Appointment Reminder App subscription fee | | | $1035 |
Others | | | $1415 |
Clinical supplies (e.g. gauge butterflies, syringe, vials, and sharp container) | | $1633 |
Gulick tape | | 10 | $484 |
POC HbA1c testb | | 575 | $4428 |
Stadiometer | | 2 | $301 |
Sphygmomanometer, stethoscope, arm pressure monitor, & scale | | | $390 |
Total non-labor costs | | | $147453 |
Total recruitment costs | | | $389949 |
Total costs per screened patient | | | $276 |
Total costs per enrolled patient | | | $651 |
aThe hourly wage for EHR query and PCP recruit and review activities were $44.29 and 124.87, respectively. Otherwise, the hourly wage for other activities was $16.35. |
bThe screening protocol was switched to a lab HbA1c testing from a POC HbA1c fingerstick test to determine eligibility 6 months after the initiation of study recruitment due to a high proportion of false positive POC results (52%) (see Wilson et al. [30] for more detail) |
Data analysis
We used descriptive analyses to estimate the total number of labor hours, and total labor and non-labor costs associated with study participant recruitment. Measures included total recruitment costs broken down into labor and non-labor costs, and costs per participant screened and recruited by dividing total recruitment costs by the number of participants screened and enrolled. Additionally, exploratory descriptive analyses were conducted to estimate the cost to replicate the PHM approach for participant recruitment for preventive interventions.
Estimated costs for replication
For the estimate of replication costs, we used the process map (Fig. 1) to map replication resources needed to guide our cost estimate. We focused on activities that would be required for a healthcare system to implement the PHM strategy. We excluded any tasks, activities, and expenses that dealt with the clinical trial protocol development, clinical trial assessment and data collection, and any other clinical trial-related activities that would not need to be replicated if the study were continued at the organization or if it were replicated or adopted in another setting.
We further conducted one-way (deterministic) sensitivity analyses (varied 1 input parameter at a time) to evaluate the uncertainty and variation of the recruitment cost estimates to the parameter assumptions or in a variety of settings and circumstances. Specifically, we first calculated the minimum and maximum plausible values for each parameter by varying the original costs by 50% [34] if not specified. Each input variable further labeled as required vs. optional depending on whether they are identified as needed resources during the replication process. For labor costs, we varied the per-hour salary amount and the hourly wage for study personnel. The percentage of computer programming time used to query the EHR ranged from 50–150%, because it is the essential element for a recruitment strategy applying a PHM approach. In addition, we considered that PCPs reviewing potential participant list as an optional activity because it is not required when referring patients to CDC-recognized DPP programs. We assumed discounted resources associated with participant screening calls and schedule, and follow-up for screening visit and enrollment (varied from 50%-100%) because a telephone screening for a randomized trial is more laborious than a general screening call to offer a preventive service and less intensive follow-up. For non-labor costs, we varied the cost of HbA1c testing ($94 per unit) to be compatible with other glucose testing (i.e., fasting glucose test ($39 per unit), and 2-hour oral glucose tolerance test ($105 per unit)) using local institutional expenses. Currently, HbA1c testing is not reimbursed by Medicare, even though the testing result is used to determine the eligibility to enroll in a Medicare DPP program [35, 36]; whereas the glucose testing is not required for participation in CDC-recognized DPPs. Therefore, the cost range of a glucose testing was assumed between 0 (not required) to 100% (required). For the optional activities or resources, we assumed that the cost range between 0% and 100%. These range estimates were derived via expert consensus from the study investigators. We used tornado diagrams [34] to summarize the effects of varying key input parameters one at a time on the replication costs. The parameters were sorted in descending order by their influence on the cost outcomes. The longer bars indicated the most important parameters. In addition, we conducted a scenario analysis to estimate the potential replication costs of recruitment when considering different stakeholders (e.g., Medicare, or private payers).