Design of a RCT evaluating a lifestyle intervention in patients with type 2 diabetes and a critical appraisal of the recruitment process
Authors: Hohberg Vivien , Streckmann Fiona , Kreppke Jan-Niklas , Gerber Markus , Faude Oliver 
Published: February 2023

Introduction
Changing lifestyle can delay the progression of type 2 diabetes (T2D). Although there are evidence-based recommendations on diet and physical activity (PA; Colberg et al., 2016; Evert et al., 2019), T2D patients have difficulties implementing them (Booth, et al., 2013). Therefore, we have developed an intervention to promote PA and a healthy diet. While providing a supportive lifestyle change program for T2D patients, the recruitment entails difficulties.
Objective
The objective is to describe the design of the study and the intervention. As the study is still ongoing, the screening and recruitment process is to be analysed in more detail.
Methods
The intervention is investigated in a two-arm randomised controlled trial with N = 90 participants. Participants of the intervention group receive a one-year personal health coaching via telephone and access to an application. The intervention adapts the lifestyle recommendations to the individual needs based on achievable goals. The motivation and volition concept and behavior change techniques are used to empower participants to implement a healthy lifestyle. The control group receives access to the application. Primary outcomes are objectively measured PA and HbA1c. All outcomes are measured at baseline, at 27 weeks after inclusion and at 54 weeks after inclusion. Since May 2021, patients with T2D have been screened in two hospitals according to the study criteria (Hohberg et al., 2022). Due to a small number of eligible and interested patients, the criteria were adjusted in the course of the study and recruitment strategies were evaluated and adapted.
Results
Before the amendment of the inclusion criteria, 6.4% (113/1776; 05/2021-01/2022), and after the amendment, 22% (274/1243; 02/2022-10/2022) of T2D patients were eligible for the study. Finally, 1.8% (54/3019) of screened and 14% (54/387) of patients eligible for the study could be included. Reasons leading to a decline in participation are still being reviewed up to the conference. Exemplary reasons are e.g. no motivation, no time or too much stress, the program is not suitable for them or they are no longer contactable.
Conclusion
A strict definition of inclusion criteria as it is common in clinical trials with T2D patients results in only a very small part of the patients treated in the hospital being eligible for the study. Of these patients, only a few have interest or capacity to participate in the study. Researchers planning lifestyle interventions for T2D patients need to critically reflect on inclusion criteria and the recruitment process in order to obtain study results which are finally applicable to the real-world clinical population.
References
Booth, A. O., Lowis, C., Dean, M., Hunter, S. J., & McKinley, M. C. (2013). Diet and physical activity in the self-management of type 2 diabetes: barriers and facilitators identified by patients and health professionals. Primary Health Care Research & Development, 14(3), 293-306. https://doi.org/10.1017/S1463423612000412
Colberg, S. R., Sigal, R. J., Yardley, J. E., Riddell, M. C., Dunstan, D. W., Dempsey, P. C., Horton, E. S., Castorino, K., & Tate, D. F. (2016). Physical activity/exercise and diabetes: A position statement of the American Diabetes Association. Diabetes Care, 39(11), 2065-2079.
https://doi.org/10.2337/dc16-1728
Evert, A. B., Dennison, M., Gardner, C. D., Garvey, W. T., Lau, K. H. K., MacLeod, J., Mitri, J., Pereira, R. F., Rawlings, K., Robinson, S., Saslow, L., Uelmen, S., Urbanski, W. S., & Yancy Jr., W. S. (2019). Nutrition therapy for adults with diabetes or prediabetes: A consensus report. Diabetes Care, 42(5), 731-754.
https://doi.org/10.2337/dci19-0014
Hohberg, V., Kreppke, J.-N., Kohl, J., Seelig, E., Zahner, L., Streckmann, F., Gerber, M., König, D., & Faude, O. (2022). Effectiveness of a personal health coaching intervention (diabetescoach) in patients with type 2 diabetes: Protocol for an open-label, pragmatic randomised controlled trial. BMJ Open, 12(6), Article e057948. https://doi.org/10.1136/bmjopen-2021-057948