Cost-effectiveness of a periodic fasting-mimicking diet programme in patients with type 2 diabetes: a trial-based analysis and a lifetime model-based analysis

van den Burg et al. BMC Primary Care (2025) 26:351 https://doi.org/10.1186/s12875-025-03027-1 BMC Primary Care Open Access RESEARCH Cost-effectiveness of a periodic fastingmimicking diet programme in patients with type 2 diabetes: a trial-based analysis and a lifetime model-based analysis Elske L. van den Burg1*, Petra G. van Peet1, Marjolein P. Schoonakker1, Ayla C. Esmeijer1, Hildo J. Lamb2, Mattijs E. Numans1, Hanno Pijl1,3 and M. Elske van den Akker – van Marle4 Abstract Background The prevalence of type 2 diabetes continues to rise worldwide, which is associated with a decrease in quality of Life and an increase in healthcare costs. The aim of this study was to determine cost-effectiveness of a one year monthly 5-consecutive day fasting-mimicking diet (FMD) programme for patients with type 2 diabetes treated with lifestyle advice only or lifestyle advice plus metformin, compared to usual care. Methods A trial-based cost-utility analysis with quality-adjusted life-years (QALYs) and healthcare costs was performed. These results were extrapolated to a lifetime horizon using the United Kingdom Prospective Diabetes Study Outcomes Model, predicting cardiovascular events and mortality. Cost-effectiveness acceptability curves were assessed, representing the probability of the FMD programme being cost-effective compared to usual care across a range of willingness-to-pay (WTP) thresholds per QALY. Results In the trial-based analysis (n = 92), QALYs were insignificantly lower (-0.04, 95% CI -0.10 to + 0.03), while healthcare costs were significantly higher (+ €2241, 95% CI + 182 to + 2660) in the FMD group. In contrast, from a lifetime horizon, QALYs were insignificantly higher in the FMD group (+ 0.16, 95% CI -1.16 to + 1.48) and costs were insignificantly higher as well (+ €1336, 95% CI -753 to + 3425), yielding an incremental cost-effectiveness ratio of €8369/QALY. Thus, in the lifetime analysis the probability of cost-effectiveness of the FMD programme was around 0.6 as compared to usual care at most WTP thresholds. Conclusions The FMD programme does not appear to be cost-effective over the first year of its application in the context of the Dutch healthcare system. However, this conclusion should be interpreted with caution due to the small sample size. In the extrapolations of the lifetime model-based cost-effectiveness analysis, a gain in QALYs in the FMD group was seen and the FMD programme’ costs were largely offset by savings in the costs of diabetic complications. This suggests that adding an FMD programme to usual care may potentially be cost-effective in the long term. Trial registration ClinicalTrials.gov: NCT03811587. Registered 22 January 2019. *Correspondence: Elske L. van den Burg Full list of author information is available at the end of the article © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creati vecommons.org/licenses/by-nc-nd/4.0/. van den Burg et al. BMC Primary Care (2025) 26:351 Page 2 of 10 Keywords Diet, Fasting-mimicking diet, Therapy, Cost-effectiveness, Primary care, Type 2 diabetes Background The prevalence of type 2 diabetes continues to rise worldwide. The number of people suffering from it surpassed 536 million people in 2021 and is projected to reach an estimated 783 million by 2045, affecting approximately 11% of the world’s population [1]. The prevalence of type 2 diabetes related complications, which are associated with a significant decline in quality of life, is increasing as well [1–3]. As a consequence, the costs involved in disease management rise, since complications are responsible for most healthcare costs associated with type 2 diabetes [4–7]. Adopting a healthy lifestyle can improve glycaemic control, may positively influence quality of life, and may decrease costs as it is associated with a lower risk of complications [8–11]. Various dietary interventions effectively improve metabolic parameters in patients with type 2 diabetes [12, 13]. However, as increasing healthcare costs threaten economic stability worldwide, it is imperative to any medical intervention to be cost-effective as well, particularly in the long term. The Fasting In diabetes Treatment (FIT) trial revealed clinical benefits of 12 monthly cycles of a so called fasting-mimicking diet (FMD) programme as an adjunct to usual care of patients with type 2 diabetes treated with lifestyle advice and/or metformin as the only glucose-lowering drug [14, 15]. FMD programmes comprise cycles of low protein-, low sugar/starch food, mimicking the physiological effects of water-only fasting, while still allowing light meals to be consumed [16, 17]. Here we present the results of two cost-effectiveness analyses of an FMD programme as deployed in the FIT trial: one evaluating short-term effects using trial data only, and another estimating long-term effects based on United Kingdom Prospective Diabetes Study Outcomes Model (version 2.2) [18]. Methods Clinical trial design The FIT trial was a randomised, controlled, assessorblinded intervention trial, which investigated the effectiveness and costs of twelve monthly, 5-consecutive-days FMD cycles as an adjunct to usual care in patients with type 2 diabetes [14]. The trial was conducted at the Leiden University Medical Centre (LUMC) in the Netherlands, between 20 November 2018 and 5 August 2021. The trial was performed according to the principles of the Declaration of Helsinki, in accordance with the Medical Research Involving Human Subjects Act, and to the standards of Good Clinical Practice. The Medical Research Ethics Committee of the LUMC approved the protocol and amendments. All participants provided written informed consent before entry into the study. The study was registered at ClinicalTrials.gov: NCT03811587. Registration was initiated prior to the start of the trial, but due to a delay within the registration process, online publication occurred after the start of the trial. Participants and intervention Participants were recruited from general practice centres. They (...truncated)