Fasting-Mimicking Diet for Type 2 Diabetes Shows Long-Term Cost-Effectiveness Promise
A Dutch RCT finds monthly 5-day fasting-mimicking diet cycles cost more short-term but may save money over a lifetime by reducing diabetic complications.
Summary
Researchers analyzed the cost-effectiveness of a 12-month fasting-mimicking diet (FMD) programme for type 2 diabetes patients in the Netherlands. In the short term (one year), the FMD group had higher healthcare costs and no significant QALY gain compared to usual care. However, when extrapolated to a lifetime horizon using the UKPDS Outcomes Model, the FMD group showed a small QALY gain and an incremental cost-effectiveness ratio of approximately €8,369 per QALY — well below typical willingness-to-pay thresholds. The probability of long-term cost-effectiveness was around 60%, suggesting the intervention may be economically viable over a patient's lifetime, primarily because reduced diabetic complication costs offset the programme's expense.
Detailed Summary
Type 2 diabetes affects over 536 million people globally and is projected to reach 783 million by 2045. Complications drive the majority of healthcare costs, making cost-effective lifestyle interventions critically important. The fasting-mimicking diet (FMD) — a structured, low-calorie, low-protein meal replacement programme mimicking physiological fasting — has shown metabolic benefits in prior research, but its economic value had not been rigorously evaluated.
The FIT trial (NCT03811587) was a randomized, controlled, assessor-blinded trial conducted at Leiden University Medical Centre. Patients with type 2 diabetes managed with lifestyle advice alone or with metformin were randomized to receive 12 monthly 5-consecutive-day FMD cycles (approximately 750–1100 kcal/day; low protein, low sugar) alongside usual care, or usual care alone. Of 100 enrolled participants, 92 completed baseline assessments and were included in the cost-effectiveness analysis. Quality of life was measured via EQ-5D-5L at baseline and at 3, 6, 9, and 12 months, with QALYs calculated using the area-under-the-curve method. Healthcare costs were tracked via patient questionnaires and medication records, valued using Dutch reference prices updated to 2023 euros.
In the trial-based analysis, the FMD group showed no significant QALY improvement (-0.04 QALYs, 95% CI -0.10 to +0.03) but incurred significantly higher healthcare costs (+€2,241, 95% CI +€182 to +€2,660), driven largely by the FMD programme costs themselves. Cost-effectiveness acceptability curves showed the FMD was unlikely to be cost-effective at standard willingness-to-pay thresholds within the trial period.
For the lifetime analysis, the UKPDS Outcomes Model v2.2 was used to extrapolate individual participant data — including HbA1c, weight, HDL-cholesterol, cardiovascular history, and age — from trial end to death. Two scenarios were modeled: a base-case where FMD use stops at trial end, and an alternative where adherent participants continue 4 FMD cycles/year for life. In the base-case lifetime projection, the FMD group gained +0.16 QALYs (95% CI -1.16 to +1.48) with modestly higher costs (+€1,336, 95% CI -€753 to +€3,425), yielding an ICER of €8,369/QALY. The probability of cost-effectiveness was approximately 60% across most willingness-to-pay thresholds. Savings from reduced diabetic complications largely offset the FMD programme costs over a lifetime horizon.
These findings suggest that while the FMD programme is not cost-effective within the first year of use, it may become cost-effective over a patient's lifetime. The intervention's metabolic benefits — including reductions in HbA1c, body weight, and HDL improvements seen in the FIT trial — translate into lower predicted rates of cardiovascular events and complications, which carry substantial long-term healthcare costs. Sensitivity analyses including a 50% price reduction scenario and societal perspective analyses were also conducted, further supporting potential long-term value.
Key Findings
- FMD added €2,241 in healthcare costs over one year with no significant QALY gain vs. usual care.
- Lifetime model shows FMD yields +0.16 QALYs and an ICER of €8,369/QALY — below common cost-effectiveness thresholds.
- Probability of FMD being cost-effective at lifetime horizon is approximately 60% across most willingness-to-pay thresholds.
- Reduced diabetic complication costs largely offset the FMD programme expense over a patient's lifetime.
- HbA1c, body weight, and HDL improvements from FMD drove favorable long-term projections in the UKPDS model.
Methodology
Randomized controlled trial (n=92) with 12-month follow-up comparing monthly 5-day FMD cycles plus usual care vs. usual care alone in Dutch T2D patients. Trial-based cost-utility analysis used EQ-5D-5L QALYs and healthcare cost questionnaires; lifetime extrapolation used UKPDS Outcomes Model v2.2 with 100 multiple imputations and 1000 Monte Carlo loops. Bootstrapping and seemingly unrelated regression adjusted for baseline confounders.
Study Limitations
Small sample size (n=92) limits statistical power and generalizability of both trial-based and modeled results. Lifetime projections rely on UKPDS model assumptions derived from a UK population and may not fully reflect Dutch patients or modern diabetes management. Long-term FMD adherence is uncertain, and no post-trial data exists to validate the extrapolated scenarios.
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