For people living with diabetes, foot ulcers remain one of the most challenging and costly complications, with a lifetime incidence approaching 19–34% and a strong association with lower extremity amputation. While offloading, debridement, infection control, and revascularization remain the foundations of wound care, glycemic control is an often-underemphasized variable that directly influences how — and whether — a diabetic foot ulcer (DFU) heals. As continuous glucose monitoring (CGM) becomes more accessible, clinicians are beginning to ask whether real-time glucose data, and the metric of “time in range” (TIR), can meaningfully improve foot outcomes.
Why Glycemic Control Matters in Wound Healing
Hyperglycemia interferes with virtually every phase of wound repair. Elevated glucose impairs neutrophil function and chemotaxis, blunts the inflammatory response, reduces fibroblast proliferation, disrupts collagen synthesis, and contributes to microvascular dysfunction in the wound bed. The downstream effect is a wound that lingers, becomes susceptible to infection, and is more likely to progress toward amputation.
A 2018 prospective cohort study by Fesseha and colleagues, published in Diabetes Care, quantified this relationship directly: in 270 patients with DFUs, the daily wound area healing rate decreased by approximately 0.028 cm² per day for every 1% increase in HbA1c (Fesseha et al., 2018). A 2020 systematic review and meta-analysis by Lane and colleagues in the Journal of Diabetes and Its Complications reinforced this association, finding that an HbA1c ≥ 8% and fasting glucose ≥ 126 mg/dL were associated with a higher risk of lower extremity amputation in patients with DFUs (Lane et al., 2020).
The Limits of HbA1c as a Sole Marker
HbA1c reflects average glycemia over roughly 8–12 weeks but does not capture day-to-day glucose excursions, hypoglycemic episodes, or short-term variability — all of which appear relevant to wound healing. A retrospective study by Dhatariya and colleagues found that greater glycemic variability was associated with delayed wound healing in patients presenting to a specialist multidisciplinary foot clinic (Dhatariya et al., 2018). A 2024 cohort study published in Diabetes Therapy similarly examined HbA1c variability in relation to 12-week and 12-month DFU outcomes, underscoring that single-point HbA1c measurements may be insufficient for risk stratification (Crocker et al., 2024).
These findings have driven interest in CGM, which produces a richer picture of glucose behaviour, including time in range (typically 3.9–10.0 mmol/L), time below range (hypoglycemia), time above range (hyperglycemia), and the glucose management indicator (GMI).
What CGM-Derived Time in Range Adds
The first study to specifically link CGM-derived TIR to major amputation risk was published by Yang and colleagues in 2022 in Therapeutic Advances in Endocrinology and Metabolism. In hospitalized patients with diabetic foot osteomyelitis undergoing amputation, lower TIR was independently associated with major amputation (odds ratio 0.83; 95% CI 0.71–0.99; p = 0.039) after adjustment for HbA1c and other clinical variables. Notably, increased time below range — a marker of hypoglycemia — was also independently associated with major amputation, suggesting that both extremes of glycemia carry risk (Yang et al., 2022).
A 2022 propensity-matched analysis in BMC Surgery reported that maintaining higher TIR during hospitalization was associated with improved clinical outcomes in diabetic patients undergoing toe amputation, including shorter length of stay and reduced postoperative complications (Lu et al., 2022).
A 2026 narrative review by Pantazopoulos and colleagues in the International Journal of Lower Extremity Wounds, titled “Continuous Glucose Monitoring and Diabetic Foot Ulcers: Is it Time to Walk in Range?”, synthesized the emerging evidence and concluded that optimizing glycemic control with CGM in patients with DFUs may help promote wound healing and reduce amputation risk, while emphasizing the need for prospective trials to confirm causality (Pantazopoulos et al., 2026).
Where CGM Fits Within the IWGDF Framework
The 2023 IWGDF guidelines on interventions to enhance healing of foot ulcers in people with diabetes underscore that best standard of care — including sharp debridement, infection management, offloading, vascular assessment, and metabolic optimization — must be in place before adjunctive therapies are considered (Chen et al., 2024). While IWGDF does not (yet) issue a specific recommendation on CGM for DFU management, the guidelines explicitly recognize glycemic control as a fundamental component of healing. CGM can be viewed as a tool that operationalizes this principle: it makes glycemic patterns visible, identifies hypoglycemia that HbA1c misses, and provides actionable feedback for therapy adjustment.
Clinical Takeaways
The available evidence supports several practical conclusions. HbA1c remains a useful but incomplete measure of glycemic control in patients with active foot ulcers, and both hyperglycemia and hypoglycemia are associated with adverse foot outcomes. CGM-derived TIR is emerging as a clinically meaningful metric that correlates with wound healing trajectory and amputation risk, particularly in higher-risk inpatient populations. Glycemic variability appears to influence healing independently of average glucose, and CGM is well-suited to detect it. Larger prospective trials are still needed to define optimal TIR targets specifically for patients with active DFUs and to determine whether CGM-guided care changes hard endpoints such as ulcer recurrence and amputation rates.
For now, integrating CGM data into the multidisciplinary diabetic foot care pathway represents a logical extension of evidence-based glycemic management — one that may help close the gap between metabolic control and wound outcomes.
References
- Fesseha BK, Abularrage CJ, Hines KF, et al. Association of Hemoglobin A1c and Wound Healing in Diabetic Foot Ulcers. Diabetes Care. 2018;41(7):1478-1485.
- Lane KL, Abusamaan MS, Voss BF, et al. Glycemic control and diabetic foot ulcer outcomes: A systematic review and meta-analysis of observational studies. Journal of Diabetes and Its Complications. 2020;34(10):107638.
- Dhatariya KK, Li Ping Wah-Pun Sin E, Cheng JOS, et al. The impact of glycaemic variability on wound healing in the diabetic foot — A retrospective study of new ulcers presenting to a specialist multidisciplinary foot clinic. Diabetes Research and Clinical Practice. 2018;135:23-29.
- Yang Y, Long Q, Jackson SL, et al. Association of continuous glucose monitoring-derived time in range with major amputation risk in diabetic foot osteomyelitis patients undergoing amputation. Therapeutic Advances in Endocrinology and Metabolism. 2022;13:20420188221099337.
- Lu J, et al. Impact of time in range during hospitalization on clinical outcomes in diabetic patients with toe amputation: a propensity score matching analysis. BMC Surgery. 2022;22:368.
- Crocker RM, et al. The Association of HbA1c Variability with 12 Week and 12 Month Outcomes on Diabetes Related Foot Ulcer Healing. Diabetes Therapy. 2024.
- Chen P, Vilorio NC, Dhatariya K, et al. Guidelines on interventions to enhance healing of foot ulcers in people with diabetes (IWGDF 2023 update). Diabetes/Metabolism Research and Reviews. 2024;40(3):e3644.
- Pantazopoulos D, Gouveri E, Popovic DS, Papanas N. Continuous Glucose Monitoring and Diabetic Foot Ulcers: Is it Time to Walk in Range? A Brief Narrative Review. International Journal of Lower Extremity Wounds. 2026.
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