Activity Reduction vs Advice for Plantar Hotspots in Diabetes

This is a prospective, multicenter, randomized, parallel-group, controlled proof-of-concept trial in adults with diabetes at high risk of diabetic foot ulceration.

Potential participants will undergo standardized bilateral plantar temperature assessment. A confirmed plantar thermal hotspot is defined as an inter-foot temperature difference greater than 2.2°C at the same anatomically comparable plantar site on two consecutive daily measurements. Only participants with a confirmed hotspot, intact skin at the index site, and no foot condition requiring immediate therapeutic treatment or offloading will enter the randomized trial.

Eligible participants will be randomized 1:1 to individualized, objectively monitored activity reduction or standard non-quantified activity-reduction advice. Both groups will receive guideline-concordant diabetic-foot preventive care, daily visual foot inspection, continued use of prescribed protective footwear, daily plantar-temperature monitoring, and objective step-count recording.

Participants assigned to the individualized activity-reduction group will ordinarily receive a temporary daily step-count target of no more than 50% of their objectively recorded habitual daily activity. When a 50% reduction is judged clinically inappropriate, a prespecified modified target requiring at least a 25% reduction may be used. Participants will receive feedback on their recorded activity relative to the prescribed target.

Participants assigned to the comparator group will receive standardized verbal and written advice to substantially reduce unnecessary walking and weight-bearing activity while the hotspot remains present, but they will not receive an individualized numerical step target or structured feedback comparing their activity with a prescribed target.

The primary outcome is time to uncomplicated sustained resolution of the index plantar thermal hotspot through Day 14. Sustained resolution is defined as an inter-foot temperature difference of 2.2°C or less at the index site on two consecutive valid daily measurements. Development before resolution of a clinically important foot complication requiring treatment will be considered failure to achieve uncomplicated resolution during the primary outcome period.

Participants will continue follow-up through Day 28 for assessment of hotspot recurrence, temperature-monitoring adherence, foot-related clinical outcomes, safety, and acceptability.

Inclusion criteria

• Age ≥18 years.
• Type 1 or type 2 diabetes mellitus.
• Loss of protective sensation demonstrated by standardized 10-g monofilament testing.
• IWGDF risk category 3.
• Previous diabetic foot ulceration and/or lower-extremity amputation consistent with IWGDF risk category 3.
• Any previous ulcer on the relevant foot completely epithelialized and clinically healed for at least 4 weeks.
• Confirmed plantar thermal hotspot, defined as an inter-foot temperature difference >2.2°C at the same anatomically comparable plantar site on two consecutive days.
• Intact skin at the index hotspot.
• Community ambulatory.
• Able to perform daily foot-temperature measurements independently or with caregiver assistance.
• Able to reduce ambulatory activity temporarily if assigned to the experimental intervention.
• At least five valid days of objectively recorded daily step-count data during Days -21 through -3 relative to the first positive thermal screening measurement.
• Objective historical activity data available from a smartphone, smartwatch, activity tracker, pedometer with stored daily counts, or another verifiable device-based source.
• Willing to continue objective activity measurement during randomized follow-up whenever technically possible.
• Able to provide informed consent and complete study procedures.

Exclusion criteria

• Active diabetic foot ulcer or other open foot wound.
• Blister, hemorrhagic callus, skin breakdown, or another pre-ulcerative lesion requiring immediate therapeutic management.
• Active or suspected Charcot neuro-osteoarthropathy.
• Clinical evidence of foot infection.
• Critical limb-threatening ischaemia or another vascular condition requiring urgent management.
• Recent acute foot trauma or surgery that could independently alter local foot temperature.
• Predominantly non-ambulatory or wheelchair-dependent status.
• Medical condition for which substantial temporary reduction in ambulatory activity would be unsafe.
• Inability to provide the required pre-hotspot objective activity history.
• Cognitive or functional impairment preventing study procedures without suitable caregiver assistance.
• Absence of an anatomically valid contralateral comparison site for the proposed index hotspot.