PAINLESS — Control-IQ for painful diabetic neuropathy
What this study tests
A UK randomized crossover study testing whether Control-IQ changes neuropathic pain in adults with established T1D. The protocol targets 40 randomized participants; no outcome results are reported. The registry lists recruiting in its March 2026 update, but current site openings are unconfirmed.
Editorial review: . 16 September review-note archive (earlier notes may not cover later changes).
Registry checked: 2026-09-17. Registry’s own update: 2026-03-02.
Most recent recorded citation date: 2026-09-08. Only explicit date metadata is included; an undated citation may be newer. This does not mean every claim was reviewed on that date.
Trial status, labels and access can change between reviews. Review coverage and open work · How to read the evidence
Evidence at a glance
- Who can enter the study?
- The published protocol specifies age over 18, T1D for at least five years, neuropathic pain for more than three months, confirmed polyneuropathy and a screening pain score of at least 4/10. HbA1c and other restrictions apply. Protocol and registry medication-stability criteria differ; the study team must confirm the currently applicable criteria. Registered eligibility ↗Enrollment criteria describe who may enter. They do not establish who was analyzed or the denominator for a reported result.
- Reported benefit and results
- No pain, glycemic or safety outcome results are reported in the protocol or registry reviewed. Approximately 49 people are planned for screening to achieve 40 randomized participants; these are targets, not observed enrollment or an analysis denominator.Read the result sources and their limitations →
- Important harms
- Read the reported results, safety discussion and original sources. A separate harms summary is not available; this does not establish safety.
- Research access and approval
- Study regions: United Kingdom. A trial listing does not establish product approval or current recruitment at a particular site. Check the study’s current entry requirements.
- What remains uncertain?
- Read the 16 September review-note archive and current review coverage. Later changes and new records may not appear in the earlier notes. Planned endpoints and completion dates are not results.
Research status alone does not establish approval, clinical benefit or local availability.
Registry status: Recruiting. The displayed trial status also reflects the cited study evidence.
Primary endpoints
- Change in seven-day average 24-hour pain intensity on a 0–10 numerical rating scale, from baseline to the end of each 12-week treatment period
The full picture
What is being tested
PAINLESS compares the Tandem t:slim X2 pump with Control-IQ against standard care with CGM in adults with T1D and painful diabetic neuropathy. After four weeks of screening, each participant is assigned to two 12-week treatment periods in random order. The protocol targets 40 randomized participants after approximately 49 enter screening across Sheffield and Leicester. These are planned numbers, not results.1
What remains unknown
The main outcome is change in seven-day average 24-hour pain intensity, measured on a 0–10 scale at the end of each treatment period. The published protocol provides no outcome data, so it does not establish that Control-IQ relieves neuropathic pain. There is no washout between periods, making possible carryover an interpretation issue for future results.1
The protocol includes safety monitoring and precautions against treatment-induced neuropathy after rapid glucose improvement. It allows return to standard care if hybrid closed-loop treatment is judged harmful, including worsening pain or recurrent ketoacidosis. These are planned safeguards, not observed adverse-event rates or proof of safety.1
Registry status and source differences
The registry PDF was last edited on 2 March 2026 and lists recruiting and ongoing. The September protocol also describes recruitment as ongoing, but neither source confirms which sites are accepting new participants today. The record therefore labels current recruitment as unconfirmed.21
The registry gives 9 February 2026 as first enrollment; the protocol says the first participant was recruited on 27 March 2026. The protocol anticipates data collection ending in September 2027 and results by February 2028, while the registry gives overall completion as 9 February 2028. These are source-specific dates and forecasts, not a reconciled timetable or a promise of results.21
Eligibility also differs: the registry asks for stable neuropathic-pain medication for three months, while the protocol specifies no dose change in the previous month. The protocol specifies age over 18; the registry labels the population adult. Consult the study team and full documents for current eligibility.21
Funding
Sheffield Teaching Hospitals NHS Foundation Trust is the registered sponsor. The protocol discloses a Tandem Diabetes Care grant and provision of pumps and supplies, plus equipment from other manufacturers. It states that funders and suppliers had no role in design, data collection, analysis or interpretation.21
References
Sources
- [1]Pain alleviation in diabetic neuropathy using hybrid closed loop insulin pumps (PAINLESS) — A randomised crossover trial protocol · Peer-reviewed study · 2026-09-08 — Published study protocol, not an outcome report. Full Methods distinguishes approximately 49 screened from the target of 40 randomized participants.
- [2]ISRCTN24233750 — PAINLESS registry PDF · Trial registry · 2026-03-02 — Registry registered and last edited 2 March 2026; PDF accessed 17 September. Recruiting is the registry's dated status, not confirmation of current site openings. Some dates and eligibility wording differ from the September protocol.