NCT07416656Recruiting
Validation of Hemoglobin A1c in Patients With Inflammatory Arthritis Treated With Sulfasalazine
How Can We Prevent the Underdiagnosis of Diabetes and the Undertreatment of Known Diabetes in Patients With Inflammatory Arthritis Treated With Sulfasalazine?
Source: ClinicalTrials.gov · Last updated 25 Jun 2026
Brief summary (registry, in English)
The purpose of this study is to examine whether the blood test Hemoglobin A1c (HbA1c) gives an accurate picture of blood glucose levels in patients with inflammatory arthritis who are treated with sulfasalazine. HbA1c is widely used to diagnose and monitor diabetes, but sulfasalazine can shorten red blood cell lifespan and thereby lower HbA1c values independently of actual glucose levels. This may lead to underdiagnosis of diabetes in patients who develop diabetes during sulfasalazine treatment, and to undertreatment in patients with known diabetes due to falsely reassuring HbA1c values. The study aims to answer two main questions: 1. How many patients treated with sulfasalazine have undiagnosed diabetes despite having HbA1c values below the diagnostic threshold? 2. Does HbA1c underestimate actual glucose levels when compared with continuous glucose monitoring (CGM) in patients with sulfasalazine-treated inflammatory arthritis, both in those with known diabetes and those that are not diagnosed with diabetes but have borderline HbA1c values (≥ 38 mmol/mol)?
- Status (registry)
- Recruiting
- Study type
- Observational
- Enrollment
- 75 (estimated)
- First submitted
- 10 Feb 2026
- Start date
- 10 Mar 2026
- Primary completion date
- 30 Sept 2026
- Lead sponsor
- Klavs Würgler Hansen
- NCT number
- NCT07416656
What you commit to
- Study type: Observational
- Planned participants: 75
- From 10 Mar 2026 to the primary completion date, 30 Sept 2026
- 1 site in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- Systemic treatment or local injections with glucocorticoids within the previous 2 months or planned within the following 4 weeks
Other illness
- Allergy towards the adhesive used in the CGM
- Considered ineligible for participating (e.g. patients without decision-making capacity, , malignancy, terminal illness, ect.)
Lab values
- Clinical conditions interfering with the interpretation of HbA1c expect for sulfasalazine alterations in red cell lifespan (etc. Dapson treatment)
Who the study is looking for
- Age ≥18 years
- Treatment with sulfasalazine for at least 2 months prior to inclusion
- Inflammatory arthritis diagnosis (Reumatoid Arthritis, Reaktive Arthritis, Axial spa, Psoriatic spondylitis, and Juvenil artrit)
- HbA1c ≥38 mmol/mol obtained at least 2 months after sulfasalazine initiation OR a diabetes mellitus diagnosis (Type 1 diabetes mellitus, Type 2 diabetes mellitus, Malnutrition-related diabetes mellitus, Other specified diabetes mellitus (andre specificerede former for diabetes), and Unspecified diabetes mellitus (uspecificeret diabetes))
- Can communicate in Danish
- Informed consent including permission to upload glucose data and study ID to the Libreview Platform.
Age in the registry: 18 years to - · Sex: All · Does not accept healthy volunteers
Sites (1)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| Medical Diagnostic Center Coordinator of this site? Confirm its status | Silkeborg | Denmark | Recruiting |
This page is information, not medical advice. Discuss any trial with your doctor.