Phase 4
Completed N=13
Trial of an Intervention to Improve Metformin Persistence and Adherence
Metformin Adverse Reaction · Tolerance
Source: ClinicalTrials.gov NCT03467763 ↗
Enrolled (actual)
13
Serious AEs
0.0%
Results posted
Dec 2020
Primary outcomePrimary: Treatment Satisfaction as Measured by the Treatment Satisfaction Questionnaire for Medication (TSQM II) — 39.42; 51.92 score on a scale
◆ Published Evidence
No publication linked
No peer-reviewed publication reporting this trial's results has been linked yet. This can indicate results are unpublished — a known publication-bias signal. We re-check periodically.
Summary
Metformin is a safe and effective first-line drug for type 2 diabetes that is also widely recommended for weight loss and diabetes prevention. But, metformin is associated with gastrointestinal and other side effects which prevent its use in 10-20% of patients and appear to limit the usable dose in others. This study is an N-of-1 trial design that will recruit 20 previously metformin-intolerant patients for re-challenge with metformin in a double-blind scenario. In this setting, 'intolerant' means either unable to take metformin at all, or unable to increase the dose past 1,000 mg despite the treating physician's recommendation to do so. Patients will be assigned to take their baseline medication regimen plus 2 weeks of 250 mg per day of metformin extended release, followed by 500 mg metformin XR, 750 mg, and 1,000 mg metformin XR with each treatment period separated by a 2-week course of placebo. Initial treatment, placebo or metformin XR, will be decided randomly. At the end of each two-week treatment period, participants will complete questionnaires assessing overall satisfaction with the medication, gastrointestinal symptoms, and adherence. Six months after the conclusion of the intervention, patients will be asked if they are continuing metformin at a higher dose than upon entry to the trial. This trial has two aims. First, to test the hypothesis that medication satisfaction will be the same during periods of placebo treatment and during periods of treatment with the active drug. The second aim is to test the hypothesis that > 30% of metformin-intolerant patients in an N of 1 crossover trial are able to tolerate higher-dose metformin at 6-months.
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Treatment Satisfaction as Measured by the Treatment Satisfaction Questionnaire for Medication (TSQM II) |
39.42; 51.92 | — |
| PRIMARY Number of Subjects Able to Tolerate Higher Dose of Metformin, |
2 | — |
| SECONDARY Change in Score of Gastrointestinal Symptom Rating Scale (GSRS) |
1.885; 1.78; 2.564; 2.346; 2.705; 2.667 | — |
Eligibility Criteria
Inclusion Criteria
- Diagnosis of diabetes, pre-diabetes, or obesity
- Previously attempted to take metformin for an above indication
- History of metformin intolerance (defined based on treating physician's assessment that a history of metformin intolerance (defined as the inability, due to side effects, to use metformin at the otherwise medically appropriate dose) exists, confirmed by the patient's recollection of the same history)
Exclusion Criteria
- Contraindication to metformin (i.e, advanced renal or liver disease, history of metformin attributed lactic acidosis, or advanced heart failure)
- Pregnant women
Data sourced from ClinicalTrials.gov (NCT03467763). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication. Informational only — not medical advice.