Plain English Summary
Background and study aims
There is an increased prevalence of hyperandrogenism (excessive production of male hormones) in women with type 1 diabetes. We do not know the best treatment for this condition. This study evaluated the effect of an insulin-sensitizing drug called metformin which has been used for the treatment of hyperandrogenism in women without type 1 diabetes. We investigated the effect of metformin on hyperandrogenism and ovulation in adolescents with type 1 diabetes mellitus.
Who can participate?
Women younger than 22 years who have type 1 diabetes and either increased body hair (hirsutism) or elevated androgen plasmatic levels participated.
What does the study involve?
Participants were randomly allocated to take either metformin (850 mg twice a day) or a pill without any medication (placebo twice a day) for nine months. A hormonal study was performed at the beginning and at the end of the study and an assessment of menstrual cycles and presence of ovulation was carried-out throughout the study. No healthy volunteers were included in this study.
What are the possible benefits and risks of participating?
The benefits of participating included a monthly evaluation by a nurse and diabetologist.
Side effects were mainly nausea or abdominal discomfort, at the beginning of the treatment. Metformin has been studied in many adults and adolescents with type 1 diabetes and no major side effects have been reported.
Where is the study run from?
The lead centre taking part in this trial is Instituto de Investigaciones Materno Infantil, School of Medicine, University of Chile. This is an academic centre located in a General Hospital (Hospital San Borja Arriarán) in Santiago, Chile. Some patients were referred from Hospital Calvo Mackena in Santiago, Hospital de Talca and Concepción (Chile).
When is the study starting and how long is it expected to run for?
January 2005 to January 2008.
Who is funding the study?
The study was funded by a Chilean governmental organism, Fondecyt. The support was
started in 2005 and finished in 2008.
Who is the main contact?
Dr. Ethel Codner
Fondecyt Grant 1050452
Metformin for the treatment of hyperandrogenism in adolescents with type 1 diabetes mellitus: a double blind randomized study
It is hypothesized that metformin will be a useful treatment for adolescents with type 1 diabetes and hyperandrogenism.
Chilean Ministry of Health, Central Metropolitan Service, Resolution 24/07, 27 August 2004
9 months double-blind placebo-controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Type 1 diabetes
Metformin 850 mg twice a day or placebo given twice daily.
Total duration of intervention: 9 months
Hormonal measurement in a blood sample at the beginning and end of the protocol
Menstrual cycle duration and ovulation assessment
In order to asses ovulation, measurement of progesterone in blood obtained together with capillary blood glucose measurement.
Primary outcome measure
Hyperandrogenism: One blood sample was obtained at the beginning of the trial (baseline) and a second one was obtained at the end of the trial (9 months).
Secondary outcome measures
1. Hirsutism score. A medical control was performed monthly in order to evaluate hirsutism, and for adjusting insulin dose and check possible side effects. Clinical assessment of hirsutism with a visual scale, Ferriman-Gallwey score, was performed monthly.
2. Metabolic control. HbA1c assessment was performed every three months with blood obtained from capillary puncture of the fingers.
3. Ovulatory function. During the nine months protocol, the patients obtained a sample of capillary blood in a filter paper for measurement of progesterone levels and determine the presence of ovulation. The filter paper was obtained in days 18-23-28 of each menstrual cycle. The capillary blood sample was obtained together with the procedure of capillary blood puncture for measuring glucose levels, which the patients do every day.
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Type 1 diabetes
2. Insufficient metabolic control
3. Clinical or biochemical hyperandrogenism
4. Already had menarche and younger than 22 yr
Target number of participants
Participant exclusion criteria
1. Type 2 or other type of diabetes.
2. Honeymoon period defined as an insulin daily requirement lower than 0.5 U/kg/day and HbA1c lower than 7%.
3. Diabetes duration less than 1.5 years
4. Abnormal thyroid function; elevated creatinine level
5. Use of contraceptive pills, steroids or any other type of medication
6. Presence of other chronic conditions
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Scientific and Technological Development Fund (FONDECYT Fondo de Desarrollo Científico y Tecnológico) (Chile)
Bernarda Morin 551
Scientific and Technological Development Fund (FONDECYT Fondo de Desarrollo Científico y Tecnológico) (Chile) - Chilean government Grant number: 1050452
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
Abstract of the 8th Joint Meeting of the Pediatric Endocrinology Societies LWPES/ESPE, APEG, APPES, JSPE and SLEP. New York, N.Y., USA, September 9-12, 2009 (Poster PO3-267) Horm Res 2009;72(S3):431; Metformin for the treatment of hyperandrogenism in adolescents with type 1 diabetes mellitus: a double blind randomized study.