UMMS Affiliation

Department of Pediatrics, Division of Pediatric Endocrinology; Department of Quantitative Health Sciences

Document Type


Publication Date


File Format & Size

.xlsx (33 KB)


Clinical trial identification number: NCT01334125


This study was supported by an investigator-initiated research grant to Benjamin U. Nwosu from Novo Nordisk, Inc. This study was also supported by the University of Massachusetts (UMass) Center for Clinical and Translational Science. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Grant Number

H-13938, UL1 TR001453, UL1 TR001453


UMCCTS funding, type 1 diabetes mellitus, biguanides, metformin, insulin resistance


Manuscript abstract:

CONTEXT: Insulin resistance has been proposed as one of the causes of poor glycemic control in overweight/obese youth with type 1 diabetes (T1D). However, the role of adjunctive metformin, an insulin sensitizer, on glycemic control in these patients is unclear.

OBJECTIVE: To compare the effect of metformin vs. placebo on hemoglobin A1c (HbA1c), total daily dose (TDD) of insulin, and other parameters in overweight/obese youth with T1D.

HYPOTHESIS: Adjunctive metformin therapy will improve glycemic control in overweight/obese youth with T1D.

DESIGN, SETTING, AND PARTICIPANTS: A 9-mo randomized, double-blind, placebo controlled trial of metformin and placebo in 28 subjects (13m/15f) of ages 10-20years (y), with HbA1c >8% (64 mmol/mol), BMI >85%, and T1D > 12 months was conducted at a university outpatient facility. The metformin group consisted of 15 subjects (8 m/ 7f), of age 15.0 ± 2.5 y; while the control group was made up of 13 subjects (5m/ 8f), of age 14.5 ± 3.1y. All participants employed a self-directed treat-to-target insulin regimen based on a titration algorithm of (-2)-0-(+2) units to adjust their long-acting insulin dose every 3rd day from -3 mo through +9 mo to maintain fasting plasma glucose (FPG) between 90-120 mg/dL (5.0-6.7 mmol/L). Pubertal maturation was determined by Tanner stage.

RESULTS: Over the course of the 9 months of observation, the between-treatment differences in HbA1c of 0.4% (9.85% [8.82 to 10.88] for placebo versus 9.46% [8.47 to 10.46] for metformin) was not significant (p = 0.903). There were non-significant reduction in fasting plasma glucose (189.4 mg/dL [133.2 to 245.6] for placebo versus 170.5 mg/dL [114.3 to 226.7] for metformin), (p = 0.927); total daily dose (TDD) of short-acting insulin per kg body weight/day(p = 0.936); and the TDD of long-acting insulin per kg body weight per day (1.15 units/kg/day [0.89 to 1.41] for placebo versus 0.90 units/kg/day [0.64 to 1.16] for metformin) (p = 0.221). There was no difference in the occurrence of hypoglycemia between the groups.

CONCLUSIONS: This 9-month RCT of adjunctive metformin therapy in overweight and obese youth with T1D resulted in a 0.4% lower HbA1c value in the metformin group compared to the placebo group.

Data Collection Start Date


Data Collection End Date



Methodology is documented in published manuscript.





Code Lists

The code list for this dataset is available under "Additional Files."

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Nwosu T1DM Dataset Codes.pdf (14 kB)
Nwosu T1DM Dataset Code List

Nwosu_T1DM_data.csv (14 kB)
Dataset in csv format

.xlsx (33 KB)