- Metformin improved some metabolic parameters and clinical outcomes for glucocorticoid-treated patients with inflammatory disease.
- Metformin did not affect visceral-to-subcutaneous fat area ratio.
Why this matters
- Long-term glucocorticoids are prescribed for ≤3% of European adults.
- Chronic glucocorticoid exposure can raise metabolic, infectious, and cardiovascular risks.
- Randomized, double-blind, placebo-controlled, proof-of-concept, 12-week phase 2 trial of 53 adults without diabetes and with inflammatory disease treated with continuous prednisolone (≥20 mg/day for ≥4 weeks, ≥10 mg/day for subsequent ≥12 weeks, or cumulative dose-equivalent) randomly allocated to metformin (titrated up to 850 mg 3 times a day) vs placebo.
- Funding: Barts Charity, Merck Serono.
- No change in the primary outcome: visceral-to-subcutaneous fat area ratio over 12 weeks (0.11; P=.09).
- Facial adiposity observed in 10% of metformin vs 52% of placebo groups (P=.007).
- Dysglycemia present in 0% of metformin vs 33% of placebo groups (P=.009).
- Metformin improved insulin resistance, β-cell function, liver function, fibrinolysis, carotid intima-media thickness, inflammatory parameters, and disease activity severity markers.
- Metformin was associated with lower incidences of pneumonia (1 vs 7; P=.01), moderate-severe infections (2 vs 11; P=.001), and all-cause hospitalizations for adverse events (1 vs 9; P=.001).
- More diarrhea with metformin (18 vs 8 events; P=.01).
- Small sample size.
- Patient heterogeneity.
- Relatively short treatment duration.
- Possible selection bias.