Metformin use linked to Anemia risk in Type 2 Diabetes patients: study

The findings that emerged were as follows.

• A total of 1,458 individuals (41.8%) had a moderate anemia event during the follow-up period: 745 in current users, 194 in former users, and 519 in never-user.
• In ADOPT, compared with sulfonylureas, the odds ratio (OR) (95% CI) for anemia was 1.93 (1.10, 3.38) for metformin and 4.18 (2.50, 7.00) for thiazolidinediones.
• In UKPDS, compared with diet, the OR (95% CI) was 3.40 (1.98, 5.83) for metformin, 0.96 (0.57, 1.62) for sulfonylureas, and 1.08 (0.62, 1.87) for insulin.
• In ADOPT, hemoglobin and hematocrit dropped after metformin initiation by 6 months, with no further decrease after 3 years. In UKPDS, hemoglobin fell by 3 years in the metformin group compared with other treatments.
• At years 6 and 9, hemoglobin was reduced in all treatment groups, with no greater difference seen in the metformin group.
• In GoDARTS, each 1 g/day of metformin use was associated with a 2% higher annual risk of anemia.

The authors believed that because the mechanisms for metformin-related moderate anemia are unknown, the effects are modest, and the benefits of metformin are proven, avoidance or discontinuation of metformin would not be advocated, even in patients with anemia, but a reduction in Hb in the first few years after initiation of metformin might be anticipated.

"The mechanism for this early fall in hemoglobin is uncertain, but given the time course, is unlikely to be due to vitamin B12 deficiency alone." researchers concluded.

Primary source: Diabetes Care

For the full article click on the link: https://doi.org/10.2337/dc20-1104