Background: In 2016, metformin’s prescribing label was revised to permit it to be started with estimated glomerular filtration rate (eGFR) 45-60 ml/min and continued with eGFR 30-44 ml/min. We examined whether subsequent metformin prescribing in these groups increased.

Methods: We conducted an interrupted time series study using data from the New York City Clinical Data Research Network. We identified episodes from 2014-2017 in which adult patients with HbA1c ≥6.5% received outpatient antidiabetic prescriptions ≤7 days after an eGFR measurement. Trends in the proportion of episodes that included metformin were examined using linear regression in 4 eGFR subgroups: ≥60 (reference), 45-59, 30-44, and <30 ml/min. Sensitivity analysis examined episodes with no antidiabetic prescription in the prior 180 days.

Results: We identified 10,608 prescribing episodes among 6,505 patients. Lower eGFR was associated with less metformin prescribing. In the eGFR 30-44 ml/min group, there were significant increases in metformin prescribing after the label change (p<0.001). In sensitivity analysis, an increasing trend in metformin prescriptions in the 45-59 ml/min eGFR group started before the label change (p=0.04) and leveled off.

Conclusion: Metformin prescribing for patients with eGFR 30-60 ml/min was increasing prior to the label change. Rates of metformin use at eGFR 30-45 ml/min remain relatively low.


J. Min: None. X. Wu: None. J. Orloff: None. A.I. Mushlin: None. J. Flory: None.


Patient-Centered Outcomes Research Institute (CER-9230)

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