Metformin failure in people with type 2 diabetes is very common, particularly among those with high A1c levels at the time of diagnosis, new findings suggest.
An analysis of electronic health record data for more than 22,000 patients starting metformin at three US clinical sites found that over 40% experienced metformin failure.
This was defined as either failure to achieve or maintain A1c less than 7% within 18 months or the use of additional glucose-lowering medications.
Other predictors that metformin use wouldn’t be successful included increasing age, male sex, and race/ethnicity. However, the latter ceased to be linked after adjustment for other clinical risk factors.
“Our study results suggest increased monitoring with potentially earlier treatment intensification to achieve glycemic control may be appropriate in patients with clinical parameters described in this paper,” Suzette J. Bielinski, PhD, and colleagues say.
“Further, these results call into question the ubiquitous use of metformin as the first-line therapy and suggest a more individualized approach may be needed to optimize therapy,” they add in their article published online in the Journal of Clinical Endocrinology and Metabolism.
The study is also noteworthy in that it demonstrated the feasibility of using electronic health data with a machine-learning approach to discover risk biomarkers, Bielinski, professor of epidemiology at the Mayo Clinic, Rochester, Minnesota, told Medscape Medical News in an interview.
“We wanted to repurpose clinical data to answer questions…I think more studies using these types of techniques repurposing data meant for one thing could potentially impact care in other domains…If we can get the bang for the buck from all these data that we generate on people I just think it will improve healthcare and maybe save healthcare dollars.”
Baseline A1c Strongest Predictor of Metformin Failure
The investigators identified a total of 22,047 metformin initiators from three clinical primary care sites: the University of Mississippi’s Jackson centers, which serves a mostly African American population, the Mountain Park Health Center in Arizona, a seven-clinic federally qualified community health center in Phoenix that serves a mostly Latino population, and the Rochester Epidemiology Project, which includes the Mayo Clinic and serves a primarily White population.
Overall, a total of 43% (9407) of patients met one of two criteria for metformin failure by 18 months. Among those, median time to failure on metformin was 3.9 months.
Unadjusted failure rates were higher among African Americans, Hispanics, and other racial groups compared with non-Hispanic White patients.
However, the racial groups also differed by baseline characteristics. Mean A1c was 7.7% overall, 8.1% for the African American group, 7.9% for Asians, and 8.2% for Hispanics, compared with 7.6% for non-Hispanic Whites.
Of 150 clinical factors examined, higher A1c was the strongest predictor of metformin failure, with a rapid …….