Clinicians could be confusing metformin nonadherence with pharmacologic failure and moving onto second-line therapy too quickly, researchers concluded after conducting a retrospective cross-sectional study involving >52,500 individuals. Participants with type 2 diabetes were identified in the Aetna claims database between 2010 and 2015. Investigators looked at metformin prescriptions and use of second-line treatment. Among the results:

• Nearly 23,000 patients were given second-line treatment.
• Only 8% of them had used metformin in the prior 2 months.
• 28% had no evidence of having taken metformin.
• At the top range of sensitivity analysis, ~half of patients could have had recommended use.
• Patients were more likely to get additional second-line treatment or insulin if they were given their initial second-line medication without metformin first.

The authors noted that processes are needed to monitor and improve guideline adherence.