Objectives: To examine the association between service volume and guideline adherence via multiyear observations.
Study design: Repeated cross-sectional study.
Methods: This study employed nationwide claims data from Taiwan's National Health Insurance scheme and identified patients with newly diagnosed type 2 diabetes from 2001, 2005, and 2009; a new prescription guideline for diabetes care was introduced in 2006. Physician service volume was measured by the number of total outpatients with diabetes. The outcome variable indicated whether a patient was receiving metformin, the guideline-recommended antihyperglycemic agent, at the index date.
Results: Patients visiting physicians who had high or medium volumes of patients with diabetes were more likely to receive metformin than patients visiting physicians who had low volumes; the odds ratios (ORs) were 2.48 (95% CI, 2.03-3.04) and 1.76 (95% CI, 1.45-2.13), respectively. Patients with newly diagnosed diabetes in 2009 and 2005 were more likely to receive metformin than their counterparts in 2001, with ORs of 12.00 (95% CI, 11.19-12.86) and 2.44 (95% CI, 2.30-2.59), respectively. We also found that patients who visited younger physicians, physicians with fewer practice years, physicians practicing in large-scale hospitals, or physicians practicing in urban areas were more likely to receive metformin than their counterparts.
Conclusions: In the process of implementing a new practice guideline for treating patients with diabetes, physicians with higher patient volumes are more likely to adhere to the guideline recommendation.