Real-world comparison of HbA1c reduction at 6-, 12- and 24-months by primary care provider type

Abstract

Aims: To assess differences in hemoglobin A_1c (HbA_1c) over time in diabetics treated by internal medicine physicians using the chronic care model (IMP-ancillary) or an advanced practice nurse (APN-IMP).

Methods: Retrospective, 2-group comparative design using administrative databases and matching of IMP-ancillary and APN-IMP subjects 2:1 based on patient age (±3years), gender and race. Subjects were diabetics treated ≥2 times during 2007-2010, had ≥1 follow-up visit 6-months from baseline and ≥2 HbA_1c levels. HbA_1c levels were assessed longitudinally using linear mixed effect models. Pearson chi-square and two-sample t-tests compared groups on patient characteristics.

Results: A total of 774 patients were identified. After matching 93 APN-IMP patients with 176 IMP-ancillary patients (N=269), there were no differences between groups in demographics; however, baseline mean (SD) HbA_1c was higher in APN-IMP group, p<0.001. Compared to baseline, at follow-up there were no between-group differences in HbA_1c levels at 6 and 12 months; at 24month follow-up, APN-IMP tended to have a large decrease in HbA_1c compared to the IMP-ancillary group; mean difference (95% CI), -0.26 (-0.56, 0.05) p=0.097.

Conclusion: Compared to baseline HbA_1c, patients treated by APN-IMP and IMP-ancillary provider groups had equivalent reductions in HbA_1c.

Keywords: Advanced practice nurse; Ambulatory care; Diabetes.