Health care costs in patients with painful diabetic peripheral neuropathy prescribed pregabalin or duloxetine.

Background: Pregabalin and duloxetine are two FDA-approved medications for the treatment of pain associated with diabetic peripheral neuropathy (pDPN). The objective of this study was to compare changes in all-cause and pDPN-related health care costs in patients with pDPN initiated on pregabalin or duloxetine. Methods: Patients at least 18 years of age initiating pregabalin or duloxetine between March 1, 2006 and December 31, 2008 were identified from a large U. S. managed care plan database. The date of the first pregabalin or duloxetine prescription was defined as the index date. Patients with claims-based evidence of pDPN and who had continuous enrollment for 6-month pre-and post-index periods were selected for study inclusion. Duloxetine patients with depression or generalized anxiety disorder (GAD) were excluded. All-cause and pDPN-related total health care costs (over 6 month pre-index and post-index periods) were analyzed with difference-in-differences (DiD) models. Results: A total of 2,136 patients (1,785 pregabalin and 351 duloxetine) were identified. No significant differences in gender, age, or pre-index Quan-Charlson comorbidity score were observed between the two cohorts. No significant differences (pregabalin vs. duloxetine) in pre-index to post-index change in mean all-cause health care costs ($ 1,411 vs. $ 1,560, P = 0.93) or mean pDPN-related health care costs ($ 704 vs.)$ 240, P = 0.22) were found. The DiD models showed no significant difference in all-cause (mean) costs attributable to pregabalin vs. duloxetine therapy between pre-index and post-index periods (mean cost ratio = 0.97, 95% CI: 0.75 to 1.26), but showed that patients receiving pregabalin had a significantly higher increase in pDPN-related costs compared with patients receiving duloxetine (mean cost ratio = 2.35, 95% CI: 1.01 to 5.46). However, the difference (pre-to post-index) in pDPN-related costs attributable to pregabalin vs. duloxetine therapy was nonsignificant (mean cost ratio = 2.30, 95% CI: 0.93 to 5.68) in a sensitivity analysis in which patients with depression and GAD were excluded from both cohorts. Conclusion: No differences were noted in all-cause costs attributable to pregabalin or duloxetine. Although patients receiving pregabalin had a significantly greater pre-to post-index increase in pDPN-related health care costs compared with patients receiving duloxetine, this may have been due to an imbalance in patient exclusion criteria between cohorts.