A retrospective, matched cohort study of potential drug-drug interaction prevalence and opioid utilization in a diabetic peripheral neuropathy population initiated on pregabalin or duloxetine

Table 7 **Model-based* 6-month post-index all-cause total healthcare costs by index medication and DDI status and difference-in-difference comparison between pregabalin and duloxetine**

	All-cause healthcare costs
	Mean	95% confidence interval
Pregabalin
No DDI present	$31,878	$9,545 - $106,461
DDI present	$33,942	$8,995 - $128,076
Difference**	$2,064	-
P value	0.8159	-
Duloxetine
No DDI present	$36,424	$10,847 - $122,314
DDI present	$39,445	$11,904 - $130,702
Difference**	$3,021	-
P value	0.4208	-
Difference-in-difference comparison	$2,064 vs. $3,021
Statistical difference†	p = 0.8950

*GLMM model with gamma distribution and log link. Model-based means, standard errors, and confidence intervals were derived from model and transformed into dollar values through exponentiation. All p values are calculated using Wald chi square tests through LSMEANS option. Presence of potential DDI, Drug used (duloxetine versus pregabalin), DDI*Drug interaction term, baseline demographic characteristics, baseline comorbidities present, and pre-index medication utilization controlled for in GLM model.
**Represents the additional healthcare costs associated with the presence of a potential DDI.
† t-test, utilizing model estimates, comparing pregabalin difference (DDI minus No DDI) to duloxetine difference (DDI minus No DDI).
DDI, Drug-Drug Interaction.
CI, Confidence Interval.

ISSN: 1472-6963