Step Therapy Restriction Policy for Pregabalin

Cincinnati—Implementation of a step therapy (ST) restriction policy for pregabalin to treat patients with chronic pain conditions reduced utilization of pregabalin but did not decrease medical or pharmacy costs, reported investigators in a study presented during a poster session at the AMCP meeting. The poster was titled Impact of a Step Therapy Policy Restriction for Pregabalin on Healthcare Utilization and Expenditures in a Commercial Population.

In 2009, Humana implemented an ST policy for new starts on pregabalin for the management of neuropathic pain associated with diabetic peripheral neuropathy (pDPN), post-herpetic neuralgia (PHN), and fibromyalgia (FM). Prior to approving coverage for pregabalin in these patients, the ST policy requires a treatment trial of gabapentin.

In this retrospective, observational study, researchers evaluated the impact of a pregabalin ST policy on healthcare resource utilization, costs, and medication use by comparing these measures among patients treated for painful pDPN, PHN, and FM in a commercial health plan implementing a pregabalin ST policy (restricted cohort) versus similar patients in health plans without this ST policy (unrestricted cohort).

All patients included in the study were members of a commercial health plan with continuous coverage from January 2008 to December 2009, were 18 to 65 years of age, had ≥1 medical claims with a diagnosis of pDPN, PHN, or FM during the study period, and had received at least 1 medication treatment or pain intervention procedure within 60 days after diagnosis for 1 of these chronic pain conditions.

Patients with any claim for epilepsy, cancer, or transplant surgery during the study period were excluded, as were residents in long-term care facilities for ≥90 days, and those with a diagnosis for >1 of the listed conditions.

A total of 3876 members were included in the restricted cohort and matched by geographic region and diagnosis to 3876 members from the unrestricted health plans. Overall, most members included in the study had a diagnosis of FM (84.7%), were female (70.8%), and were from the South (65.1%). Compared with members in the restricted cohort, members in the unrestricted cohort were older (47.6 years vs 49.0 years, P<.001) and had greater morbidity (4.4 vs 5.4, P<.001).

The study found a greater decrease in pregabalin utilization in the restricted cohort with a decrease from 9.7% in 2008 to 5.0% in 2009, compared with the unrestricted cohort that had a decrease from 15.0% in 2008 to 12.9% in 2009.

These decreases resulted in an unadjusted between-group differences in differences (DID) for pregabalin of -2.6, which was significant at P=.008. No significant differences in unadjusted DIDs were found for gabapentin and other evaluated medical classes.

The study found no statistically significant DIDs for all-cause or disease-related total healthcare costs from 2008 to 2009 between the unrestricted cohort and restricted cohort, nor were there any significant differences in DIDs observed for any individual costs.

Based on a multivariate model of prescription utilization, the study found that the pregabalin ST policy was associated with a relative decrease in the odds of pregabalin use with an odds ratio (OR) of 0.04 (95% confidence interval [CI], 0.02-0.08; P<.001) as well as a relative increase in the odds of gabapentin use with an OR of 2.60 (95% CI, 1.72-3.94; P<.001).

No significant associations were found between restricted plan membership and the increase in all-cause total medical costs and disease-free total healthcare costs. In addition, no significant differences between the two cohorts were found in all-cause total healthcare costs, all-cause total pharmacy costs, disease-related medical costs, and disease-related pharmacy costs.

Based on these results, the investigators concluded that the reduced use of pregabalin under the ST policy did not translate to decreased medical or pharmacy costs.

Limitations of the study included the use of DID analysis, reliance on pharmaceutical claims for medications as it is possible that the medications were prescribed for conditions other than the conditions studied, the over-representation of FM patients that calls for caution when extrapolating results to patients with pDPN and PHN, and the inability of the study design to assess pregabalin restriction on clinical outcomes.

This study was supported by Humana, Pfizer Inc., and Competitive Health Analytics.