An assessment of treatment patterns and healthcare costs among working-aged individuals initiated with duloxetine for fibromyalgia

Abstract

This study examined the association between maximum titrated dosage of duloxetine, treatment patterns and healthcare costs among commercially-insured fibromyalgia patients. Administrative claims data were assessed for fibromyalgia patients aged 18-64 who initiated (no pill coverage in the previous 90 days) duloxetine in 2006, with the first initiation date as the index date. All patients had continuous enrollment in the 12 months pre- and post-index periods, and at least 30 supply days of duloxetine in the 12-month post-index period. Duloxetine patients with diabetic peripheral neuropathic pain or depression diagnosis during the 12 months pre-index period were excluded. Three cohorts were constructed based on the maximum titrated duloxetine dosage: <60mg, 60mg, and >60mg. Duloxetine utilization including index dose, average daily dose (ADD), and adherence (measured by medication possession ratio ≥0.8) were compared across cohorts. Regression models were estimated to examine the relationship between maximum dosage and healthcare costs. Of the 4,869 fibromyalgia patients identified, 18.8% had a maximum duloxetine dosage of <60mg, 61.5% of 60mg, and 19.7% of >60mg. Patients in the <60mg, 60mg, and >60mg cohorts, on average, had 8, 19, and 110 days to reach the maximum dosage, and spent 114, 175, and 115 days on the maximum dosage, respectively. Duloxetine patients with lower maximum dosage had worse adherence (17.2% vs. 33.6% vs. 41.7%), lower index dose (30.3mg vs. 54.9mg vs. 73.3mg), and ADD (30.5mg vs. 56.9mg vs. 84.5mg). Controlling for differences in demographics and comorbidities, patients in the >60mg (<60mg) cohort had $5,538 (-$2,317) higher (lower) total healthcare costs than those in the 60mg cohort (all p<0.05). Among commercially-insured fibromyalgia patients initiated on duloxetine, the maximum duloxetine dosage was correlated with duloxetine adherence, index dose, and ADD. Patients with higher maximum dose also had higher total healthcare costs. (Funding for this project was provided by Eli Lilly and Company.) This study examined the association between maximum titrated dosage of duloxetine, treatment patterns and healthcare costs among commercially-insured fibromyalgia patients. Administrative claims data were assessed for fibromyalgia patients aged 18-64 who initiated (no pill coverage in the previous 90 days) duloxetine in 2006, with the first initiation date as the index date. All patients had continuous enrollment in the 12 months pre- and post-index periods, and at least 30 supply days of duloxetine in the 12-month post-index period. Duloxetine patients with diabetic peripheral neuropathic pain or depression diagnosis during the 12 months pre-index period were excluded. Three cohorts were constructed based on the maximum titrated duloxetine dosage: <60mg, 60mg, and >60mg. Duloxetine utilization including index dose, average daily dose (ADD), and adherence (measured by medication possession ratio ≥0.8) were compared across cohorts. Regression models were estimated to examine the relationship between maximum dosage and healthcare costs. Of the 4,869 fibromyalgia patients identified, 18.8% had a maximum duloxetine dosage of <60mg, 61.5% of 60mg, and 19.7% of >60mg. Patients in the <60mg, 60mg, and >60mg cohorts, on average, had 8, 19, and 110 days to reach the maximum dosage, and spent 114, 175, and 115 days on the maximum dosage, respectively. Duloxetine patients with lower maximum dosage had worse adherence (17.2% vs. 33.6% vs. 41.7%), lower index dose (30.3mg vs. 54.9mg vs. 73.3mg), and ADD (30.5mg vs. 56.9mg vs. 84.5mg). Controlling for differences in demographics and comorbidities, patients in the >60mg (<60mg) cohort had $5,538 (-$2,317) higher (lower) total healthcare costs than those in the 60mg cohort (all p<0.05). Among commercially-insured fibromyalgia patients initiated on duloxetine, the maximum duloxetine dosage was correlated with duloxetine adherence, index dose, and ADD. Patients with higher maximum dose also had higher total healthcare costs. (Funding for this project was provided by Eli Lilly and Company.)