Duloxetine use

Objective:  The study aims to examine predictors associated with duloxetine adherence and its association with healthcare costs among fibromyalgia patients.

Methods:  Administrative claims from both commercially and Medicare supplemental-insured fibromyalgia patents aged 18+ who initiated duloxetine in 2006 were analyzed. Initiation was defined as a 90-day clean period without duloxetine. The dispense date of the first duloxetine prescription was denoted as the index date. Two cohorts were constructed based on duloxetine adherence over the 12-month postindex period (high adherence as medication possession ratio ≥ 0.8). Predictors of high adherence were examined via logistic regression. Generalized linear regressions were performed to estimate the association between duloxetine adherence and healthcare costs.

Results:  A total of 4,869 commercially and 566 Medicare supplemental-insured fibromyalgia patients were identified. Two-thirds of patients had low adherence. Higher duloxetine average daily dose (ADD) was associated with increased adherence (reference group = 30 mg; Commercial: Odds ratio [OR] = 3.03, 2.40, and 3.73 for 31 to 59 mg, 60 mg, and > 60 mg, respectively, all P < 0.05; Medicare supplemental: OR = 3.11, 2.33, and 4.76 for 31 to 59 mg, 60 mg, and >60 mg, respectively, all P < 0.05). Commercially insured patients with high adherence had significantly lower total healthcare costs than low-adherence patients (−$1,164, P < 0.05), primarily because of lower inpatient (−$2,222, P < 0.05) and outpatient (−$1,075, P < 0.05) costs. Medicare supplemental-insured patients with high adherence had similar overall and inpatient costs, but significantly lower outpatient costs (−$2,025, P < 0.05).

Conclusion:  Fibromyalgia patients with higher duloxetine ADD were more likely to adhere to the therapy. High duloxetine adherence was associated with lower (Commercial) or similar (Medicare supplemental) healthcare costs.
http://onlinelibrary.wiley.com/doi/10.1111/j.1533-2500.2010.00431.x/abstract;jsessionid=42859CD7803D77B64B24969880E2F0E4.d02t01