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Cost Implications of Early Treatment Initiation Among Patients With Newly Diagnosed Fibromyalgia

Initiation of treatment with guideline-recommended medications within 60 days of fibromyalgia diagnosis was associated with immediate annual healthcare cost savings.
Published Online: Nov 16,2017
Feride Frech, PhD; Chunlin Qian, PhD; Mugdha Gore, PhD; and Qiaoyi Zhang, MD, PhD
Abstract
Objectives: To evaluate treatment initiation timing and healthcare costs among newly diagnosed fibromyalgia patients receiving pain medications commonly used in fibromyalgia treatment.
Study Design: Retrospective cohort study (IMS Pharmetrics Plus).
Methods: Eligible patients had ≥2 International Classification of Diseases, Ninth Revision, Clinical Modification codes 729.1X within a year (first [index] diagnosis in 2012; none in 12 months prior to index diagnosis [baseline]), and no baseline use of medications commonly used in fibromyalgia management (pregabalin, duloxetine, milnacipran, gabapentin, tramadol, venlafaxine, amitriptyline, cyclobenzaprine). “Early-” (≤60 days after index diagnosis) and “late-” treated cohorts were propensity score (PS) matched using patient characteristics and other pain-related medications. Total healthcare costs during the 12-month follow-up period were compared for early- versus late-treated cohorts and were adjusted for baseline costs, unbalanced comorbidities, and follow-up use of other pain medications.
Results: Among 33,470 newly diagnosed fibromyalgia patients identified, 5208 (15.6%) received common fibromyalgia medications. Median age for PS matched cohorts (n = 2019 each) was 47 years, and 72.2% were female. Most frequent comorbidities were rheumatic conditions, hyperlipidemia, back and neck pain, and depression. Proportion of patients receiving other pain-related medications was similar in both cohorts, with >20% receiving opioid, anti-inflammatory, anti-anxiety, and selective serotonin reuptake inhibitor medications, respectively. Total follow-up costs were 15% lower ($1970 less) in the early-treated cohort (adjusted mean costs: $11,287 versus $13,258; P <.0001).
Conclusions: Total healthcare costs were significantly lower among early-treated patients, suggesting that prompt use of fibromyalgia-related medications is a potential cost-saving strategy. Patients with fibromyalgia had a substantial comorbidity burden.

                                                                                          Am J Pharm Benefits. 2017;9(6):200-207

Fibromyalgia is a chronic pain syndrome characterized by widespread neuromuscular pain and generalized tender points.1,2 It is estimated that fibromyalgia affects as many as 6% of US adults and 3% of adults worldwide.1,3,4 Symptoms of fibromyalgia may be subjective, and diagnosis may be difficult and may vary between practitioners. Frequent misdiagnosis of fibromyalgia results in underdiagnosis in the general population, since fibromyalgia may often be confused with other regional pain syndromes and systemic disorders that share pathophysiologic features with fibromyalgia.1,5 Although early treatment is optimal, current diagnosis time averages about 5 years.1 Patients with fibromyalgia have frequent comorbidities, including other pain disorders, sleep disorders, depression, and mood/anxiety disorders,1,6,7 and fibromyalgia patients average 4.2 comorbid conditions each year.8 Studies estimate that up to half of fibromyalgia patients also suffer from obesity, and an additional 21% to 30% are overweight.9-12

Fibromyalgia is associated with significant direct and indirect costs,13-16 and total annual costs among patients with fibromyalgia have been estimated at $17,165 (2012 US$), with approximately 68% of total costs attributed to indirect costs due to pain.16 High prescription costs may be due to polypharmacy, attributable not only to fibromyalgia management but also reflective of the high comorbidity burden associated with fibromyalgia.13 Fibromyalgia is associated with significant indirect costs since it has an impact on patient productivity.14-16 Furthermore, fibromyalgia has a significant impact on patient quality of life, as it can impair the patient’s ability to participate in everyday activities and affect relationships with family, friends, and employers.1

Fibromyalgia treatment recommendations have been put forth by the European League Against Rheumatism (EULAR)17 and the American Pain Society (APS)18; however, the APS cautions that its treatment guidelines are outdated and should not be used for current medical practice.19 EULAR 2016 guidelines recommend the use of amitriptyline (at low dose), duloxetine, milnacipran, tramadol, pregabalin, and cyclobenzaprine for pharmacological management of fibromyalgia, although initial non-pharmacological management strategies are encouraged. Absent from the EULAR recommendation is gabapentin, which, despite not having a specific indication for fibromyalgia, is often used in this patient population.19,20 The American College of Rheumatology summarizes medications for fibromyalgia treatment on its patient/caregiver website; this list includes antidepressants and gabapentin.19 In 2012, Canadian Guidelines for the Diagnosis and Management of Fibromyalgia were developed21; however, milnacipran, which is FDA approved for fibromyalgia treatment, is not available in Canada. Only 3 medications (pregabalin, duloxetine, and milnacipran) are approved by the FDA in the United States to treat fibromyalgia pain.22-24 The use of nonsteroidal anti-inflammatory drugs (NSAIDs) and/or opioid medications to manage fibromyalgia is common, despite a lack of evidence supporting their use in fibromyalgia.25 While there is some consensus that opioids are not recommended options for treating fibromyalgia, tramadol, a weak opioid with mild serotonin-noradrenaline reuptake inhibitor activity, is supported for short-term use if the prescriber believes that opioid treatment is needed to treat fibromyalgia pain.17,19

Previous research has suggested that fibromyalgia treatment rates are low, and that more than two-thirds of patients newly diagnosed with fibromyalgia are not treated with prescription pain medication within 1 year of diagnosis.20 Furthermore, among patients who are treated pharmacologically, discontinuation of prescribed pain medications is common,20,26 and doses of medications prescribed to patients with fibromyalgia are frequently lower than recommended.20 While underdiagnosis, undertreatment, and delayed diagnosis are described in the fibromyalgia literature,1,5,20 and early treatment is recommended,1 little is known regarding the impact of treatment initiation timing on patient outcomes or healthcare cost.
 
The primary objective of this study was to assess the impact of prompt fibromyalgia treatment on total healthcare costs. Secondary objectives included the evaluation of the initial pain management therapy for newly diagnosed fibromyalgia patients, and to estimate the proportion of patients treated with common fibromyalgia-related medications.

METHODS

Study Patients
This was a retrospective cohort study that used administrative medical and pharmacy claims for commercial, employer self-insured, and Medicare risk plans from the IMS Pharmetrics Plus™ database. Patients who were aged ≥18 years at the time of first diagnosis (index date) of fibromyalgia (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] 729.1) during 2012, with a second fibromyalgia diagnosis within 1 year of the index date, were identified. Patients were required to have continuous health plan enrollment for both medical and pharmacy coverage during the 12 months prior to and following the index date, with no fibromyalgia diagnosis during 1 year prior to the index date. The 12-month period preceding the index date was used as the study baseline period. Patients were excluded if they received any of the following common fibromyalgia-related prescription medications during the 12-month study baseline period: amitriptyline, cyclobenzaprine, venlafaxine, duloxetine, milnacipran, pregabalin, gabapentin, or tramadol.19,20

Measurements and Study Endpoints
Patient demographic information was obtained from claims data and subsequently assessed. Comorbid conditions were evaluated at baseline using ICD-9-CM codes from medical claims. Study endpoints included the proportion of patients treated with pain medications within 1 year of index date. These included prescription medications commonly prescribed to treat fibromyalgia in the United States (amitriptyline, cyclobenzaprine, venlafaxine, duloxetine, milnacipran, pregabalin, gabapentin, tramadol),19,20 as well as other prescription medications which may be used in fibromyalgia, including opioid (excluding tramadol) and non-opioid pain medications, muscle relaxants, antidepressants, sleep aids, attention-deficit/hyperactivity disorder (ADHD) medications, and anti-anxiety medications (eAppendix Table; eAppendices available at www.ajpb.com). Time to initial prescription fill of common fibromyalgia-related medications from the index date was evaluated, and patients were categorized and placed in an “early-treated” (≤60 days) or “late-treated” (>60 days) cohort. A sensitivity analysis was performed to evaluate the impact of using an alternate threshold for the early-treated cohort (<90 days). Total healthcare costs for all healthcare services during 1 year following index date were obtained from administrative claims data, including inpatient, outpatient, and pharmacy total costs, and these costs were compared between early- and late-treated patient groups. Pharmacy costs represent costs associated with prescriptions filled outside a hospital setting; inpatient costs represent the total cost associated with hospitalizations; and all other costs (not pharmacy or inpatient) were attributed to outpatient costs (eg, emergency department visits, physician office visits, outpatient surgical or diagnostic procedures, laboratory, pathology, or radiology encounters).

Statistical Analyses
Descriptive statistics (means, SDs, and frequencies) were calculated for patient characteristics. These characteristics and baseline healthcare costs during the follow-up period were compared using t tests for continuous variables, and χ2 and Fisher’s exact tests for categorical variables, between early- and late-treated patient groups. Early- and late-treated groups were propensity score matched to ensure comparability of baseline characteristics and to reduce the possibility of selection bias.27-29 Propensity scores were calculated using logistic regression, with patient demographics, comorbidities, health plan payer type, and other pain-related therapies at baseline as independent variables. Chi-square and Fisher’s exact tests were used to assess the balance between groups across all independent variables at P >.1. Generalized linear regression with a gamma distribution and log link function was used to compare costs between early- and late-treated patient groups, adjusting for baseline costs, unbalanced baseline comorbidities, and other pain medication use during the follow-up period.

RESULTS

Study Patients
Preliminary inclusion criteria were met by 33,470 newly diagnosed fibromyalgia patients (Figure 1). During the follow-up period, 15.6% (5208) received common fibromyalgia-related medications; 39.9% of these patients started therapy within 60 days and 47.7% within 90 days, of diagnosis. During the baseline period, 45.8% of the 33,470 newly diagnosed patients were prescribed >1 other pain medication. Almost half (49.4%) of all patients were prescribed other pain medications during follow-up.

Among all patients treated with a fibromyalgia-related medication (N = 5208), median age was 47 years and 70.0% were female (Table 1). Female patients were more likely to be early-treated than late (72.6% vs 68.3%; P <.05). The majority of patients (65.3%) were covered by a health maintenance organization health plan. The most frequent comorbid conditions were rheumatic conditions, hyperlipidemia, back/neck pain, and depression. Late-treated patients had higher rates of back/neck pain and lumbago (Table 1). Characteristics for the propensity score matched cohort are also included in Table 1 (N = 2019 for each group). The median age for the propensity score matched cohort was 47 years, and 72.2% were female. Subsequent to propensity score matching, only depression remained slightly unbalanced between groups (P = .09).