Patterns of Health Care Utilization in Fibromyalgia
Patterns of Health Care Utilization in Fibromyalgia
Introduction Several pharmacologic treatments are available for fibromyalgia, but little is known about the comparative effectiveness of these treatments on health care utilization.
Methods Using US commercial insurance claims data (covering 2007 to 2009), we conducted a cohort study to examine the comparative effectiveness of amitriptyline, duloxetine, gabapentin, and pregabalin on health care utilization in patients with fibromyalgia. We measured patients' medication adherence using the proportion of days covered (PDC) and estimated multivariable rate ratios (RRs) for outpatient visits, prescriptions, hospitalization, and emergency department (ED) visits in propensity score (PS)–matched cohorts.
Results Cohorts of 8,269 amitriptyline, 9,941 duloxetine, and 18,613 gabapentin initiators were compared with their PS-matched pregabalin initiators. During the baseline 180-day period, patients had, on average, seven to nine physician visits, including six to eight specialist visits, and received eight prescription drugs. The mean PDC up to 180 days varied from 38.6% to 67.7%. The number of outpatient visits, prescriptions, and hospitalizations decreased slightly after initiating one of the study drugs, but the number of ED visits increased after treatment initiation. Compared to pregabalin, duloxetine was associated with decreased outpatient visits (RR, 0.94; 95% confidence interval (CI), 0.88 to 1.00), prescriptions (RR, 0.94; 95% CI, 0.90 to 0.98), hospitalizations (RR, 0.75; 95% CI, 0.68 to 0.83), and ED visits (RR, 0.85; 95% CI, 0.79 to 0.91). Little difference in health care utilization rates was noted among amitriptyline and gabapentin initiators compared to those who were started on pregabalin.
Conclusions Fibromyalgia patients had high health care utilization before and after initiation of amitriptyline, duloxetine, gabapentin, or pregabalin. Medication adherence was suboptimal. Overall, fibromyalgia treatment had little impact on reducing health care utilization, but duloxetine initiators had less health care utilization than those started on pregabalin.
Fibromyalgia is a common, highly disabling syndrome characterized by chronic widespread pain, fatigue, and problems with sleep, memory, and mood. Treatment of fibromyalgia is challenging and often requires both pharmacologic and nonpharmacologic treatments. For pharmacologic treatment, tricyclic antidepressants (TCAs) such as amitriptyline, selective serotonin reuptake inhibitors (SSRIs), serotonin and noradrenaline reuptake inhibitors (SNRIs) such as duloxetine and milnacipran, and monoamine oxidase inhibitors are used to reduce pain, depression, fatigue, and health-related quality of life. Gabapentin and pregabalin are also commonly prescribed to ameliorate pain and sleep problems associated with fibromyalgia.
Patients with fibromyalgia are known to be heavy users of health care systems, including outpatient visits, hospitalizations, and prescription drug use. Despite the number of available drugs for fibromyalgia, few studies have directly compared the effects of different pharmacologic agents for fibromyalgia on health care utilization. In studies comparing pre- and posttreatment, pregabalin initiators had increased inpatient and outpatient visits after initiating pregabalin, whereas duloxetine initiators had decreased inpatient and outpatient visits after initiating duloxetine. In another study, researchers reported increases in total health care costs after initiating treatment with pregabalin or duloxetine for fibromyalgia. In a study comparing pregabalin to TCAs, pregabalin initiators had increased total health care costs from pretreatment to follow-up. Although all of these studies were performed using US claims data, the effects of fibromyalgia treatment on health care utilization may vary across different health care systems, particularly across different countries.
The objective of this study was to examine the comparative effectiveness of four commonly used drugs for fibromyalgia—amitriptyline, duloxetine, gabapentin, and pregabalin—on the rate of health care utilization in a US population-based cohort of commercially insured patients with fibromyalgia. Patients' adherence to these drug regimens (that is, continuation or discontinuation) was also assessed. We hypothesized that the effect of amitriptyline, duloxetine, or gabapentin on health care utilization would differ from the effect of pregabalin.
Abstract and Introduction
Abstract
Introduction Several pharmacologic treatments are available for fibromyalgia, but little is known about the comparative effectiveness of these treatments on health care utilization.
Methods Using US commercial insurance claims data (covering 2007 to 2009), we conducted a cohort study to examine the comparative effectiveness of amitriptyline, duloxetine, gabapentin, and pregabalin on health care utilization in patients with fibromyalgia. We measured patients' medication adherence using the proportion of days covered (PDC) and estimated multivariable rate ratios (RRs) for outpatient visits, prescriptions, hospitalization, and emergency department (ED) visits in propensity score (PS)–matched cohorts.
Results Cohorts of 8,269 amitriptyline, 9,941 duloxetine, and 18,613 gabapentin initiators were compared with their PS-matched pregabalin initiators. During the baseline 180-day period, patients had, on average, seven to nine physician visits, including six to eight specialist visits, and received eight prescription drugs. The mean PDC up to 180 days varied from 38.6% to 67.7%. The number of outpatient visits, prescriptions, and hospitalizations decreased slightly after initiating one of the study drugs, but the number of ED visits increased after treatment initiation. Compared to pregabalin, duloxetine was associated with decreased outpatient visits (RR, 0.94; 95% confidence interval (CI), 0.88 to 1.00), prescriptions (RR, 0.94; 95% CI, 0.90 to 0.98), hospitalizations (RR, 0.75; 95% CI, 0.68 to 0.83), and ED visits (RR, 0.85; 95% CI, 0.79 to 0.91). Little difference in health care utilization rates was noted among amitriptyline and gabapentin initiators compared to those who were started on pregabalin.
Conclusions Fibromyalgia patients had high health care utilization before and after initiation of amitriptyline, duloxetine, gabapentin, or pregabalin. Medication adherence was suboptimal. Overall, fibromyalgia treatment had little impact on reducing health care utilization, but duloxetine initiators had less health care utilization than those started on pregabalin.
Introduction
Fibromyalgia is a common, highly disabling syndrome characterized by chronic widespread pain, fatigue, and problems with sleep, memory, and mood. Treatment of fibromyalgia is challenging and often requires both pharmacologic and nonpharmacologic treatments. For pharmacologic treatment, tricyclic antidepressants (TCAs) such as amitriptyline, selective serotonin reuptake inhibitors (SSRIs), serotonin and noradrenaline reuptake inhibitors (SNRIs) such as duloxetine and milnacipran, and monoamine oxidase inhibitors are used to reduce pain, depression, fatigue, and health-related quality of life. Gabapentin and pregabalin are also commonly prescribed to ameliorate pain and sleep problems associated with fibromyalgia.
Patients with fibromyalgia are known to be heavy users of health care systems, including outpatient visits, hospitalizations, and prescription drug use. Despite the number of available drugs for fibromyalgia, few studies have directly compared the effects of different pharmacologic agents for fibromyalgia on health care utilization. In studies comparing pre- and posttreatment, pregabalin initiators had increased inpatient and outpatient visits after initiating pregabalin, whereas duloxetine initiators had decreased inpatient and outpatient visits after initiating duloxetine. In another study, researchers reported increases in total health care costs after initiating treatment with pregabalin or duloxetine for fibromyalgia. In a study comparing pregabalin to TCAs, pregabalin initiators had increased total health care costs from pretreatment to follow-up. Although all of these studies were performed using US claims data, the effects of fibromyalgia treatment on health care utilization may vary across different health care systems, particularly across different countries.
The objective of this study was to examine the comparative effectiveness of four commonly used drugs for fibromyalgia—amitriptyline, duloxetine, gabapentin, and pregabalin—on the rate of health care utilization in a US population-based cohort of commercially insured patients with fibromyalgia. Patients' adherence to these drug regimens (that is, continuation or discontinuation) was also assessed. We hypothesized that the effect of amitriptyline, duloxetine, or gabapentin on health care utilization would differ from the effect of pregabalin.
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