title: Patterns of health care utilization related to initiation of amitriptyline, duloxetine, gabapentin, or pregabalin in fibromyalgia.
abstract: BACKGROUND
  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.
authors: Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital and Harvard Medical School, 1620 Tremont St, Suite 3030, Boston, MA, 02120, USA. skim62@partners.org.
authors: Seoyoung C
authors: SC
authors: Kim
authors: Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital and Harvard Medical School, 1620 Tremont St, Suite 3030, Boston, MA, 02120, USA. jlandon@partners.org.
authors: Joan E
authors: JE
authors: Landon
authors: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital and Harvard Medical School, 1620 Tremont St, Suite 3030, Boston, MA, 02120, USA. ylee9@partners.org.
authors: Yvonne C
authors: YC
authors: Lee
mesh_terms: D000328:Adult; D000588:Amines / Q000627:therapeutic use; D000639:Amitriptyline / Q000627:therapeutic use; D018712:Analgesics, Non-Narcotic / Q000627:therapeutic use*; D015331:Cohort Studies; D003509:Cyclohexanecarboxylic Acids / Q000627:therapeutic use; D000068736:Duloxetine Hydrochloride / Q000627:therapeutic use; D005260:Female; D005356:Fibromyalgia / Q000188:drug therapy*; D000077206:Gabapentin; D006296:Health Services / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D000069583:Pregabalin / Q000627:therapeutic use; D005680:gamma-Aminobutyric Acid / Q000627:therapeutic use
chemical_list: D000588:Amines; D018712:Analgesics, Non-Narcotic; D003509:Cyclohexanecarboxylic Acids; D000639:Amitriptyline; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D000068736:Duloxetine Hydrochloride
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