title: A retrospective, matched cohort study of potential drug-drug interaction prevalence and opioid utilization in a diabetic peripheral neuropathy population initiated on pregabalin or duloxetine.
abstract: BACKGROUND
  Anticipating and controlling drug-drug interactions (DDIs) in older patients with painful diabetic peripheral neuropaty (pDPN) presents a significant challenge to providers. The purpose of this study was to examine the impact of newly initiated pregabalin or duloxetine treatment on Medicare Advantage Prescription Drug (MAPD) plan pDPN patients' encounters with potential drug-drug interactions, the healthcare cost and utilization consequences of those interactions, and opioid utilization.
  
  
  METHODS
  Study subjects required a pregabalin or duloxetine pharmacy claim between 07/01/2008-06/30/2012 (index event), ≥1 inpatient or ≥2 outpatient medical claims with pDPN diagnosis between 01/01/2008-12/31/2012, and ≥12 months pre- and ≥6 post-index enrollment. Propensity score matching was used to balance the pregabalin and duloxetine cohorts on pre-index demographics and comorbidities. Potential DDIs were defined by Micromedex 2.0 and identified by prescription claims. Six-month post-index healthcare utilization (HCU) and costs were calculated using pharmacy and medical claims.
  
  
  RESULTS
  No significant differences in pre-index demographics or comorbidities were found between pregabalin subjects (n = 446) and duloxetine subjects (n = 446). Potential DDI prevalence was significantly greater (p < 0.0001) among duoxetine subjects (56.7%) than among pregabalin subjects (2.9%). There were no significant differences in HCU or costs between pregablin subjects with and without a potential DDI. By contrast, duloxetine subjects with a potential DDI had higher mean all-cause costs ($13,908 vs. $9,830; p = 0.001), more subjects with ≥1 inpatient visits (35.6% vs 25.4%; p = 0.02), and more subjects with ≥1 emergency room visits (32.8% vs. 20.7%; p = 0.005) in comparison to duloxetine subjects without a potential DDI. There was a trend toward a difference between pregabalin and duloxetine subjects in their respective pre-versus-post differences in milligrams (mg) of morphine equivalents/30 days used (60.2 mg and 176.9 mg, respectively; p = 0.058).
  
  
  CONCLUSIONS
  The significantly higher prevalence of potential DDIs and potential cost impact found in pDPN duloxetine users, relative to pregabalin users, underscore the importance of considering DDIs when selecting a treatment.
authors.affiliation: Comprehensive Health Insights Inc., 325 West Main Street WFP6W, Louisville, KY, 40202, USA. jellis21@humana.com.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Ellis
authors.affiliation: Pfizer Inc., 235 East 42nd Street, NewYork, NY, 10017, USA. Alesia.Sadosky@pfizer.com.
authors.forename: Alesia B
authors.initials: AB
authors.lastname: Sadosky
authors.affiliation: Formerly of Comprehensive Health Insights Inc., 325 West Main Street WFP6W, Louisville, KY, 40202, USA. lten_eyck@humana.com.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Ten Eyck
authors.affiliation: Comprehensive Health Insights Inc., 325 West Main Street WFP6W, Louisville, KY, 40202, USA. pmudumby@humana.com.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Mudumby
authors.affiliation: Pfizer Inc., 235 East 42nd Street, NewYork, NY, 10017, USA. joseph.c.cappelleri@pfizer.com.
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Cappelleri
authors.affiliation: Humana Inc., 323 West Main Street WFP-05C, Louisville, KY, 40202, USA. lndehi@humana.com.
authors.forename: Lilian
authors.initials: L
authors.lastname: Ndehi
authors.affiliation: Comprehensive Health Insights Inc., 325 West Main Street WFP6W, Louisville, KY, 40202, USA. bsuehs6@humana.com.
authors.forename: Brandon T
authors.initials: BT
authors.lastname: Suehs
authors.affiliation: Pfizer Inc., 235 East 42nd Street, NewYork, NY, 10017, USA. Bruce.Parsons@pfizer.com.
authors.forename: Bruce
authors.initials: B
authors.lastname: Parsons
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000191:economics / Q000627:therapeutic use*; D015331:Cohort Studies; D003929:Diabetic Neuropathies / Q000188:drug therapy* / Q000191:economics; D004347:Drug Interactions; D000068736:Duloxetine Hydrochloride / Q000191:economics / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D020398:Medicare Part C / Q000191:economics; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy*; D000069583:Pregabalin / Q000191:economics / Q000627:therapeutic use*; D055553:Prescription Drugs / Q000191:economics / Q000627:therapeutic use*; D015995:Prevalence; D012189:Retrospective Studies; D014481:United States; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D055553:Prescription Drugs; D000069583:Pregabalin; D000068736:Duloxetine Hydrochloride