title: A naturalistic comparison of amoxicillin/clavulanate extended release versus immediate release in the treatment of acute bacterial sinusitis in adults: A retrospective data analysis.
abstract: BACKGROUND
  Choosing the most effective treatment for acute bacterial sinusitis (ABS) is helpful to avoid treatment failure. To date, studies comparing antibiotic options for ABS have compared amoxicillin/clavulanate (AMX/CA) immediate release (IR) versus other antibiotics, but have not included AMX/CA extended release (XR).
  
  
  OBJECTIVE
  The purpose of this study was to determine whether the clinical advantages of AMX/CA XR found in a clinical trial setting translate to a naturalistic setting, relative to AMX/CA IR.
  
  
  METHODS
  Data for this retrospective analysis were obtained from a managed care benchmark database that included >25 million patients from >30 health plans covering 7 US census divisions. Data from all patients aged > or =18 years with an index diagnosis of ABS between July 1, 2001, and December 31, 2003, were included. Episodes of ABS were classified as treatment successes (no additional prescriptions for antibiotics, ABS-related emergency department [ED] visits, or ABS-related inpatient hospitalizations within 30 days after the index prescription) or failures (> or =1 subsequent antibiotic prescription, an ABS-related ED visit, or an ABS-related inpatient hospitalization within 30 days after the index prescription). Treatment failures were subclassified as early or late. Mean costs were assessed for medical claims linked with a primary diagnosis of ABS and antibiotic pharmacy claims within the follow-up time period (through February 28, 2004). Descriptive statistics for demographic characteristics, utilization patterns, and success rates were calculated for each cohort. A multivariate general linear regression model was developed to assess differences in costs between the 2 cohorts.
  
  
  RESULTS
  : Of the patients with an index antibiotic prescription filled within 3 days of ABS diagnosis (n = 241,511), a total of 3224 in the AMX/CA XR cohort (mean [SD] age, 41.8 [11.6] years; women, 57.7%) and 23,638 in the AMX/CA IR cohort (mean [SD] age, 41.9 [11.6] years; women, 62.7%) were included in the analysis. The rate of treatment success in patients treated with AMX/CA XR was 82.8% versus 81.0% in patients treated with AMX/CA IR (P < 0.015). Treatment success costs were significantly lower than treatment failure costs regardless of an early or late designation and ranged from 98 dollars to 110 dollars per episode (P < 0.001). After adjustment for background covariates, the mean cost of treating an episode of ABS was significantly lower for patients receiving AMX/CA XR versus those receiving AMX/CA IR (166.32 dollars vs 177.34 dollars [US 2004 dollars]; P < 0.001), representing a mean cost savings of 11.02 dollars per patient treated with AMX/CA XR over AMX/CA IR for ABS, regardless of treatment outcome.
  
  
  CONCLUSIONS
  The results from this data analysis suggest that AMX/CA XR had significantly higher treatment success in ABS relative to AMX/CA IR in this naturalistic setting. AMX/CA XR was associated with significantly decreased total ABS-related costs in these adults.
authors.affiliation: Xcenda, Palm Harbor, Florida 34685, USA. jjackson@xcenda.com
authors.forename: James
authors.initials: J
authors.lastname: Jackson
authors.forename: Ancilla W
authors.initials: AW
authors.lastname: Fernandes
authors.forename: Winnie
authors.initials: W
authors.lastname: Nelson
mesh_terms: D000208:Acute Disease; D000328:Adult; D000658:Amoxicillin / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D001424:Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology; D019818:Clavulanic Acid / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D003365:Costs and Cost Analysis; D003692:Delayed-Action Preparations; D004180:Direct Service Costs; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007345:Insurance Claim Review / Q000706:statistics & numerical data; D008297:Male; D012189:Retrospective Studies; D012852:Sinusitis / Q000188:drug therapy* / Q000382:microbiology; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D019818:Clavulanic Acid; D000658:Amoxicillin