title: Comparative effectiveness of colony-stimulating factors for febrile neutropenia: a retrospective study.
abstract: BACKGROUND
  Granulocyte colony stimulating factors (G-CSFs) decrease the incidence of febrile neutropenia (FN) in cancer patients receiving myelosuppressive chemotherapy. There are two G-CSFs (pegfilgrastim and filgrastim) that differ in dosing schedules from which oncologists may prescribe.
  
  
  OBJECTIVE
  This study aimed to compare the effectiveness of prophylactic pegfilgrastim and filgrastim on the risk of hospitalizations. The secondary objective was to compare the effectiveness of the timing of initiation (prophylactic versus delayed).
  
  
  METHODS
  A retrospective study of administrative claims from US commercial payers included adult patients with Non-Hodgkin's lymphoma, breast, or lung cancer, treated with chemotherapy between July 2004 and January 2008. For these patients, the first course of chemotherapy and each unique cycle with use of G-CSF was identified and designated 'prophylaxis' if used within the first 5 days of each cycle, or 'delayed', if after day 5. The risk of neutropenia-related and all-cause hospitalization was evaluated for the pegfilgrastim and filgrastim prophylaxis cohorts and for the prophylaxis and delayed G-CSF initiation cohorts.
  
  
  RESULTS
  Among 5,571 patient-cycles identified, 88.9% and 11.1% used pegfilgrastim and filgrastim respectively. The rate of neutropenic hospitalization was 1.1% for pegfilgrastim prophylaxis and 3.5% for filgrastim prophylaxis (P = 0.001). Compared to chemotherapy cycles with filgrastim prophylaxis, those with pegfilgrastim prophylaxis had decreased risk of neutropenia-related (adjusted odds ratio (OR) = 0.38, 95% confidence interval (CI) 0.17-0.83) and all-cause hospitalization (adjusted OR = 0.51, 95% CI 0.31-0.84). The neutropenic hospitalization rate was 1.2% for G-CSF prophylactic initiation and 3.7% for delayed G-CSF initiation (P < 0.001). Chemotherapy cycles with prophylactic initiation of either G-CSF had decreased risk of neutropenia-related (adjusted OR = 0.34, 95% CI 0.21-0.56) and all-cause hospitalization (adjusted OR = 0.67, 95% CI 0.49-0.91) compared with delayed initiation of G-CSF.
  
  
  CONCLUSIONS
  Pegfilgrastim prescribed as prophylaxis resulted in lower risk of neutropenia-related and all-cause hospitalizations compared to filgrastim prophylaxis. This reduction was similar for prophylactic G-CSF initiation when compared to delayed G-CSF initiation.
authors.affiliation: HealthCore, Inc., 800 Delaware Ave, 5th Floor, Wilmington, DE 19801, USA. jtan@healthcore.com
authors.forename: Hiangkiat
authors.initials: H
authors.lastname: Tan
authors.forename: Karen
authors.initials: K
authors.lastname: Tomic
authors.forename: Dana
authors.initials: D
authors.lastname: Hurley
authors.forename: Gregory
authors.initials: G
authors.lastname: Daniel
authors.forename: Rich
authors.initials: R
authors.lastname: Barron
authors.forename: Jen
authors.initials: J
authors.lastname: Malin
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use; D003115:Colony-Stimulating Factors / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005334:Fever / Q000139:chemically induced / Q000150:complications / Q000188:drug therapy*; D000069585:Filgrastim; D016179:Granulocyte Colony-Stimulating Factor / Q000009:adverse effects / Q000627:therapeutic use; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy; D009503:Neutropenia / Q000139:chemically induced / Q000150:complications / Q000188:drug therapy*; D011092:Polyethylene Glycols; D011994:Recombinant Proteins; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D003115:Colony-Stimulating Factors; D007166:Immunosuppressive Agents; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; C455861:pegfilgrastim; D011092:Polyethylene Glycols; D000069585:Filgrastim