title: Assessing functional status and the survival benefit of chemotherapy for advanced non-small cell lung cancer using administrative claims data.
abstract: OBJECTIVE
  Borderline or poor performance status (PS) patients comprise a significant proportion of those diagnosed with advanced non-small cell lung cancer (AdvNSCLC), but are often excluded from clinical trials. It is difficult to draw conclusions about the benefit of therapy in borderline PS patients due to lack of reliable PS assessments, and small clinical trial samples. Retrospective population-based secondary analyses may allow investigators to study under-represented populations in clinical trials. We hypothesized that patients with poor functional status derive benefit from chemotherapy compared good functional status, but that the magnitude of the benefit is lower compared to patients with good functional status. By utilizing a "disability status" (DS) measure as a proxy for PS, we offer a reliable mechanism for patient stratification that can be implemented in administrative claims data.
  
  
  METHODS
  Medicare beneficiaries diagnosed with AdvNSCLC between 2001 and 2005 were selected from the Surveillance, Epidemiology and End Results database linked to Medicare claims. Disability status, a previously developed and validated claims-based proxy for baseline PS, was implemented. Patients were assigned to good versus poor DS. Cox proportional hazard models were used to examine the differential effects of chemotherapy for the two DS groups on all-cause mortality, controlling for tumor and patient characteristics.
  
  
  RESULTS
  Most patients in the cohort (n=21,019) were ≥75 years of age (59%), and non-Hispanic white (85%); 91% were assigned to good DS; 38% received chemotherapy. Chemotherapy had a strong protective effect among good DS patients (hazard ratio, 0.43; CI 0.42-0.45; p<0.001), with a slightly smaller effect for poor DS (hazard ratio, 0.50; CI 0.44-0.57).
  
  
  CONCLUSIONS
  Chemotherapy improves survival for advanced NSCLC patients with poor DS but to a lower magnitude than for good DS patients. The DS measure opens the door to assess outcomes for cancer patients with poor functional status using insurance claims data.
authors.affiliation: University of Maryland, Greenebaum Cancer Center, 22 South Greene Street, Baltimore, MD 21201, United States. Electronic address: jfeliciano@umm.edu.
authors.forename: Josephine
authors.initials: J
authors.lastname: Feliciano
authors.affiliation: University of Maryland, Greenebaum Cancer Center, 22 South Greene Street, Baltimore, MD 21201, United States.
authors.forename: Lisa
authors.initials: L
authors.lastname: Gardner
authors.affiliation: University of Maryland, Greenebaum Cancer Center, 22 South Greene Street, Baltimore, MD 21201, United States. Electronic address: fhend001@umaryland.edu.
authors.forename: Franklin
authors.initials: F
authors.lastname: Hendrick
authors.affiliation: University of Maryland, Greenebaum Cancer Center, 22 South Greene Street, Baltimore, MD 21201, United States.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Edelman
authors.affiliation: University of Maryland, Greenebaum Cancer Center, 22 South Greene Street, Baltimore, MD 21201, United States. Electronic address: amy.davidoff@yale.edu.
authors.forename: Amy
authors.initials: A
authors.lastname: Davidoff
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology; D015897:Comorbidity; D004185:Disability Evaluation; D005260:Female; D006304:Health Status; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000453:epidemiology* / Q000473:pathology; D008297:Male; D009026:Mortality; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D062486:Public Health Surveillance; D012307:Risk Factors; D018426:SEER Program; D016896:Treatment Outcome
keywords: Advanced lung cancer; Chemotherapy; Lung cancer; Medicare; Performance status; SEER; Survival