Comparative Effectiveness of White Blood Cell Growth Factors on Neutropenia,Infection, and Survival in Older People with Non‐Hodgkin's Lymphoma Treated with Chemotherapy

OBJECTIVES: To determine the effect of colony‐stimulating factor (CSF) on incidence of febrile neutropenia, infection, and survival in older people with non‐Hodgkin's lymphoma (NHL) treated with chemotherapy. DESIGN: Retrospective cohort study. SETTING: The Surveillance, Epidemiology, and End Results–Medicare database. PARTICIPANTS: Thirteen thousand two hundred twenty‐three people diagnosed with NHL at age 65 and older (mean age 74.9, range 65–102) in 1992 to 2002 who received chemotherapy within 12 months of diagnosis. MEASUREMENTS: Primary prophylaxis was defined as CSF administered at the start of chemotherapy before febrile neutropenia or infection; secondary prophylaxis was defined as CSF use after febrile neutropenia or infection. RESULTS: Participants with five to nine administrations of primary prophylactic CSF had a 42% lower risk of febrile neutropenia (odds ratio (OR)=0.58, 95% confidence interval (CI)=0.41–0.83), and participants with 10 or more administrations had a 48% lower risk (OR=0.52, 95% CI=0.36–0.76) after adjusting for age, stage, histology, and comorbidity. Results did not differ significantly after adjusting for propensity score of receiving CSF. There was no significant association between primary prophylactic CSF and overall survival, but secondary prophylactic CSF was significantly associated with better survival. Four to 10 administrations of secondary prophylactic CSF was associated with 9% lower mortality risk (hazard ratio (HR)=0.91, 95% CI=0.84–0.99), 11 to 23 administrations was associated with 23% lower mortality risk (HR=0.77, 95% CI=0.71–0.84) and 24 or more administrations was associated with 13% lower mortality risk (HR=0.87, 95% CI+0.79–0.95) than in participants not receiving CSF after neutropenia or infection. CONCLUSION: Primary prophylactic CSF was observed to be effective in reducing the incidence of neutropenia and infection. These findings substantiate the clinical guidelines for recommending prophylactic CSF in older people with NHL receiving chemotherapy.