Duration of short-acting granulocyte colony-stimulating factor for primary prophylaxis and risk of neutropenia-related hospitalization in older patients with cancer.

PURPOSE: Evaluate the relationship between duration of primary prophylactic short-acting granulocyte colony-stimulating factor (PP-sG-CSF) and risk of neutropenia-related hospitalization (NRH) in older patients receiving myelosuppressive chemotherapy.

METHODS

Using the Medicare claims database, we conducted a nested case-control study in a cohort of patients aged ≥66 years with breast, colorectal, lung, ovarian, or prostate cancer, or non-Hodgkin lymphoma who initiated a first cycle of any myelosuppressive chemotherapy January 1, 2008-September 30, 2016, and received PP-sG-CSF. We matched up to four controls to each NRH case by age, cancer type, regimen febrile neutropenia (FN) risk category, and year using incidence density sampling. We used conditional logistic regression adjusted for race, sex, and modified Charlson comorbidity index (CCI) to estimate relative risk of NRH related to duration of PP-sG-CSF categorized as <5 and ≥ 5 days.

RESULTS

Of 2148 patients receiving PP-sG-CSF, 108 (5%) experienced NRH in the first cycle. We matched 333 controls to 96 cases. Cases were similar to controls in mean age, tumor type, and intermediate/high-risk regimen, but were more likely to have CCI ≥5 and less likely to use PP-sG-CSF ≥5 days (31% vs. 39%). Adjusted ORs (95% CI) for NRH were 0.69 (0.40-1.19) for ≥5 vs. <5 days of PP-sG-CSF among patients receiving any myelosuppressive chemotherapy, 0.43 (0.21-0.89) for intermediate/high-risk regimen, and 0.42 (0.19-0.89) for any myelosuppressive chemotherapy with all agents given on cycle day one only.

CONCLUSIONS

Among older patients with cancer who are receiving PP-sG-CSF, ≥5 days of use was associated with substantial reduction in NRH risk.