Overuse and underuse of pegfilgrastim for primary prophylaxis of febrile neutropenia.

Introduction Guidelines recommend pegfilgrastim for primary prophylaxis of febrile neutropenia after highly myelosuppressive chemotherapy. While deviations from guidelines could result in overuse and increased costs, underuse is also a concern and could compromise quality of care. Our objectives were to evaluate guideline adherence and quantify the extent to which physician heterogeneity may influence pegfilgrastim use. Methods We randomly sampled 550 patients from a retrospective cohort of those who received infusions at an academic cancer center between 1 September 2013 and 1 September 2014. Electronic medical and drug dispensing records provided information on patient characteristics, chemotherapy characteristics, prescribing physician, and pegfilgrastim administration. Results We included 154 patients treated by 25 physicians. About half of patients were male and mean age was 61.3 years. Forty (26.1%) patients had no febrile neutropenia risk factors, 62 (40.5%) had one, and 51 (33.3%) had two or more. Thirty patients (19.5%) received pegfilgrastim, of which 12 (40%) received palliative chemotherapy. Nine (60%) of 15 patients on a regimen with a febrile neutropenia risk  ≥ 20% received pegfilgrastim. Pegfilgrastim use significantly varied by cancer type (p < 0.01), chemotherapy regimen (p < 0.001), and regimen febrile neutropenia risk (p < 0.001). Multivariable analysis reaffirmed the association between chemotherapy regimen febrile neutropenia risk ≥ 20% and pegfilgrastim use (odds ratio (OR) = 10.1, 95% confidence interval (CI): 1.6-62.7) and suggested that 31% (95% CI: 8%-71%) of the variation in use was attributable to physician characteristics. Conclusion Pegfilgrastim was potentially overused for palliative chemotherapy and underused for chemotherapy regimens with febrile neutropenia risk ≥ 20%. Successful interventions to modify prescribing practices likely require an understanding of the relationship between specific physician characteristics and pegfilgrastim use.