Investigating the Association Between Advanced Practice Providers and Chemotherapy-Related Adverse Events in Women With Breast Cancer: A Nested Case-Control Study

Purpose: The effect of advanced practice provider (APP) involvement in oncology care on cancer-specific outcomes is unknown. We examined the association between team-based APP–physician care during chemotherapy and chemotherapy-related adverse events (AEs) among women with breast cancer. Methods: We performed separate nested case-control analyses in two national cohorts of women who received chemotherapy for incident breast cancer. Cohorts were identified from Medicare (≥ 65 years of age) and MarketScan (18 to 64 years of age) data. Cases experienced a chemotherapy-related AE (emergency room visit and/or hospitalization). Controls were matched 1:1 on the basis of each patient’s age, comorbidities, census region, state’s APP scope of practice regulations, and observation period from chemotherapy initiation to first AE. APP exposure (any outpatient claim billed by an APP during the observation period) was assessed for each matched pair member. Results: Among the 1,948 cases in the Medicare cohort, 225 (12%) had APP exposure before the first chemotherapy-related AE, compared with 213 controls (11%; P = .54). Among the 725 cases in the MarketScan cohort, 52 (7%) had APP exposure compared with 65 controls (9%; P = .21). In the matched case-control analysis, there was no association between outpatient APP exposure during chemotherapy and AEs in either cohort (Medicare: OR, 1.06 [95% CI, 0.87 to 1.30]; MarketScan: OR, 0.76 [95% CI, 0.50 to 1.14]). Conclusion: Our results suggest that team-based APP-physician care that includes an APP who is billing independently, at least for certain patients receiving chemotherapy, may be a viable strategy to safely leverage the scarce oncology workforce to increase access and delivery of cancer care.