How comfortable are primary care physicians and oncologists prescribing medications for comorbidities in patients with cancer?

Background: Treating cancer and existing chronic comorbidities requires a dynamic mix of primary care and specialist providers. However, little is known regarding primary care physicians' (PCPs) and oncologists' comfort level prescribing for comorbid conditions. Objectives: The objectives of this study were to describe oncologists' and PCPs': 1) comfort-level prescribing, 2) perceptions of providers' role in prescribing cardiometabolic and psychiatric medications in persons with cancer and comorbidity, and 3) provider factors associated with comfort-levels. Methods: This cross-sectional online survey examined responses from practicing U.S. PCPs and oncologists. A 33-question survey was used to assess PCPs' and oncologists' comfort-levels for prescribing 6 classes of medications used to treat common comorbid cardiometabolic or psychiatric conditions. Using t-tests, chi-square tests, or Fisher's Exact tests, physicians' own comfort and comfort with other physicians prescribing medications for shared patients were compared between PCPs and oncologists. Linear regression models were used to analyze predictors of comfort-level scale score for prescribing medications. Results: Oncologists were more comfortable with PCPs initiating or refilling antidiabetics, antihyperlipidemics, antidepressants, and antipsychotics, and PCPs were more comfortable initiating antihypertensives, antidiabetics, antihyperlipidemics, antidepressants, and antipsychotics themselves as opposed to having an oncologist initiate or refill these medications. Compared to oncologists, PCPs reported a 32.3% higher comfort-level for initiating cardiometabolic medications (Adjusted Coefficient (standard error) = 0.323 (0.033), p < 0.001), and a 25.0% higher comfort-level for initiating psychiatric medications in cancer patients (Adjusted Coefficient (standard error) = 0.250 (0.030), p < 0.001), after controlling for prescriber demographics and practice site characteristics. Conclusions: Findings suggest that when a cancer diagnosis is made for patients with pre-existing cardiometabolic or psychiatric conditions, oncologists prefer PCPs to manage these medications. This enhanced understanding of PCPs' and oncologists' comfort managing these medications may help develop a standard for defining physician roles in medication therapy as part of a shared care plan for patients with cancer and comorbidities.