Also, invariably the studies employed an English-speaking sample, which excludes an understanding of analgesic adherence for cancer pain in linguistically diverse Americans. In addition, most studies included patients who were either white Americans or African Americans and some studies lumped several racial ethnic minority subgroups as “nonwhites” or “other.”
A majority of studies were cross-sectional [4,12,15,16]. For instance, studies used a 24-hour time period to assess ATC medication as well as as-needed regimens, which may not capture the information needed to understand adherence to as-needed regimens . With longitudinal studies, a greater understanding of adherence can be determined. However, there is potential bias with studies that track patients primarily at follow-up appointments. Individuals who are compliant with follow-up appointments may present with different analgesic adherence compared to those who do not attend follow-up appointments. This potential bias should be evaluated in longitudinal studies with various sensitivity analyses or using tools that identify healthy user bias.
Most studies recruited patients from outpatient oncology clinics, however, 1 study was conducted with a sample from an outpatient supportive care center managed by a palliative care team . Due to the goals of palliative care, which include specialized treatment for individuals with serious illness and a focus on symptom management and relief, patients in this setting may have a different attitude toward using opioids.
Although data remain limited, our review suggests that while overuse of opioids has been a well-cited concern in patients with chronic non-cancer pain [21,33], cancer patients demonstrate considerable underuse and inconsistent use of prescribed analgesics. This is important as a recent study found that inconsistent adherence to prescribed around-the-clock analgesics, specifically the interaction of strong opioids and inconsistent adherence, is a strong risk factor for hospitalization among cancer outpatients who are prescribed analgesics for pain . Of note, adherence to opioids in patients with cancer may be driven by a unique set of factors and these factors may differ for minorities and non-minority patients. For instance, studies in this review indicate that income is a strong predictor of analgesic adherence for African Americans but not for whites. This is because race and socioeconomic status frequently overlap in the United States . In addition, like cancer pain, analgesic side effects may also be poorly managed among African Americans and other minorities. For example, in 1 study, Meghani et al used a trade-off analysis technique (conjoint analysis) to understand trade-offs African Americans and whites employ in using analgesics for cancer pain . The authors found that African Americans were more likely to make analgesic adherence decisions based on side effects whereas whites were more likely to make adherence decisions based on pain relief . In subsequent analysis, these authors showed that the race effect found in their previous studies was mediated by the type of analgesics prescribed to African Americans vs. whites . African Americans with cancer pain were prescribed analgesics that had a worse side effect profile after statistically adjusting for insurance type and clinical risks such as renal insufficiency .