Cancer Type and Stage
Most studies did not find significant associations between analgesic adherence rates and cancer type and stage [3,12,14]. However, 1 study that sought to identify unique factors underlying analgesic adherence for African Americans and whites found that whites reported higher analgesic adherence in relation to “time since cancer diagnosis,” possibly indicating disease severity and progression . In another study that involved a majority of African-American patients, individuals with colon and rectal cancer had lower adherence rates . In this study, patients with colon and rectal cancer had more analgesic prescriptions (2.5 +/– 2.3 analgesics) compared to patients with other cancer diagnoses. The authors concluded that an increased medication burden might have contributed to a decreased adherence rate. Overall, other cancer types did not correlate with adherence rates .
Six studies examined pain intensity and duration [3,4,13–16]. Three studies found a difference in reported pain intensity between racial/ethnic groups [3,13,16], 1 found no correlation between pain intensity and race/ethnicity , and 3 concluded that pain intensity was a significant predictor of adherence rates [3,13,15].
Meghani and Bruner’s pilot study explored possible correlates associated with intentional and unintentional nonadherence . Overall, individuals were more likely to report forgetfulness (unintentional nonadherence) and to stop taking pain medicine when feeling “worse” (intentional nonadherence) if they believed that it was easier to deal with pain than with the side effects of analgesia . Further, forgetfulness was negatively associated with the need for “stronger” pain medication. Concern about using too much pain medication was positively correlated with both forgetfulness and carelessness. The need for stronger pain medication was also correlated with significantly higher pain levels and lower pain relief .
In a comparative study of African Americans and whites, African Americans reported greater cancer pain and lower pain relief on the Brief Pain Inventory (BPI) and had a negative PMI. The PMI measure is a simple index linking the usual severity of cancer pain with the category of medication prescribed to treat it. PMI is calculated by subtracting patient’s pain levels (“pain worst” score from the BPI coded as mild, moderate, or severe) from the most potent analgesia prescribed. A negative PMI implies inadequate analgesic prescription relative to the reported pain level. Pain intensity was a significant factor related to increased adherence in whites but not African Americans. For African Americans, analgesic adherence was predicted by socioeconomic status, provider communication factors, and side effects. Similarly, in another study that compared African Americans and Hispanics, African Americans were more likely to have a negative PMI than Hispanics and were less likely to report that pain medication relieved pain . In a pilot study that compared Medicaid recipients to self-pay/charity care patients, African-American participants had lower reported pain scores than Hispanics and Caucasians . In the larger follow-up study, however, ethnicity did not prove a significant predictor for pain levels .
In a study with exclusively African-American patients, a significant correlation was found between pain intensity and adherence; specifically, as intensity increased, adherence increased . Results for the entire African-American cohort indicated that 90% of patients had analgesic prescriptions for cancer-related pain, but 86% continued to report having moderate to severe worst pain . A study that compared African Americans and whites showed that lower pain relief with analgesics was associated with lower adherence to analgesia for cancer pain among whites . For every unit increase in “least pain” scores (indicating lower pain relief) on the BPI item, dose adherence decreased by 2.88%. Pain levels and relief did not explain adherence rates among African Americans. Whites were also more likely to make decisions on analgesic use based on the amount of relief anticipated from the use of analgesics  whereas African Americans were more likely to make analgesic use decisions based on analgesic side effects.