Racial Differences in Adherence to Prescribed Analgesia in Cancer Patients: An Integrated Review of Quantitative Research

Factors Associated with Adherence

Multiple studies investigated factors underlying reported analgesic adherence rates for the ethnic and racial groups studied. Both clinical and sociodemographic variables were associated with analgesic adherence (Table 4). These included cancer type and disease stage [3,4,13,14], pain intensity [3,4,13–16], side effects [13,15], type of analgesic prescribed [3,4,13–16], income/socioeconomic status [3,13,14], behavioral history [3,12,13], gender [3,4,12–16], and perceived barriers [3,4,13,15,16].

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 [13]. In another study that involved a majority of African-American patients, individuals with colon and rectal cancer had lower adherence rates [4]. 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 [4].

Pain Intensity

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 [14], 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 [15]. 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 [15]. 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 [15].

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 [16]. 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 [3]. In the larger follow-up study, however, ethnicity did not prove a significant predictor for pain levels [14].

In a study with exclusively African-American patients, a significant correlation was found between pain intensity and adherence; specifically, as intensity increased, adherence increased [4]. 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 [4]. 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 [13]. 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 [13] whereas African Americans were more likely to make analgesic use decisions based on analgesic side effects.

Side Effects

In a pilot study that explored the intricacies of adherence, some individuals felt it was easier to deal with pain than with the side effects of pain medications. These individuals were also more likely to report forgetfulness and to stop taking medications if feeling “worse” [15]. One study, which included African-American and white cohorts, found that an increase in the severity of side effects was associated with lower adherence to analgesia for African Americans but not whites. Furthermore, African Americans reported a greater number of analgesic side effects at baseline. African Americans were also more likely to make analgesic decisions based on side effects in comparison to whites participants, who made decisions based on expectation of pain relief [13]. In a study with exclusively African-American patients, patients with concerns about pain medication possibly causing confusion were more likely to have poor adherence [4].

Type of Analgesic Prescribed

In the analyses, 3 studies found a difference between analgesic prescriptions among ethnic groups [12,13,16], 3 found that there was a statistical significance between type of prescription and adherence [4,13,16], and 2 studies [3,14] found no statistical correlation between type of analgesic prescribed and adherence.

In a study of African Americans and Hispanics, both groups took analgesics on an “as-needed” basis despite the guidelines for cancer pain management [16]. However, African Americans reported taking analgesics less than twice daily. Overall, only a small percentage of patients took sustained-release analgesics that require fewer doses per day [16]. Similarly, in another study that compared adherence between African Americans and whites, the overall analgesic adherence rate was different on sub-analysis for specific analgesic prescriptions. The analgesic adherence rates for African Americans ranged from 34% for weak opioids to 63% for long-acting opioids. In comparison, the analgesic adherence rates for whites ranged from 55% for weak opioids to 78% for long-acting opioids [13]. In conclusion, patients on long-acting opioids were more likely to have higher adherence. Adherence rates for African Americans were found in another study. The adherence rate for adjuvant analgesics was highest at 65%, step 2 opioids at 44% and step 3 opioids at 43% [4].

In a study with exclusively African-American patients, poor adherence was significantly correlated with step 3 opioids [4]. Another study that explored the correlation between type of analgesic and adherence found that intentional nonadherence was less likely in individuals that were prescribed step 3 opioids [15]. Specifically, individuals with this behavior were also more likely to report lower pain levels and chose to stop the use of analgesics when feeling better [15].

Within a pilot study that compared benefit programs and payor groups, the differences in the prescription of long-acting opiates did not reach statistical significance [3]. However, in the larger, definitive study, the comparison revealed that patients in the self-pay/charity care group were less likely to receive a prescription for long-acting opiates. The data further revealed that Hispanic and Asian patients were prescribed long-acting opiates at a lower rate compared to the larger sample. Further, African Americans and Caucasians were prescribed long-acting opiates at a higher rate than the larger sample. In another analysis, with benefits and race/ethnicity, benefits were the only statistically significant predictor. While statistically controlling for race/ethnicity, Medicaid patients were 2.4 times more likely to receive a prescription for long-acting opioids than the self-pay/charity care patients [14].

Income/Socioeconomic Status

Three studies in this analysis [3,13,14] found that income and socioeconomic status were significant predictors of analgesic adherence for cancer pain. In a comparison between African Americans and whites, income was the strongest predictor of analgesic adherence for cancer pain in African Americans [13]; specifically, individuals with a household income of less than $10,000 a year had a 41.83% lower percentage of dose adherence. Among whites, income did not have a significant correlation with analgesic rates [13].

A pilot study and larger definitive study [3,14] were conducted to compare the effects of prescription benefits. The prescription benefits included were Medicaid and self-pay/charity care. Through comparison, none of the Medicaid patients reported financial barriers but the self-pay/charity care patients were more likely to report financial barriers to adherence [3]. In the larger study, the findings indicated that there was significant association of adherence by benefits and race/ethnicity. As mentioned above, benefits were a dominant predictor of long acting opiate use and further adherence [14].

Gender

Apart from ethnicity or race as a variable associated with adherence, association of analgesic adherence and gender were observed in 4 studies [3,13–15] and evaluated in 2 studies. One study [4] found that a patient’s gender and education level did not correlate with adherence rates. However, in another study [12] men were more likely to deviate from the prescribed dose. Overall, within the entire cohort [12] men and minority patients were most likely to deviate from the prescribed dosing regimen in comparison to all other patient demographic factors.

Attitudes and Barriers

Five of the 7 studies investigated perceived barriers to analgesic adherence [3,4,13,15,16]. Four used the Barriers Questionnaire II (BQ-II) [18] to further understand patients’ beliefs about cancer pain management [3,12,13,15]. Using this validated tool, 1 study found that non-white individuals had higher scores on the BQ-II than white patients [12]. Within the non-white group in the above study, the mean score on the BQ-II for African Americans was 1.76 (± 0.81) and the mean score for “other” was 2.16 (± 0.93) [12]. Further, low MMAS scores were significantly associated with higher BQ-II scores. Similarly, higher BQ-II scores correlated with opioid deviation toward higher than prescribed dose [12].