Sociological Factors Influencing Patient-Reported Outcomes in RA

According to findings published in Arthritis Care & Research, disparities in patient-reported outcomes in rheumatoid arthritis (RA) may be driven less by ethnicity than by sociodemographic or psychological factors. Researchers found that Hispanic, Spanish-speaking women had worse function, pain, and fatigue in RA compared with white, English-speaking women and Hispanic, English-speaking women.

“Despite advances in therapies, disparities in outcomes have been documented for RA patients for both ethnicity and English language proficiency,” wrote Patricia P. Katz, PhD, from the University of California, San Francisco and colleagues. “The goals of these analyses were to compare differences in RA patient-reported outcomes, by both self-identification of ethnicity and English language proficiency, and to identify factors that might explain differences among groups.”

“Future research on the measurement of patient reported outcomes should place examination and achievement of cultural and linguistic equivalence at high priority,” the researchers concluded.

The researchers collected data through structured telephone interviews of 438 participants with physician-diagnosed RA; only 335 women were included in the study. Of the women included, 219 were white English speakers, 39 were Hispanic English speakers, and 77 were Hispanic Spanish speakers. 

The researchers examined patient-reported physical functioning, pain, and the presence of moderate or severe fatigue. Outcomes among the groups were compared using multivariate regression analyses and were adjusted for sociodemographic characteristics, health and disease factors, and depression.

The researchers found that Hispanic Spanish-speaking women had worse function, pain, and fatigue compared with either English-speaking group. Depression was associated with all outcomes (P < .0001), and accounted for greater differentials in scores than ethnicity or language proficiency. Scores for non-depressed Hispanic Spanish-speakers were significantly worse than scores for non-depressed Hispanic English-speakers. After adjustment for sociodemographic factors and depression, language remained significantly associated with outcomes.

“Sociodemographic differences clearly played a significant role in explaining disparities in patient reported outcomes,” the researchers wrote. Hispanic Spanish-speakers had lower education levels, were more likely to have low incomes, low health literacy, had no health insurance or Medicaid, and were less likely to have been born in the US. Low education levels and low income have consistently been linked to poor health outcomes.

However, the researchers noted that depression also played an important role in explaining disparities in patient outcomes. “Depression was significantly more prevalent among the Hispanic [Spanish-speakers], and was the variable most strongly related to all outcomes in multivariate analyses,” the researchers wrote. “Other research has noted high rates of depression among Hispanics in the general population and among Spanish-speaking RA patients in particular, and has found a strong association of depression with patient reported outcomes.”

The researchers also explored whether the disparities they found could be due to differences in disease status, reporting bias, measurement issues, or other factors, noting that it is difficult to separate assessment of disease status from patient reports of pain or function from global assessments, because these are often inputs to assessing disease status.

The researchers also explored the possibility of pain threshold and acculturation playing differences. “There is some evidence that Hispanics may have a lower pain threshold in experimental settings compared to non-Hispanic whites. However, effect sizes in these studies were small, and could not explain the large differences we found,” the researchers wrote.

“Our finding that English-proficient Hispanics and whites had similar outcomes suggests that factors related to acculturation may play an important role, although the mechanism by which this occurs is unclear. Some have noted that extremely positive ratings of health may be viewed culturally by Hispanics as boasting, and therefore be unacceptable. However, a systematic problem with the measurement of PROs in different languages may also exist.”

Summary & Clinical Applicability

Researchers found that Hispanic, Spanish-speaking women had worse function, pain, and fatigue in RA compared with white, English-speaking women and Hispanic, English-speaking women. It is unclear whether these disparities are due to differences in disease status, reporting bias, measurement issues, or other factors, although the disparities may be driven less by ethnicity than by sociodemographic or psychological factors.

The researchers noted that due to the high prevalence of depression found in Hispanic, Spanish-speaking women, there is a particular need of effective treatments for depression in this population.

Limitations & Disclosures

• There were a small number of English-speaking Hispanics in the sample; a larger sample may have yielded more information.
• The majority of the Spanish-speaking participants were recruited from a public hospital rheumatology clinic and so were primarily from Mexico and Central America, which may limit generalizability.
• Language, sociodemographic characteristics, and literacy were clustered, so the ability to separate the effects of one of these factors may have been limited.