Hispanics are the most robustly growing segment of the U.S. population. Research has not explored longitudinal trends in functional disability in Hispanic patients with rheumatoid arthritis (RA). However, when compared with the general RA population in the U.S., some groups have reported graver cross-sectional disability and worse functional outcomes in Hispanics, highlighting the importance of determining the potentially unique clinical features of their RA course.
To address this knowledge gap, George A. Karpouzas, MD, and colleagues from the Harbor-UCLA Medical Center and Los Angeles Biomedical Research Institute evaluated the change in disability over time and determinants of clinically meaningful change in functional disability in low-income Hispanic patients with established RA. The results were published in the February 2017 issue of Arthritis Care & Research.
One hundred and fifty-six Hispanic participants were selected from the extended Harbor-University of California at Los Angeles (UCLA) RA observational cohort. Most participants were immigrant Hispanic patients of low-socioeconomic status: 80% were uninsured and 20% had Medicaid coverage. Ninety percent declared Spanish was their preferred language. Participants were evaluated during three consecutive visits (baseline, six- and 12-month follow-ups) for disability, disease activity (Disease Activity Score in 28 joints [DAS28]), pain and depression. Serology results, radiographs, treatments and irreversible articular damage were also recorded.
The Results
“We confirmed that disease activity, depression and pain were modifiable parameters with sizeable, independent and additive contributions to HAQ DI [Health Assessment Questionnaire disability index] variance,” write the authors. Overall, time was a factor in the improvement of disability, with 51% of patients who had HAQ DI ≥1 at baseline showing significant improvement.
At baseline, 71% of participants had significant disability (HAQ DI >1) and 34% were depressed. However, the disability score improved significantly (P=0.032). At the third visit, 65 patients (42%) had clinically meaningful improvement in disability (DHAQ DI .0.22), 36 (23%) had deterioration, and 55 (35%) remained unchanged. Researchers also established that the absence of depression, less pain, lack of erosions and no biologic agent use at baseline all predicted the greatest improvement (P<0.001) in disability.
Despite the results, clinically meaningful improvement was not limited to patients with favorable profiles. The authors note, “Improvement was rather contingent upon simultaneous, reciprocal, and synergistic recovery in DAS28 [Patient Health Questionnaire (PHQ)]-9 and pain, regardless of original severity and further facilitated by lack of erosions or of biologic agent use. Notably, isolated improvement in PHQ-9 greater than [minimum clinically important difference] was sufficient and able to independently yield significant disability improvement.”
In their discussion, the authors write, despite seeing a clinically relevant improvement in disability over time, “Our results confirm the persistence of significant residual disability; 53% of patients exhibited HAQ DI ≥1 throughout the entire observation period.” Many of the study participants entered the health care system with their disease well underway, commonly undiagnosed, and inconsistently or inadequately treated for years. Because the study observation period was short, “we are therefore uncertain how sustainable this improvement in disability might be over a longer time frame.”
For Hispanic patients with RA, “improvement over time, collectively or in isolation, and regardless of their original severity, may yield clinically measurable improvements in functional disability and reaffirms all of them as actionable items in a patient-centered treat-to-target approach,” conclude the authors.
Karpouzas GA, Draper T, Moran R, et al. Trends in functional disability and determinants of clinically meaningful change over time in Hispanic patients with rheumatoid arthritis in the U.S. Arthritis Care Res (Hoboken). 2017 Feb;69(2):294–298. doi: 10.1002/acr.22924.
