Background/Purpose: Disease activity measurement is a cornerstone of the Treat to Target strategy. However, all currently used measures include a Patient Global Score (PtGLB ) as one of the components.  We assessed disparities in Patient Global Scores in White vs. Black patients in a community based practice and its impact CDAI. 

Methods: Data from random visits of 236 RA patients was obtained.  Data regarding patient demographics, as well as other measures of clinical status were evaluated.  Regression analysis was used to determine impact of race on PtGLB, controlling for age, sex, disease duration, education level, swollen joint count, and Fibromyalgia co-diagnosis. CDAI was calculated by using standard measures and, also, corrected for ethnicity. 

Results: 236 patients with RA, 198 Caucasian and 38 of African descent were analyzed. Two sample t-test to compare the two racial groups revealed no significant differences in age, duration of disease, education level, Fibromyalgia co-diagnosis, and swollen joint count (all p-values >0.05). Statistically significant differences were found in gender and PtGLB, with a higher proportion of female patients and higher PtGLB in the black population (mean of 5.09, 95% CI 4.15 – 6.04 vs. 3.62, 95% CI 3.23 – 4.02) (p=0.004). Higher Provider Global Scores were seen in the black population vs. the white population ( 1.92, 95% CI 1.09 – 2.75 vs. 1.27, 95% CI 1.04-1.50) (p=0.04).

After controlling for age, sex, duration of disease, education level, Fibromyalgia co-diagnosis, and swollen joint count, it was found that the average patient-reported global assessment score was 3.83 in the white population vs. 5.17 in the black population (D= 1.34).

When CDAI scores were calculated without correcting for influence of race on PtGLB, the mean CDAI score in whites were lower than in the blacks (10.97, 95% CI 9.59 – 12.36 vs. 14.35, 95% CI 10.05 – 18.64). 57% (112 of 198 patients) of whites were in low disease activity or remission state vs. 37% (14 of 38 patients) of the black population. (p=0.033)

After correcting for the influence of race, the percentage of patients in remission/low disease state in the black population increased to 47% (18 of 38 patients). After correction thee was no statistically significant differences between the two groups. (p=0.374)

Conclusion: African-American patients on average have higher self-reported global disease activity levels. This may lead to misclassification of patients as being outside of the remission/low disease activity range, which may lead to over-treatment of patients who would otherwise have no changes made to their management plan.

Further studies with larger numbers of patients and inclusion of additional racial/ethnic groups to substantiate the results of this study are required.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/impact-of-race-on-patient-global-scores-and-the-misclassification-of-disease-activity/