Increased Morbidity and Mortality of Scleroderma in African Americans Compared to Non–African Americans

Abstract

Objective. African Americans with scleroderma have more severe disease and higher mortality than non-African Americans. Differences in rates of diffuse disease, autoantibody status, or socioeconomic status have not completely explained this phenomenon. Our study evaluates these risks at our site.Methods. A retrospective study comparing African American and non-African American patients with scleroderma seen from 2008 to 2016 was performed. Groups were matched by sex, age at first visit, date of first visit, disease duration at first visit, and limited versus diffuse cutaneous disease. Demographic, serologic, and clinical features were compared. Mortality risks were assessed by a Cox proportional hazards model with covariates of race, marital status, education, employment, insurance, and imputed household income.Results. African Americans comprised 202 of 402 patients. They demonstrated reduced forced vital capacity and diffusing capacity for carbon monoxide, more severe lung fibrosis, a higher prevalence of pulmonary hypertension, and more severe cardiac involvement. The autoantibody profile statistically differed between the 2 groups. Death during follow-up was 21% in African Americans versus 11% in non-African Americans (P = 0.005). African American race demonstrated an unadjusted hazard ratio for death during follow-up of 2.061 (P = 0.006) that declined with adjustment for socioeconomic covariates to 1.256 (P = 0.633). The only significant covariate was median income in tens of thousands of dollars by zip code (hazard ratio 0.845; P = 0.033).Conclusion. African American patients with scleroderma have more severe pulmonary disease and higher unadjusted mortality than matched non-African Americans. Following adjustment for socioeconomic factors, African American race was not a significant risk factor for mortality; however, independent of race, a lower median household income predicted increased mortality.

Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study

“…African Americans, for example, are known to have a higher incidence of SSc, an earlier age of onset, and a greater frequency of interstitial lung disease (ILD) and pulmonary hypertension (PH) compared to white SSc patients [4,5,[7][8][9]. Data on black SSc patients however mostly stem from African Americans and figures may be influenced by environmental and socioeconomic factors and access to health care [10,11]. Differences in the autoantibody profile have also been reported between races; anticentromere antibodies (ACA) for example are frequent in Caucasian patients, whereas anti-topoisomerase-I antibodies (ATA) are highly prevalent in Choctaw Native Americans, Thais and African Americans [1,3,12,13].…”

Natural history of systemic sclerosis–related interstitial lung disease: How to identify a progressive fibrosing phenotype

“…[13][14][15] Similarly, African American patients with SSc-ILD may also exhibit more severe ILD. [16][17][18] However, a recent analysis demonstrated that after adjustment for socioeconomic factors, African American race was not a significant risk factor for mortality in a relatively large cohort of SSc patients (N = 402) 18 Among SSc-ILD patients who participated in SLS I and II, there was no difference in the course of the FVC% predicted, nor long-term survival, between African American and non-African American participants, even after adjustment for baseline disease severity. 19 These findings suggest that confounding factors should be considered when interpreting the results of observational studies where patients have varying access to care, treatment, and follow-up.…”

African Americans and Scleroderma: Examining the Root Cause of the Association

“…Overall, and in the context of these published reports that underscore the disproportionate and adverse impact of scleroderma among African Americans, and in light of the ongoing efforts of the GRASP study, the current article by Moore et al emphasizes the importance of socioeconomic status and of socioeconomic determinants of health, to account for differences in clinically relevant outcomes . These reports emphasize to the reader, each in its own way, the value of an optimal study design, which can concomitantly examine the independent contribution of socioeconomic status, and of clinical, serologic, and genetic determinants to outcomes of interest in scleroderma.…”

“…In addition, the mean age at death was younger among the African American patients. Many years later, directly related to the study by Moore et al in this issue of Arthritis Care & Research , the question remains: why are African Americans disproportionately affected with greater morbidity and excess mortality once diagnosed with scleroderma?…”

“…In this issue of the journal, Moore et al examine the contribution of socioeconomic determinants of health to explain excess mortality among African Americans with scleroderma, using data assembled from 2008 to 2016 at a single university medical center in the District of Columbia . Race and ethnicity were self‐reported.…”