Increased risk of death in African American patients with end-stage renal disease secondary to lupus

The inequity of global healthcare in pediatric rheumatology

In pediatric rheumatology, global health inequity relates to the uneven distribution of healthcare resources, accessibility, and health outcomes among children with rheumatic conditions across various countries, regions, and socioeconomic groups. This inequity can manifest in various ways. This review article provides an overview of common rheumatic diseases, such as juvenile idiopathic arthritis and systemic lupus erythematosus, which significantly contribute to and are affected by disparities in global healthcare. Subsequently, we delve into the inequalities in accessing patient care, encompassing issues related to diagnosis and treatment. Additionally, we address challenges in educational advancement and identify research gaps within the field of pediatric rheumatology. We also reveal successful global collaborations, such as a Global Task Force for Pediatric Musculoskeletal Health and special working groups among international organizations, aimed at bridging the disparities gap. Through these efforts, we try to enhance understanding, cooperation, and resource allocation to ensure equal access to quality care worldwide for children with rheumatic conditions. Futhermore, we present a case study from Thailand, highlighting their successful initiatives in developing pediatric rheumatology within their healthcare system.

Dermatology in black skin

The vast majority of publications in dermatology refer to lightly pigmented skin, with few addressing the peculiarities of black skin. In addition there is no consensus on what it means to be black in different regions of the world. The lack of knowledge on the subject makes it difficult to recognize and manage dermatoses in this type of skin. This article aims to review the literature on intrinsic characteristics, as well as epidemiological and clinical aspects of the cutaneous manifestations of different dermatoses in black skin. It was found that there are sometimes striking differences, in the structural, biological, and functional aspects when comparing lightly pigmented and black skin. There are also physiological changes that need to be recognized to avoid unnecessary interventions. Some dermatoses have a higher incidence in black skin, such as acne, eczema, dyschromia and dermatophytosis. On the other hand, several dermatoses are more specific to black skin, such as pseudofolliculitis barbae, keloid, dermatosis papulosa nigra, ulcers caused by sickle-cell anemia, dactylolysis spontanea, confluent and reticulated papillomatosis of Gougerot and Carteaud, and some diseases of the hair and scalp (including fragile and brittle hair, traction alopecia, folliculitis keloidalis nuchae, folliculitis dissecans and central centrifugal cicatricial alopecia). A spectrum of peculiar aspects of specific dermatoses, including sarcoidosis, lichen planus (with emphasis on the pigmentosus variant), psoriasis, lupus erythematosus, vitiligo, syphilis, pityriasis versicolor, and neoplasms are highlighted. In the latter, characteristics of basal cell carcinoma, squamous cell carcinoma, and melanoma are compared, in addition to highlighting unusual aspects of primary cutaneous T-cell lymphoma, endemic Kaposi sarcoma, and dermatofibrosarcoma protuberans.

Socioeconomic Factors Are Associated With Severity of Hospitalization in Pediatric Lupus: An Analysis of the 2016 Kids' Inpatient Database

OBJECTIVE

Health disparities in adult lupus, including higher disease severity and activity among those in poverty, have been identified. Similar associations in pediatric lupus have not been clearly established. This study was undertaken to investigate the relationship of income level and other socioeconomic factors with length of stay (LOS) in the hospital and severe lupus features using the 2016 Kids' Inpatient Database (KID).

METHODS

Lupus hospitalizations were identified in children ages 2-20 years in the 2016 KID using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes (M32). Univariate and multivariate negative binomial regression analyses were used to analyze the association of income level, race and ethnicity, and insurance status with LOS in the hospital. Univariate and multivariate logistic regression analyses were used to analyze the association of the same predictors with the presence of severe lupus features, defined using ICD-10 codes associated with lupus sequelae (e.g., lupus nephritis).

RESULTS

A total of 3,367 unweighted (4,650 weighted) lupus hospitalizations were identified. Income level was found to be a statistically significant predictor of increased LOS in the hospital for those in the lowest income quartile (adjusted incidence rate ratio 1.12 [95% confidence interval (95% CI) 1.02-1.23]). Black race, "other" race, and public insurance were also associated with severe lupus features (adjusted odds ratio [ORadj ] 1.51 [95% CI 1.11-2.06]; ORadj 1.61 [95% CI 1.01-2.55]; and ORadj 1.51 [95% CI 1.17-2.55], respectively).

CONCLUSION

Using a nationally representative data set, income level was found to be a statistically significant predictor of LOS in the hospital among those with the lowest reported income, highlighting a potential target population for intervention. Additionally, Black race and public insurance were associated with severe lupus features.

Impact of patient ancestry on heterogeneity of Sjögren's disease

OBJECTIVES

We aimed to compare disease characteristics between primary Sjögren's syndrome (pSS) patients of African ancestry (AA) and Caucasian ancestry.

METHODS

We conducted a retrospective, case-control study in a French national and European referral centre for pSS. All patients with pSS of AA were matched with two Caucasians patients having similar follow-up duration. We explored clinical and biological parameters associated with a cumulative EULAR Sjögren's Syndrome Disease Activity Index (cumESSDAI ≥5) (consisting of individual clinESSDAI domain maximum throughout follow-up).

RESULTS

We identified 74 patients of AA matched with 148 Caucasian. Median age at pSS diagnosis was younger in AA patients (43 years (IQR 33-51) vs 56 years (44.8-59.2), p<0.001). AA patients presented higher median titre of gammaglobulins (18.5 g/L (IQR 15-22.8) vs 13.4 g/L (9.9-16.9), p<0.001), more frequently positive for anti-SSA (88% vs 72%, p=0.007) and anti-RNP (11% vs 2.7%, p=0.023) antibodies. During the follow-up (median: 6 years (IQR 2-11)), AA patients presented more systemic complications: arthritis, myositis, interstitial lung disease, lymphadenopathy, central nervous system involvement. Median cumESSDAI score was higher in AA patients (7.5 (IQR 3.2-16.0) vs 4.0 (IQR 2.0-9.0), p=0.002). Interestingly, in multivariate analyses, factors associated with disease activity were sub-Saharan AA (OR 2.65 (95% CI 1.06 to 6.94)), rheumatoid factor (OR 2.50 (95% CI 1.28 to 4.96)) and anti-RNP positivity (OR 11.1 (95% CI 1.88 to 212)).

CONCLUSION

Patients of AA display higher disease activity with a hallmark of higher B-cell activation. Studies to investigate biological drivers behind such differences are needed.

Ethnicity and Antiphospholipid Syndrome in Israel

OBJECTIVE

Antiphospholipid syndrome (APS) is an acquired coagulopathy associated with the presence of antiphospholipid antibodies. Whether ethnicity modulates APS clinical course is not known. The aim of our study was to assess the interplay of ethnicity and APS in Israel.

METHODS

We retrospectively evaluated the ethnic distribution of APS patients from 3 medical centers in Israel compared to the general population. Ethnic groups were defined according to the Israeli Bureau of Statistics as Ashkenazi (European), former Union of Soviet Socialist Republics (USSR), North African, Asian (West Asia, Greece, and Turkey), Israeli Arab individuals, and others.

RESULTS

Our cohort included 382 patients. The prevalence of Ashkenazi and Asian ethnicities was more pronounced (33% versus 12.8% and 15.4% versus 7.7%, respectively; P < 0.001), while Israeli Arabs were less represented (5.2% versus 31.1%; P < 0.001) relative to their part in the general population. Arab patients were younger at presentation (mean ± SD 28 ± 10 years versus 34 ± 13 years; P < 0.001) and were more likely to present with venous thrombosis (50% versus 35%; P = 0.037) and to suffer from venous thrombotic recurrence (45% versus 16%; P < 0.001) compared to other ethnicities. Mortality was higher among patients of Asian ethnic origin (8.8% versus 1.1%; P = 0.005); intriguingly, this group experienced cardiovascular risk factors more often (i.e., dyslipidemia and hypertension).

CONCLUSION

Ethnicity may affect the prevalence and/or natural course of APS, which is less prevalent and differs clinically in Israeli Arab patients, while mortality was linked with Asian ethnicity.

Kidney transplant outcomes in children and adolescents with systemic lupus erythematosus

BACKGROUND

Literature supports equivalent kidney transplant outcomes in adults with systemic lupus erythematosus (SLE) compared with those without SLE. However, there are conflicting and scant data on kidney transplant outcomes, as well as controversy over optimal timing of transplantation, in children and adolescents with SLE.

METHODS

Analysis included kidney-only transplant recipients aged 2-21 years from 2000 to 2017 enrolled in the Organ Procurement and Transplant Network (OPTN). The relationship between diagnosis (SLE n = 457, non-SLE glomerular disease n = 4492, and non-SLE non-glomerular disease n = 5605) and transplant outcomes was evaluated. The association between dialysis time and outcomes was analyzed in the SLE group only.

RESULTS

In adjusted models, SLE had higher mortality compared with non-SLE glomerular recipients (HR 1.24 CI 1.07-1.44) and non-glomerular recipients (HR 1.42 CI 1.20-1.70). SLE was associated with higher graft failure compared with non-SLE glomerular (HR 1.42 CI 1.20-1.69) and non-glomerular disease (HR 1.67 CI 1.22-2.28). SLE had a higher risk of acute rejection at 1 year compared with non-glomerular disease (HR 1.39 CI 1.03-1.88). There was a decreased risk of delayed graft function compared with non-SLE glomerular disease (HR 0.54, CI 0.36-0.82). There were no significant associations between dialysis time and transplant outcomes in the SLE group.

CONCLUSION

SLE in children and adolescents is associated with worse patient and graft survival compared with non-SLE diagnoses. Outcomes in children and adolescents with SLE are not associated with dialysis time. Further studies are needed to assess implications of potential earlier transplantation and shorter time on dialysis prior to transplantation.

Using a Multi-Institutional Pediatric Learning Health System to Identify Systemic Lupus Erythematosus and Lupus Nephritis: Development and Validation of Computable Phenotypes

BACKGROUND AND OBJECTIVES

Performing adequately powered clinical trials in pediatric diseases, such as SLE, is challenging. Improved recruitment strategies are needed for identifying patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Electronic health record algorithms were developed and tested to identify children with SLE both with and without lupus nephritis. We used single-center electronic health record data to develop computable phenotypes composed of diagnosis, medication, procedure, and utilization codes. These were evaluated iteratively against a manually assembled database of patients with SLE. The highest-performing phenotypes were then evaluated across institutions in PEDSnet, a national health care systems network of >6.7 million children. Reviewers blinded to case status used standardized forms to review random samples of cases (n=350) and noncases (n=350).

RESULTS

Final algorithms consisted of both utilization and diagnostic criteria. For both, utilization criteria included two or more in-person visits with nephrology or rheumatology and ≥60 days follow-up. SLE diagnostic criteria included absence of neonatal lupus, one or more hydroxychloroquine exposures, and either three or more qualifying diagnosis codes separated by ≥30 days or one or more diagnosis codes and one or more kidney biopsy procedure codes. Sensitivity was 100% (95% confidence interval [95% CI], 99 to 100), specificity was 92% (95% CI, 88 to 94), positive predictive value was 91% (95% CI, 87 to 94), and negative predictive value was 100% (95% CI, 99 to 100). Lupus nephritis diagnostic criteria included either three or more qualifying lupus nephritis diagnosis codes (or SLE codes on the same day as glomerular/kidney codes) separated by ≥30 days or one or more SLE diagnosis codes and one or more kidney biopsy procedure codes. Sensitivity was 90% (95% CI, 85 to 94), specificity was 93% (95% CI, 89 to 97), positive predictive value was 94% (95% CI, 89 to 97), and negative predictive value was 90% (95% CI, 84 to 94). Algorithms identified 1508 children with SLE at PEDSnet institutions (537 with lupus nephritis), 809 of whom were seen in the past 12 months.

CONCLUSIONS

Electronic health record-based algorithms for SLE and lupus nephritis demonstrated excellent classification accuracy across PEDSnet institutions.

Incidence of Kidney Replacement Therapy and Subsequent Outcomes Among Patients With Systemic Lupus Erythematosus: Findings From the ERA Registry

RATIONALE AND OBJECTIVE

There is a dearth of data characterizing patients requiring kidney replacement therapy (KRT) for kidney failure due to systemic lupus erythematosus (SLE) and their clinical outcomes. The aim of this study was to describe trends in incidence and prevalence of KRT among these patients as well as to compare their outcomes to patients treated with KRT for diseases other than SLE.

STUDY DESIGN

Retrospective cohort study based on kidney registry data.

SETTING & PARTICIPANTS

Patients recorded in 14 registries of patients receiving kidney replacement therapy that provided data to the European Renal Association (ERA) Registry between 1992 and 2016.

PREDICTOR

SLE as cause of kidney failure.

OUTCOMES

Incidence and prevalence of KRT, patient survival while receiving KRT, patient and graft survival after kidney transplantation, and specific causes of death.

ANALYTICAL APPROACH

Kaplan-Meier methods and Cox regression models were fit to compare patient survival between the SLE and non-SLE groups, overall KRT, dialysis and patient and graft survival after kidney transplantation.

RESULTS

In total, 1826 patients commenced KRT for kidney failure due to SLE, representing an incidence of 0.80 per million population (pmp) per year. The incidence remained stable during the study period (annual percent change=0.1 [95%CI: -0.6 ; 0.8]). Patient survival among patients with SLE receiving KRT was similar to survival within the comparator group (HR=1.11 [95%CI: 0.99-1.23]). After kidney transplantation, the risk of death was greater among patients with SLE than among patients within the comparator group (HR=1.25 [95%CI: 1.02-1.53]), while the risk of all-cause graft failure was similar (HR=1.09 [95%CI: 0.95-1.27]). Ten-year patient overall survival on KRT, and patient and graft survival after kidney transplantation improved over the study period (HR=0.71 [95%CI: 0.56-0.91], 0.43 [0.27-0.69] and 0.60 [0.43-0.84], respectively). Patients with SLE receiving KRT were significantly more likely to die from infections (24.8%) than patients in the comparator group (16.9%, p<0.001).

LIMITATIONS

No data were available on extrarenal manifestations of SLE, drug treatments, comorbidities, kidney transplant characteristics, or relapses of SLE.

CONCLUSION

The prognosis of patients with SLE receiving KRT has improved over time. Survival of patients with SLE requiring KRT was similar when compared to patients requiring KRT due to other causes of kidney failure. Survival following kidney transplantation was worse among patients with SLE.

Dialysis Outcomes for Children With Lupus Nephritis Compared to Children With Other Forms of Nephritis: A Retrospective Cohort Study

RATIONALE & OBJECTIVE

Children with lupus nephritis (LN) are at high risk of developing kidney failure requiring initiation of kidney replacement therapy. This study compared outcomes among children with LN on dialysis with children with non-lupus glomerular disease and investigated risk factors for adverse outcomes among children with LN on dialysis.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Children and adolescents aged 6-20 years with LN (n = 231) and non-lupus glomerular disease (n = 1,726) who initiated maintenance dialysis 1991-2018 and were enrolled in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) registry.

EXPOSURE

Lupus nephritis.

OUTCOME

Hospitalization, mortality, and time to transplant.

ANALYTICAL APPROACH

Contingency tables were used to compare hospitalizations, and multivariable cause-specific hazards models were used to compare rates of death and transplantation in children with LN compared with those with non-lupus glomerular disease. Using data from children with LN, multivariable logistic regression models were fit to evaluate the risk factors for hospitalization, and multivariable Cox regression models were fit to evaluate factors associated with kidney transplantation.

RESULTS

Children with LN were more likely to be hospitalized in the first year after dialysis initiation (63.3% vs 48.6%, P < 0.001) and were less likely to receive a kidney transplant in the first 3 years after dialysis initiation (year 0-1: adjusted hazard ratio [AHR], 0.36 [95% CI, 0.23-0.57], P < 0.001; year 1-3: AHR, 0.73 [95% CI, 0.54-0.98], P = 0.04). Anemia was associated with hospitalization after dialysis initiation (adjusted OR, 4.44 [95% CI, 1.44-13.66], P = 0.01). Non-White race was associated with a lower rate of kidney transplantation (AHR, 0.47 [95% CI, 0.27-0.82], P = 0.01). LN was not associated with death while on dialysis (AHR, 1.21 [95% CI, 0.47-3.11], P = 0.7).

LIMITATIONS

The NAPRTCS registry does not collect information on lupus disease activity or medication doses and has limited data on medication use.

CONCLUSIONS

Children and adolescents with LN on dialysis are at higher risk for adverse outcomes including hospitalization and lower rates of kidney transplantation compared with children with non-lupus glomerular disease receiving maintenance dialysis.

Health Disparities in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease characterized by autoantibody production and diverse clinical manifestations. The many complex, overlapping, and closely associated factors that influence SLE susceptibility and outcomes include ethnic disparities, low adherence to medications, and poverty, and geography. Epigenetic mechanisms may provide the link between these environmental exposures and behaviors and the disproportionate burden of SLE seen in ethnic minorities. Attention to these modifiable social determinants of health would not only improve outcomes for vulnerable patients with SLE but likely reduce susceptibility to SLE as well through epigenetic changes.

Racial Discrimination, Disease Activity, and Organ Damage: The Black Women's Experiences Living With Lupus (BeWELL) Study

Black women are disproportionately affected by systemic lupus erythematosus (SLE), a chronic, potentially debilitating autoimmune disease, and they also experience more rapid progression and worse outcomes compared with other groups. We examined if racial discrimination is associated with disease outcomes among 427 black women with a validated diagnosis of SLE, who live in the Atlanta, Georgia, metropolitan area, and were recruited to the Black Women's Experiences Living with Lupus Study (2015-2017). Frequency of self-reported experiences of racial discrimination in domains such as employment, housing, and medical settings was assessed using the Experiences of Discrimination measure. SLE activity in the previous 3 months, including symptoms of fatigue, fever, skin rashes, and ulcers, was measured using the Systemic Lupus Activity Questionnaire; irreversible damage to an organ or system was measured using the Brief Index of Lupus Damage. Results of multivariable linear regression analyses examining the Systemic Lupus Activity Questionnaire and log-transformed Brief Index of Lupus Damage scores indicated that increasing frequency of racial discrimination was associated with greater SLE activity (b = 2.00, 95% confidence interval: 1.32, 2.68) and organ damage (b = 0.08, 95% confidence interval: 0.02, 0.13). Comprehensive efforts to address disparities in SLE severity should include policies that address issues of racial discrimination.

All-Cause and Cause-Specific Mortality Trends of End-Stage Renal Disease Due to Lupus Nephritis From 1995 to 2014

OBJECTIVE

A prior study showed that premature mortality among patients with end-stage renal disease (ESRD) due to lupus nephritis (LN) persisted in the US between 1995 and 2006. The present study was undertaken to extend this analysis through 2014 to examine more recent trends, including key cause-specific mortality trends.

METHODS

Using the national registry of patients with ESRD, we identified all patients with incident ESRD due to LN between January 1, 1995 and December 31, 2014, divided into four 5-year cohorts of ESRD onset by calendar year (1995-1999, 2000-2004, 2005-2009, 2010-2014). We assessed mortality within each cohort. Temporal trends in all-cause mortality and cause-specific mortality were examined, adjusting for covariates.

RESULTS

We identified 20,974 individuals with incident ESRD due to LN from 1995 through 2014. The mortality rate per 100 patient-years declined from 11.1 (95% confidence interval [95% CI] 10.4-11.8) in 1995-1999 to 6.7 (95% CI 6.2-7.2) in 2010-2014 (P for trend < 0.01). Adjusted mortality hazard ratios in 2010-2014, compared with 1995-1999, were 0.68 (95% CI 0.58-0.78) for white patients, 0.67 (95% CI 0.57-0.78) for African American patients, and 0.51 (95% CI 0.38-0.69) for Hispanic patients. Deaths from cardiovascular disease (CVD) and infection declined by 44% and 63%, respectively, from 1995-1999 to 2010-2014 (P for trend < 0.01 for both).

CONCLUSION

In the more recent years of the period 1995-2014, there was a considerable reduction in all-cause mortality among white, African American, and Hispanic patients, with reduced risk of death from CVD and infection. Collectively, these trends provide an important benchmark of improving care in this high-risk population.

The Risk of Curve Progression and Surgery in African Americans With Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective clinical cohort study.

OBJECTIVE

To determine if certain risk factors (age, curve magnitude, skeletal maturity, gender, and curve pattern) traditionally associated with curve progression and surgical intervention in the general population apply equally to African Americans.

SUMMARY OF BACKGROUND DATA

Currently, information is limited on the role that a patient's race plays in the risk of curve progression of adolescent idiopathic scoliosis (AIS), and existing studies have conflicting results.

METHODS

Retrospective search of records identified patients who were African American, had been diagnosed with AIS, had a major curve Cobb angle of 10 degrees or more, and had at least two clinical visits with spinal radiographs at least 90 days apart to determine the risk factors for surgical treatment, and 2 years apart to determine the risk factors for curve progression. Patients with a medical condition likely to cause scoliosis were excluded.

RESULTS

Of 738 African American patients with AIS, 223 were assessed for surgical risk factors, and 72 were assessed for curve progression risk factors. Fifty-six (29.17%) had progression of the major coronal curve, and 38 (17.04%) underwent surgery. Age at presentation and curve magnitude at presentation were significant risk factors for surgical intervention. Curve magnitude at presentation was a significant risk factor for curve progression. No significant relationships were found for gender or curve type as they relate to surgical intervention or curve progression.

CONCLUSION

Age and curve magnitude at presentation were significantly associated with surgery, as is true in other scoliosis populations. Curve magnitude at presentation was associated with curve progression. In contrast to studies in other populations, however, no significant association was observed between curve progression and age at presentation, curve type, or gender, or between surgery and curve type or gender.

LEVEL OF EVIDENCE

Level III, prognostic cohort study.

Severe disease presentation and poor outcomes among pediatric systemic lupus erythematosus patients in South Africa

Background Systemic lupus erythematosus (SLE) is a life-threatening multisystem autoimmune disease that is more severe in patients of African ancestry and children, yet pediatric SLE on the African continent has been understudied. This study describes a cohort of pediatric SLE (PULSE) patients in South Africa. Methods Patients with a diagnosis of SLE (1997 American College of Rheumatology criteria) diagnosed prior to age 19 years in Cape Town, South Africa, were enrolled in this cross-sectional study from September 2013 to December 2014. Information on clinical and serological characteristics was extracted from medical records. Results were compared to a well-described North American pediatric SLE cohort. Results Seventy-two South African patients were enrolled in the study; mean age 11.5 years; 82% were girls. The racial distribution was 68% Coloured, 24% Black, 5% White and 3% Asian/Indian. Most patients presented with severe lupus nephritis documented by renal biopsy (61%). Of patients with lupus nephritis, 63% presented with International Society of Nephrology/Renal Pathology Society class III or IV. Patients in the PULSE cohort were more likely to be treated with cyclophosphamide, methotrexate and azathioprine. The PULSE cohort had high disease activity at diagnosis (mean Systemic Lupus Erythematosus Disease Activity Index-2K (SLEDAI-2K) 20.6). The SLEDAI-2K at enrolment in the PULSE cohort (5.0) did not differ from the North American pediatric SLE cohort (4.8). Sixty-three per cent of the PULSE cohort had end organ damage with Systemic Lupus International Collaborating Clinics Damage Index (SLICC-DI) score >0 (mean SLICC-DI 1.9), compared to 23% in a previously reported US cohort. Within the PULSE cohort, nine (13%) developed end-stage renal disease with six (8%) requiring transplant, strikingly higher than North American peers (transplant rate <1%). Conclusions The PULSE cohort had highly active multiorgan disease at diagnosis and significant disease damage at enrolment in the South African registry. South African patients have severe lupus nephritis and poor renal outcomes compared to North American peers. Our study revealed a severe disease phenotype in the PULSE cohort resulting in poor outcomes in this high-risk population.

B cells from African American lupus patients exhibit an activated phenotype

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease driven by both innate and adaptive immune cells. African Americans tend to present with more severe disease at an earlier age compared with patients of European ancestry. In order to better understand the immunological differences between African American and European American patients, we analyzed the frequencies of B cell subsets and the expression of B cell activation markers from a total of 68 SLE patients and 69 normal healthy volunteers. We found that B cells expressing the activation markers CD86, CD80, PD1, and CD40L, as well as CD19⁺CD27^-IgD^- double-negative B cells, were enriched in African American patients vs. patients of European ancestry. In addition to increased expression of CD40L, surface levels of CD40 on B cells were lower, suggesting the engagement of the CD40 pathway. In vitro experiments confirmed that CD40L expressed by B cells could lead to CD40 activation and internalization on adjacent B cells. To conclude, these results indicate that, compared with European American patients, African American SLE patients present with a particularly active B cell component, possibly via the activation of the CD40/CD40L pathway. These data may help guide the development of novel therapies.

Survival Disparity of African American Versus Non-African American Patients With ESRD Due to SLE

BACKGROUND

A recent study showed an increased risk of death in African Americans compared with whites with end-stage renal disease (ESRD) due to lupus nephritis (LN). We assessed the impact of age stratification, socioeconomic factors, and kidney transplantation on the disparity in patient survival among African American versus non-African American patients with LN-caused ESRD, compared with other causes.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Using the US Renal Data System database, we identified 12,352 patients with LN-caused ESRD among 1,132,202 patients who initiated maintenance dialysis therapy from January 1, 1995, through December 31, 2006, and were followed up until December 31, 2010.

PREDICTORS

Baseline demographics and comorbid conditions, Hispanic ethnicity, socioeconomic factors (employment status, Medicare/Medicaid insurance, and area-level median household income based on zip code as obtained from the 2000 US census), and kidney transplantation as a time-dependent variable.

OUTCOME

All-cause mortality.

MEASUREMENTS

Multivariable Cox and competing-risk regressions.

RESULTS

Mean duration of follow-up in the LN-caused ESRD and other-cause ESRD cohorts were 6.24±4.20 (SD) and 4.06±3.61 years, respectively. 6,106 patients with LN-caused ESRD (49.43%) and 853,762 patients with other-cause ESRD (76.24%) died during the study period (P<0.001). Patients with LN-caused ESRD were significantly younger (mean age, 39.92 years) and more likely women (81.65%) and African American (48.13%) than those with other-cause ESRD. In the fully adjusted multivariable Cox regression model, African American (vs non-African American) patients with LN-caused ESRD had significantly increased risk of death at age 18 to 30 years (adjusted HR, 1.43; 95% CI, 1.24-1.65) and at age 31 to 40 years (adjusted HR, 1.17; 95% CI, 1.02-1.34). Among patients with other-cause ESRD, African Americans were at significantly increased risk at age 18 to 30 years (adjusted HR, 1.17; 95% CI, 1.11-1.22).

LIMITATIONS

We used zip code-based median household income as a surrogate for patient income. Residual socioeconomic confounders may exist.

CONCLUSIONS

African Americans are at significantly increased risk of death compared with non-African Americans with LN-caused ESRD at age 18 to 40 years, a racial disparity risk that is 10 years longer than that in the general ESRD population. Accounting for area-level median household income and transplantation significantly attenuated the disparity in mortality of African American versus non-African American patients with LN-caused ESRD.