Phenome-wide association study identifies marked increased in burden of comorbidities in African Americans with systemic lupus erythematosus

Phenotype Risk Score but Not Genetic Risk Score Aids in Identifying Individuals With Systemic Lupus Erythematosus in the Electronic Health Record

OBJECTIVE

Systemic lupus erythematosus (SLE) poses diagnostic challenges. We undertook this study to evaluate the utility of a phenotype risk score (PheRS) and a genetic risk score (GRS) to identify SLE individuals in a real-world setting.

METHODS

Using a de-identified electronic health record (EHR) database with an associated DNA biobank, we identified 789 SLE cases and 2,261 controls with available MEGAEX genotyping. A PheRS for SLE was developed using billing codes that captured American College of Rheumatology SLE criteria. We developed a GRS with 58 SLE risk single-nucleotide polymorphisms (SNPs).

RESULTS

SLE cases had a significantly higher PheRS (mean ± SD 7.7 ± 8.0 versus 0.8 ± 2.0 in controls; P < 0.001) and GRS (mean ± SD 12.2 ± 2.3 versus 11.0 ± 2.0 in controls; P < 0.001). Black individuals with SLE had a higher PheRS compared to White individuals (mean ± SD 10.0 ± 10.1 versus 7.1 ± 7.2, respectively; P = 0.002) but a lower GRS (mean ± SD 9.0 ± 1.4 versus 12.3 ± 1.7, respectively; P < 0.001). Models predicting SLE that used only the PheRS had an area under the curve (AUC) of 0.87. Adding the GRS to the PheRS resulted in a minimal difference with an AUC of 0.89. On chart review, controls with the highest PheRS and GRS had undiagnosed SLE.

CONCLUSION

We developed a SLE PheRS to identify established and undiagnosed SLE individuals. A SLE GRS using known risk SNPs did not add value beyond the PheRS and was of limited utility in Black individuals with SLE. More work is needed to understand the genetic risks of SLE in diverse populations.

APOL1 and the risk of adverse renal outcomes in patients of African ancestry with systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) disproportionately affects individuals of African ancestry (AA) compared to European ancestry (EA). In the general population, high risk (HR) variants in the apolipoprotein L1 (APOL1) gene increase the risk of renal and hypertensive disorders in individuals of AA. Since SLE is characterized by an interferon signature and APOL1 expression is driven by interferon, we examined the hypothesis that APOL1 HR genotypes predominantly drive higher rates of renal and hypertensive-related comorbidities observed in SLE patients of AA versus those of EA.

METHODS

We performed a retrospective cohort study in patients with SLE of EA and AA using a genetic biobank linked to de-identified electronic health records. APOL1 HR genotypes were defined as G1/G1, G2/G2, or G1/G2 and low risk (LR) genotypes as 1 or 0 copies of the G1 and G2 alleles. To identify renal and hypertensive-related disorders that differed in prevalence by ancestry, we used a phenome-wide association approach. We then used logistic regression to compare the prevalence of renal and hypertensive-related disorders in EA and AA patients, both including and excluding patients with the APOL1 HR genotype. In a sensitivity analysis, we examined the association of end stage renal disease secondary to lupus nephritis (LN-related ESRD) with ancestry and the APOL1 genotype.

RESULTS

We studied 784 patients with SLE; 195 (24.9%) were of AA, of whom 27 (13.8%) had APOL1 HR genotypes. Eighteen renal and hypertensive-related phenotypes were more common in AA than EA patients (p-value ≤ 1.4E-4). All phenotypes remained significantly different after exclusion of patients with APOL1 HR genotypes, and most point odds ratios (ORs) decreased only slightly. Even among ORs with the greatest decrease, risk for AA patients without the APOL1 HR genotype remained significantly elevated compared to EA patients. In the sensitivity analysis, LN-related ESRD was more prevalent in SLE patients of AA versus EA and AA patients with the APOL1 HR genotype versus LR (p-value < .05 for both).

CONCLUSION

The higher prevalence of renal and hypertensive disorders in SLE patients of AA compared to those of EA is not fully explained by the presence of APOL1 high risk variants.

Cardiovascular events and risk in patients with systemic lupus erythematosus: Systematic literature review and meta-analysis

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease that typically affects women aged 16-55 years. Cardiovascular disease (CVD) is a well-recognized complication of SLE. This systematic literature review and meta-analysis evaluated the relative risk (RR; compared with non-SLE controls), absolute risk (AR; as incidence proportion, n/N), and incidence rate (IR) of CVD events (including stroke, myocardial infarction [MI], and CVD [composite or undefined]) in adult patients with SLE. The RR of CV risk factors (including hypertension, diabetes, and metabolic syndrome [MetS]) was also examined.

METHODS

PubMed and Embase were searched on September 10, 2020. Observational studies published between January 2010 and September 2020 that reported RR, AR, and/or IR of CVD events, or RR of CV risk factors, were eligible. Pooled risk estimates were calculated using a random-effects model.

RESULTS

Forty-six studies (16 cross-sectional, 15 retrospective cohort, 14 prospective cohort, and 1 case-control) were included in meta-analyses. Most studies were considered high quality (Critical Appraisal Skills Programme checklists). Compared with adults without SLE, patients with SLE had statistically significantly higher RRs (95% CIs) of stroke (2.51 [2.03-3.10]; 12 studies), MI (2.92 [2.45-3.48]; 11 studies), CVD (2.24 [1.94-2.59]; 8 studies), and hypertension (2.70 [1.48-4.92]; 7 studies). RRs of diabetes (1.24 [0.78-1.96]; 3 studies) and MetS (1.49 [0.95-2.33]; 7 studies) were elevated but not significant. RRs of stroke and MI were generally higher in younger versus older patients with SLE. In patients with SLE, the pooled estimate of AR (95% CI) was 0.03 (0.02-0.05), 0.01 (0.00-0.02), and 0.06 (0.03-0.10) for stroke (7 studies), MI (6 studies), and CVD (8 studies), respectively. The pooled estimate of IR per 1000 person-years (95% CI) was 4.72 (3.35-6.32), 2.81 (1.61-4.32), and 11.21 (8.48-14.32) for stroke (10 studies), MI (6 studies), and CVD (8 studies), respectively. Although heterogeneity (based on I² value) was high in most analyses, sensitivity analyses confirmed the robustness of the pooled estimates.

CONCLUSIONS

This meta-analysis found an increased risk of stroke, MI, CVD, and hypertension in patients with SLE compared with the general population, despite substantial heterogeneity across the included studies.

Mendelian randomization and pathway analysis demonstrate shared genetic associations between lupus and coronary artery disease

Coronary artery disease (CAD) is a leading cause of death in patients with systemic lupus erythematosus (SLE). Despite clinical evidence supporting an association between SLE and CAD, pleiotropy-adjusted genetic association studies are limited and focus on only a few common risk loci. Here, we identify a net positive causal estimate of SLE-associated non-HLA SNPs on CAD by traditional Mendelian randomization (MR) approaches. Pathway analysis using SNP-to-gene mapping followed by unsupervised clustering based on protein-protein interactions (PPIs) identifies biological networks composed of positive and negative causal sets of genes. In addition, we confirm the casual effects of specific SNP-to-gene modules on CAD using only SNP mapping to each PPI-defined functional gene set as instrumental variables. This PPI-based MR approach elucidates various molecular pathways with causal implications between SLE and CAD and identifies biological pathways likely causative of both pathologies, revealing known and novel therapeutic interventions for managing CAD in SLE.

Deconvoluting the heterogeneity of SLE: The contribution of ancestry

Systemic lupus erythematosus (SLE) is a multiorgan autoimmune disorder with a prominent genetic component. Evidence has shown that individuals of non-European ancestry experience the disease more severely, exhibiting an increased incidence of cardiovascular disease, renal involvement, and tissue damage compared with European ancestry populations. Furthermore, there seems to be variability in the response of individuals within different ancestral groups to standard medications, including cyclophosphamide, mycophenolate, rituximab, and belimumab. Although the widespread application of candidate gene, Immunochip, and genome-wide association studies has contributed to our understanding of the link between genetic variation (typically single nucleotide polymorphisms) and SLE, despite decades of research it is still unclear why ancestry remains a key determinant of poorer outcome in non-European-ancestry patients with SLE. Here, we will discuss the impact of ancestry on SLE disease burden in patients from diverse backgrounds and highlight how research efforts using novel bioinformatic and pathway-based approaches have begun to disentangle the complex genetic architecture linking ancestry to SLE susceptibility. Finally, we will illustrate how genomic and gene expression analyses can be combined to help identify novel molecular pathways and drug candidates that might uniquely impact SLE among different ancestral populations.

Cardiovascular Health in Pediatric Rheumatologic Diseases

Cardiovascular disease risk is evident during childhood for patients with juvenile systemic lupus erythematosus, juvenile dermatomyositis, and juvenile idiopathic arthritis. The American Heart Association defines cardiovascular health as a positive health construct reflecting the sum of protective factors against cardiovascular disease. Disease-related factors such as chronic inflammation and endothelial dysfunction increase cardiovascular disease risk directly and through bidirectional relationships with poor cardiovascular health factors. Pharmacologic and nonpharmacologic interventions to improve cardiovascular health and long-term cardiovascular outcomes in children with rheumatic disease are needed.

The coexistence of familial Mediterranean fever (FMF) in systemic lupus erythematosus (SLE) patients - A cross sectional study

BACKGROUND

Systemic lupus erythematosus (SLE) is a systemic autoimmune inflammatory disease characterized by antibody production against a myriad of autoantigens. Familial Mediterranean fever (FMF) is a genetic autoinflammatory disorder, triggered by FMF-associated point genes mutations. It has been hypothesized that the two conditions rarely coexist.

AIM

The aim of this study was to examine the proportions of FMF among SLE patients compared with the general population without SLE. We hypothesized that the proportion of FMF among SLE patients might be higher than the general population.

METHODS

To conduct this cross-sectional study, data of adult patients with a physician diagnosis of SLE were retrieved from Clalit Health Services database, the largest Health Maintenance Organization in Israel, serving 4,400,000 members. Chi-square and T-test was used for univariate analysis.

RESULTS

The study population included 4,886 SLE patients and 24,430 age and sex matched controls. Within the SLE group we detected a significantly higher proportion of FMF patients compared with non-SLE controls (0.68% and 0.21% respectively; p < 0.001).

CONCLUSIONS

Our study indicated that FMF is more prevalent in an Israeli population of SLE patients.

A Phenome-Wide Analysis of Healthcare Costs Associated with Inflammatory Bowel Diseases

INTRODUCTION

Crohn's disease (CD) and ulcerative colitis (UC) are associated with considerable direct healthcare costs. There have been few comprehensive analyses of all IBD- and non-IBD comorbidities that determine direct costs in this population.

METHODS

We used data from a validated cohort of patients with inflammatory bowel disease (IBD). Total healthcare costs were estimated as a sum of costs associated with IBD-related hospitalizations and surgery, imaging (CT or MR scans), outpatient visits, endoscopic evaluation, and emergency room (ER) care. All ICD-9 codes were extracted for each patient and clustered into 1804 distinct phecode clusters representing individual phenotypes. A phenome-wide association analysis (PheWAS) was performed using logistic regression to identify predictors of being in the top decile of costs.

RESULTS

Our cohort is comprised of 10,721 patients with IBD among whom 50% had CD. The median age was 46 years. The median total cost per patient is $11,203 (IQR $2396-30,563). The strongest association with total healthcare costs was intestinal obstruction without mention of hernia (p = 5.93 × 10^-156) and other intestinal obstruction (p = 9.24 × 10^-131). In addition, strong associations were observed for symptoms consistent with severity of IBD including the presence of fluid-electrolyte imbalance (p = 1.90 × 10^-130), hypovolemia (p = 1.65 × 10^-114), abdominal pain (p = 7.29 × 10^-60), and anemia (p = 1.90-10^-83). Cardiopulmonary diseases and psychological comorbidity also demonstrated significant associations with total costs with the latter being more strongly associated with ER visit-related costs.

CONCLUSIONS

Surrogate markers suggesting possible irreversible bowel damage and active disease demonstrate the greatest influence on IBD-related healthcare costs.

Apolipoprotein L1 risk genotypes in Ghanaian patients with systemic lupus erythematosus: a prospective cohort study

Objective

Two apolipoprotein L1 (APOL1) risk variants (RV) are enriched in sub-Saharan African populations due to conferred resistance to Trypanosoma brucei. These variants associate with adverse renal outcomes by multiple causes including SLE. Despite emerging reports that SLE is common in Ghana, where APOL1 variant allelic frequencies are high, the regional contribution to SLE outcomes has not been described. Accordingly, this prospective longitudinal cohort study tested the associations between APOL1 high-risk genotypes and kidney outcomes, organ damage accrual and death in 100 Ghanaian patients with SLE.

Methods

This was a prospective cohort study of 100 SLE outpatients who sought care at Korle bu Teaching Hospital in Accra, Ghana. Adult patients who met 4 American College of Rheumatology criteria for SLE were genotyped for APOL1 and followed longitudinally for SLE activity as measured by the Safety of Estrogens in Lupus National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) hybrid and organ injury as measured by the Systemic Lupus International Collaborating Clinics Damage Index (SDI) at baseline and every 6 months for 1 year. Outcomes of interest were kidney function, SDI and case fatality.

Results

Assuming a recessive inheritance, the APOL1 high-risk genotype (2RV) associated with end-stage renal disease (ESRD) at an OR of 14 (p=0.008). These patients accrued more SDI points particularly in renal and neurological domains. The SDI was 81.3% higher in 2RV patients compared with 0RV or 1RV patients despite no difference in SLE activity (p=0.01). After a 12-month period of observation, 3/12 (25%) of the 2RV patients died compared with 2/88 (2.3%) of the 0RV or 1RV carriers (OR=13.6, p=0.01). Deaths were due to end-stage kidney disease and heart failure.

Conclusion

APOL1 RVs were heritable risk factors for morbidity and mortality in this Ghanaian SLE cohort. Despite no appreciable differences in SLE activity, APOL1 high-risk patients exhibited progressive renal disease, organ damage accrual and a 13-fold higher case fatality.

Interferon-directed therapies for the treatment of systemic lupus erythematosus: a critical update

The interferon (IFN) pathway, especially type I IFN, plays a critical role in the immunopathogenesis of systemic lupus erythematosus (SLE). We have gained significant insights into this pathway over the past two decades, including a better understanding of the key mediators of inflammation upstream and downstream of type I IFN. This has led to the identification of multiple potential targets for the treatment of SLE, for which a significant unmet need remains due to the failure of many patients to adequately respond to standard-of-care medications. Unfortunately, most new therapies in SLE have disappointed in preclinical or clinical trials to date, including a number that target type I IFN. Nevertheless, several IFN-directed therapies aimed at specific steps within this immunologic pathway have recently shown promise, and additional agents are in the treatment pipeline. In this review, we focus on the results of key therapeutic studies targeting the type I IFN pathway and discuss the future state of IFN-blockade in SLE.

The risk of infections in adult patients with systemic lupus erythematosus: systematic review and meta-analysis

Objectives

We conducted a systematic review and meta-analysis to determine the magnitude of infection risk in patients with SLE and evaluate the effect of general and SLE-related factors on infection risk.

Methods

We searched MEDLINE and Embase from inception to July 2018, screening for observational studies that evaluated infection risk in patients with SLE compared with the general population/healthy controls. Outcomes of interest included overall severe infection, herpes zoster infection/reactivation, opportunistic infections, pneumonia and tuberculosis. Random-effects models were used to calculate pooled risk ratios (RRs) for each type of infection. Sensitivity analysis assessed the impact of removing studies with high risk of bias.

Results

Eleven retrospective or prospective cohort studies were included in the meta-analysis: overall severe infection (n = 4), pneumonia (n = 6), tuberculosis (n = 3) and herpes zoster (n = 2). Pooled RRs for overall severe infection significantly increased for patients with SLE compared with the general population/healthy controls [RR 2.96 (95% CI 1.28, 6.83)]. Pooled RRs for pneumonia, herpes zoster and tuberculosis showed significantly increased risk compared with the general population/healthy controls [RR 2.58 (1.80, 3.70), 2.50 (2.36, 2.65) and 6.11 (3.61, 10.33), respectively]. Heterogeneity and evidence of publication bias were present for all analyses, except herpes zoster. Sensitivity analyses confirmed robustness of the results.

Conclusion

Patients with SLE have significantly higher risk of infection compared with the general population/healthy controls. Efforts to strengthen strategies aimed at preventing infections in SLE are needed.

Protocol registration

PROSPERO number: CRD42018109425.

Analysis of Trans-Ancestral SLE Risk Loci Identifies Unique Biologic Networks and Drug Targets in African and European Ancestries

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disorder with a prominent genetic component. Individuals of African ancestry (AA) experience the disease more severely and with an increased co-morbidity burden compared to European ancestry (EA) populations. We hypothesize that the disparities in disease prevalence, activity, and response to standard medications between AA and EA populations is partially conferred by genomic influences on biological pathways. To address this, we applied a comprehensive approach to identify all genes predicted from SNP-associated risk loci detected with the Immunochip. By combining genes predicted via eQTL analysis, as well as those predicted from base-pair changes in intergenic enhancer sites, coding-region variants, and SNP-gene proximity, we were able to identify 1,731 potential ancestry-specific and trans-ancestry genetic drivers of SLE. Gene associations were linked to upstream and downstream regulators using connectivity mapping, and predicted biological pathways were mined for candidate drug targets. Examination of trans-ancestral pathways reflect the well-defined role for interferons in SLE and revealed pathways associated with tissue repair and remodeling. EA-dominant genetic drivers were more often associated with innate immune and myeloid cell function pathways, whereas AA-dominant pathways mirror clinical findings in AA subjects, suggesting disease progression is driven by aberrant B cell activity accompanied by ER stress and metabolic dysfunction. Finally, potential ancestry-specific and non-specific drug candidates were identified. The integration of all SLE SNP-predicted genes into functional pathways revealed critical molecular pathways representative of each population, underscoring the influence of ancestry on disease mechanism and also providing key insight for therapeutic selection.

Leveraging Heterogeneity in Systemic Lupus Erythematosus for New Therapies

Systemic lupus erythematosus (SLE) is a multisystem, chronic autoimmune disease where treatment varies by patient and disease activity. Strong preclinical results and clinical correlates have motivated development of many drugs, but many of these have failed to achieve efficacy in clinical trials. FDA approval of belimumab in 2011 was the first successful SLE drug in nearly six decades. In this article, we review insights into the molecular and clinical heterogeneity of SLE from transcriptomics studies and detail their potential impact on drug development and clinical practices. We critically examine the pipeline of SLE drugs, including past failures and their associated lessons and current promising approaches. Finally, we identify opportunities for integrating these findings and drug development with new multidisciplinary advances to enhance future SLE treatment.

Systemic lupus erythematosus; stroke and myocardial infarction risk: a systematic review and meta-analysis

OBJECTIVE

To evaluate the risk of stroke and myocardial infarction (MI) in adult patients with systemic lupus erythematosus (SLE) through a systematic review and meta-analysis.

METHODS

We searched MEDLINE and EMBASE from inception to May 2020 to identify observational studies (cohort and cross-sectional) that evaluated risk of stroke and MI in adult patients with SLE compared with the general population or healthy controls. Studies were included if they reported effect-size estimates that could be used for calculating pooled-effect estimates. Random-effects models were used to calculate pooled risk ratios (RRs) and 95% CIs for stroke and MI. Heterogeneity quantified by the I² test and sensitivity analyses assessed bias.

RESULTS

In total, 26 studies were included in this meta-analysis: 14, 5 and 7 studies on stroke, MI and both stroke and MI, respectively. The pooled RR for ischaemic stroke was 2.18 (95% CI 1.78 to 2.67; I² 75%), intracerebral haemorrhage 1.84 (95% CI 1.16 to 2.90; I² 67%), subarachnoid haemorrhage 1.95 (95% CI 0.69 to 5.52; I² 94%), composite stroke 2.13 (95% CI 1.73 to 2.61; I² 88%) and MI 2.99 (95% CI 2.34 to 3.82; I² 85%). There was no evidence for publication bias, and sensitivity analyses confirmed the robustness of the results.

CONCLUSIONS

Overall, patients with SLE were identified to have a twofold to threefold higher risk of stroke and MI. Future research on the interaction between known SLE-specific modifiable risk factors and risk of stroke and MI to support development of prevention and treatment strategies are needed.

PROSPERO REGISTRATION NUMBER

CRD42018098690.

Racism-related stress and psychological distress: Black Women's Experiences Living with Lupus study

Disparate health consequences in African American women with systemic lupus erythematosus include greater severity of physical and psychological distress. Racism-related stress is also related to psychological distress correlates in this population. This study examined the relationships between racism-related experiences, psychological distress, and systemic lupus erythematosus activity in 430 African American women from the Black Women's Experiences Living with Lupus study. The structural equation model suggests that psychological distress mediates the relationship between racism-related stress and systemic lupus erythematosus disease activity. The impact of racism-related stress on systemic lupus erythematosus disease activity may occur primarily through their impact on psychological health variables. Implications for clinical care and future directions are explored.

Inpatient mortality in transition-aged youth with rheumatic disease: an analysis of the National Inpatient Sample

BACKGROUND

Transition from pediatric to adult care is a vulnerable time for youth with chronic diseases. In youth with rheumatic disease, studies show high rates of loss to follow up and increased disease activity. However, mortality data are lacking. In this study, we assessed whether transitional age is a risk factor for inpatient mortality.

METHODS

We analyzed the 2012-2014 National Inpatient Sample database, a representative sample of discharges in the United States. Individuals with rheumatic diseases were identified by International Statistical Classification of Disease - 9 (ICD-9) codes at time of discharge. Youth were categorized into three age groups: pre-transitional (11-17), transitional (18-24) and post transitional (25-31). We fitted univariable and multivariable logistic regression models to assess whether transitional age was a risk factor for inpatient mortality.

RESULTS

There were 30,269 hospital discharges which met our inclusion criteria of diagnosis and age. There were 195 inpatient deaths (0.7%). The most common causes of death were infection (39.5%), pulmonary disease (13.8%), and cardiac disease (11.2%). The Odds ratio for inpatient mortality of a transitional-aged individual was 1.18 compared to controls (p = 0.3). Black race (OR = 1.4), male sex (OR = 1.75), and a diagnosis of systemic sclerosis (OR = 4.81) or vasculitis (OR = 2.85) were the greatest risk factors of inpatient mortality.

CONCLUSION

Transitional age was not a risk factor for inpatient mortality in this study. We did identify other risk factors other than age. Further studies are required to assess if there is an increased risk of mortality in outpatients of the transitional age group.

Burden of comorbidities in South Africans with systemic lupus erythematosus

INTRODUCTION

To investigate the prevalence and spectrum of comorbidities in South Africans with systemic lupus erythematosus (SLE).

PATIENTS AND METHODS

A nested case-control study of a known alive group (AG) and deceased group (DG) of 200 and 40 patients, respectively, matched for age and sex, attending a tertiary Lupus Clinic. Comorbidities that were documented included, but not restricted to, those listed in the Charlson comorbidity index (CCI). Lupus disease severity was assessed using the lupus severity index (LSI).

RESULTS

Patients were mainly black female (94%), and the median age (IQR) and median disease duration (IQR) were 33 (25-42) and 6 (3-11) years, respectively. Overall, 191 (79.5%) patients experienced ≥ 1 comorbidities. The median (IQR) LSI and CCI scores were significantly higher in the DG than the AG (8.5 (6.7-9.1) vs 6.3 (5.2-8.3), p < 0.001 and 1 (1-3) vs 0 (0-2), p = 0.002, respectively). The commonest comorbidities were hypertension (42%), serious infections (36.6%) and tuberculosis (TB) (18.8%), the latter two being significantly more common in the DG (OR = 7.34, p < 0.0001 and OR = 3.40, p = 0.001, respectively). Of the CCI comorbidities, congestive cardiac failure (OR = 10.39, p = 0.0003), cerebrovascular disease (OR = 7.29, p = 0.01) and chronic kidney disease (OR = 3.08, p = 0.02) were more common in the DG. Both serious infections and TB were independent predictors of death.

CONCLUSION

In this study of predominantly black South African SLE patients, comorbidities were common, with serious infections and TB amongst the commonest comorbidities. Unlike in industrialised Caucasian populations, cardiovascular comorbidities were rare in spite of a high prevalence of HPT.

Effect of pericardial effusion on outcomes in children admitted with systemic lupus erythematosus: a multicenter retrospective cohort study from the United States

OBJECTIVE

We sought to describe characteristics of children admitted with pericardial effusion (PCE) and systemic lupus erythematosus (SLE) and determine the association between PCE and outcomes of interest.

METHODS

We performed a retrospective cohort study of the Pediatric Health Information System (PHIS). Patients were included if they were admitted to a PHIS participating hospital from 2004 to 2015 with a diagnosis of SLE and age ≤18 years. Children with congenital heart disease or who had undergone heart surgery were excluded. PCE was the primary predictor variable; multivariable analysis was used to evaluate the effect of PCE on the following outcomes: mortality, length of stay (LOS), and readmission within 30 days.

RESULTS

There were 5679 admissions, of which 705 (12.4%) had PCE. Median age at admission was 15 years (interquartile range: 13-17). There were no significant differences for age or sex between patients admitted either with or without PCE. A significantly higher percentage of children in the PCE group were black compared with those without PCE (43% vs. 31%, p < 0.001). In multivariable analysis, the odds of a black patient having PCE were 1.7 higher than non-black patients ( p < 0.001). In-hospital mortality was 2.5 times higher in children with PCE compared with those without PCE ( p = 0.027). Those with PCE also had 1.5 greater odds of readmission within 30 days ( p < 0.001). PCE was not associated with increased LOS (0.99, p = 0.753).

CONCLUSION

PCE is common in admissions of children with SLE. There are disproportionately more black patients with SLE affected by PCE than non-black. PCE is associated with significantly higher mortality and rates of readmission.

Phenome-wide association study identifies dsDNA as a driver of major organ involvement in systemic lupus erythematosus

In systemic lupus erythematosus (SLE), dsDNA antibodies are associated with renal disease. Less is known about comorbidities in patients without dsDNA or other autoantibodies. Using an electronic health record (EHR) SLE cohort, we employed a phenome-wide association study (PheWAS) that scans across billing codes to compare comorbidities in SLE patients with and without autoantibodies. We used our validated algorithm to identify SLE subjects. Autoantibody status was defined as ever positive for dsDNA, RNP, Smith, SSA and SSB. PheWAS was performed in antibody positive vs. negative SLE patients adjusting for age and race and using a false discovery rate of 0.05. We identified 1097 SLE subjects. In the PheWAS of dsDNA positive vs. negative subjects, dsDNA positive subjects were more likely to have nephritis ( p = 2.33 × 10^-9) and renal failure ( p = 1.85 × 10^-5). After adjusting for sex, race, age and other autoantibodies, dsDNA was independently associated with nephritis and chronic kidney disease. Those patients negative for dsDNA, RNP, SSA and SSB negative subjects were all more likely to have billing codes for sleep, pain and mood disorders. PheWAS uncovered a hierarchy within SLE-specific autoantibodies with dsDNA having the greatest impact on major organ involvement.