Linda T. Hiraki

Causal Relationship Between Obesity and Vitamin D Status: Bi-Directional Mendelian Randomization Analysis of Multiple Cohorts

A mendelian randomization study based on data from multiple cohorts conducted by Karani Santhanakrishnan Vimaleswaran and colleagues re-examines the causal nature of the relationship between vitamin D levels and obesity.

Clinical and Laboratory Characteristics and Long-Term Outcome of Pediatric Systemic Lupus Erythematosus: A Longitudinal Study

OBJECTIVES To determine the frequency and characteristics of clinical signs, symptoms, laboratory findings, and medication use in children with pediatric systemic lupus erythematosus (pSLE) at presentation and during the course of the disease, and to examine correlations among disease manifestations, disease activity, and damage over time. STUDY DESIGN The study involved an analysis of medical records and the SLE database of an inception cohort of 256 patients with pSLE (female:male ratio, 4.7:1). RESULTS The most common clinical manifestations were arthritis (67%), malar rash (66%), nephritis (55%), and central nervous system (CNS) disease (27%). At diagnosis, patients with both renal and CNS disease had the highest SLE Disease Activity Index (SLEDAI) scores (P < .0001), but these scores were similar to those of the total group at 1 year (P = .11). Patients who developed renal and CNS disease more than 1 year after diagnosis had higher SLEDAI scores at disease onset. Some 34% of patients had Systemic Lupus International Collaborative Clinics Damage Index (SLICC-DI) scores >1 at a mean follow-up of 3.5 years. A greater proportion of patients with renal and CNS disease had SLICC-DI scores of >1, and these patients had higher mean scores compared with patients without major organ involvement (70% vs 11% [P < .0001] and 1.4 vs 0.1 [P < .0001], respectively). CONCLUSIONS Most of the patients in our cohort exhibited major organ involvement. These patients had the highest SLEDAI scores at diagnosis, which normalized at 1 year but preceded development of renal and CNS disease. The average SLICC-DI score was lower than that previously reported in patients with pSLE.

Epidemiology and sociodemographics of systemic lupus erythematosus and lupus nephritis among US adults with Medicaid coverage, 2000–2004

OBJECTIVE Systemic lupus erythematosus (SLE) and lupus nephritis (LN) disproportionately affect individuals who are members of racial/ethnic minority groups and individuals of lower socioeconomic status (SES). This study was undertaken to investigate the epidemiology and sociodemographics of SLE and LN in the low-income US Medicaid population. METHODS We utilized Medicaid Analytic eXtract data, with billing claims from 47 states and Washington, DC, for 23.9 million individuals ages 18-65 years who were enrolled in Medicaid for >3 months in 2000-2004. Individuals with SLE (≥3 visits >30 days apart with an International Classification of Diseases, Ninth Revision [ICD-9] code of 710.0) and with LN (≥2 visits with an ICD-9 code for glomerulonephritis, proteinuria, or renal failure) were identified. We calculated SLE and LN prevalence and incidence, stratified by sociodemographic category, and adjusted for number of American College of Rheumatology (ACR) member rheumatologists in the state and SES using a validated composite of US Census variables. RESULTS We identified 34,339 individuals with SLE (prevalence 143.7 per 100,000) and 7,388 (21.5%) with LN (prevalence 30.9 per 100,000). SLE prevalence was 6 times higher among women, nearly double in African American compared to white women, and highest in the US South. LN prevalence was higher among all racial/ethnic minority groups compared to whites. The areas with lowest SES had the highest prevalence; areas with the fewest ACR rheumatologists had the lowest prevalence. SLE incidence was 23.2 per 100,000 person-years and LN incidence was 6.9 per 100,000 person-years, with similar sociodemographic trends. CONCLUSION In this nationwide Medicaid population, there was sociodemographic variation in SLE and LN prevalence and incidence. Understanding the increased burden of SLE and its complications in this low-income population has implications for resource allocation and access to subspecialty care.

Trends in the Incidence, Demographics, and Outcomes of End-Stage Renal Disease Due to Lupus Nephritis in the US From 1995 to 2006

OBJECTIVE This study was undertaken to investigate whether recent advances in lupus nephritis treatment have led to changes in the incidence of end-stage renal disease (ESRD) secondary to lupus nephritis, or in the characteristics, treatments, and outcomes of patients with lupus nephritis ESRD. METHODS Patients with incident lupus nephritis ESRD (1995-2006) were identified in the US Renal Data System. Trends in sociodemographic and clinical characteristics were assessed. We tested for temporal changes in standardized incidence rates (SIRs) for sociodemographic groups using Poisson regression. Changes in rates of waitlisting for kidney transplant, kidney transplantation, and all-cause mortality were examined using crude and adjusted time-to-event analyses. RESULTS We identified 12,344 incident cases of lupus nephritis ESRD. Mean age at ESRD onset was 41 years; 81.6% of the patients were women and 49.5% were African American. SIRs for lupus nephritis ESRD among those who were ages 5-39 years, African American, or lived in the southeastern US increased significantly from 1995 to 2006. Increases in body mass index and in the prevalence of both diabetes mellitus and hypertension were detected. Mean serum hemoglobin level at ESRD onset increased, while that of serum creatinine decreased over time. More patients received hemodialysis and fewer received peritoneal dialysis. There was a slight increase in the frequency of preemptive kidney transplantation at ESRD onset, but kidney transplantation rates within the first 3 years of ESRD declined. Mortality did not change over the 12 years of study. CONCLUSION Our findings indicate that the characteristics of patients with lupus nephritis ESRD and initial therapies have changed in recent years. While SIRs rose in younger patients, among African Americans, and in the South, outcomes did not improve in over a decade of evaluation.

Being overweight or obese and risk of developing rheumatoid arthritis among women: a prospective cohort study

Objectives To examine the relationship between being overweight or obese and developing rheumatoid arthritis (RA) in two large prospective cohorts, the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHSII). Methods We followed 109 896 women enrolled in NHS and 108 727 in NHSII who provided lifestyle, environmental exposure and anthropometric information through biennial questionnaires. We assessed the association between time-varying and cumulative Body Mass Index (BMI) in WHO categories of normal, overweight and obese (18.5–<25, 25.0–<30, ≥30.0 kg/m2) and incident RA meeting the 1987 American College of Rheumatology (ACR) criteria. We estimated HRs for overall RA and serologic subtypes with Cox regression models adjusted for potential confounders. We repeated analyses restricted to RA diagnosed at age 55 years or younger. Results During 2 765 195 person-years of follow-up (1976–2008) in NHS and 1 934 518 person-years (1989–2009) in NHSII, we validated 1181 incident cases of RA (826 in NHS, 355 in NHSII). There was a trend toward increased risk of all RA among overweight and obese women (HR (95% CI) 1.37 (0.95 to 1.98) and 1.37 (0.91, 2.09), p for trend=0.068). Among RA cases diagnosed at age 55 years or younger, this association appeared stronger (HR 1.45 (1.03 to 2.03) for overweight and 1.65 (1.34 to 2.05) for obese women (p trend <0.001)). Ten cumulative years of being obese, conferred a 37% increased risk of RA at younger ages (HR 1.37 (1.11 to 1.69)). Conclusions Risks of seropositive and seronegative RA were elevated among overweight and obese women, particularly among women diagnosed with RA at earlier ages.

Ethnic Differences in Pediatric Systemic Lupus Erythematosus

Objective. Prevalence and severity of systemic lupus erythematosus (SLE) in adults is suggested to be distinctly different between ethnic groups. The impact of ethnicity is not as well delineated in pediatric SLE (pSLE). We compared prevalence and extent of major organ involvement, disease activity, and damage in pSLE between different ethnic groups. Methods. Ethnic demographic profiles of an inception cohort of 265 patients with pSLE followed at Sick Kids Hospital in Toronto were determined and compared to the Metropolitan Toronto at-risk population. Patients were categorized into ethnic subsets based on self-designated ethnic origins. Disease characteristics including major organ involvement, disease activity, and damage measures were longitudinally determined and compared among ethnic groups. Results. Ethnicity data were available on 259/265 pSLE patients (99.6%); the majority were non-Caucasian (60%) compared to the Metropolitan Toronto at-risk population (40%) (p < 0.0001). Non-Caucasian patients were younger at diagnosis than Caucasian patients, Black patients being the youngest at diagnosis (12.6 vs 14.6 yrs; p = 0.007). Renal disease was significantly more common in non-Caucasian than in Caucasian pSLE patients (62% vs 45%; p = 0.01). There was a trend toward increased prevalence of central nervous system disease in Black patients compared to Asian patients (p = 0.108). There was no difference in gender ratio, SLE Disease Activity Index, or damage scores between ethnic groups. Conclusion. Non-Caucasian ethnicity is associated with increased pSLE disease prevalence. Non-Caucasian pSLE patients were significantly younger and more likely to have nephritis. However, disease activity and damage were strongly associated with major organ disease independent of the patient’s ethnicity.

Prevalence, incidence, and demographics of systemic lupus erythematosus and lupus nephritis from 2000 to 2004 among children in the US medicaid beneficiary population

OBJECTIVE To investigate the nationwide prevalence, incidence, and sociodemographics of systemic lupus erythematosus (SLE) and lupus nephritis among children in the US Medicaid beneficiary population. METHODS Children ages 3 years to <18 years with a diagnosis of SLE (defined as ≥3 claims with an International Classification of Diseases, Ninth Revision [ICD-9] code of 710.0 for SLE, each >30 days apart) were identified from the US Medicaid Analytic eXtract database from 2000 to 2004. This database contains all inpatient and outpatient Medicaid claims for 47 US states and the District of Columbia. Lupus nephritis was identified from ≥2 ICD-9 billing codes for glomerulonephritis, proteinuria, or renal failure, each recorded >30 days apart. The prevalence and incidence of SLE and lupus nephritis were calculated among Medicaid-enrolled children overall and within sociodemographic groups. RESULTS Of the 30,420,597 Medicaid-enrolled children during these years, 2,959 were identified as having SLE. The prevalence of SLE was 9.73 (95% confidence interval [95% CI] 9.38-10.08) per 100,000 Medicaid-enrolled children. Among the children with SLE, 84% were female, 40% were African American, 25% were Hispanic, 21% were White, and 42% resided in the South region of the US. Moreover, of the children with SLE, 1,106 (37%) had lupus nephritis, representing a prevalence of 3.64 (95% CI 3.43-3.86) per 100,000 children. The average annual incidence of SLE was 2.22 cases (95% CI 2.05-2.40) and that of lupus nephritis was 0.72 cases (95% CI 0.63-0.83) per 100,000 Medicaid enrollees per year. The prevalence and incidence rates of SLE and lupus nephritis increased with age, were higher in girls than in boys, and were higher in all non-White racial/ethnic groups. CONCLUSION In the current study, the prevalence and incidence rates of SLE among Medicaid-enrolled children in the US are high compared to studies in other populations. In addition, these data represent the first population-based estimates of the prevalence and incidence of lupus nephritis in the US to date.

Autoantibodies in Pediatric Systemic Lupus Erythematosus: Ethnic Grouping, Cluster Analysis, and Clinical Correlations

Objective. (1) To evaluate the spectrum of serum autoantibodies in pediatric-onset systemic lupus erythematosus (pSLE) with a focus on ethnic differences; (2) using cluster analysis, to identify patients with similar autoantibody patterns and to determine their clinical associations. Methods. A single-center cohort study of all patients with newly diagnosed pSLE seen over an 8-year period was performed. Ethnicity, clinical, and serological data were prospectively collected from 156/169 patients (92%). The frequencies of 10 selected autoantibodies among ethnic groups were compared. Cluster analysis identified groups of patients with similar autoantibody profiles. Associations of these groups with clinical and laboratory features of pSLE were examined. Results. Among our 5 ethnic groups, there were differences only in the prevalence of anti-U1RNP and anti-Sm antibodies, which occurred more frequently in non-Caucasian patients (p < 0.0001, p < 0.01, respectively). Cluster analysis revealed 3 autoantibody clusters. Cluster 1 consisted of anti-dsDNA antibodies. Cluster 2 consisted of anti-dsDNA, antichromatin, antiribosomal P, anti-U1RNP, anti-Sm, anti-Ro and anti-La autoantibody. Cluster 3 consisted of anti-dsDNA, anti-RNP, and anti-Sm autoantibody. The highest proportion of Caucasians was in cluster 1 (p < 0.05), which was characterized by a mild disease with infrequent major organ involvement compared to cluster 2, which had the highest frequency of nephritis, renal failure, serositis, and hemolytic anemia, or cluster 3, which was characterized by frequent neuropsychiatric disease and nephritis. Conclusion. We observed ethnic differences in autoantibody profiles in pSLE. Autoantibodies tended to cluster together and these clusters were associated with different clinical courses.

End-stage renal disease due to lupus nephritis among children in the US, 1995–2006†

OBJECTIVE To identify predictors of wait-listing for kidney transplantation, kidney transplantation, and mortality among children with lupus nephritis-associated end-stage renal disease (ESRD). METHODS Children ages 5-18 years with new-onset lupus nephritis-associated ESRD were identified in the US Renal Data System (1995-2006). Demographic and clinical characteristics, causes of death, and predictors of wait-listing for kidney transplantation, kidney transplantation, and mortality during the first 5 years of ESRD were investigated. Cox proportional hazards models were used. RESULTS A total of 583 children had incident lupus nephritis-associated ESRD. The mean ± SD age of the patients at the time of ESRD onset was 16.2 ± 2.4 years; 49% were African American, and 24% were Hispanic. During the 5-year period after the onset of ESRD, 292 (49%) were wait-listed, 193 (33%) received a kidney transplant, and 131 (22%) died. The main causes of death were cardiopulmonary (31%) and infectious (16%). Children living in the northeast and west were more than twice as likely as children in the south to be wait-listed and were >50% more likely than children in the south to undergo transplantation. There were fewer kidney transplants among older versus younger patients (odds ratio [OR] 0.59, P = 0.009), African American versus white patients (OR 0.48, P < 0.001), Hispanic versus non-Hispanic patients (OR 0.63, P = 0.03), and those with Medicaid versus those with private insurance (OR 0.70, P = 0.03). Mortality among African American children was almost double that among white children (OR 1.83, P < 0.001). CONCLUSION Among US children with lupus nephritis-associated ESRD, age, race, ethnicity, type of medical insurance, and geographic region were associated with significant variation in 5-year wait-listing for kidney transplantation, kidney transplantation, and mortality.

Thrombocytopenia and thromboembolism in pediatric systemic lupus erythematosus

To define in children with systemic lupus erythematosus (SLE) the incidence, outcome, and association of thrombocytopenia with other SLE manifestations, specifically thromboembolic events (TEs), we retrospectively reviewed 106 pediatric patients with SLE diagnosed between 1992 and 2001. Thrombocytopenia was found in 50%, which was of a moderate or severe degree in 34%. The thrombocytopenia was sustained in 29% of all patients. Twelve patients were diagnosed with autoimmune thrombocytopenic purpura 2 to 69 months before the diagnosis of SLE. Of them, 10 children required treatment, and three patients underwent splenectomy. TEs occurred in 10.4% of the total cohort of 106. Lupus anticoagulant, but not anticardiolipin antibodies and sustained thrombocytopenia, were associated with a higher risk for TEs.