Association Between Frailty Status and Readmissions in Hospitalized Patients With Systemic Lupus Erythematosus

OBJECTIVE

The objective of this study was to evaluate the association between frailty status and risk of readmissions, inpatient death, and cost of admission among patients with systemic lupus erythematosus (SLE).

METHODS

We conducted a retrospective cohort study using the National Readmissions Database. Using International Statistical Classification of Diseases, Tenth Revision codes, we identified individuals >18 years of age who had a primary or secondary diagnosis of SLE and were hospitalized between January and June 2018. Using the validated claims-based Hospital Frailty Risk Score, we categorized individuals as frail (score ≥ 5) or nonfrail (score < 5) at the time of index hospitalization. Our primary outcome was readmission rates post discharge from index hospitalization. Secondary outcomes were rates of inpatient mortality and the total cost of hospitalizations. Cox proportional hazard models were used to estimate the association between frailty and risk of readmissions, with adjustment for age, sex, insurance type, household income, and Elixhauser Comorbidity Index score.

RESULTS

A total of 39,738 patients with SLE met eligibility criteria. Over a median follow-up of eight months, frail patients with SLE (n = 18,385) had higher Elixhauser Comorbidity Index scores and longer length of stay compared to nonfrail patients with SLE (n = 21,353). Frail patients with SLE had higher readmission rates, a higher proportion of prolonged hospitalizations, and higher costs per hospitalization. Frailty was independently associated with a 10% higher risk of readmission after adjustment for covariates.

CONCLUSION

Among hospitalized adults with SLE, presence of frailty was associated with higher readmission and inpatient mortality rates. Our results highlight that frailty status can help risk stratify patients with SLE at increased risk for readmissions and other adverse health outcomes.

Receipt of rheumatology care and lupus-specific labs among young adults with systemic lupus erythematosus: A US Medicare retention in care cohort study

OBJECTIVE

In systemic lupus erythematosus, poor disease outcomes occur in young adults, patients identifying as Black or Hispanic, and socioeconomically disadvantaged patients. These identities and social factors differentially shape care access and quality that contribute to lupus health disparities in the US. Thus, our objective was to measure markers of care access and quality, including rheumatology visits (longitudinal care retention) and lupus-specific serology testing, by race and ethnicity, neighborhood disadvantage, and geographic context.

METHODS

This cohort study used a geo-linked 20% national sample of young adult Medicare beneficiaries (ages 18-35) with lupus-coded encounters and a 1-year assessment period. Retention in lupus care required a rheumatology visit in each 6-month period, and serology testing required ≥1 complement or dsDNA antibody test within the year. Multivariable logistic regression models were fit for visit-based retention and serology testing to determine associations with race and ethnicity, neighborhood disadvantage, and geography.

RESULTS

Among 1,036 young adults with lupus, 39% saw a rheumatologist every 6 months and 28% had serology testing. White beneficiaries from the least disadvantaged quintile of neighborhoods had higher visit-based retention than other beneficiaries (64% vs 30%-60%). Serology testing decreased with increasing neighborhood disadvantage quintile (aOR 0.80; 95% CI 0.71, 0.90) and in the Midwest (aOR 0.46; 0.30, 0.71).

CONCLUSION

Disparities in care, measured by rheumatology visits and serology testing, exist by neighborhood disadvantage, race and ethnicity, and region among young adults with lupus, despite uniform Medicare coverage. Findings support evaluating lupus care quality measures and their impact on US lupus outcomes.

Trends in avascular necrosis and related arthroplasties in hospitalized patients with systemic lupus erythematosus and rheumatoid arthritis

OBJECTIVE

Avascular necrosis (AVN) is a devastating complication often necessitating arthroplasty, particularly common in systemic lupus erythematosus (SLE). Limited research exists on arthroplasty trends since new steroid-sparing agents. We analyzed trends and characteristics associated with AVN and AVN-related arthroplasties among SLE and RA hospitalizations using two decades of data from the U.S. National Inpatient Sample (NIS).

METHODS

This cross-sectional study used NIS (2000-2019) to identify hospitalized adults with SLE and RA, with or without AVN, using ICD codes. AVN was further grouped by arthroplasty status. Primary outcomes were AVN and AVN-related arthroplasty rates and time trends in SLE and RA. Baseline sociodemographics and comorbidities were compared. Analyses used STATA and Joinpoint regression to calculate annual percent change (APC).

RESULTS

Overall, 42,728 (1.3 %) SLE and 43,600 (0.5 %) RA hospitalizations had concomitant AVN (SLE-AVN and RA-AVN). Of these, 16,724 (39 %) and 25,210 (58 %) underwent arthroplasties, respectively. RA-AVN increased (APC: 0.98*), with a decrease in arthroplasties (APC: -0.82*). In contrast, SLE-AVN initially increased with a breakpoint in 2011 (APC 2000-2011: 1.94* APC 2011-2019 -2.03), with declining arthroplasties (APC -2.03*). AVN hospitalizations consisted of individuals who were younger and of Black race; while arthroplasties were less likely in individuals of Black race or Medicaid coverage.

CONCLUSION

We report a breakpoint in rising SLE-AVN after 2011, which may relate to newer steroid-sparing therapies (i.e., belimumab). AVN-associated arthroplasties decreased in SLE and RA. Fewer AVN-associated arthroplasties were noted for Black patients and those with Medicaid, indicating potential disparities. Further research should examine treatment differences impacting AVN and arthroplasty rates.

Direct medical charges in a population-based systemic lupus erythematosus cohort

AIM

This study aimed to obtain estimates for the direct medical charges associated with hospitalizations and emergency department visits of validated SLE cases in a diverse Systemic Lupus Erythematosus (SLE) population.

METHODS

The Georgians Organized Against Lupus (GOAL) cohort is a population-based cohort of adult SLE patients from metropolitan Atlanta, GA USA, an area having a diverse SLE population. The GOAL cohort aims to study the impact of social determinants of health (SDoH) on outcomes relevant to patients, healthcare providers, and policymakers. For this study, survey data collected during 2011-2012 was linked to the Georgia Hospital Discharge Database (HDD) to capture hospital admissions (HAs) and emergency department visits (EDVs) throughout Georgia from 2012 through 2013. Direct medical charges were summarized by HCU type among all patients, among those with actual visits, and by socio-demographics and healthcare factors.

RESULTS

Among 829 patients (94% women, 78% Black, 64% non-private insurance, 64% not-employed, mean age of 46), 170 (20.5%) and 300 (36.2%) participants had at least one HA and one EDV in 1-year of follow-up, respectively, with 111(13.4%) having both HA and EDV. On average, each patient experienced 0.38 HAs and 0.91 EDVs, with per-patient direct medical charges of $14,968 for HAs & $3,022 for EDVs, and $39,645 per HA & $3,305 per EDV. Patients with higher social vulnerability or more severe disease had higher charges for both HA and EDV (p < 0.01), likely due to the delayed care and neglected health needs leading to more advanced and costly medical treatments. Living below the federal poverty level was associated with higher charges for EDVs (p < 0.001) but with lower charges for HAs (p = 0.036).

CONCLUSIONS

This study underscores the economic burden of SLE on vulnerable populations, emphasizing the importance of including socio-economic factors in healthcare planning. Policy efforts should prioritize reducing disparities in access to care and implementing preventive strategies.

Epidemiology and outcomes of emergency department visits in systemic lupus erythematosus: Insights from the nationwide emergency department sample (NEDS)

BACKGROUND

Systemic lupus erythematosus (SLE) patients are prone to frequent emergency department (ED) visits. This study explores the epidemiology and outcomes of ED visits by patients with SLE utilizing the Nationwide Emergency Department Sample (NEDS).

METHODS

Using NEDS (2019), SLE ED visits identified using ICD-10 codes (M32. xx) were compared with non-SLE ED visits in terms of demographic and clinical features and primary diagnoses associated with the ED visits. Factors associated with inpatient admission were analyzed using logistic regression. Variations in ED visits by age and race were assessed.

RESULTS

We identified 414,139 (0.35%) ED visits for adults ≥ 18 years with SLE. ED visits with SLE comprised more women, Black patients, ages 31-50 years, Medicare as the primary payer, and had higher comorbidity burden. A greater proportion of Black and Hispanic SLE patients who visited the ED were in the youngest age category of 18-30 years (around 20%) compared to White patients (less than 10%). Non-White patients had higher Medicaid utilization (27%-32% vs 19% in White patients). Comorbidity patterns varied based on race, with more White patients having higher rates of hyperlipidemia and ischemic heart disease (IHD) and more Black patients having chronic kidney disease (CKD), hypertension, and heart failure. Categorizing by race, SLE/connective tissue disease (CTD) and infection were the most prevalent primary ED diagnosis in non-White and White patients, respectively. Age ≥ 65 years, male sex, and comorbidities were linked to a higher risk of admission. Black race (OR 0.86, p = .01) and lowest income quartile (OR 0.78, p = .003) had lower odds of inpatient admission.

CONCLUSION

Infection and SLE/CTD were among the top diagnoses associated with ED visits and inpatient admission. Despite comprising a significant proportion of SLE ED visits, Black patients had lower odds of admission. While the higher prevalence of older age groups, hyperlipidemia, and IHD among White patients may partly explain the disparate results, and further study is needed to understand the role of other factors including reliance on the ED for routine care compared among Black patients, differences in insurance coverage, and potential socioeconomic biases among healthcare providers.

Development of American College of Rheumatology Quality Measures for Systemic Lupus Erythematosus: A Modified Delphi Process With Rheumatology Informatics System for Effectiveness (RISE) Registry Data Review

OBJECTIVE

We aimed to develop readily measurable digital quality measure statements for clinical care in systemic lupus erythematosus (SLE) using a multistep process guided by consensus methods.

METHODS

Using a modified Delphi process, an American College of Rheumatology (ACR) workgroup of SLE experts reviewed all North American and European guidelines from 2000 to 2020 on treatment, monitoring, and phenotyping of patients with lupus. Workgroup members extracted quality constructs from guidelines, rated these by importance and feasibility, and generated evidence-based quality measure statements. The ACR Rheumatology Informatics System for Effectiveness (RISE) Registry was queried for measurement data availability. In 3 consecutive Delphi sessions, a multidisciplinary Delphi panel voted on the importance and feasibility of each statement. Proposed measures with consensus on feasibility and importance were ranked to identify the top 3 measures.

RESULTS

Review of guidelines and distillation of 57 quality constructs resulted in 15 quality measure statements. Among these, 5 met high consensus for importance and feasibility, including 2 on treatment and 3 on laboratory monitoring measures. The 3 highest-ranked statements were recommended for further measure specification as SLE digital quality measures: 1) hydroxychloroquine use, 2) limiting glucocorticoid use >7.5 mg/day to <6 months, and 3) end-organ monitoring of kidney function and urine protein excretion at least every 6 months.

CONCLUSION

The Delphi process selected 3 quality measures for SLE care on hydroxychloroquine, glucocorticoid reduction, and kidney monitoring. Next, measures will undergo specification and validity testing in RISE and US rheumatology practices as the foundation for national implementation and use in quality improvement programs.

Comparative Risks of Infection With Belimumab Versus Oral Immunosuppressants in Patients With Nonrenal Systemic Lupus Erythematosus

OBJECTIVE

We investigated the comparative risk of infection with belimumab versus oral immunosuppressants for the treatment of systemic lupus erythematosus (SLE).

METHODS

Using observational data from a US multicenter electronic health record database, we identified patients with SLE but without lupus nephritis who initiated belimumab, azathioprine, methotrexate, or mycophenolate between 2011 and 2021. We designed and emulated hypothetical target trials to estimate the cumulative incidence and hazard ratios (HRs) of serious infection and hospitalization for serious infection comparing belimumab versus each oral immunosuppressant. We used propensity score overlap weighting to balance baseline covariates and adjusted for adherence to treatment group using inverse probability of treatment weighting. We also assessed the control outcome of traumatic injury.

RESULTS

Among 21,481 patients, we compared 2841 and 6343 initiators of belimumab and azathioprine, 2642 and 8242 initiators of belimumab and methotrexate, and 2813 and 8407 initiators of belimumab and mycophenolate, respectively. After propensity score overlap weighting, all covariates were balanced in each comparison. The mean age of the cohort was 45 years, and 94% were women. Compared with azathioprine and mycophenolate, belimumab was associated with lower risks of both serious infection (HR 0.82; 95% confidence interval [CI] 0.72-0.92 and HR 0.69; 95% CI 0.61-0.78) and hospitalization for infection (HR 0.73; 95% CI 0.57-0.94 and HR 0.56 95% CI 0.43-0.71). The risk of infection was also lower for belimumab compared with methotrexate (HR 0.86; 95% CI 0.76-0.97). There were no differences in traumatic injury risks across treatment groups.

CONCLUSION

Belimumab was associated with lower risks of serious infection than with oral immunosuppressants. This finding should inform risk/benefit considerations for SLE treatment.

Associations of Postdischarge Follow-Up With Acute Care and Mortality in Lupus: A Medicare Cohort Study

OBJECTIVE

Patients with systemic lupus erythematosus experience the sixth highest rate of 30-day readmissions among chronic diseases. Timely postdischarge follow-up is a marker of ambulatory care quality that can reduce readmissions in other chronic conditions. Our objective was to test the hypotheses that 1) beneficiaries from populations experiencing health disparities, including patients from disadvantaged neighborhoods, will have lower odds of completed follow-up, and that 2) follow-up will predict longer time without acute care use (readmission, observation stay, or emergency department visit) or mortality.

METHODS

This observational cohort study included hospitalizations in January-November 2014 from a 20% random sample of Medicare adults. Included hospitalizations had a lupus code, discharge to home without hospice, and continuous Medicare A/B coverage for 1 year before and 1 month after hospitalization. Timely follow-up included visits with primary care or rheumatology within 30 days. Thirty-day survival outcomes were acute care use and mortality adjusted for sociodemographic information and comorbidities.

RESULTS

Over one-third (35%) of lupus hospitalizations lacked 30-day follow-up. Younger age, living in disadvantaged neighborhoods, and rurality were associated with lower odds of follow-up. Follow-up was not associated with subsequent acute care or mortality in beneficiaries age <65 years. In contrast, follow-up was associated with a 27% higher hazard for acute care use (adjusted hazard ratio [HR] 1.27 [95% confidence interval (95% CI) 1.09-1.47]) and 65% lower mortality (adjusted HR 0.35 [95% CI 0.19-0.67]) among beneficiaries age ≥65 years.

CONCLUSION

One-third of lupus hospitalizations lacked follow-up, with significant disparities in rural and disadvantaged neighborhoods. Follow-up was associated with increased acute care, but 65% lower mortality in older systemic lupus erythematosus patients. Further development of lupus-specific postdischarge strategies is needed.

Birth Outcomes and Rehospitalizations Among Pregnant Women With Rheumatoid Arthritis and Systemic Lupus Erythematosus and Their Offspring

OBJECTIVE

To compare obstetric/birth outcomes and rehospitalization among women with and without rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) and their infants.

METHODS

This population-based retrospective cohort study identified women with RA (n = 1,223) and SLE (n = 1,354) and unexposed women with singleton births 1987-2014 in Washington State in linked vital hospital discharge records. Outcomes, including cause-specific hospitalizations <2 years postpartum, were compared by estimating adjusted relative risks (RRs) and cause-specific rehospitalization hazard ratios (HRs) with 95% confidence intervals (95% CIs).

RESULTS

We observed increased risks of several adverse outcomes; RRs were often greatest for SLE. Women with RA/SLE more often required rehospitalization, most notably at <6 months postpartum (RA: 4% versus 2%; RR 2.22 [95% CI 1.62-3.04]; SLE: 6% versus 2%; RR 2.78 [95% CI 2.15-3.59]). Maternal postpartum rehospitalization was greatest for musculoskeletal conditions (RA: HR 19.1 [95% CI 13.6-26.8]; SLE: HR 29.8 [95% CI 22.1-40.1]). Infants of women with SLE more often had malformations (9% versus 6%; RR 1.46 [95% CI 1.21-1.75]), and increased mortality at <2 years (RR 2.11 [95% CI 1.21-3.67]). Infants of women with SLE also experienced more frequent rehospitalizations in their first year of life.

CONCLUSION

Women with RA or SLE and their infants experienced adverse outcomes, particularly infants of women with SLE. Maternal/infant rehospitalization was more common; most marked in the early months postpartum. Close follow-up during these time periods is crucial to minimize adverse outcomes.

Leveraging machine learning to identify acute myeloid leukemia patients and their chemotherapy regimens in an administrative database

BACKGROUND

Administrative datasets are useful for identifying rare disease cohorts such as pediatric acute myeloid leukemia (AML). Previously, cohorts were assembled using labor-intensive, manual reviews of patients' longitudinal chemotherapy data.

METHODS

We utilized a two-step machine learning (ML) method to (i) identify pediatric patients with newly diagnosed AML, and (ii) among the identified AML patients, their chemotherapy courses, in an administrative/billing database. Using 2558 patients previously manually reviewed, multiple ML algorithms were derived from 75% of the study sample, and the selected model was tested in the remaining hold-out sample. The selected model was also applied to assemble a new pediatric AML cohort and further assessed in an external validation, using a standalone cohort established by manual chart abstraction.

RESULTS

For patient identification, the selected Support Vector Machine model yielded a sensitivity of 0.97 and a positive predictive value (PPV) of 0.97 in the hold-out test sample. For course-specific chemotherapy regimen and start date identification, the selected Random Forest model yielded overall PPV greater than or equal to 0.88 and sensitivity greater than or equal to 0.86 across all courses in the test sample. When applied to new cohort assembly, ML identified 3016 AML patients with 10,588 treatment courses. In the external validation subset, PPV was greater than or equal to 0.75 and sensitivity was greater than or equal to 0.82 for patient identification, and PPV was greater than or equal to 0.93 and sensitivity was greater than or equal to 0.94 for regimen identifications.

CONCLUSION

A carefully designed ML model can accurately identify pediatric AML patients and their chemotherapy courses from administrative databases. This approach may be generalizable to other diseases and databases.

Predictors of Thirty-Day Hospital Readmissions in Systemic Lupus Erythematosus in the United States: A Nationwide Study

OBJECTIVE

To evaluate independent risk factors for readmission and to determine the major reasons for readmission in a nationally representative sample of patients with systemic lupus erythematosus (SLE).

METHODS

We used the Nationwide Readmissions Database to identify adults with SLE who were discharged from hospital to home during January-November of 2016 and 2017. Thirty-day all-cause readmissions were identified. A multivariable adjusted survey-specific logistic regression model was used to identify factors associated with readmission.

RESULTS

A total of 132,400 hospitalized adults with SLE were discharged home during the study period; 88.3% were female, with a median age of 51.0 years (interquartile range 38.7-61.9 years). Of these, 18,973 individuals (14.3%) were readmitted within 30 days of discharge from their index hospitalization. In multivariable analyses, the factors associated with the highest odds for readmission were autoimmune hemolytic anemia (odds ratio [OR] 1.86 [95% confidence interval (95% CI) 1.51-2.29]), glomerular disease (OR 1.27 [95% CI 1.19-1.36]), pericarditis (OR 1.35 [95% CI 1.14-1.60]), heart failure (OR 1.34 [95% CI 1.24-1.44]), age 18-30 years (OR 1.28 [95% CI 1.17-1.41] versus age ≥​65 years), and Medicare (OR 1.20 [95% CI 1.13-1.28]) and Medicaid insurance (OR 1.26 [95% CI 1.18-1.34]). Sepsis (7.6%), SLE (7.4%), heart failure (3.5%), and pneumonia (3.2%) were among the most common causes for readmission.

CONCLUSION

In this nationally representative study of SLE readmissions, the strongest risk factors for 30-day readmission were younger age, SLE-related manifestations, and public insurance. These results identify patient groups with SLE that would benefit from postdischarge interventions designed to reduce hospitalizations and improve health outcomes.

Infection-related hospitalisation in young adults with systemic lupus erythematosus: data from the National Inpatient Sample

INTRODUCTION

Care of young adults with SLE (YA-SLE, 18-24 years) is challenging due to major life transitions co-occurring with chronic healthcare needs. Studies have demonstrated poorer outcomes in the post-transition period. Epidemiological studies focused on serious infection-related hospitalisation (SIH) in YA-SLE are lacking.

METHODS

We used National Inpatient Sample from 2010 to 2019 to study the epidemiology and outcomes of SIH for five common infections in SLE, namely sepsis, pneumonia, urinary tract infections, skin and soft tissue infections, and opportunistic infections. For time trends, we extended the dataset to cover 2000-2019. The primary outcome was the rate of SIH in YA-SLE compared with adults (25-44 years) with SLE and with young adults without SLE (YA-no SLE).

RESULTS

From 2010 to 2019, we identified 1 720 883 hospital admissions with SLE in patients aged ≥18 years. Rates of SIH were similar in young adults and adults with SLE (15.0% vs 14.5%, p=0.12), but considerably higher than in the YA-no SLE group (4.2%, p<0.001). Among SLE with SIH, sepsis followed by pneumonia was the most common diagnosis. Significantly higher proportions of SIH among young adults than adults with SLE were comprised of non-white patients, belonged to the lowest income quartile and had Medicaid. However, only race/ethnicity was associated with SIH among YA-SLE. There was a higher prevalence of comorbid lupus nephritis and pleuritis among young adults compared with adults with SLE and SIH, and both comorbidities were associated with SIH in YA-SLE. Increasing rates of SIH, driven by sepsis, were seen over time.

DISCUSSION

YA- SLE had similar rates of SIH to adults with SLE. While hospitalised YA-SLE differed sociodemographically from SLE adults and YA-no SLE, only race/ethnicity was associated with SIH in the YA-SLE group. Lupus nephritis and pleuritis were associated with higher SIH in YA-SLE. Among SLE with SIH, increasing trends of sepsis deserve further study.

Using a data-driven approach for the development and evaluation of phenotype algorithms for systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown origin. The objective of this research was to develop phenotype algorithms for SLE suitable for use in epidemiological studies using empirical evidence from observational databases.

METHODS

We used a process for empirically determining and evaluating phenotype algorithms for health conditions to be analyzed in observational research. The process started with a literature search to discover prior algorithms used for SLE. We then used a set of Observational Health Data Sciences and Informatics (OHDSI) open-source tools to refine and validate the algorithms. These included tools to discover codes for SLE that may have been missed in prior studies and to determine possible low specificity and index date misclassification in algorithms for correction.

RESULTS

We developed four algorithms using our process: two algorithms for prevalent SLE and two for incident SLE. The algorithms for both incident and prevalent cases are comprised of a more specific version and a more sensitive version. Each of the algorithms corrects for possible index date misclassification. After validation, we found the highest positive predictive value estimate for the prevalent, specific algorithm (89%). The highest sensitivity estimate was found for the sensitive, prevalent algorithm (77%).

CONCLUSION

We developed phenotype algorithms for SLE using a data-driven approach. The four final algorithms may be used directly in observational studies. The validation of these algorithms provides researchers an added measure of confidence that the algorithms are selecting subjects correctly and allows for the application of quantitative bias analysis.

The Effect of Psychiatric Comorbidity on Healthcare Utilization for Youth With Newly Diagnosed Systemic Lupus Erythematosus

OBJECTIVE

To examine the effect of psychiatric diagnoses on healthcare use in youth with systemic lupus erythematosus (SLE) during their first year of SLE care.

METHODS

We conducted a retrospective cohort study using claims from 2000 to 2013 from Clinformatics Data Mart (OptumInsight). Youth aged 10 years to 24 years with an incident diagnosis of SLE (≥ 3 International Classification of Diseases, 9th revision, codes for SLE 710.0, > 30 days apart) were categorized as having: (1) a preceding psychiatric diagnosis in the year before SLE diagnosis, (2) an incident psychiatric diagnosis in the year after SLE diagnosis, or (3) no psychiatric diagnosis. We compared ambulatory, emergency, and inpatient visits in the year after SLE diagnosis, stratified by nonpsychiatric and psychiatric visits. We examined the effect of childhood-onset vs adult-onset SLE by testing for an interaction between age and psychiatric exposure on outcome.

RESULTS

We identified 650 youth with an incident diagnosis of SLE, of which 122 (19%) had a preceding psychiatric diagnosis and 105 (16%) had an incident psychiatric diagnosis. Compared with those without a psychiatric diagnosis, youth with SLE and a preceding or incident psychiatric diagnosis had more healthcare use across both ambulatory and emergency settings for both nonpsychiatric and psychiatric-related care. These associations were minimally affected by age at time of SLE diagnosis.

CONCLUSION

Psychiatric comorbidity is common among youth with newly diagnosed SLE and is associated with greater healthcare use. Interventions to address preceding and incident psychiatric comorbidity may decrease healthcare burden for youth with SLE.

Hydroxychloroquine and immunosuppressant adherence patterns and their association with subsequent hospitalization rates among children with systemic lupus erythematosus

OBJECTIVES

Using a representative sample of children with systemic lupus erythematosus (SLE) in the United States, we characterized prescription claim-based hydroxychloroquine and immunosuppressant adherence estimates and evaluated their concurrent and predictive validity.

METHODS

We identified children ages 5-18 with SLE in the Truven Health MarketScan® Commercial and Medicaid claims databases (2013-2018). Among new users of hydroxychloroquine and immunosuppressant medications, we calculated proportion of days covered (PDC) over 365 days to estimate adherence by user group (mycophenolate, azathioprine, methotrexate, and any immunosuppressant use). Agreement between adherence estimates was evaluated with intraclass correlation coefficients (ICC) and kappa statistics. Separate negative binomial regression models were used to estimate associations between (a) hydroxychloroquine, (b) immunosuppressant, or (c) concurrent immunosuppressant/hydroxychloroquine non-adherence and subsequent hospitalizations, adjusted for baseline demographics, disease severity, and healthcare utilization.

RESULTS

Among 423 new hydroxychloroquine/immunosuppressant users, 63% were Medicaid recipients. Sufficient adherence (PDC≥80%) ranged from 33 to 45% for immunosuppressants vs. 51-52% for hydroxychloroquine. Agreement between hydroxychloroquine and immunosuppressant adherence was modest overall, but better for mycophenolate (ICC 0.55) than methotrexate (0.27). Hydroxychloroquine non-adherence was associated with a 2.9-fold higher incidence of subsequent hospitalizations (95% CI [1.2-7.1]), whereas immunosuppressant and concurrent non-adherence were associated with 5.9 [2.4-14.6] and 5.6-fold [2.0-15.5] increased incidence, respectively. Use of concurrent adherence improved upon estimation of hospitalization risk compared to hydroxychloroquine adherence, but not immunosuppressant adherence alone.

CONCLUSIONS

Hydroxychloroquine adherence is an imperfect proxy for adherence to other lupus medications among children with SLE, and therefore assessing immunosuppressant adherence concurrently adds value to hydroxychloroquine adherence assessments. Prescription claims-based immunosuppressant adherence measures are predictive of acute care utilization and may inform population management strategies.

PheValuator 2.0: Methodological improvements for the PheValuator approach to semi-automated phenotype algorithm evaluation

PURPOSE

Phenotype algorithms are central to performing analyses using observational data. These algorithms translate the clinical idea of a health condition into an executable set of rules allowing for queries of data elements from a database. PheValuator, a software package in the Observational Health Data Sciences and Informatics (OHDSI) tool stack, provides a method to assess the performance characteristics of these algorithms, namely, sensitivity, specificity, and positive and negative predictive value. It uses machine learning to develop predictive models for determining a probabilistic gold standard of subjects for assessment of cases and non-cases of health conditions. PheValuator was developed to complement or even replace the traditional approach of algorithm validation, i.e., by expert assessment of subject records through chart review. Results in our first PheValuator paper suggest a systematic underestimation of the PPV compared to previous results using chart review. In this paper we evaluate modifications made to the method designed to improve its performance.

METHODS

The major changes to PheValuator included allowing all diagnostic conditions, clinical observations, drug prescriptions, and laboratory measurements to be included as predictors within the modeling process whereas in the prior version there were significant restrictions on the included predictors. We also have allowed for the inclusion of the temporal relationships of the predictors in the model. To evaluate the performance of the new method, we compared the results from the new and original methods against results found from the literature using traditional validation of algorithms for 19 phenotypes. We performed these tests using data from five commercial databases.

RESULTS

In the assessment aggregating all phenotype algorithms, the median difference between the PheValuator estimate and the gold standard estimate for PPV was reduced from -21 (IQR -34, -3) in Version 1.0 to 4 (IQR -3, 15) using Version 2.0. We found a median difference in specificity of 3 (IQR 1, 4.25) for Version 1.0 and 3 (IQR 1, 4) for Version 2.0. The median difference between the two versions of PheValuator and the gold standard for estimates of sensitivity was reduced from -39 (-51, -20) to -16 (-34, -6).

CONCLUSION

PheValuator 2.0 produces estimates for the performance characteristics for phenotype algorithms that are significantly closer to estimates from traditional validation through chart review compared to version 1.0. With this tool in researcher's toolkits, methods, such as quantitative bias analysis, may now be used to improve the reliability and reproducibility of research studies using observational data.

Use of renin angiotensin aldosterone system inhibitors in children with lupus and time to glucocorticoid discontinuation

There is little data to inform use of renin angiotensin aldosterone system (RAAS) inhibitors in pediatric patients with systemic lupus erythematosus (SLE). Here, we sought to characterize RAAS inhibitor use in pediatric SLE, and determine whether early RAAS inhibitor initiation among children with incident lupus nephritis is associated with decreased duration of chronic glucocorticoid exposure. A retrospective cohort study was performed of children (ages 5-18) with SLE and/or lupus nephritis in the Truven MarketScan^ΤΜ Medicaid and Commercial databases (2013-2018) and estimated RAAS inhibitor use. Among incident nephritis cases, we used competing risk hazard models with inverse probability of treatment weighting to estimate the association between RAAS inhibitor initiation less than 180 days after diagnosis and time to glucocorticoid discontinuation with kidney failure as a competing event. Among 592 children with nephritis and 1407 children with non-kidney SLE, 67% and 15% ever received RAAS inhibitors, respectively. Median duration of RAAS inhibitor use among 323 incident users was 14 and 9 months in children with and without nephritis, respectively. Medicaid enrollment was independently associated with greater likelihood of RAAS inhibitor use, irrespective of nephritis. Among 158 incident nephritis cases, early RAAS inhibitor initiation was significantly associated with a faster rate of glucocorticoid discontinuation (adjusted sub-distribution hazard ratio 1.81, 95% confidence interval [1.09 - 3.00]). Thus, early initiation of RAAS inhibitors may have a role in children newly diagnosed with lupus nephritis; not only those with refractory proteinuria after induction therapy. Hence, integrated health systems data could be leveraged to confirm these findings and optimize adjunctive therapies in pediatric lupus.

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.

One Quarter of Medicare Hospitalizations in Patients with Systemic Lupus Erythematosus Readmitted within Thirty Days

OBJECTIVE

Thirty-day hospital readmissions in systemic lupus erythematosus (SLE) approach proportions in Medicare-reported conditions including heart failure (HF). We compared adjusted 30-day readmission and mortality among SLE, HF, and general Medicare to assess predictors informing readmission prevention.

METHODS

This database study used a 20% sample of all US Medicare 2014 adult hospitalizations to compare risk of 30-day readmission and mortality among admissions with SLE, HF, and neither per discharge diagnoses (if both SLE and HF, classified as SLE). Inclusion required live discharge and ≥12 months of Medicare A/B before admission to assess baseline covariates including patient, geographic, and hospital factors. Analysis used observed and predicted probabilities, and multivariable GEE models clustered by patient to report adjusted risk ratios (ARRs) of 30-day readmission and mortality.

RESULTS

SLE admissions (n=10,868) were younger, predominantly female, more likely to be Black, disabled, and have Medicaid or end-stage renal disease (ESRD). Observed 30-day readmissions of 24% were identical for SLE and HF (p = 0.6), and higher than other Medicare (16%, p < 0.001). Both SLE and HF had elevated readmission risk (ARR 1.08, (95% CI (1.04, 1.13)); 1.11, (1.09, 1.13)). SLE readmissions were higher for Black (30%) versus White (21%) populations, and highest in ages 18-33 (39%) and ESRD (37%). Admissions of Black patients with SLE from least disadvantaged neighborhoods had highest 30-day mortality (9% versus 3% White).

CONCLUSION

Thirty-day SLE readmissions rivaled HF at 24%. Readmission prevention programs should engage young, ESRD patients with SLE and examine potential causal gaps in SLE care and transitions.

Assessment of the Accuracy of Using ICD-10 Codes to Identify Systemic Sclerosis

Importance

With the increased use of data from electronic medical records for research, it is important to validate in-patient electronic health records/hospital electronic health records for specific diseases identification using International Classification of Diseases, Tenth Revision (ICD-10) codes.

Objective

To assess the accuracy of using ICD-10 codes to identify systemic sclerosis (SSc) in the French hospital database.

Design Setting and Participants

Electronic health record database analysis. The setting of the study's in-patient database was the Toulouse University Hospital, a tertiary referral center (2880 beds) that serves approximately 2.9 million inhabitants. Participants were patients with ICD-10 discharge diagnosis codes of SSc seen at Toulouse University Hospital between January 1, 2010, and December 31, 2017.

Main Outcomes and Measures

The main outcome was the positive predictive value (PPV) of discharge diagnosis codes for identifying SSc. The PPVs were calculated by determining the ratio of the confirmed cases found by medical record review to the total number of cases identified by ICD-10 code.

Results

Of the 2766 hospital stays, 216 patients were identified by an SSc discharge diagnosis code. Two hundred were confirmed as SSc after medical record review. The overall PPV was 93% (95% CI, 88-95%). The PPV for limited cutaneous SSc was 95% (95% CI, 85-98%).

Conclusions and Relevance

Our results suggest that using ICD-10 codes alone to capture SSc is reliable in The French hospital database.

Development and validation of lupus nephritis case definitions using United States veterans affairs electronic health records

OBJECTIVE

International Classification of Diseases (ICD) codes are commonly used to identify patients with rare diseases in electronic health records (EHRs). However, misclassification is common, impacting the validity of study results. In this study, we compared the accuracies of several ICD-based case definitions of lupus nephritis (LN) in identifying United States veterans with LN.

METHODS

Using the Department of Veterans Affairs (VA) EHR, we identified all veterans with ≥1 ICD-9 or 10 diagnostic codes for systemic lupus erythematosus (SLE) between October 1, 1999 and September 30, 2017. A cohort was randomly selected for diagnostic validation and 9 ICD-based LN case definitions were applied to this cohort. The diagnostic accuracy of each definition was assessed against gold standard criterion of biopsy-proven LN.

RESULTS

18,420 veterans had ≥1 ICD-9 or 10 diagnostic codes for SLE; 981 were randomly selected for diagnostic validation. 95 veterans (9.7%) had biopsy-proven LN. The case definitions had high specificity and NPV but variable sensitivity and PPV. The definition containing ≥2 ICD -9 codes for SLE and ≥2 nephritis indicators had the highest combination of sensitivity and specificity (87.4% and 94.6% respectively). ICD-10 code for LN had high specificity (99.8%) and PPV (93.9%).

CONCLUSION

ICD-based case definitions of LN in the VA population have high specificity and NPV but variable sensitivity and PPV. Our results may help guide the design of future LN studies in VA cohorts. The choice of specific case definitions depends on the relative importance of different accuracy measures to individual studies.

Immunomodulatory Medication Use in Newly Diagnosed Youth With Systemic Lupus Erythematosus

OBJECTIVE

To examine glucocorticoid-sparing immunomodulatory medication use in youth with systemic lupus erythematosus (SLE) during their first year of care.

METHODS

We conducted a retrospective cohort study using administrative claims for 2000 to 2013 from Clinformatics DataMart for youth ages 10-24 years with an incident diagnosis of SLE (≥3 International Classification of Diseases, Ninth Revision codes for SLE [710.0], each >30 days apart). We determined the proportion of subjects filling a prescription for immunomodulatory medications within 12 months of the first SLE code (index date). We used multivariable regression to examine associations between demographic/disease factors and time to prescription fill in the first year, and also between prescription fill at any time after the index date.

RESULTS

We identified 532 youth with an incident SLE diagnosis, of which 413 (78%) had a glucocorticoid-sparing immunomodulatory prescription fill in the first year. Prescriptions for hydroxychloroquine and immunosuppressants were filled in the first year by 366 youth (69%) and by 182 (34%), respectively. Those with adult-onset (versus childhood-onset) disease were less likely to fill an immunomodulatory medication by 12 months. No other statistically significant associations were found, although there was increasing likelihood of immunomodulatory medication fills with each subsequent calendar year.

CONCLUSION

Among youth with newly diagnosed SLE, hydroxychloroquine use is prevalent although not universal, and prescription immunosuppressant use is notably low during the first year of care. Further research is needed to identify factors contributing to suboptimal immunomodulatory medication use during the first year of care.

Lupus: the new epidemic

Is systemic lupus erythematosus (SLE) is occurring more frequently now than in decades past? Despite improvements in the identification of patients with SLE, the development of new classification criteria, and the recognition of several biomarkers used alone or in combination, the diagnosis of SLE is still a challenge for clinicians, in particular early in the course of the disease, which makes the recognition of secular trends difficult to ascertain. Lacking a uniform definition of preclinical lupus or incomplete lupus, it is difficult to predict accurately which patients would go on to develop SLE. We will briefly review the classification criteria, early or preclinical SLE, the epidemiology of SLE, antinuclear antibodies-negative SLE, and biomarkers of the disease.

Socioeconomic status at diagnosis influences the incremental direct medical costs of systemic lupus erythematosus: A longitudinal population-based study

OBJECTIVES

To assess the incremental direct medical costs of a population-based cohort of incident systemic lupus erythematosus (SLE) for the first five years after diagnosis, and impact of socioeconomic status (SES) on such incremental costs.

METHODS

From the administrative health databases in British Columbia, Canada, we identified all adults with newly-diagnosed SLE from 1996 to 2010 and obtained a sample from the general non-SLE population matched on sex, age, and calendar-year. We captured costs for outpatient encounters, hospitalisations, and dispensed medications. Using two-part generalised linear models, we estimated per-person-year incremental costs of SLE (difference in costs between SLE and non-SLE, controlling for covariates) during the first five years after diagnosis, and assessed differences in incremental costs across SES groups.

RESULTS

We included 4679 newly-diagnosed SLE (86% identified from hospitalisations or rheumatologists) and 23,219 non-SLE individuals. Per-person direct costs for SLE in the first year after diagnosis averaged $13,038 (2013 Canadian), with 61% from hospitalisations, 23% from outpatient encounters, and 16% from medications; costs for non-SLE averaged $2,431. Following adjustment, incremental costs of SLE during the first five years after diagnosis averaged $10,078 per-person-year (95% CI=$2062-$32,254). Predicted incremental hospitalisation, outpatient, and medication costs were all significantly-greater for the low-SES patients versus high-SES (additional $1922 per-person-year in incremental costs for low-SES). Similar patterns were observed when restricting to those followed the full five-years after index date.

CONCLUSION

Even in a single-payer, publicly-funded healthcare setting, low SES at SLE diagnosis was associated with significantly-greater direct medical costs for the management of SLE and associated complications.

High Health Care Utilization Preceding Diagnosis of Systemic Lupus Erythematosus in Youth

OBJECTIVE

Childhood-onset systemic lupus erythematosus (SLE) is associated with high risk for organ damage, which may be mitigated by early diagnosis and treatment. We characterized health care utilization for youth in the year preceding SLE diagnosis compared to controls.

METHODS

Using Clinformatics DataMart (OptumInsight) de-identified administrative data from 2000 to 2013, we identified 682 youth ages 10-24 years with new-onset SLE (≥3 International Classification of Diseases, Ninth Revision codes for SLE 710.0, each >30 days apart), and 1,364 age- and sex-matched healthy controls. We compared the incidence of ambulatory, emergency, and inpatient visits 12 months before SLE diagnosis and frequency of primary diagnoses. We examined subject characteristics associated with utilization preceding SLE diagnosis.

RESULTS

Youth with SLE had significantly more visits in the year preceding diagnosis than controls across ambulatory (incidence rate ratio [IRR] 2.48, P < 0.001), emergency (IRR 3.42, P < 0.001), and inpatient settings (IRR 3.02, P < 0.001). The most frequent acute-care diagnoses and median days to SLE diagnosis were: venous thromboembolism (313, interquartile range [IQR] 18-356), thrombocytopenia (278, IQR 39-354), chest pain (73, IQR 29.5-168), fever (52, IQR 17-166), and acute kidney failure (14, IQR 5-168). Having a psychiatric diagnosis prior to SLE diagnosis was strongly associated with increased utilization across all settings.

CONCLUSION

Youth with SLE have high health care utilization throughout the year preceding SLE diagnosis. Examining variable diagnostic trajectories of youth requiring acute care preceding SLE diagnosis, and increased attention to psychiatric morbidity, may help improve care for youth with new-onset SLE.

Incremental direct medical costs of systemic lupus erythematosus patients in the years preceding diagnosis: A general population-based study

Objective We estimated the incremental (extra) direct medical costs of a population-based cohort of newly diagnosed systemic lupus erythematosus (SLE) for five years before and after diagnosis, and the impact of sex and socioeconomic status (SES) on pre-index costs for SLE. Methods We identified all adults newly diagnosed with SLE over 2001-2010 in British Columbia, Canada, and obtained a sample of non-SLE individuals from the general population, matched on sex, age, and calendar-year of study entry. We captured costs for all outpatient encounters, hospitalisations, and dispensed medications each year. Using generalised linear models, we estimated incremental costs of SLE each year before/after diagnosis (difference in costs between SLE and non-SLE, controlling for covariates). Similar models were used to examine the impact of sex and SES on costs within SLE. Results We included 3632 newly diagnosed SLE (86% female, mean age 49.6 ± 15.9) and 18,060 non-SLE individuals. Over the five years leading up to diagnosis, per-person healthcare costs for SLE patients increased year-over-year by 35%, on average, with the biggest increases in the final two years by 39% and 97%, respectively. Per-person all-cause medical costs for SLE the year after diagnosis (Year + 1) averaged C$12,019 (2013 Canadian) with 58% from hospitalisations, 24% outpatient, and 18% from prescription medications; Year + 1 costs for non-SLE averaged C$2412. Following adjustment for age, sex, urban/rural residence, socioeconomic status, and prior year's comorbidity score, SLE was associated with significantly greater hospitalisation, outpatient, and medication costs than non-SLE in each year of study. Altogether, adjusted incremental costs of SLE rose from C$1131 per person in Year -5 (fifth year before diagnosis) to C$2015 (Year -2), C$3473 (Year -1) and C$6474 (Year + 1). In Years -2, -1 and +1, SLE patients in the lowest SES group had significantly greater costs than the highest SES. Unlike the non-SLE cohort, male patients with SLE had higher costs than females. Annual incremental costs of SLE males (vs. SLE females) rose from C$540 per person in Year -2, to C$1385 in Year -1, and C$2288 in Year + 1. Conclusion Even years before diagnosis, SLE patients incur significantly elevated direct medical costs compared with the age- and sex-matched general population, for hospitalisations, outpatient care, and medications.

A Population-based Study of Perinatal Infection Risk in Women with and without Systemic Lupus Erythematosus and their Infants

BACKGROUND

Increased risk of adverse birth outcomes is well described in women with systemic lupus erythematosus (SLE), but risk of maternal or infant infection in the peripartum period has not been well studied. We conducted a population-based cohort study of infection risk in women with and without SLE and their infants.

METHODS

Linked birth-hospital discharge data identified 1297 deliveries to women with SLE and a 4:1 comparison cohort of deliveries to women without SLE in Washington State, 1987-2013. Maternal and infant infections during the first 30 days after delivery were identified. Relative risks (RR) and 95% confidence intervals (CI) were estimated.

RESULTS

Women with SLE were 1.7 times more likely (95% CI 1.4, 2.0) to have an infection during the birth hospitalisation and more likely to receive antibiotics during labour (RR 1.3, 95% CI 1.1, 1.5), though there was no increased risk of chorioamnionitis in women with SLE. Infants of women with SLE had an increased risk for an infection during the birth hospitalisation (RR 2.2, 95% CI 1.3, 3.5), although the size of the difference was smaller when adjusted for gestational age (RR 1.4, 95% CI 0.9, 2.1). Risks of neonatal infection, sepsis, receipt of antibiotics, and admission to neonatal intensive care were also increased, and were also attenuated after adjustment for gestational age.

CONCLUSIONS

Women with SLE have an increased risk of peripartum infections and antibiotic exposure. Their neonates have a greater likelihood of infection, much of which is attributable to preterm birth.

Utilization of Ambulatory Physician Encounters, Emergency Room Visits, and Hospitalizations by Systemic Lupus Erythematosus Patients: A 13-Year Population Health Study

OBJECTIVE

To determine total physician encounters, emergency room (ER) visits, and hospitalizations in an incident cohort of systemic lupus erythematosus (SLE) cases and matched control patients over 13 years.

METHODS

A retrospective cohort study was performed utilizing administrative health care data from approximately 1 million people with access to universal health care. Using International Classification of Diseases, Ninth and Tenth Revisions diagnostic codes, 7 SLE case definitions were used. Each case was matched by age and sex to 4 randomly selected controls. Data included physician billings, ER visits, and hospital discharges over 13 years.

RESULTS

The number of incident SLE cases varied from 564 to 4,494 depending on the case definition used. The mean age varied from 47.7 to 50.6 years and the proportion of females from 78.0% to 85.1%. SLE utilization of physicians was highest in the index year, and declined significantly thereafter for all case definitions. By the fourth year, encounters with subspecialty physicians fell by 60% (rheumatologists), 50% (internists), and 31% (other physicians). In contrast, visits to family physicians fell by only 9%. Visits to the ER and hospital admissions for SLE cases were also more frequent early in the disease course and fell significantly over the study for both ER visits (all case definitions) and hospitalizations (2 of 7 case definitions).

CONCLUSION

In SLE patients, health care utilization is highest in the first few years following the diagnosis, which is also the time of maximal involvement by rheumatologists. Utilization declines over time, and encounters with patients' family physicians predominate over those of other physician groups.

Epidemiology of systemic lupus erythematosus

INTRODUCTION

Systemic lupus erythematosus (SLE) is a disease distributed worldwide, which occurs in both genders, and across racial/ethnic and age groups; however, higher rates are observed in adults, in women and in non-Caucasians. Genetic, environmental, sociodemographic and methodological issues are responsible not only for these differences but for the variable course and outcome of the disease. Non-Caucasians have a more severe disease with a higher risk for early mortality and damage accrual. Males also have a more severe disease; however, a negative impact of male gender on lupus outcomes has not been firmly established. Childhood-onset is associated with a more severe disease; moreover, it is also associated with higher damage and diminished survival; finally, late-onset lupus is mild but it is associated with higher damage accrual and a diminished survival. Areas covered: In this review, we discuss the incidence and prevalence of SLE, the impact of age, gender and race/ethnicity in SLE and in the survival of those affected. Expert commentary: Age, gender and race/ethnicity impact disease expression in SLE patients; despite improvements in survival, mortality in SLE remains almost three times higher than in the general population.

Capture-recapture methodology to study rare conditions using surveillance data for fragile X syndrome and muscular dystrophy

BACKGROUND

Rare conditions can be catastrophic for families and the implications for public health can be substantial. Our study compared basic surveillance through active medical record review with a linked administrative data file to assess the number of cases of two rare conditions, fragile X syndrome (FXS) and muscular dystrophy (MD) in a population.

METHODS

Two methods of data collection were used to collect information from five counties comprising two standard metropolitan statistical areas of South Carolina. The passive system relied mostly on health claims data using ICD-9 CM diagnostic codes. The active system relied on a nurse abstracting records from a list of all licensed physicians with specialties in neurology, orthopedics, and genetics.

RESULTS

There were 141 FXS cases and 348 MD cases that met the case definitions using active surveillance. Additional cases were found for both conditions but they were determined to not be true cases. After linking the actively collected MD and FXS cases to passive datasets, we found that the estimated total numbers of cases were similar to using capture-recapture analysis; the positive predictive values for cases identified in the passive system were 56.6% for MD and 75.7% for FXS.

CONCLUSIONS

Applying capture-recapture methods to passively collected surveillance data for rare health conditions produced an estimate of the number of true cases that was similar to that obtained through active data collection.

Disease characterization of systemic lupus erythematosus (SLE) patients in Quebec

Objective Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by an array of organ manifestations that can appear during flares and disappear during remissions. The objectives of this study were: (i) to examine SLE manifestation groups longitudinally in an SLE cohort; and (ii) to assess the association between early antimalarial treatment and renal manifestations. Methods Seven SLE manifestation groups-cutaneous, hematologic, lung, musculoskeletal, neuropsychiatric, serositis, renal-were tracked using Kaplan-Meier survival curves in an incident SLE cohort from Quebec health administrative data ( n = 2010). A subgroup with provincial drug insurance coverage was followed over time to examine the association between early antimalarial treatment (within three months after SLE diagnosis) and renal manifestations using a Cox proportional hazards survival model. Results Cutaneous manifestations was the most common manifestation at SLE diagnosis (30.0%, 95% CI: 27.7-32.2%). About two-thirds (66.2%, 95% CI: 63.4-68.9%) of patients had evidence of at least one SLE manifestation at diagnosis, which increased to 87.2% (95% CI: 84.2-90.3%) by the end of follow-up. After adjusting for age, sex, early concomitant systemic steroid therapy, Charlson comorbidity index, primary care visits in the year prior and other SLE manifestations at baseline, no statistically significant association was established between antimalarial therapy and renal manifestations. Conclusion This study provides insight regarding organ manifestations within a population-based sample. Most patients identified with SLE had other diagnostic evidence that supports an underlying diagnosis of SLE. No protective effects for antimalarial agents against renal manifestations could be established in this population-based cohort.