Predictors of infection requiring hospitalization in patients with systemic lupus erythematosus: a time-to-event analysis

Systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease characterised by the presence of autoantibodies towards nuclear antigens, immune complex deposition, and chronic inflammation at classic target organs such as skin, joints, and kidneys. Despite substantial advances in the diagnosis and management of SLE, the burden of disease remains high. It is important to appreciate the typical presentations and the diagnostic process to facilitate early referral and diagnosis for patients. In most patients, constitutional, mucocutaneous, and musculoskeletal symptoms represent the earliest complaints; these symptoms can include fatigue, lupus-specific rash, mouth ulcers, alopecia, joint pain, and myalgia. In this Seminar we will discuss a diagnostic approach to symptoms in light of the latest classification criteria, which include a systematic evaluation of clinical manifestations (weighted within each domain) and autoantibody profiles (such as anti-double-stranded DNA, anti-Sm, hypocomplementaemia, or antiphospholipid antibodies). Non-pharmacotherapy management is tailored to the individual, with specific lifestyle interventions and patient education to improve quality of life and medication (such as hydroxychloroquine or immunosuppressant) adherence. In the last decade, there have been a few major breakthroughs in approved treatments for SLE and lupus nephritis, such as belimumab, anifrolumab, and voclosporin. However the disease course remains variable and mortality unacceptably high. Access to these expensive medications has also been restricted across different regions of the world. Nonetheless, understanding of treatment goals and strategies has improved. We recognise that the main goal of treatment is the achievement of remission or low disease activity. Comorbidities due to both disease activity and treatment adverse effects, especially infections, osteoporosis, and cardiovascular disease, necessitate vigilant prevention and management strategies. Tailoring treatment options to achieve remission, while balancing treatment-related comorbidities, are priority areas of SLE management.

SLESIS-R: an improved score for prediction of serious infection in patients with systemic lupus erythematosus based on the RELESSER prospective cohort

OBJECTIVE

To develop an improved score for prediction of severe infection in patients with systemic lupus erythematosus (SLE), namely, the SLE Severe Infection Score-Revised (SLESIS-R) and to validate it in a large multicentre lupus cohort.

METHODS

We used data from the prospective phase of RELESSER (RELESSER-PROS), the SLE register of the Spanish Society of Rheumatology. A multivariable logistic model was constructed taking into account the variables already forming the SLESIS score, plus all other potential predictors identified in a literature review. Performance was analysed using the C-statistic and the area under the receiver operating characteristic curve (AUROC). Internal validation was carried out using a 100-sample bootstrapping procedure. ORs were transformed into score items, and the AUROC was used to determine performance.

RESULTS

A total of 1459 patients who had completed 1 year of follow-up were included in the development cohort (mean age, 49±13 years; 90% women). Twenty-five (1.7%) had experienced ≥1 severe infection. According to the adjusted multivariate model, severe infection could be predicted from four variables: age (years) ≥60, previous SLE-related hospitalisation, previous serious infection and glucocorticoid dose. A score was built from the best model, taking values from 0 to 17. The AUROC was 0.861 (0.777-0.946). The cut-off chosen was ≥6, which exhibited an accuracy of 85.9% and a positive likelihood ratio of 5.48.

CONCLUSIONS

SLESIS-R is an accurate and feasible instrument for predicting infections in patients with SLE. SLESIS-R could help to make informed decisions on the use of immunosuppressants and the implementation of preventive measures.

Risk factors for initial and recurrent severe infections in first hospitalized patients with systemic lupus erythematosus: A retrospective study of a Chinese cohort

OBJECTIVE

To evaluate the incidence and associated factors of initial and recurrent severe infections in hospitalized patients with systemic lupus erythematosus (SLE).

METHODS

SLE patients that first hospitalized between 2010 and 2021 were studied retrospectively and divided into SLE with and without baseline severe infection groups. The primary outcome was the occurrence of severe infection during follow-up. Cox regression models were used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for initial and recurrent severe infections.

RESULTS

Among 1051 first hospitalized SLE patients, 164 (15.6%) had severe infection on admission. During a median follow-up of 4.1 years, 113 (10.8%) patients reached severe infection outcomes, including 27 with reinfection and 86 with initial severe infection (16.5% vs. 9.7%, p = .010). Patients with baseline severe infection had a higher cumulative incidence of reinfection (p = .007). After adjusting for confounding factors, renal involvement, elevated serum creatinine, hypoalbuminemia, cyclophosphamide, and mycophenolate mofetil treatment were associated with an increased risk of severe infection, especially initial severe infection. Low immunoglobulin, anti-dsDNA antibody positivity, and cyclophosphamide use significantly increased the risk of recurrent severe infection, with adjusted HR (95% CI) of 3.15 (1.22, 8.14), 3.60 (1.56, 8.28), and 2.14 (1.01, 5.76), respectively. Moreover, baseline severe infection and low immunoglobulin had a multiplicative interaction on reinfection, with adjusted RHR (95% CI) of 3.91 (1.27, 12.09).

CONCLUSION

In this cohort of SLE, patients with severe infection had a higher risk of reinfection, and low immunoglobulin, anti-dsDNA antibody positivity, and cyclophosphamide use were independent risk factors for recurrent severe infection.

The economic burden of systemic lupus erythematosus in United Arab Emirates

AIMS

Our study aims to provide an enhanced comprehension of systemic lupus erythematosus (SLE) burden in United Arab Emirates (UAE), over a five-year period from payer and societal perspective.

MATERIALS AND METHODS

A Markov model was established to simulate the economic consequences of SLE among UAE population. It included four health states: i) the three phenotypes of SLE, representing mild, moderate, and severe states, and ii) death. Clinical parameters were retrieved from previous literature and validated using the Delphi panel-the most common clinical practice within the Emirati healthcare system. We calculated the disease management, transient events, and indirect costs by macro costing. One-way sensitivity analysis was conducted.

RESULTS

The estimated number of SLE patients in our study was 13,359. The number of SLE patients with mild, moderate, and severe phenotypes was 3,914, 8,109, and 1,336, respectively. Disease management costs, including treatment of each phenotype and disease follow-up, were AED 2 billion ($0.89 billion), whereas the costs of transient events (infections, flares, and consequences of SLE-related organ damage) were AED 1 billion ($0.44 billion). The productivity loss costs among adult-employed patients with SLE in the UAE were estimated at AED 7 billion ($3.1 billion). The total SLE cost over five years from payer and societal perspectives is estimated at AED 3 ($1.3 billion) and 10 billion ($4.4 billion), respectively. Additionally, the costs per patient per year from the payer and societal perspectives were AED 45,960 ($20,610) and AED 148,468 ($66,578), respectively.

CONCLUSION

Our findings demonstrate that the burden of SLE in the UAE is enormous, mainly because of the costly complications and productivity loss. More awareness should be created to limit the progression of SLE and reduce the occurrence of flares, necessitating further economic evaluations of novel treatments that could help reduce the economic consequences of SLE in the UAE.

Clinical and economic burden of systemic lupus erythematosus in Colombia

AIMS

Our cost-of-illness (COI) model adopted payer and societal perspectives over five years to measure the economic burden of Systemic Lupus Erythematosus (SLE) in Colombia.

MATERIALS AND METHODS

A prevalence-based model was constructed to estimate costs and economic consequences for SLE patients in Colombia. The model included four health states: three phenotypes of SLE representing mild, moderate, and severe states and death. The clinical inputs were captured from the published literature and validated by the Delphi panel. Our model measured direct medical and indirect costs, including disease management, transient events, and indirect costs. One-way sensitivity analysis was also performed.

RESULTS

The number of Colombian SLE patients was 37,498. The number of SLE patients with mild, moderate, and severe phenotypes was 5343, 28757 and 3,397, respectively. SLE-patients with moderate (Colombian pesos; COP 146 billion) and severe phenotypes (COP276 billion) incurred higher costs than those with mild phenotypes (COP2 billion), over 5 years. The total SLE cost in Colombia over five years from the payer and societal perspectives was estimated to be COP 915 billion and 8 trillion, respectively. The costs per patient per year from the payer and societal perspectives were COP 4,881,902 ($3,510) and COP 46,637,054 ($33,528), respectively.

CONCLUSION

The burden of SLE in Colombia over five years is substantially high, mainly due to the consequences of economic loss because it affects women and men of working age, in addition to the costs of SLE management and its consequences, such as flares, infection, and organ damage. Our COI indicated that disease management costs among patients with moderate and severe SLE were substantially higher than those among patients with a mild phenotype. Therefore, more attention should be paid to limiting the progression of SLE and the occurrence of flares, with the need for further economic evaluation of novel treatment strategies that help in disease control.

Economic burden of systemic lupus erythematosus in Malaysia

INTRODUCTION

Our cost-of-illness (COI) model adopted the perspective of both payer and society over a time horizon of 5 years to measure the economic burden of systemic lupus erythematosus (SLE) in Malaysia.

METHODOLOGY

Our COI model utilized a prevalence-based model to estimate the costs and economic consequences of SLE in Malaysia. The clinical parameters were obtained from published literature and validated using the Delphi panel. Direct and indirect medical costs were measured, including disease management, transient events, and indirect costs. One-way sensitivity analysis was also performed.

RESULTS

The number of target Malaysian patients with SLE in the COI model was 18,121. At diagnosis, the numbers of SLE patients with mild, moderate, and severe phenotypes were 2,582, 13,897, and 1,642, respectively. The total SLE cost in Malaysia over 5 years from both payer and society perspectives was estimated at MYR 678 million and 2 billion, respectively. The results showed a considerable cost burden due to productivity losses resulting from SLE-related morbidity and mortality. Over a 5-year time horizon, the costs per patient per year from the payer and society perspectives were MYR 7,484 ($4766) and 24,281($15,465), respectively.

CONCLUSION

Our study demonstrated the substantial economic burden of SLE in Malaysia over a time horizon of 5 years. It affects adults of working age, in addition to the costs of SLE management and its consequences, such as flares, infection, and organ damage. Our COI model indicated that disease management costs among patients with higher disease severity were higher than those among patients with a mild phenotype. Hence, more attetion should be paid to limiting the progression of SLE and the occurrence of flares, with the need for further economic evaluation of novel treatments that could lead to better outcomes.

The economic burden of systemic lupus erythematosus in Mexico

AIMS

Our cost of illness study aimed to provide an estimate of the burden related to systemic lupus erythematosus (SLE) in the Mexican context.

METHODS

Our model was used to simulate the resource utilization and economic consequences over a period of 5 years for patients with SLE in Mexico. The model simulated four health states-three phenotypes of SLE, including mild, moderate, and severe states, and death. Clinical parameters were retrieved from the literature. Resource utilization in our model represents the most common practice in the Mexican healthcare system. These include disease management, transient events (e.g. infections, flares, and complications due to SLE-related organ damage), and indirect costs. Direct non-medical costs were not considered. One-way sensitivity analysis was performed.

RESULTS

The number of targeted Mexican SLE patients was 57,754. The numbers of SLE patients diagnosed with mild, moderate, and severe phenotypes were 8,230, 44,291, and 5,233, respectively. Disease management costs, including the treatment of each phenotype and disease follow-up, were MXN 4 billion ($ 415 million); the costs of transient events (infections, flares, and consequences of SLE-related organ damage) were MXN 5 billion ($ 478 million). Productivity loss costs among adult employed Mexican patients with SLE were estimated at MXN 17 billion ($ 1.6 billion). The total SLE cost in Mexico over 5 years from the payer and societal perspectives is estimated at MXN 9 billion ($ 893 million) and 26 billion ($ 2.5 billion), respectively. Over 5 years, the costs per patient per year from the payer and societal perspectives were MXN 32,131($ 3,095) and MXN 91,661($ 8,830), respectively.

CONCLUSION

The findings pointed out the substantial economic burden associated with SLE, including the costs of disease progression and SLE transient events, such as flare-ups, infections, and organ damage, in addition to productivity loss due to work capacity impairment.

The economic burden of systemic lupus erythematosus in Taiwan

BACKGROUND

Our cost-of-illness (COI) model adopted both payer and societal perspectives over a time horizon of 5 years to measure the economic burden of systemic lupus erythematosus (SLE) in Taiwan.

METHODOLOGY

A prevalence-based model was established to estimate the economic consequences of SLE after diagnosis in Taiwan. The model included four health states: (i) the three phenotypes representing mild, moderate, and severe SLE, and (ii) death. The inputs were obtained from a literature review of all the clinical trials and validated using a Delphi panel. The Delphi panel's insights included commonly used treatment strategies for patients with SLE within the Taiwanese healthcare system. The costs mentioned in this model are disease management, monitoring, transient event, and indirect costs. One-way sensitivity analyses were conducted to assess the model uncertainty.

RESULTS

The number of patients with SLE in our COI model was 20,189. At diagnosis, the number of SLE patients with mild, moderate, and severe phenotypes was 5,916, 12,255, and 2019, respectively. The total SLE cost in Taiwan over 5 years from both payer and societal perspectives was estimated at TWD 3.9 and 47 billion, respectively. The costs per patient per year from the payer and societal perspective were TWD 38,775 ($2,758) and TWD 466,119 ($33,152), respectively.

CONCLUSION

The findings demonstrated that the burden of SLE in Taiwan over a time horizon of 5 years is substantially high, mainly due to the consequences of economic loss as it affects women and men during their working age, in addition to the costs of SLE management and its consequences, such as flares, infection, and organ damage. Therefore, more attention should be paid to limiting the progression of SLE and the occurrence of flares, and further economic evaluations are necessary to assess novel treatment strategies that could control the disease.

Association Between Mycophenolate Mofetil Use and Subsequent Infections Among Hospitalized Patients with Systemic Lupus Erythematosus: A Nested Case-Control Study

INTRODUCTION

The association between mycophenolate mofetil (MMF) and infection in patients with systemic lupus erythematosus (SLE) has not been clarified. This study evaluated the degree and factors in effect of MMF use on infection in patients with SLE.

METHODS

A hospitalized-based observational study was conducted to collect medical records on patients with SLE during 2010-2021. A nested case-control study was performed among 3339 patients with SLE, including 1577 cases and 1762 controls by whether they developed any type of infection. The exposure of MMF use was determined within 1 year before diagnosed infection or the end of follow-up. Logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (CI) for association between MMF and subsequent infection.

RESULTS

MMF was significantly associated with the risk of overall infection (adjusted OR 1.90, 95% CI 1.48-2.44) and different types of infections, including bacterial infection (adjusted OR 2.07, 95% CI 1.55-2.75), viral infection (adjusted OR 1.92, 95% CI 1.23-3.01), and opportunistic infection (adjusted OR 2.13, 95% CI 1.31-3.46). The top three risks of specific types of infections were bacteremia/septicemia, urinary tract infection/pyelonephritis, and herpes zoster. Stratification analysis showed risk of overall infection increased especially in MMF users with age over 55 years, diabetes, central nervous system involvement, and thrombocytopenia. Moreover, the risk of infection increased with increasing dosage and duration of MMF use. Additionally, the combination of MMF with CYC and other immunosuppressants significantly increases the risk of infections compared to using a single one.

CONCLUSIONS

MMF use is associated with various type of infections in patients with SLE, particularly in those with longer use, older age, complications with comorbidities, and concomitant use of CYC or other immunosuppressants.

Impact of SARS-CoV-2 infection on patients with systemic lupus erythematosus in England prior to vaccination: a retrospective observational cohort study

OBJECTIVES

Determine the prevaccination healthcare impact of COVID-19 in patients with systemic lupus erythematosus (SLE) in England.

DESIGN

Retrospective cohort study of adult patients with SLE from 1 May to 31 October 2020.

SETTING

Clinical Practice Research Datalink (CPRD) Aurum and Hospital Episode Statistics (HES) databases from general practitioners across England combining primary care and other health-related data.

PARTICIPANTS

Overall, 6145 adults with confirmed SLE diagnosis ≥1 year prior to 1 May 2020 were included. Most patients were women (91.0%), white (67.1%), and diagnosed with SLE at age <50 (70.8%). Patients were excluded if they had a COVID-19 diagnosis before 1 May 2020.

PRIMARY AND SECONDARY OUTCOME MEASURES

Demographics and clinical characteristics were compared. COVID-19 severity was determined by patient care required and procedure/diagnosis codes. COVID-19 cumulative incidence, hospitalisation rates, lengths of stay and mortality rates were determined and stratified by SLE and COVID-19 severity.

RESULTS

Of 6145 patients, 3927 had mild, 1288 moderate and 930 severe SLE at baseline. The majority of patients with moderate to severe SLE were on oral corticosteroids and antimalarial treatments. Overall, 54/6145 (0.88%) patients with SLE acquired and were diagnosed with COVID-19, with 45 classified as mild, 6 moderate and 3 severe COVID-19. Cumulative incidence was higher in patients with severe SLE (1.4%) compared with patients classified as mild (0.8%) or moderate (0.8%). Ten COVID-19-specific hospital admissions occurred (n=6 moderate; n=4 severe). Regardless of COVID-19 status, hospital admission rates and length of stay increased with SLE severity. Of 54 patients with SLE diagnosed with COVID-19, 1 (1.9%) COVID-19-related death was recorded in a patient with both severe SLE and severe COVID-19.

CONCLUSIONS

SLE severity did not appear to impact COVID-19 outcomes in this study. The COVID-19 pandemic is evolving and follow-up studies are needed to understand the relationship between COVID-19 and SLE.

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.

Early infection risk in patients with systemic lupus erythematosus treated with rituximab or belimumab from the British Isles Lupus Assessment Group Biologics Register (BILAG-BR): a prospective longitudinal study

BACKGROUND

Patients with systemic lupus erythematosus (SLE) are at an increased risk of infection relative to the general population. We aimed to describe the frequency and risk factors for serious infections in patients with moderate-to-severe SLE treated with rituximab, belimumab, and standard of care therapies in a large national observational cohort.

METHODS

The British Isles Lupus Assessment Group Biologics Register (BILAG-BR) is a UK-based prospective register of patients with SLE. Patients were recruited by their treating physician as part of their scheduled care from 64 centres across the UK by use of a standardised case report form. Inclusion criteria for the BILAG-BR included age older than 5 years, ability to provide informed consent, a diagnosis of SLE, and starting a new biological therapy within the last 12 months or a new standard of care drug within the last month. The primary outcome for this study was the rate of serious infections within the first 12 months of therapy. Serious infections were defined as those requiring intravenous antibiotic treatment, hospital admission, or resulting in morbidity or death. Infection and mortality data were collected from study centres and further mortality data were collected from the UK Office for National Statistics. The relationship between serious infection and drug type was analysed using a multiple-failure Cox proportional hazards model.

FINDINGS

Between July 1, 2010, and Feb 23, 2021, 1383 individuals were recruited to the BILAG-BR. 335 patients were excluded from this analysis. The remaining 1048 participants contributed 1002·7 person-years of follow-up and included 746 (71%) participants on rituximab, 119 (11%) participants on belimumab, and 183 (17%) participants on standard of care. The median age of the cohort was 39 years (IQR 30-50), 942 (90%) of 1048 patients were women and 106 (10%) were men. Of the patients with available ethnicity data, 514 (56%) of 911 were White, 169 (19%) were Asian, 161 (18%) were Black, and 67 (7%) were of multiple-mixed or other ethnic backgrounds. 118 serious infections occurred in 76 individuals during the 12-month study period, which included 92 serious infections in 58 individuals on rituximab, eight serious infections in five individuals receiving belimumab, and 18 serious infections in 13 individuals on standard of care. The overall crude incidence rate of serious infection was 117·7 (95% CI 98·3-141·0) per 1000 person-years. Compared with standard of care, the serious infection risk was similar in the rituximab (adjusted hazard ratio [HR] 1·68 [0·60-4·68]) and belimumab groups (1·01 [0·21-4·80]). Across the whole cohort in multivariate analysis, serious infection risk was associated with prednisolone dose (>10 mg; 2·38 [95%CI 1·47-3·84]), hypogammaglobulinaemia (<6 g/L; 2·16 [1·38-3·37]), and multimorbidity (1·45 [1·17-1·80]). Additional concomitant immunosuppressive use appeared to be associated with a reduced risk (0·60 [0·41-0·90]). We found no significant safety signals regarding atypical infections. Six infection-related deaths occurred at a median of 121 days (IQR 60-151) days from cohort entry.

INTERPRETATION

In patients with moderate-to-severe SLE, rituximab, belimumab, and standard immunosuppressive therapy have similar serious infection risks. Key risk factors for serious infections included multimorbidity, hypogammaglobulinaemia, and increased glucocorticoid doses. When considering the risk of serious infection, we propose that immunosupppressives, rituximab, and belimumab should be prioritised as mainstay therapies to optimise SLE management and support proactive minimisation of glucocorticoid use.

FUNDING

None.

Tuberculosis remains a leading contributor to morbidity due to serious infections in Indian patients of SLE

INTRODUCTION

Infections are a major cause of morbidity and mortality in systemic lupus erythematosus (SLE). We assessed the incidence and risk factors for major infections in SLE in India.

METHODS

A retrospective review of a cohort of 1354 patients of adult SLE (ACR 1997 criteria) seen between 2000 and 2021 at a single center was conducted. Serious infections (need for hospitalisation, prolonged intravenous antibiotics, disability, or death) were recorded. Cox regression was used to determine factors associated with serious infection and the effects of serious infection on survival and damage.

RESULTS

Among the 1354 patients (1258 females, mean age of 30.3 years, follow-up of 7127.89 person-years), there were 439 serious infections in 339 patients (61.6 per 1000 person-years follow-up). Bacterial infections (N = 226) were the most common infection followed by mycobacterial infections (n = 81), viral (n = 35), and then invasive fungal infections (N = 13). Mycobacterium tuberculosis was the single most common microbiologically confirmed organism with incidence of 1136.4/100,000 person-years with 72.8% of them being extrapulmonary. Infection free survival at 1 year and 5 years was 82.9% and 73.8%. There were 119 deaths with infection attributable mortality in 65 (54.6%). On multivariable Cox regression analysis, higher baseline activity (HR 1.02, 1.01-1.05), gastrointestinal involvement (HR 2.75, 1.65-4.69), current steroid dose (HR 1.65, 1.55-1.76), and average cumulative steroid dose per year (HR 1.007, 1.005-1.009) were associated with serious infection and higher albumin (HR 0.65, 0.56-0.76) was protective. Serious infections led to greater damage accrual (median SLICC damage index of 1 vs. 0) and mortality (HR was 18.2, 32.7 and 81.6 for the first, second, and third infections).

CONCLUSION

Serious infections remain a major cause of mortality and damage accrual in SLE and higher disease activity, gastrointestinal involvement, hypoalbuminemia, current steroid dose, and cumulative steroid dose are the risk factors for it.