Hospital Admissions and Disease Outcomes in Systemic Lupus Erythematosus: A Retrospective Study from a Tertiary Rheumatology Care Unit

Technical Summary: Hospital Admissions and Disease Outcomes in Systemic Lupus Erythematosus

Problem Statement
Systemic Lupus Erythematosus (SLE) is a heterogeneous chronic autoimmune disorder characterized by fluctuating disease activity and potential for progressive organ damage. While hospital admissions for SLE are well-documented globally, there is a scarcity of localized research from tertiary rheumatology care units in Egypt. Specifically, there is a need to understand the interplay between infectious complications, cardiovascular events, and patient outcomes within the specific context of recent healthcare practices and demographics in this region. This study addresses the gap in data regarding the clinical characteristics, comorbidities, and in-hospital outcomes of SLE patients admitted to a specialized care unit.

Methodology
The authors conducted a retrospective observational cohort study at the Rheumatology and Clinical Immunology Unit of Alexandria University's Main University Hospital, a tertiary referral center.

• Cohort: The study included 89 adult patients (aged ≥18) with a confirmed SLE diagnosis based on the 2012 SLICC classification criteria, admitted between May 2022 and May 2023.
• Data Collection: Data were extracted from medical records using REDCap, covering demographics, comorbidities, clinical presentations, laboratory parameters, and therapeutic interventions.
• Assessment Tools: Disease activity was quantified using the SLEDAI-2K index, and irreversible organ damage was assessed via the SLICC/ACR Damage Index.
• Variables: The study analyzed causes of admission (categorized as infection, organ-specific, or hematological), types of infections, treatment regimens (glucocorticoids, immunosuppressants, antimalarials), length of stay, ICU referrals, and in-hospital mortality.
• Statistical Analysis: Data were analyzed using SPSS v20.0, with categorical variables expressed as frequencies/percentages and continuous variables as means ± SD or medians/IQR. Significance was set at p < 0.05.

Key Results

• Demographics: The cohort was predominantly female (97.8%) with a mean age of 34.96 ± 13.78 years.
• Admission Drivers: Infection was the leading cause of admission (51.7%), with bacterial infections comprising 84% of all infectious cases. Lower respiratory tract infections (46%) and urinary tract infections (40%) were the most common sources. Renal involvement accounted for 43.8% of admissions, and hematological abnormalities were also frequent. Notably, 65.16% of admissions involved combined causes (e.g., infection with renal flare).
• Disease Activity and Damage: The mean SLEDAI score was 13.09 ± 5.53, with 51.7% of patients experiencing a severe flare (SLEDAI > 12). Irreversible organ damage was documented in 70.8% of patients (SLICC/ACR score ≥ 1).
• Comorbidities: Hypertension was the most prevalent comorbidity (37.1%), followed by diabetes mellitus (10.1%) and hypothyroidism (9.0%).
• Treatment: Glucocorticoids were administered to 98.9% of patients. Hydroxychloroquine was prescribed in 91% of cases. Immunosuppressants were used selectively: Mycophenolate mofetil (39.3%), Azathioprine (28.1%), and Cyclophosphamide (13.5%).
• Outcomes: The in-hospital mortality rate was 6.7% (6 patients). Cardiovascular complications were the primary cause of death (50%), followed by sepsis, intra-alveolar hemorrhage, and CNS vasculitis (each 16.7%). 93.3% of patients improved clinically by discharge.

Key Contributions
This study provides a comprehensive profile of SLE patients requiring hospitalization in a specialized Egyptian tertiary care setting. Its primary contributions include:

1. Identification of Admission Etiologies: It establishes that infectious complications, particularly bacterial sepsis, are the predominant driver of hospitalization in this cohort, surpassing disease flares alone.
2. Mortality Drivers: It highlights that while infection drives admission, cardiovascular complications are the leading cause of in-hospital mortality, a distinction that may differ from other regional reports where infection is cited as the primary cause of death.
3. Local Context: It offers localized data on disease activity scores, damage indices, and comorbidity patterns (specifically hypertension) relevant to the Egyptian healthcare context, addressing the lack of recent studies from this region.

Significance and Claims
The paper claims that the findings underscore the critical need for improved infection monitoring and proactive cardiovascular risk management to reduce morbidity and mortality in hospitalized SLE patients. The authors suggest that the high rates of disease activity and irreversible damage observed necessitate early detection and personalized therapy.

The study concludes that while the in-hospital mortality rate (6.7%) may reflect improved access to specialized care and early intervention, the burden of infection and cardiovascular risk remains high. The authors advocate for rheumatologists to remain vigilant regarding infection risks, carefully balance immunosuppressive therapy, and implement targeted cardiovascular risk reduction strategies.

Limitations
The authors acknowledge that the retrospective, single-center design limits the generalizability of the findings. The relatively small sample size (n=89) may affect statistical power for detecting associations in specific subgroups. Additionally, the study is limited to in-hospital outcomes and does not capture long-term morbidity or mortality trends post-discharge.