Prevalence and Risk Factors Associated with Neutropenia in Hospitalized Patients with Systemic Lupus Erythematosus

Abstract

Background and aims This study was performed to identify the prevalence and risk factors that are associated with neutropenia in Korean patients with systemic lupus erythematosus (SLE). Methods A total 160 admissions of 85 SLE patients between 2006 and 2013 were retrospectively reviewed. Neutropenia was defined as absolute neutrophil count (ANC) below 1500/mm3. Baseline characteristics of the patients were compared between patients who experienced neutropenia and those without. Clinical and serological factors related to neutropenia episode during admission were analysed. Results Thirty two (37.6%) patients experienced neutropenia, and neutropenia episode was found in 35 (21.9%) of admissions. Most of the neutropenia episodes were mild to moderate. Severe neutropenia of ANC<500/mm3 occurred in 3.1% of the cases. Patients with neutropenia had higher frequencies of ANA (100.0 vs 86.8%, p=0.042) and anti-dsDNA (87.5 vs 60.4%, p=0.008), and satisfied more SLE classification criteria at the time of the diagnosis than those without (4.8 vs 4.1, p=0.014) Clinical characteristics at admission such as comorbidities, concomitant medications, and SLEDAI were not different between admissions with and without neutropenia. Anaemia, leukopenia, thrombocytopenia and low complement levels were frequently associated with neutropenia. Co-existence of chronic kidney disease (OR, 16.91; 95% confidence interval (CI), 2.09-136.6; p=0.008) and Sjögren's syndrome (OR, 6.48; 95% CI, 1.46-28.66; p=0.014) was associated with increased risk of developing neutropenia. Conclusions This study demonstrates that most of neutropenia in SLE patients occur as part of hematologic and immunologic abnormalities. SLE patients with renal damage and Sjogren's syndrome should be closely monitored for development of neutropenia.