Increased Prevalence of Autoimmunity and Connective Tissue Diseases in Sickle Cell Disease

Abstract

Connective tissue disease (CTD) and sickle cell disease (SCD) are diverse group of disorders; however, both of these diseases are characterized by underlying chronic inflammation. CTD is perceived to have a higher incidence and to affect the disease severity in SCD. Objectives: We seek to describe prevalence of autoimmunity and CTD and itsimpact on SCD disease severity as this is not well described in the literature. Methods: We retrospectively reviewed the medical records of 722 patients with SCD, seen over an 11 year period followed at a tertiary care hospital in London, UK. During the last 2 years of the study, number of hospitalizations and length of hospital stay were compared in patients with SCD with and without CTD. Results: In the study cohort, hemoglobin SS was the most common genotype (n = 451; 62%) and 411 (57%) were female. Twenty-three patients (3.1% had documented evidence of CTD, with rheumatoid arthritis (n = 14; 2%) and systemic lupus erythematosus (n = 2; 0.3%) being the most common. Antinuclear antibody was present in 108 (15%) of the patients and anti-smooth muscle antibody was present in 60 (8%). The mean number of hospitalizations (1.9 ± 2.7 vs. 1.5 ± 2.7) and mean length of hospital stay (6 days ± 4.1 vs. 7 days ± 11.4) were not different between those with or without autoimmunity and/or CTD. Avascular necrosis was the most common non-CTD musculoskeletal complication, affecting 72 (10%) patients. Conclusion: Our study suggests that positive autoimmune serology and CTD were more common in SCD compared to non-SCD population of similar ethnic background; however, presence of CTD does not appear to affect the SCD severity. The high frequency of CTD and overlapping of clinical symptoms suggest a need for diagnostic vigilance in diagnosing CTD in patients with SCD.