Prevalence of the American College of Rheumatology hematological classification criteria and associations with serological and clinical variables in 460 systemic lupus erythematosus patients

OBJECTIVE To study systemic lupus erythematosus in a Brazilian population using the American College of Rheumatology hematological classification criteria and report associations of the disease with serological and clinical profiles. METHODS This is a retrospective study of 460 systemic lupus erythematosus patients followed in a single rheumatologic center during the last 10 years. Hematological manifestations considered for this study were hemolysis, leukopenia, lymphocytopenia and thrombocytopenia. RESULTS The cumulative prevalences of leukopenia, thrombocytopenia, lymphocytopenia and hemolytic anemia were 29.8%, 21.08%, 17.7% and 8.4%, respectively. A higher percentage of patients with hemolysis had anticardiolipin IgM (p-value=0.002). Those with leukopenia had more lymphopenia (p-value=0.02), psychosis (p-value=0.01), thrombocytopenia (p-value <0.0001) and anti-double stranded DNA antibodies (p-value=0.03). Patients with lymphopenia had more leukopenia (OR=1.8; 95% CI=1.01-3.29) and lupus anticoagulant antibodies (OR=2.2; 95% CI=1.16-4.39) and those with thrombocytopenia had more leukopenia (OR=3.1; 95% CI=1.82-5.44) and antiphospholipid syndrome (OR=3.1; 95% CI=1.28-7.87). CONCLUSION The most common hematological finding was leukopenia and the least common was hemolysis. Associations of low platelet count and hemolysis were found with antiphospholipid syndrome and anticardiolipin IgM positivity, respectively. Leukopenia and lymphocytopenia are correlated and leukopenia is more common in systemic lupus erythematosus patients with psychosis, thrombocytopenia and anti-double stranded DNA.