A significant subset of systemic lupus erythematosus (SLE) patients exhibit chronic tachycardia (CT) of unknown significance. We postulated that CT is a marker of lupus activity and severity.
A cross-sectional database at the University of Chicago recorded disease activity, damage, disease manifestations, pain, anxiety, and physical function (PF). CT was defined as a heart rate of ≥95 beats per minute in at least 3 out of 4 sequential visits. Demographic, disease-specific, and self-reported symptoms were compared between groups with and without tachycardia.
Of the 243 subjects analyzed, 14.8% had CT. On univariate analysis, CT was associated with younger age at the time of enrollment (P = 0.004), number of hospitalizations adjusted for years of SLE (P = 0.001), current prednisone dose (P < 0.0001), history of serositis (P = 0.03), anxiety score (P = 0.004), and poor PF (P = 0.0017). All domains of the Short Form 36 (SF-36) health survey correlated strongly with CT, but on multivariate regression this correlation appeared to be driven by poor PF. On multivariate regression, the Systemic Lupus Erythematosus Disease Activity Index score (P = 0.03), younger age (P = 0.04), and poor PF by the SF-36 domain (P = 0.006) were independently correlated with CT, and anxiety trait and hemoglobin both trended closely to significant association (P = 0.08 for both).
CT is prevalent in SLE and is a clinically relevant physical finding. It implies greater lupus activity and physical frailty. Univariate association with serositis raises the possibility of subclinical serositis or pancarditis. Further study to elucidate the cardiopulmonary status of SLE patients with unexplained CT is planned.