Background: The relationship between KD type and outcomes is not well described. We sought to describe the incidence of KD outcomes based on type of KD presentation.
Methods: Using an electronic medical record, we prospectively recorded clinical data for each KD encounter (initial treatment, 2 and 6 week follow up visits) for all pts treated with IVIG at our hospital and followed in our KD clinic from 11/2012-9/2014. Pts were grouped by KD type as determined on the day of treatment - Complete, Incomplete, or questionable KD (qKD), defined as incomplete KD and < 3 supplemental lab criteria. Late treatment was defined as IVIG given at > 10 days of fever. The correlation of KD type with outcomes of persistent fever requiring repeat IVIG, development of periungual peeling (PP), and coronary abnormalities (CAA) was assessed using chi-square.
Results: We studied 109 pts treated with IVIG; 95 were treated within 10 days of fever onset (14 late). Late treatment was most common in qKD (9/19=47%) compared to Incomplete (4/22=18%) and Complete (1/68=1.5%), p<0.01. PP was least common in qKD (4/19=21%), compared to Incomplete (12/22=54%) and Complete (49/68=72%), p<0.05. No pts with qKD developed CAA, compared to 5/67 (7%) of Complete and 3/18 (16%) of Incomplete pts treated within 10 days of fever, (p=0.16, NS). Late treatment more commonly had CAA (5/14=36%, v. 8/95=8%), relative risk = 4.2 (p=0.003). In pts with CAA, 10 /13 (77%) had CAA on the first echocardiogram. The remaining 3 pts (2 Complete, 1 Incomplete) had a pericardial effusion initially and developed CAA by the second echocardiogram. Need for repeat IVIG was not different between groups (Complete 16/68 = 24%, Incomplete 3/22=14%, qKD 2/19=11%, p=0.33). Of the 2 qKD pts who required a second dose of IVIG, one was subsequently diagnosed with juvenile idiopathic arthritis and the other with Bartonella henselae; neither developed PP or CAA.
Conclusions: The incidence of CAA was not statistically different between KD types, though no qKD pts developed CAA despite a higher incidence of late treatment with IVIG. In most pts who developed CAA, the initial echocardiogram showed either CAA or a pericardial effusion. PP was least common in qKD. In qKD, failure of initial IVIG should prompt re-evaluation of the diagnosis of KD.