Vasculitis of the coronary arteries is a well-recognized acute complication of Kawasaki disease, but the long-term risk of cardiovascular (CV) sequelae does not appear to be clinically meaningful for most patients, according to results from an analysis of data presented at the annual meeting of the Canadian Rheumatology Association.
For patients and parents, these data provide “a message of reassurance,” according to Jennifer J.Y. Lee, MD, a pediatric rheumatologist affiliated with the Hospital for Sick Children, Toronto.
The long-term outcomes were characterized as reassuring even though rates of hypertension, major adverse cardiac events (MACE), and death from CV events were higher in patients with Kawasaki disease relative to controls in a retrospective data-linkage study. In fact, these differences were highly statistically significant, but the absolute differences were extremely small.
For this analysis, the 1,174 patients diagnosed with Kawasaki disease at Dr. Lee’s institution between 1991 and 2008 were compared in a 10:1 ratio to 11,740 controls matched for factors such as age, sex, ethnicity, and geographic region. The median follow-up period was 20 years, and the maximum was 28 years.
Adjusted CV risks are significant
In an adjusted Cox proportional hazard ratio model, patients in the Kawasaki group had a more than twofold increase in risk for hypertension (aHR, 2.3; P < .0001) and all-cause mortality (aHR, 2.5; P = .009). They also had more than a 10-fold increase in risk for MACE (aHR, 10.3; P < .0001).
These statistics belie the clinical relevance, according to Dr. Lee. Because of the very low rates of all the measured events in both groups, there was just one more case of hypertension per 1,250 patient-years of follow-up, one more case of MACE per 833 patient-years of follow-up, and one more death for 3,846 patient years of follow-up.
Moreover, when these outcomes were graphed over time, most events occurred during the acute period or in the initial years of follow-up.
“There was not a constant increase in risk of these outcomes over time for patients with Kawasaki disease relative to the controls,” Dr. Lee reported. “The long-term prognosis for Kawasaki patients remains favorable.”
European group reports similar results
Similar results from a single-center experience were published 3 years ago. In that study, 207 Kawasaki patients treated at the University of Lausanne (Switzerland) were followed for 30 years. Complications after the acute phase were characterized as “rare.”
For example, only three patients (1.4%) had a subsequent episode of myocardial ischemia. All three had developed a coronary aneurysm during the acute phase of Kawasaki disease. The authors of that study reported that children who had not received immunoglobulins during the acute phase or who developed Kawasaki disease outside of the usual age range were more likely to have subsequent events, such as disease recurrence.
Other studies of long-term CV outcomes in patients with Kawasaki disease generally show similar data, according to James T. Gaensbauer, MD, a pediatric infectious disease specialist at the Mayo Clinic, Rochester, Minn.
“I generally agree with the premise that major complications are rare when you compare a cohort of patients with Kawasaki disease with the general population,” Dr. Gaensbauer said. However, he added, “I do not think you can say no one needs to worry.”