Hyponatremia is a potential risk factor for the development of coronary artery lesions (CALs) identified after acute Kawasaki disease (KD). However, the serum sodium distribution corresponding to the reference intervals differs between infants (< 1 year of age) and older children. We hypothesized the association of serum sodium level with CAL complications differs between infants and older patients with KD.
We analyzed 21,610 population-based patients who developed KD throughout Japan during 2013-2014. We performed multivariable logistic regression analyses to evaluate the association between serum sodium and CAL complications. Additionally, we stratified the serum sodium distribution associated with CAL complications by infants and older patients.
CALs were identified in 158 (3.6%) infants and 302 (1.8%) older patients. Infants were more likely to develop CALs when within the normal sodium range compared with older patients (75% vs. 29%), whereas most older patients developed CALs with a sodium level lower than the reference interval. Serum sodium ≤ 130 mEq/L indicated significantly higher risk for development of CALs in both groups (adjusted odds ratio [95% confidence intervals] = 3.21 [1.65-6.25] in infants and 1.74 [1.18-2.57] in older patients).
Serum sodium distribution associated with CAL complications differed greatly between infants and older patients. Older patients developed CALs with sodium levels lower than the reference interval; however, among infants, hyponatremia was not necessarily a risk factor for developing coronary artery lesion. When considering risk assessments for CALs using serum sodium levels, infants with KD should be distinguished from older patients. Key Points • Hyponatremia is a potential risk factor for the development of coronary artery lesions (CALs) among patients with Kawasaki disease. • However, the serum sodium distribution corresponding to the reference intervals differs between infants (< 1 year of age) and older children. • Most infants developed CALs within the normal sodium range, whereas older patients developed at a range lower than the reference interval. • These findings highlight that when considering risk assessments for CALs using serum sodium levels, infants should be distinguished from older patients.

© 2021. International League of Associations for Rheumatology (ILAR).