High IL-6 may help predict adverse outcomes in children with pulmonary arterial hypertension

Circulating interleukin (IL)-6 correlates with worse baseline haemodynamics and may be indicative of clinical worsening in kids with pulmonary arterial hypertension (PAH), a recent study has shown.

Using enzyme-linked immunosorbent assays, researchers measured IL-6 levels in serum samples from two cohorts: the Pulmonary Arterial Hypertension Biobank (PAHB; n=175; median age, 13 years; 59 percent female) and the Children’s Hospital Colorado (CHC; n=61; median age, 5 years; 60 percent female).

In the PAHB cohort, the median IL-6 value was 1.42 pg/mL, and those with disease-associated PAH (APAH) saw significantly greater median IL-6 measurements than those with other PAH subtypes (p<0.001). Specifically, IL-6 was highest in those with congenital heart disease-APAH with a repaired congenital shunt.

Nevertheless, each log-unit increase in IL-6 correlated with a significant increase in the odds of developing APAH (odds ratio [OR], 1.86, 95 percent confidence interval [CI], 1.24–2.79; p=0.003), but also led to a significant drop in the odds of idiopathic PAH (IPAH; OR, 0.56, 95 percent CI, 0.37–0.83; p=0.004).

Within 12 months of enrolment, 42 participants in the PAHB cohort underwent right heart catheterization (RHC). In these children, each log-unit increase in IL-6 correlated with a 9.06-mm Hg spike in mean pulmonary arterial pressure (mPAP; 95 percent CI, –0.01 to 18.12; p=0.05).

This was replicated in the CHC cohort, which saw a significant 2.92-mm Hg jump in mPAP (95 percent CI, 0.83–5.01; p=0.006) in association with each log-unit increase in IL-6.