White Coat Hypertension in Ex-Preterm Children Associates With Higher Ngal Levels

Objective: As preterm birth is a risk factor for hypertension (HTN), biomarkers for early detection of HTN in childhood is an emerging need. The aims of the study were to evaluate serum biomarkers in ex-preterm children and examine for associations with blood pressure (BP) phenotypes using both office BP and ambulatory BP monitoring to classify BP levels. Design and method: This prospective case-control study included 52 children and adolescents born prematurely (ex-preterms) and 22 ones born at full term (controls). All participants underwent office and ambulatory BP monitoring, and assessment of serum biomarkers at the same clinic visit. Neutrophil gelatinase-associated lipocalin (NGAL), matrix metalloproteinase-2, -9 (MMP-2, -9), and Cystatin C (CysC) were measured using enzyme-linked immunosorbent assay. Results: Mean age of the population was 10.74±3.55 years. 31% of the ex-preterm children and 23% of the controls had white-coat hypertension (WCH). Among ex-preterm children and adolescents 17% had ambulatory HTN and 31% had white-coat HTN. Among controls 23% had WCH while none of the children and adolescents in the control group had ABP HTN. NGAL, CysC, MMP -2, and -9, levels did not differ between BP phenotypes in the study population. When ex-preterm group was analyzed separately, NGAL levels were found higher in ex-preterm children with WCH compared to children with normal BP in the ex-preterm group [57.89 (IQR 50.79) versus 34.58 (IQR 46.22), p=0.018}. Receiver operator curve analysis showed that NGAL could be a significant predictor of WCH in the ex-preterm group with area under the curve (AUC) of 0.718 (95% CI 0.56-0.87, p = 0.005) (Figure). Conclusions: As WCH is common in ex-preterm children and adolescents and is associated with higher NGAL levels, regular BP measurement in children with history of prematurity or low weight at birth is recommended because of their increased risk of HTN and cardiovascular disease in the future.