Cystatin C: A more reliable biomarker of renal function in young infants? A longitudinal cohort study

AIM: We carried out a longitudinal cohort study to measure serial CysC (Cystatin C) in a cohort of neonates born preterm until the age of 2 years. We hypothesised that CysC levels are independent of body weight and would not vary with gestational age. METHODS: This prospective cohort study was conducted from August 2014 until October 2016, and follow‐up was completed in October 2018. Preterm infants at less than 28 weeks of gestation (extremely preterm infants) were recruited and followed up until the age of 24 months. Blood samples for measurement of CysC were collected at regular intervals. RESULTS: We recruited 58 preterm neonates with mean gestation was 26.2 (1.5) weeks, and a mean birth weight was 917 (140) g. One‐way analysis of variance (ANOVA) did not show any significant difference in CysC levels between 28, 32 and 37 weeks' gestation (P = .09) despite a significant increase in body weight (P < .001). The mean CysC level was higher in the neonatal period and subsequently plateaued by 24 months. CONCLUSION: Serum CysC level is independent of body weight and not influenced by postnatal age nor by gender.