Retrospective cohort study of individuals born with low birthweight: implications for screening practices

BACKGROUND: Previous studies have established an association between low birthweight (LBW) and future kidney disease, but few have explored the progression of kidney dysfunction through the pediatric years leading up through adolescence and young adulthood. METHODS: To better understand the temporal effects of birthweight on kidney disease progression, we conducted a retrospective cohort study comparing the glomerular filtration rate (GFR) between LBW (<2500 grams) and normal birthweight (NBW) infants who were admitted to the neonatal intensive care unit (NICU) at our institution from 1992 to 2006. RESULTS: Age at follow-up ranged 1–26 years old. GFR was found to be significantly lower in participants born with LBW than those born with NBW, with a mean difference of 5.5 mL/min/1.73m(2) (P < 0.01). These differences were found in the adolescent and young adult age group over 9 years of age, specifically in the extremely low birthweight group (ELBW) whose birthweight was less than 1000 grams. CONCLUSIONS: We recommend screening for CKD in ELBW individuals starting at the age of 9 years old, regardless of their previous medical history.