Assessment of Renal Function in Adults Born Preterm: The HAPI-Kidney Study

Every year in Canada, 1500 babies are born ≤29 weeks' gestational age (GA) and the majority survive to adulthood. Preterm birth occurs during a critical period of nephrogenesis. Antenatal and postnatal exposure to various insults may permanently disrupt normal kidney development. Indeed, preterm children have reduced nephron number and altered glomerular architecture, which may lead to glomerular hyperfiltration thus perpetuating renal damage. However, the long-term consequences of preterm birth on renal function remain under-studied. The existing reports on glomerular function have yielded contradictory results and were limited by use of imprecise estimates of glomerular filtration rate (GFR) or small sample size. Yet, a registry-based study has shown the increased risk of chronic kidney diseases (CKD) in individuals born preterm. In addition, individuals born preterm have higher blood pressure. As mechanisms for hypertension following preterm birth are being unravelled, the role of the kidneys, which is key in chronic hypertension, is to be determined. So far, we have shown a relationship between smaller kidney size and increased blood pressure. A better understanding of the early markers of kidney dysfunction following preterm birth will facilitate screening and intervention to halt progression to CKD as there are currently no long-term renal follow-up guidelines for individuals born preterm. This proposal builds on our previous works on long-term health outcomes of preterm birth and experimental model of prematurity-related conditions and renal development. We aim to assess glomerular function and renal vasoactive regulatory factors in relation to blood pressure using precise measures in a cohort of young adults born preterm ≤29 weeks versus full-term controls. We further take advantage of our previous assessment of this cohort (Health of Adults born Preterm Investigation (HAPI) - CIHR 2014-18) to evaluate changes in estimated GFR and albuminuria over a 5-year period.