Cross-sectional study of osteopenia of prematurity and associated risk factors

Abstract

Background Survival of very low birth weight preterm neonates born at less than 32 weeks gestational age (GA) have continued to improve. In response to this increased survival, osteopenia of prematurity or metabolic bone disease of prematurity (MBDP) became a significant comorbidity. This latter is defined as decreased bone mineral content relative to the expected level of mineralization for a fetus or infant of comparable size or GA seen in conjunction with biochemical and/or radiological changes. Aim The aim of this work was to determine the prevalence of MBDP among neonates aged 6 weeks or more, born before the 32nd week GA and weighing less than 1500 g at birth. The predisposing and contributing factors for the development of the disease were also investigated. Patients and methods This cross-sectional descriptive study comprised 32 neonates aged 6 weeks or more, delivered before the 32nd week and weighing less than 1500 g at birth, among those admitted to the neonatal intensive care unit of Alexandria University Children’s Hospital. The study had been extended over a 6-month period. According to the radiological and biochemical screening tests for MBDP, namely serum Ca, P, and alkaline phosphatase, the babies were categorized as group 1: with biochemical evidence [serum phosphorous (P) 500 IU/l], group 2: with radiological evidence using Koo’s score, and group 3: with no radiological or biochemical evidence. In addition, the contributing and precipitating factors of this bone disease were revised. Results The prevalence of MBDP, based on the biochemical workup and radiological evidence, were 12.5 and 9.4%, respectively. Important risk factors included prematurity, prolonged duration of parental nutrition, delayed full enteral feeding, increased maternal parity, and extended use of theophylline and furosemide. Use of theophylline, low-serum P and high urinary calcium/creatinine (Ca/Cr) ratio were significant predictors of radiological evidence of the disease. Conclusion Routine screening of MBDP by biochemical and radiological means for all preterm infants less than 32 weeks GA is crucial to minimize the risk factors and bony complications and optimize mineral supplementation and enteral feeding.