RSY Lee, EKT Yue, JCY Lee

Abstract

Objective: To evaluate the benefit of providing approximately 2 mmol Calcium/kg/day in parenteral nutrition for premature infants less than 1200 grams. Methods: This was a retrospective study of two historical cohorts. The Low Calcium group was from 2008 to 2012 when inorganic phosphate was used as ingredients for preparing parenteral nutrition. Parenteral nutrition provided 1.3 mmol Calcium/kg/day and 1.3 mmol Phosphorus/kg/day. The High Calcium group was from 2015 to 2017 when sodium glycerophosphate (organic phosphate) was used. Parenteral nutrition provided approximately 2 mmol Calcium/kg/day (1.8-2.2 mmol/kg/day) and 1.7 mmol Phosphorus/kg/day. Results: Fewer infants had radiological evidence of metabolic bone disease of prematurity in the High Calcium group than in the Low Calcium group (0/40 versus 6/47, p=0.02). There were significantly fewer cases of hyperphosphatasia as defined by peak alkaline phosphatase (ALP) level more than 800 IU/L in the High Calcium group than the Low Calcium group. Hypophosphataemia (serum phosphate level <1.33 mmol/L) lasting longer than 2 weeks was less common in the High Calcium group than the Low Calcium group. ALP levels were significantly lower and serum calcium and phosphate levels were significantly higher across week 0 to week 12 in the High Calcium group than the Low Calcium group. There was drop in z-score for length from birth to 37 weeks. The drop in z-score was not significantly different between the two cohorts. Conclusion: The proxy measures of metabolic bone disease of prematurity (high ALP and low phosphate level) are improved and radiological evidence of metabolic bone disease of prematurity is reduced by the prescription of higher doses of calcium and phosphate in parenteral nutrition.