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Abstract: TH-PO666

Polycythemia in Subjects Born with a History of Preterm Birth and Extremely Low Birth Weight

Session Information

  • Pediatric Nephrology
    November 02, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Developmental Biology and Inherited Kidney Diseases

  • 403 Pediatric Nephrology

Authors

  • Asada, Nariaki, Keio University School of Medicine, Tokyo, Japan
  • Matsumura, Kazuya, Keio University School of Medicine, Tokyo, Japan
  • Matsuzaki, Yohei, Keio University , Tokyo, Japan
  • Awazu, Midori, Keio University School of Medicine, Tokyo, Japan
Background

Low birth weight (LBW) infants have reduced number of nephrons and are at risk of chronic kidney disease (CKD). While capillary rarefaction has been reported in other organs, it had been unknown whether LBW affects peritubular capillary (PTC) development. We recently reported 2 subjects with a history of preterm birth and extremely LBW (ELBW) who showed PTC rarefaction and erythropoietin (EPO)-induced polycythemia in adolescence (Asada N. Pediatr Nephrol 2017). In the present study, we examined the frequency and risk factors of polycythemia in subjects born with preterm and ELBW.

Methods

Thirty-six patients with a history of ELBW whose hemoglobin, eGFR, and urinalysis had been measured were analyzed retrospectively (17 male, 19 female; age at analysis 4-19 years; birth weight 316-998 g; gestational age 22-32 weeks). Polycythemia was defined as hemoglobin levels more than 2 SD above the mean for age and gender for at least 2 consecutive years (>13.5 g/dL under 6 years, >15.5 g/dL from 6 to 12 years, and >16.0 g/dL above 12 years. Expected EPO levels were calculated from hemoglobin levels using an equation of "Log (EPO) = 3.436 – 0.1675 × Hb".

Results

Twelve patients (33.3%) showed polycythemia (7 male, 5 female; age at finding 2-16 years). Serum EPO, evaluated in 4 patients, were higher than expected levels. Birth weight was significantly smaller in polycythemia group (618 g vs 802 g). Gestational age, intrauterine growth restriction, and sex were not associated with polycythemia. In polycythemia group, eGFR was significantly smaller (72.7 vs 106.8 ml/min/1.73 m2), and eGFR less than 90 ml/min/1.73 m2 and proteinuria were found in 9 (75%) and 3 (25%), respectively. In non-polycythemia group, on the other hand, only 5 (21%, P=0.06) and 1 (4%, P<0.05) had reduced eGFR and proteinuria, respectively. Thus CKD was more prevalent in polycythemia group (75% vs 25%, P<0.05). Among perinatal complications, chronic lung disease was significantly associated with polycythemia, while retinopathy of prematurity and acute kidney injury were not.

Conclusion

Polycythemia was observed in one third of subjects born preterm with ELBW, and was associated with CKD.

Funding

  • Private Foundation Support