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Incidence of severe hyperbilirubinaemia in Switzerland: a nationwide population-based prospective study
  1. S Zoubir1,
  2. R Arlettaz Mieth2,
  3. S Berrut3,
  4. M Roth-Kleiner1,
  5. the Swiss Paediatric Surveillance Unit (SPSU)
  1. 1Department of Pediatrics, Clinic of Neonatology, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
  2. 2Clinic of Neonatology, University Hospital of Zurich, Zurich, Switzerland
  3. 3Swiss Federal Office of Statistics, Neuchâtel, Switzerland
  1. Correspondence to M Roth-Kleiner, Department of Pediatrics, Clinic of Neonatology, Centre Hospitalier Universitaire Vaudois, Avenue Pierre Decker, CH-1011 Lausanne, Switzerland; matthias.roth{at}chuv.ch

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Epidemiological data about severe hyperbilirubinaemia in neonates are scarce. We present results of a nationwide prospective study conducted in collaboration with the Swiss Federal Office for Public Health and the Swiss Paediatric Surveillance Unit (SPSU). Data for all newborn patients ≥35 0/7 weeks of gestational age (GA) born between 1 January 2007 and 31 December 2008 with at least one value of total serum bilirubin (TSB) exceeding the upper limit of exchange transfusion (ET) were included. ET limits are defined as 430 μmol/l for healthy term infants; 370 μmol/l for sick term infants or term infants with haemolysis and 320 μmol/l for preterm infants.1 A check-off form asking for neonates hospitalised with severe hyperbilirubinaemia and a detailed questionnaire were sent to all neonatal and paediatric units in Switzerland to gather clinical data. Repetitive reminders led to a return rate of 98.9%. The study was performed according to the ethical guidelines of the SPSU.

During the study period, 151 185 infants were born in Switzerland of whom 146 288 were estimated with a GA ≥35 0/7 weeks.2 Sixty patients exceeded their respective ET limit representing an incidence of 41/100 000 live births. Males were over-represented (66.7%), 68.3% were born at term, 81.7% were Caucasian. Blood group incompatibility was the most frequent aetiology (table 1). In 25 patients, maximum TSB exceeded 425 µmol/l (25 mg/dl) and only 3 patients had a TSB value >510 μmol/l. Several factors may explain this rather low incidence of severe hyperbilirubinaemia compared with other countries (table 2): (1) Swiss guidelines are conservative (low ET limits, early blood grouping in all unknown or high-risk blood group constellations); (2) prolonged postnatal hospitalisation (vaginal birth: mean 5.6 days; caesarean section: 8.4 days);7 (3) restrictive guidelines for discharge home within the first 48 h, including bilirubin measurement before discharge for risk estimation with Bhutani curves;8 (4) assured outpatient monitoring by a well-developed system of community-based midwives.

Table 1

Causes and comorbidities of severe hyperbilirubinaemia

Table 2

Epidemiological data on hyperbilirubinaemia in Switzerland compared with other Western countries

However, in 10 patients (16.7%) the first TSB measurement was performed only >24 h after the initial description of clinical jaundice and in 8 out of 10 cases this TSB was above ET limits.

Although indication was given in all patients, only in 13 cases (21.7%) ET was performed, without any correlation between performed ET and severity of hyperbilirubinaemia. Of the three cases with TSB >510 μmol/l only one newborn underwent ET.

We conclude that clinical assessment and treatment of jaundiced infants should be improved to further decrease the already low incidence of severe neonatal hyperbilirubinaemia in Switzerland.

Acknowledgments

The authors would like to thank Professor Bucher for assisting in the initial project organisation, Daniela Beeli, SPSU secretary, for coordinating the report forms and the SPSU representatives of the respective paediatric and neonatal units in Switzerland for providing reports as well as all the dedicated physicians for taking care of the patients and helping to complete the questionnaires.

References

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Footnotes

  • Swiss Paediatric Surveillance Unit representatives C Aebi, W Bär, M Bianchetti, A Blumberg, H U Bucher, L Buetti, O Carrel, P O Cattin, A Corboz, P Diebold, P Dolivo, F Farron, M Gehri, E Giannoni, C A Haenggeli, P Hüppi, P Imahorn, C Kind, B Knöpfli, B Laubscher, U Lips, A Malzacher, J Mc Dougall, P Meyer, M Mönkhoff, V Pezzoli, K Posfay Barbe, L Reinhard, F Renevey, H Roten, C Rudin, V Schlumbom, S Sizonenko, C Stüssi, R Tabin, P Terrier, J Wildhaber, M Wopmann, G Zeilinger, A Zemmouri, U Zimmermann.

  • Competing interests None.

  • Ethics approval This study was conducted according to the ethical guidelines of the SPSU and approved by the ethics committee of the University Hospital of Zurich.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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