Validation of central nervous system-induced seizures and other neurological variables in the Swedish Neonatal Quality Register.

Aim: We sought to validate neurological variables and relevant International Classification of Diseases, Tenth Revision (ICD-10) codes in the Swedish Neonatal Quality (SNQ) Register.

Methods: Register data were collected for 351 neonates, born between January 2009 and December 2016, who were treated at a neonatal unit in the Stockholm region on 385 occasions. They were eligible if the check-box for central nervous system (CNS)-induced seizures was ticked. The Register data, including relevant ICD-10 codes, were validated by checking the patients' electronic medical charts.

Results: Most of the neonates were born at term (76%) and weighed >2500 g (80%). The variable CNS-induced seizures had a positive predictive value of 46%. The ICD-10 diagnosis P90.9A had a positive predictive value of 90%. This comprises seizures validated with electroencephalography, amplitude-integrated electroencephalography or continuous function monitoring. The majority of the associated neurological variables in the Register had positive predictive values above 85%.

Conclusion: When the check-box was ticked for central nervous system-induced seizures, most of the neurological variables in the Register had high validity. However, the CNS-induced seizures variable per se had a lower positive predictive value. Future SNQ Register-based studies of such neonatal seizures should also include ICD-10 P90.9A.