Abstracts

Rationale: Importance: The number of children with multiple febrile seizures (FSs) within the same febrile illness is largely unknown. Estimates range from 5%-30%. Imprecise estimates can lead to under or overpowering research into the evaluation, treatment and anticipatory guidance of FSs.
Objective: To assess the percentage of children with multiple FSs in the same febrile illness cited in the literature from 2000 to 2020.

Methods: Data Sources: MEDLINE and Embase were searched from January 1 2000 to December 31 2020.

Study Selection: The inclusion criteria were: (1) FS studies that include data on the number of children with multiple FSs in 24 hours or the same febrile illness. Exclusion criteria: (1) studies that did not include sample size data for both complex and simple FSs; (2) prior epilepsy diagnosis or other neurological conditions (3) if a particular disease state was the inclusion criteria and not FSs. For example, if a study examined the rate of FSs within patients with hyponatremia then it was excluded. However, if it examined the rate of hyponatremia within patients with a FS then it was included.

Data Extraction and Synthesis: The extracted information included: prospective versus retrospective, study question, number of patients, country, number multiple of FSs in the same febrile illness, whether the study defined multiple in 24 hours or within the same febrile study, setting such as admitted versus outpatient (emergency department) versus both, year of enrollment, and interventions used. A random effects model was used to estimate the population proportion of multiple FSs within 24 hours or the same illness. The heterogeneity of the proportion between studies was calculated using Cochran’s Q and Higgin’s I2. To test the significance of the heterogeneity, Cochran’s Q is compared to a chi-squared distribution.

Trial Registration: PROSPERO CRD42020191784

Results: 74 studies met the inclusion criteria for a total of 24,008 febrile illnesses with FSs. 64% of the studies were from Asia. The estimated proportion of multiple FSs in the same febrile illness was 0.17 (95% CI: [0.15, 0.18]). However, the 32 studies that included both admitted and patients discharged without admission had a lower proportion 0.13 (95% CI: [0.12, 0.15]) than the 30 studies that enrolled only admitted patients 0.20 (95% CI: [0.16, 0.24]).

Conclusions: This is the largest aggregation of data used to estimate the number of children with multiple FSs within the same febrile illness. Researchers can use this estimate to design future studies while also controlling for biases discussed in this paper. Clinicians could use our estimate in their clinical assessment and to set parental expectations about their child’s chances of having another FS during the current illness.

Funding: Please list any funding that was received in support of this abstract.: Statistical analysis was supported by the Biostatistics Consulting Laboratory, which is partially supported by Award No. UL1TR002649 from the National Institutes of Health’s National Center for Advancing Translational Science.