Estimating the prevalence of cerebral palsy in Taiwan: A comparison of different case definitions.

The estimated prevalence of cerebral palsy (CP) worldwide ranged from 0.74 to 3.6 per 1000 live births according to different studies, which may be due to different data sources and case definitions used. We used a representative sample of one million patients (about 1/23 of total population) covered by Taiwan's National Health Insurance (NHI) to estimate the prevalence using different case definitions. Eight years of NHI Research Database claims data for all children born between 1996 and 2000 were reviewed for CP diagnoses. The estimated prevalence of CP (cases per 1000 live births) varied from 4.1 to 1.3 for different case definitions. For a minimum age of 4 years old at diagnosis, a diagnosis made by specialists (pediatricians and physicians of physical medicine and rehabilitation), and the CP diagnosis was mentioned at least three times in claims data, the mean estimated prevalence of CP was 3.2 (95% CI 2.8-3.7). According to this definition, which is most compatible with previous studies, the estimated prevalence in Taiwan was 3.4 (95% CI 2.8-4.0) for boys and 3.1 (95% CI 2.5-3.7) for girls, significantly higher than that in other countries. Additional studies are needed to determine the reasons of higher prevalence in Taiwan.