Global prevalence of cerebral palsy: A systematic analysis.

The pooled current prevalence figures come only from high-income regions with CP registers. No low- or middle-income region had data recent enough to be included, so the headline 1.5 and 1.6 per 1000 figures do not describe the world. No low- or middle-income region could supply the 10 consecutive years of data needed for a trend, so the documented decline applies only to Europe and Australia. Prevalence varied substantially between regions (I squared about 70%), so a single pooled number hides wide differences. Trend data stopped at different years, between 1995 and 2014, so recent changes may not be captured; the one US region analysed had data only to the early 2000s, and the Swiss region covers a very small population. Studies that identified children with CP from administrative data alone carry a higher risk of bias, because CP is coded inconsistently in those datasets. Where a denominator was not reported it was estimated from the number of cases and the reported prevalence, which adds uncertainty to those rates. Postneonatal CP numbers were small with wide confidence intervals, and the authors say they have less confidence in those trends; some brain injuries close to age 2 years may be recorded as acquired brain injury instead. Low- and middle-income estimates are likely to be underestimates because of deaths before a diagnosis could be made and incomplete case finding.

The individual participating registers report their own funding: the Australian and NSW/ACT registers are funded by the Cerebral Palsy Alliance, the Northern Ireland register by the Public Health Agency Northern Ireland, the Norwegian register by the South-Eastern Norway Regional Health Authority, and the French registers by the Public Health Agency France and the National Institute of Health and Medical Research. No commercial sponsor appears in the funding statement supplied.

Do not read the falling prevalence as a worldwide trend. Only high-income regions in Europe and Australia could supply enough years of data to measure a trend, no low- or middle-income region could, and the birth prevalence reported from two of those regions was more than double the high-income figures.