Decreasing prevalence of cerebral palsy in birth cohorts in South Carolina using Medicaid, disability service, and hospital discharge data, 1996 to 2009.

South Carolina does not have a cerebral palsy registry, so the study relied on linked administrative records rather than a dedicated surveillance system. The data quality and linkage in the administrative sources were not evaluated or monitored. There is uncertainty about misclassification, duplicate entries, and coding influenced by financial incentives. Medicaid records may miss services that were prescribed but unused, not reimbursed, or not billed. The methods did not capture postnatally acquired cerebral palsy or cases first diagnosed after age 4, and they did not exclude milder forms that may have been outgrown. The administrative codes did not allow analysis of cerebral palsy severity or subtype because codes varied across encounters, providers, or sites. Findings from South Carolina may not generalise to other states because of differences in population composition, environmental exposures, and clinical practice. The study included children who died before age 4, and the authors say these deaths need further validation of diagnosis and survival status. The study did not exclude children with progressive neurological disorders.

The paper says a transdisciplinary team secured federal seed funding for the primary study on birth settings and neonatal seizures, and that this cerebral palsy work was conducted as a pilot and quick assessment. No other conflict statement is supplied.

Do not read the falling cerebral palsy prevalence as proof that clinical practice changes reduced cerebral palsy. This study counted diagnosis codes in administrative records, did not evaluate data quality or linkage, and missed postnatally acquired cases or cases first diagnosed after age 4.