Survival of individuals with cerebral palsy born in Victoria, Australia, between 1970 and 2004

Aim: This study used data collected prospectively since 1986 from a population-based cerebral palsy registry to explore the rates, predictors, trends, and causes of mortality for individuals born in Victoria, Australia, between 1970 and 2004.

Method: Data were extracted for 3507 individuals (1972 males; 1535 females). The probability of survival before 31 May 2010 was determined using the Kaplan-Meier method; age-specific mortality rates were calculated per 1000 person-years and related to population rates. Using Cox proportional hazards regression, relative risks of mortality were estimated for different categories of chosen demographic and clinical variables. Causes were tabulated according to the direct cause of death.

Results: There were 418 deaths. Crude mortality was 20% at the age of 40 years. Relative to the population, mortality was highest in children aged under 15 years and decreased to twice the population rate at the age of 35 years. The strongest independent predictor of mortality was no independent ambulation (adjusted hazard ratio 6.2 [95% confidence interval 3.3-11.8]); additional predictors were severe intellectual impairment (3.0 [1.7-5.2]), epilepsy (1.4 [1.1-1.9]), deafness (2.6 [1.4-4.7]), and term birth (1.8 [1.3-2.4]). No improvement in survival was seen over time (unadjusted hazard ratio 1.00 [95% CI 0.99-1.01]). Respiratory causes were the most common direct causes of death.

Interpretation: Rates, predictors, and causes of death for individuals with cerebral palsy in Victoria were similar to those found in other population cohorts. Lack of improvement in survival since 1970 was an unexpected finding that warrants further investigation.