Which growth parameters can affect mortality in cerebral palsy?

Background: The objective of this study was to identify growth parameters that can affect mortality of cerebral palsy (CP). Method: This was a birth cohort study based on the National Health Screening Program for Infants and Children database along with the National Health Insurance Service, which were linked using a personal identifier number. The birth cohort consisted of 2 191 956 subjects, representing 93.5% of live births from 2007–2011, with maximal 10-year follow-up (range, 5–10 years) until October 2016. Subjects with CP were identified. Growth parameters in terms of birth weight, underweight (weight-for-age below the 3rd percentile), rate of body weight gain were collected, along with all-cause mortality after the age of 1 year. Result: Prevalence of CP was 2.0 per 1000 live births (95% CI, 1.94–2.06). All-cause mortality after the age of 1 year was 0.09 deaths/1000 person-years (95% CI, 0.08–0.09) in the general population (GP) and 2.85 deaths/1000 person-years (95% CI, 2.32–3.50) in subjects with CP during the follow-up. Therefore, the incidence rate ratio for all-cause mortality was 32.15 (95% CI, 25.72–39.76) in subjects with CP compared to GP. Presence of underweight was significantly associated with higher mortality in both subjects with CP and GP, where the adjusted hazard ratio of death was 2.60 (95% CI, 1.93–3.50) at the age of 18–24 months, 3.12 at 30–36 months, 4.37 at 42–48 months, 5.12 at 54–60 months, and 4.17 at 66–71 months. Birth weight did not affect mortality in both subjects with CP and GP after the age of 1 year (p > 0.05). Conclusion: While subjects with CP shows higher mortality, underweight is an important growth parameter that affects all-cause mortality of both subjects with CP and GP. This study urges increased awareness that subjects with CP who are underweight require special care.