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Changes in the prevalence of cerebral palsy for children born very prematurely within a population-based program over
Charlene M T Robertson1, Man-Joe Watt, Yutaka Yasui
1Section of Neurosciences, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada. charlene.robertson@capitalhealth.ca
Insights
Cerebral palsy (CP) rates in extremely premature infants decreased significantly in the last decade, reversing earlier upward trends. This study tracked CP prevalence in infants born 20-27 weeks gestation over 30 years.
Area of Science:
- Neonatal neurology
- Developmental pediatrics
- Public health surveillance
Background:
- Cerebral palsy (CP) is a major concern for extremely premature infants.
- Comparing CP rates across studies is challenging due to variations in birth years and sites.
- Understanding trends in CP prevalence is crucial for improving infant outcomes.
Purpose of the Study:
- To evaluate changes in population-based, gestational age-specific prevalence rates of CP in extremely premature infants.
- To analyze CP trends over a 30-year period in a defined population.
- To identify shifts in CP prevalence in relation to survival rates.
Main Methods:
- A prospective, population-based longitudinal outcome study was conducted.
- Infants born between 20 to 27 weeks' gestational age and 500 to 1249 g birth weight in Northern Alberta (1974-2003) were included.
- Logistic regression with linear spline analysis assessed CP prevalence changes over time.
Main Results:
- CP prevalence per 1000 live births increased until 1992-1994 for both 20-25 and 26-27 weeks' gestational age groups.
- Following 1992-1994, CP prevalence decreased significantly in both groups, reaching 22 and 16 per 1000 live births respectively by 2001-2003.
- Population-based survival rates increased substantially for both gestational age groups during the study period.
Conclusions:
- Population-based CP prevalence rates for extremely premature infants (20-27 weeks' gestation) have shown steady reductions in the last decade.
- These reductions in CP prevalence occurred with stable or decreasing mortality rates.
- The findings indicate a reversal of trends observed prior to 1992-1994, suggesting improved outcomes for this vulnerable population.
Context:
Although cerebral palsy (CP) among extremely premature infants has been reported as a major morbidity outcome, there are difficulties comparing published CP rates from many sites over various birth years.
Objective:
To assess the changes in population-based, gestational age-specific prevalence rates of CP among extremely premature infants over 30 years.
Design:
Prospective population-based longitudinal outcome study.
Setting And Participants:
In Northern Alberta, 2318 infants 20 to 27 weeks' gestational age with birth weights of 500 to 1249 g were liveborn from 1974 through 2003. By 2 years of age, 1437 (62%) had died, 23 (1%) were lost to follow-up, and 858 (37%) had received multidisciplinary neurodevelopmental assessment.
Main Outcome Measure:
Population-based prevalence rates of CP were determined. Logistic regression with linear spline was used to assess changes in CP prevalence over time.
Results:
At age 2 years, 122 (14.2%) of 858 survivors had CP. This diagnosis was confirmed for each child by age 3 years or older. Among those whose gestational age was 20 to 25 weeks, population-based survival increased from 4% to 31% (P<.001), while CP prevalence per 1000 live births increased monotonically from 0 to 110 until the years 1992-1994 (P<.001) and decreased thereafter to 22 in the years 2001-2003 (P<.001). Among those whose gestational age was 26 to 27 weeks, population-based survival increased from 23% to between 75% and 80% (P<.001), while CP prevalence per 1000 live births increased monotonically from 15 to 155 until the years 1992-1994 (P<.001) and then decreased to 16 in the years 2001-2003 (P<.001). For all survivors born in the years 2001-2003, CP prevalence was 19 per 1000 live births.
Conclusion:
Population-based CP prevalence rates for children whose gestational age was 20 to 27 weeks and whose birth weight ranged from 500 to 1249 g show steady reductions in the last decade with stable or reducing mortality, reversing trends prior to 1992-1994.
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