A population-based nested case control study on recurrent pneumonias in children with severe generalized cerebral palsy: ethical considerations of the design and representativeness of the study sample

BACKGROUND: In children with severe generalized cerebral palsy, pneumonias are a major health issue. Malnutrition, dysphagia, gastro-oesophageal reflux, impaired respiratory function and constipation are hypothesized risk factors. Still, no data are available on the relative contribution of these possible risk factors in the described population. This paper describes the initiation of a study in 194 children with severe generalized cerebral palsy, on the prevalence and on the impact of these hypothesized risk factors of recurrent pneumonias. METHODS/DESIGN: A nested case-control design with 18 months follow-up was chosen. Dysphagia, respiratory function and constipation will be assessed at baseline, malnutrition and gastro-oesophageal reflux at the end of the follow-up. The study population consists of a representative population sample of children with severe generalized cerebral palsy. Inclusion was done through care-centres in a predefined geographical area and not through hospitals. All measurements will be done on-site which sets high demands on all measurements. If these demands were not met in "gold standard" methods, other methods were chosen. Although the inclusion period was prolonged, the desired sample size of 300 children was not met. With a consent rate of 33%, nearly 10% of all eligible children in The Netherlands are included (n = 194). The study population is subtly different from the non-participants with regard to severity of dysphagia and prevalence rates of pneumonias and gastro-oesophageal reflux. DISCUSSION: Ethical issues complicated the study design. Assessment of malnutrition and gastro-oesophageal reflux at baseline was considered unethical, since these conditions can be easily treated. Therefore, we postponed these diagnostics until the end of the follow-up. In order to include a representative sample, all eligible children in a predefined geographical area had to be contacted. To increase the consent rate, on-site measurements are of first choice, but timely inclusion is jeopardized. The initiation of this first study among children with severe neurological impairment led to specific, unexpected problems. Despite small differences between participants and non-participating children, our sample is as representative as can be expected from any population-based study and will provide important, new information to bring us further towards effective interventions to prevent pneumonias in this population

Prevalence and clinical presentation of constipation in children with severe generalized cerebral palsy

AIM Our aim was to study the prevalence and characteristics of constipation in children with profound multiple disabilities, as data in this area are scarce. METHOD A cross-sectional observational study was performed in specialized day-care centres and schools in the Netherlands. The study included 152 children (81 males, 71 females; mean age 9y 6mo, SD 4y 6mo). Intellectual disability ranged from moderate (7%) to profound (52%) in all participants who also had severe motor disabilities (83% classified at Gross Motor Function Classification System level V). We collected data on defaecation characteristics, food and fluid intake, and laxative consumption using standardized bowel diaries and interviews. Constipation was defined as (1) scybalous, pebble-like, hard stools in over a quarter of defaecations in combination with a defaecation frequency of less than three times per week during a 2-week study period; (2) large stools palpable on abdominal examination; or (3) laxative use or manual disimpaction of faeces. RESULTS Of the studied population, 57% were constipated and 55% used laxatives, 27% of whom showed symptoms of constipation. Daily intakes of water and fibre were below the required standards in 87% and 53% of participants respectively, without a proven relation to constipation. INTERPRETATION Constipation is a common problem in children with severe disabilities. Laxative use is high but dosing is frequently inadequate to prevent symptom