Children often respond differently to health care interventions than adults. This means that systematic review authors must consider specific aspects of childhood when conducting a review. Guidance in this area remains limited, but below are some of the key areas where systematic review authors need to make decisions:
Decision: to focus on child data only, or to include both adult and child data. Base this decision on clinical expertise about the condition and its trajectory at different ages.
Examples: Urinary tract infections present differently in children versus adults so results could be very different for adults and children.
Hodgkin's lymphoma has a typical age of onset of adolescence to mid-adulthood so physiological differences between children and adults are likely minimal.
Suggestion: if there is likely to be physiological or developmental differences along the age span included in the review, plan a priori subgroup analyses to avoid masking these differences.
Age-based treatment effects
Decision: in children of 0 - 18 years, age-based treatment effects may be expected. Consider where there may be important similarities or differences in terms of physiological and psychosocial development when planning a priori subgroup analyses.
Suggestion: consider the following questions when planning age-based analyses:
1. Is there any evidence of a different/distinct form of the condition at different ages in childhood?
2. Is there any evidence that different etiological factors may be operating at different ages for that disease?
3. Is the intervention largely behavioural and therefore likely to vary according to age because of different degrees of understand and participation by the child/family unit?
Decision: selection of a priori outcomes based on sound knowledge of disease trajectory and children's development. Relevant short-term outcomes may differ for adults and childre, or different tools may be used to assess similar outcomes.
Suggestion: recognize that benefits and harms of treatment for children may unfold over decades of life and this may influence the outcomes assessed and study designs to be included.
Table 2 in the paper below presents clinical areas for which studies have been done that develop or apply methodology for selecting outcome domains or outcomes to be used in clinical trials in children younger than 16 years of age, as of 2008.
Decision: which pediatric-search filters will identify material that may use varying definitions of "child" and may be inconsistent in indexing pediatric material. A librarian with experience using pediatric-search filters will be helpful.
Suggestions: "Recommended precise and sensitive PubMed systematic review and child search strategies" will be of assistance.
· Boluyt N, Tjosvold L, Lefebvre C, Klassen TP, Offringa M, “Usefulness of Systematic Review Search Strategies in Finding Child Health Systematic Reviews in MEDLINE.” Arch Pediatr Adolesc Med, 162:2, 2008.
We are grateful for the contributions from Drs. Hywel Williams (for suggesting the questions for planning age-based analyses) and Eyal Cohen.