Pharmacoepidemiological safety studies in children: a systematic review

Abstract

Purpose: In order to identify challenges in pediatric pharmacoepidemiological safety studies, we assessed the characteristics of such (published) studies.

Methods: Relevant articles from inception to 2013 were retrieved from Embase and Medline. We sequentially screened titles, abstracts and full texts with independent validation. We systematically collected data regarding general information, study methods and results.

Results: Out of 4825 unique articles, 268 full texts (5.6%) were retained; 147 (54.9%) pertained to drugs rather than vaccines. Considering the 268 studies, 202 (75.4%) concerned children and adolescents (2 to 11 years) and 14 (5.3%) included preterm newborns. Most studies originated from North America (154 [57.5%]) or Europe (92 [34.3%]). Only 47 studies (17.5%) were privately funded. The majority (174 [64.9%]) were cohort studies. Out of 268 studies, 196 (73.1%) collected data retrospectively; paper medical charts were the most common data source for the exposures (85 [31.7%]) and outcomes (122 [45.5%]). Only 3 (2.0%) drug-only studies investigated rarely used drugs. Considering all 268 studies, only 27 (10.1%) reported sample size or power calculation. Most (75 [51.0%]) drug-only studies corrected confounding by multivariate modeling unlike stratification in 66 (55.9%) vaccine-only studies. Considering 75 child-only studies without any statistically significant result, 41 (54.7%) did not discuss lack of power.

Conclusions: Although the field of pediatric pharmacoepidemiology is steadily developing evaluation seldom includes neonates, is mainly focused on few drug classes and safety outcomes and concerns mainly drug use in developed countries. Small study size is a specific challenge in pediatrics. Reporting should be improved. © 2016 The Authors. Pharmacoepidemiology and Drug Safety Published by John Wiley & Sons Ltd.

Keywords: pediatrics; pharmacoepidemiology; systematic review; ‘adverse drug reaction’.

Figure 1

Flow chart depicting the selection of relevant papers

Figure 2

Number of pharmacoepidemiological safety studies in children. Note: In order to retrieve all published pharmacoepidemiological safety studies that investigated the general population, we applied the same search algorithm that was utilized for studies in children except that for the former, we did not limit to the pediatric population; papers that were published in 2013 are those papers that were indexed in Embase and Medline as at 29 November

Figure 3

Distribution of papers according to the main divisions of the International Classification of diseases (ninth edition), and type of exposure. Note: ‘Certain conditions originating in the perinatal period’ includes ‘Other conditions originating in the perinatal period’ (764–779) which does not include maternal causes, i.e. Necrotizing enterocolitis (777.5); ‘Injury and poisoning’ includes ‘unspecified adverse effect of drug medicinal and biological substance not elsewhere classified’ (995.2)