Author Affiliations: Department of Medicine, Stanford University, Stanford, California (Dr Strunk) (email@example.com); Department of Neonatal Paediatrics, King Edward Memorial for Women and Princess Margaret Hospital for Children, Perth, Australia (Dr Simmer); and Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Australia (Dr Burgner).
To the Editor: Dr Crump and colleagues presented data from a large Swedish cohort on the association of prematurity with mortality in childhood and early adulthood.1 Although they undertook an analysis of cause-specific mortality, the categorization of mortality into largely systems-based phenotypes (such as respiratory, neurological, and endocrine) may have masked the contribution of potentially modifiable determinants of the increased mortality. In particular, there are no data presented on the effect of prematurity on the risk of infection-related mortality because all infections are categorized within affected organ systems as per the International Classification of Diseases (ICD) rather than summarized as a common group (such as mortality due to infection).
Strunk T, Simmer K, Burgner D. Prematurity and Mortality in Childhood and Early Adulthood. JAMA. 2012;307(1):32-33. doi:10.1001/jama.2011.1952