The epidemiology of cardiovascular malformations

Abstract

This thesis is submitted to Newcastle University for the degree of Doctor of Philosophy by Published Work. It includes a series of published papers as well as new unpublished work. Chapter 1 provides an introduction to epidemiology, particularly in relation to the description and analysis of malformations and birth defects. Chapter 2 gives a brief introduction to the complex topic of cardiovascular malformations, in particular the problems of definitions and terminology and the importance of diagnostic hierarchy of multiple malformations. Chapter 3 describes the paediatric cardiology database and the preliminary studies which produced the first five published papers. Chapter 4 presents 10 important papers on aspects of the epidemiology of cardiovascular malformations – which together form the main part of this thesis. Chapter 5 presents a systematic review of published studies of the prevalence of congenital cardiovascular malformations which investigates whether there is any evidence of a real difference between populations. It finds wide variation in the reported prevalence at live birth of all congenital cardiovascular malformations (2-30 per 1000 live births) and of individual malformations and concludes that differences are almost certainly explained by various types of ascertainment bias. Specific malformations predicted to show least susceptibility to ascertainment bias show least variation in reported prevalence. The review makes recommendations for consistent methodology for future reports to allow proper comparison between different populations. Chapter 6 looks forward to consider the directions in which research might go in the future, looking in particular at outcome research and its use in performance analysis, and at future investigations into the aetiology of malformations.