Estimating the prevalence of malformation of the heart in the first year of life using capture-recapture methods

The authors estimated the prevalence of heart malformation during the first year of life, using five data sets with varying degrees of completeness fr om two English regional health authorities. These areas covered a total pop ulation of 6,872,000. analysis was carried out using capture-recapture meth ods, including log-linear modeling, on data collected between June 1993 and August 1994. A large number of cases in the community were unrecorded by a ny of the current sources of information. In South East Thames, where an an tenatal training screening program for detecting heart malformations had be en implemented in the late 1980s, the estimated prevalence rate varied from 5.5 per 1,000 births (95% confidence interval (CI): 3.5, 10.8) to 9.0 per 1,000 births (95% CI: 6.4, 14.2), depending on the assumptions in the model and the number of sources used in the analysis. In the Wessex region, whic h did not have a formal training program, prevalence was lower and varied l ittle, from 4.3 per 1,000 (95% GI: 3.4, 6.0) to 5.1 per 1,000 (95% CI: 4.0, 7.2), according to assumptions. These two estimates were reasonable rates in comparison with reports in the literature. This analysis was helpful in demonstrating that the training program designed to identify severe heart m alformations during the antenatal period in one of these regions had no las ting impact on prevalence.