Prevalence, mortality and lethality of congenital heart defects from the Tuscan Registry (Tuscany Region, Central Italy), 1992-2009

OBJECTIVES: to estimate prevalence, mortality and lethality of congenital heart defects (CHDs), and to evaluate time trend by comparing two birth cohorts (1992- 2000 vs. 2001-2009). DESIGN: descriptive study using a population-based registry: the Tuscan Registry of congenital defects (RTDC), which is a member of the European network of surveillance of congenital anomalies (EUROCAT) since 1979. SETTING AND PARTICIPANTS: CHD cases were collected by the RTDC between 1992 and 2009. MAIN OUTCOME MEASURES: prevalence and mortality rates were calculated for all and non-chromosomal CHDs. The non-chromosomal cases were classified in three severity classes (SI, SII, SIII), according to decreasing perinatal mortality. It was estimated prevalence of: live births, foetal deaths (stillbirths and spontaneous abortions from 20 weeks gestation), terminations of pregnancy for foetal anomaly (TOPFAs) at any gestational age, and of prenatally diagnosed cases. Perinatal, neonatal and infant mortality were calculated. Early-neonatal, neonatal and infant lethality were calculated for the non-chromosomal cases. RESULTS: 3,653 cases were identified out of 486,947 live births and 1,883 stillbirths, 95% of which were non-chromosomal cases. The total average prevalence was 7.47/1,000 births. The overall prevalence decreased significantly in all CHDs (Prevalence ratio - PR: 0.86; 95%CI 0.80-0.91) as well as in non-chromosomal (PR: 0.86; 95%CI 0.80-0.92), while in the more severe defects (SI/SII combined cases) the total prevalence was stable over time. In more severe cases, prevalence of live births decreased significantly (PR: 0.83; 95%CI 0.71-0.97), while the greater increase of TOPFAs and of diagnosed cases was observed in the prenatal period. All three mortality rates reduced significantly over time. In the more severe cases, the greatest rate mortality reduction was observed for neonatal mortality (Mortality ratio - MR: 0.29; 95%CI 0.16-0.49) than perinatal (MR: 0.37; 95%CI 0.19-0.70) and infant mortality (MR: 0,40; 95%CI 0.28-0.56). In this group of CHDs, early neonatal lethality decreased from 10% to 3%, neonatal lethality from 17% to 6%, and infant lethality from 24% to 10%. CONCLUSIONS: the results suggest that the improvements in prenatal diagnosis and in foetal and neonatal treatment and care have reduced the burden of congenital heart defects on the health of the Tuscany population.