TRENDS IN THE PREVALENCE OF CONGENITAL HEART-DISEASE - COMPREHENSIVE OBSERVATIONS OVER A 24-YEAR PERIOD IN A DEFINED REGION OF CANADA

Objective: To determine the prevalence of congenital heart disease (CH D) in the three Maritime provinces, and to study prevalence difference s among provinces and defined regions within these provinces. Design: Each province was divided by counties into regions. All cases of CHD w ho were born alive in the study area between 1966 and 1989 were entere d in a registry. Prevalences were analyzed for each province and for s elected regions per year, per 1000 live births, and by diagnosis made by one year of age and by the 16th birthday. Comparison was then made with prevalences of a group who had severe lesions. Interventions: Exc epting a small number of CHD cases who were diagnosed by autopsy only, diagnosis was made by pediatric cardiologists using appropriate proce dures, including cardiac ultrasound and cardiac catheterization. Setti ng: The only tertiary care centre for children's heart disease in the provinces of Nova Scotia, New Brunswick and Prince Edward Island, area s of relative geographic isolation (combined population of 1.75 millio n people). Main Results: A statistically significant positive linear t rend occurred in these provinces during the study. The recorded preval ence of CHD in New Brunswick was significantly lower. Pooled prevalenc es by the first and 16th birthdays (8.0 and 12.5 per 1000 live births, respectively) of two regions of highest prevalence for 1980-86 were s ignificantly higher (P<0.05) than the pooled prevalence rate of all th e remaining regions. Prevalence rates of a group with severe lesions w ere stable for 1976-86 in all regions. Conclusions: Differences in pre valence of CHD among provinces and regions were related to ascertainme nt levels. Prevalence of CHD with diagnosis by the first and 16th birt hdays were approximately 8.0 and 12.5 per 1000 live births, respective ly. The prevalence rate of a severe lesion group was s stable measure.