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Re: Survival analysis by congenital anomaly sub type is needed

Dear Editor

We commend the study by Dastgiri and colleagues [1] as both timely and informative. There are few published papers describing the survival of children with congenital anomalies, especially reporting survival beyond the first year of life. Those which do exist mainly describe the survival of children with Down’s syndrome [2] or spina bifida,[3] but there is either limited information based on single studies for certain congenital anomaly subtypes, or no information at all. As population based information on the long-term outcome of children with a range of congenital anomalies is lacking, there is little accurate information for parents or health professionals.

Using data from a population-based register of congenital anomalies, Dastgiri and colleagues describe survival to five years of life, with 97% follow up achieved. However, the major limitation of the study is the description of survival pattern by major congenital anomaly group. Presumably the rationale for classifying cases by major group was that subtype analysis would have resulted in very small numbers. However, this analysis is misleading as the groups represent a spectrum of conditions which vary widely in their lethality. For example, neural tube defects include anencephaly, spina bifida, and encephalocele, which are known to vary greatly in outcome. Anencephaly is a lethal condition, whereas children born with spina bifida may survive many years. For example, using data from the Northern Congenital Anomaly Survey,[4] out of 199 cases of spina bifida reported to the Survey between 1985-2001, only 31 died within the first week of life.

We agree with Dastgiri and colleagues in their call for further outcome studies. Such information from long-term prospective follow up studies is required both to give appropriate information to parents and health professionals when an antenatal diagnosis is confirmed, and also to identify factors associated with successful outcome. Many individual anomalies are uncommon and knowledge of outcomes would require data from high quality, long-standing congenital anomaly registers with good case ascertainment and consistent diagnostic coding. Analyses should be extended to go beyond five years of age and take into account the influence of clinical characteristics (e.g. presence of additional anomalies, birth weight, gender, plurality) on survival. Children born with congenital anomalies have complex health and social care needs, with cost implications for health service planning. Thus there remains the need to understand and improve the survival and quality of life for these children, and to accurately plan for their future care needs.

References

(1) Dastgiri S, Gilmour WH, Stone DH. Survival of children born with congenital anomalies. Arch Dis Child 2003;88:391-94.

(2) Leonard S, Bower C, Petterson B, Leonard H. Survival of infants born with Down’s syndrome: 1980-96. Paed & Perinat Epidemiol 2000;14:163-71.

(3) Wong L-YC, Paulozzi LJ. Survival of infants with spina bifida: a population study, 1979-94. Paed & Perinat Epidemiol 2001;15:374-78.

(4) Northern Regional Survey Steering Group. Fetal Abnormality: an audit of its recognition and management. Arch Dis Child 1992;67:770-74.