We read the article by Kosiv KA et al1 with great interest and appreciate the authors’ efforts to analyze many cases of trisomy 13 and 18 with congenital heart disease. However, we would like to raise 3 concerns.
First, we believe that authors should describe the inclusion and exclusion criteria in greater detail. In particular, the definition of second admission was unclear, and additional detail about excluded cases would be welcome. The authors excluded cases with a second admission within 14 days. Under these criteria, however, patients who were discharged within 14 days for elective surgery might also have been excluded, which might have led to selection bias. Accordingly, we would appreciate the authors providing a breakdown of excluded cases and conduct a sensitivity analysis on the schedule of admission.
Second, the waiting time for surgery was considered immortal because patients needed to survive until they underwent surgery. Given the possibility that those patients who died before surgery were included in the control group, we are concerned that the study may have led to immortal bias2 and overvaluation. To examine this effect, we would like the authors to clearly state the cause of death in the congenital heart surgery (CHS) and no CHS groups, along with the number of survivors in each survival period. A sensitivity analysis with the exclusion of infants with extremely early death would also be useful.
Finally, we are concerned that adjustment for potential confounding factors was insufficient.3,4 Given that the surgery was conducted earlier in this study than in previous studies, patients in the CHS group may have received a prenatal diagnosis, and their family income may be high.4 We therefore recommend that the authors add the data for these confounding factors or adjust for them.
Potential Conflict of Interest: The authors have indicated they have no potential conflicts of interest to disclose.
- Kosiv KA,
- Gossett JM,
- Bai S,
- Collins RT II
- Lévesque LE,
- Hanley JA,
- Kezouh A,
- Suissa S
- Bruns DA,
- Martinez A
- Copyright © 2018 by the American Academy of Pediatrics