Answer to EBM Lesson #3
a. Good study? Control group not adequate.
- Control group is good with regard to age
- The number of cases, given the rarity of SIDS, is reasonably large
- Control group was not screened in the same manner for drugs (blood test for SIDS patients vs. history from parent in the non-SIDS). This is inadequate data collection in the control group; just because the care giver filling out the survey didn’t give a cold medicine doesn’t mean that the other parent, baby sitter, grandparent, or any number of others couldn’t have given one.
- The “qualitative” screen for a cold medicine doesn’t give an indication of how much medicine the infant received, just that there was some amount present.
- This is not a prospective randomized and controlled study. It is a retrospective review that can have all sorts of errors including selection bias.
b. No, the conclusion does not seem to be justified. It certainly doesn’t show that cold medicines are safe either. It does warrant further study, however, regarding the affect of cold medicines on infants.
c. Draw blood from a large group of infants with respiratory symptoms and run the same gas chromatography on it as was done in the SIDS autopsy cases. This will give you the true incidence of how many infants are treated with cold medicines. Even though these results would be retrospective in comparing to SIDS cases, the control group would be similar to the SIDS group.
