Bias against vitamins?

Townsend Letter for Doctors and Patients,  August-Sept, 2005  by Alan R. Gaby

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A large multicenter trial reported in 1999 that vitamin A given intramuscularly at a dose of 5,000 IU 3 times per week for 4 weeks decreased the risk of the combined outcome of bronchopulmonary dysplasia or death in extremely-low-birth-weight (ELBW) infants from 62% to 55%. This 7% absolute reduction gives a "number needed to treat" of 14 to 15, meaning that for every 14 or 15 infants treated, one additional infant would survive without BPD. This "number needed to treat" is smaller (more favorable) than for many other therapies used in neonates, infants, and adults. Moreover, many neonatal treatment methods have been used despite methodologically weak evidence of safety and efficacy.

To determine whether the evidence regarding vitamin A therapy is being incorporated into clinical practice, a questionnaire was sent to 102 neonatal-perinatal training program directors (TPDs) and 105 randomly selected directors of neonatal intensive care units (non-training program directors, NTPDs) in the United States. Ninety-nine percent of TPDs and 94% of NTPDs responded. In a minority of programs (20% of TPDs, 13% of NTPDs), more than 90% of eligible ELBW neonates were supplemented with vitamin A, whereas in most programs (69% of TPDs, 82% of NTPDs), routine supplementation was not being practiced. The most common reason that TPDs gave for not supplementing with vitamin A was the perceived small benefit, whereas the most common reason given by NTPDs was that they considered the intervention unproven.

Comment: This study demonstrates an inconsistency in practicing evidence-based medicine in neonatal practice, where therapies are often administered on the basis of weaker evidence of safety and benefit than that which supports vitamin A supplementation. Although we have come a long way, many doctors still appear to have a bias against the use of micronutrients. As Paul Simon said, "a man hears what he wants to hear and disregards the rest."

Ambalavanan N, et al. Survey of vitamin A supplementation for extremely-low-birth-weight infants: is clinical practice consistent with the evidence? J Pediatr 2004;145:304-307.

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