Sir.—In their article, Ellerstein and Ostrov describe weight gain patterns in hospitalized infants with "caloric-deprivation failure to thrive."1 Their exploration of this understudied phenomenon is most welcome. However, their report suffers from an omission common to most of the published literature on failure to thrive (FTT): the degree of malnutrition of the patients was not assessed.
The data analysis presented group patients by age and so we assume that this is the most relevant variable affecting the recovery rate. Yet, without information on the patients' nutritional status (beyond the usual weight percentile criteria), the unstated assumption that like-age patients were comparably debilitated cannot be supported. In fact, it is likely that the patients studied included a rather wide range of malnutrition (from marginal to very severe) and that the rate of weight gain, length of hospitalization, and complications were related to the degree of malnutrition as well as