To the Editor: In their study of the relationship
of physical fitness and body mass index to cardiac disease in women, Dr Wessel
and colleagues1 incorrectly converted the Duke
Activity Status Index (DASI) score to peak metabolic equivalent tasks (METs).
The Methods state that the actual score from the DASI questionnaire can be
divided by 3.5 to estimate METs. However, the original article on the development
of the DASI2 states that weighting of items
in the index was based on known metabolic costs, but the sum of the weighted
answers must then be converted to VO2 peak in mL/kg
per minute using the equation VO2 peak = 0.43 × DASI
score + 9.6. METs can then be calculated by dividing the estimated
VO2 peak by 3.5.
Schwark EH. Relationship of Fitness and Body Mass Index to Cardiac Disease. JAMA. 2005;293(2):161-162. doi:10.1001/jama.293.2.161-b