Method errors or unexplained biological information?

To the Editor: Left ventricular mass (LVM) is an indicator of cardiovascular status, integrating multiple adverse pathophysiologic influences and a potent, independent predictor of prognosis, making definition of optimal methods to distinguish abnormal from normal LVM a matter of high clinical priority. Different methods have been used to account for body size in the definition of “normal” LVM, and there is agreement that the ratiometric approach is not sufficient to capture the extend of abnormalities, especially in obese populations.1 In the July issue of Hypertension , Chirinos et al2 studied apparently normal members of 2 adult populations aged 35 to 55 and 45 to 84 years old and proposed a new exponent of body height (height1.7) to normalize LVM. This exponent is substantially lower than the allometric signal (height2.7) that we initially proposed,3 from a normal-weight population including infants, children, adolescents, adults, and elderly. It is also lower than other allometric powers (2.5 to 3.0) identified in other young populations and even lower than the exponent of 2 proposed by the Framingham Heart Study in an adult population. The allometric approach to identify left ventricular hypertrophy (LVH) increases the prevalence of LVH, without decreasing the LVH-associated relative risk,4,5 thus increasing the population risk attributable (PAR) to LVH.4,5 PAR is the proportion of the incident disease (cardiovascular event) …