Sanabria A et al. - The WUHNCI did not demonstrate good discriminative power compared with the ACE-27 in a cohort of older patients. To be widely used, instruments developed to measure comorbidities must be reliable in any population. It is believed that the ACE-27 is still the best index to assess comorbidities and that it should be used in studies evaluating the prognostic effect of comorbidities.