ABSTRACT
The term ‘‘comorbidity,’’ introduced by Feinstein, refers to the presence of any additional coexisting ailment in a patient with a particular index disease (3). Failure to classify and analyze comorbid diseases can create misleading medical statistics and may cause spurious comparisons during the evaluation and treatment planning for patients. Comorbidity can alter the clinical course of patients with the same diagnosis by affecting the time of detection, prognostic anticipations, therapeutic selection, and post-therapeutic outcome of an index diagnosis (4). In addition, it can also affect the length of hospital stay, response to somatic treatment, and mortality (5-7).
