[Comorbidity in internal medicine: analysis of a caseload of 4,156 subjects at their first hospitalization].

The prevalence of comorbidities in patients dismissed from hospitals has already been investigated to obtain economical, administrative and epidemiological information, or for health insurance-related problems. Originally designed for billing purposes, administrative data could be the basis for clinical research as well, although the clinical element has somehow been disregarded till now. The aim of this research is (i) to study the prevalence, and (ii) to evaluate the clinical relevance of comorbidities in patients dismissed from a Department of Internal Medicine. In a recent series of 1605 patients (since the Diagnosis-Related Groups-DRG-based hospital financing system has come into common use in Italy) comorbidities have been observed in 92.65% of the cases, while the percentage of comorbidities was rated as 71.97% in a previous series of 2551 patients dismissed from the same Department before the introduction of the DRG system. In the recent series, the prevalence of a single comorbid condition and of two and of three comorbid conditions was 19.50, 32.89 and 47.61%, respectively. In any case, the so-called comorbid conditions were active diseases requiring medical investigation and therapy. They included hypertensive heart disease, ischemic heart disease and angina, arrhythmias, peripheral vascular diseases, chronic bronchitis, chronic hepatitis, liver cirrhosis, diabetes, metabolic disorders, etc. In conclusion, patients referred to a Department of Internal Medicine have a high severity of illness due not only to the gravity of the primary diagnosis but also to the number and seriousness of comorbid conditions. For these patients more hospital resources and a high level of professional skill are required.