To the Editor,
Understanding the factors that can affect the prognosis of patients admitted into hospital due to heart failure and the resources used during their treatment is becoming more relevant. Therefore, recent multi-center data from various Spanish hospitals1 have been analyzed for the impact of comorbidity on the development of heart disease in patients who have been admitted to internal medicine units. The authors1 detected other conditions in 60% of heart disease patients, which is described as comorbidity and, although this was not associated with the multi-variable analysis, they concluded that the increase in comorbidity measured by the Charlson's index (Chi)2 is linked to greater levels of mortality.
According to clinical records, in 2008, 130 patients suffering from DRG-127 (diagnosis-related group, heart failure and shock) were admitted in the cardiology department of our tertiary hospital. We analyzed hospital stays longer than the standard 7.9 days in relation to different variables. The age was 71.5 years (median), 48.5% were female and they were described as pluripathological patients (with 2 or more conditions), using the definition of an expert committee.3 A series of patients admitted to internal medicine units showed a prevalence of pluripathology in 42% of the cases.4 Concomitant diseases3 were: 25% of a rheumatic nature or chronic kidney failure (II); 33.8% respiratory (III); 4.4% chronic inflammatory intestinal disease or hepatopathy (IV); 16% neurological (V); 11.8% peripheral arteriopathies or diabetes mellitus with visceral repercussions, excluding the coronary (VI); and 14.7% secondary oncological or hematic conditions not requiring specialist treatment (VII). Of these patients, 87% were pluripathological3,4,5,6 and 69% had been previously admitted to the unit; 48.5% suffered from auricular fibrillation and 32.4% from anemia. By logistical regression analysis, a hospital stay longer than 7.9 days was only associated with auricular fibrillation (odds ratio [OR]=2.48; 95% confidence interval [CI], 0.88–6.99; P=.04) or anemia (OR=3.4; 95% CI, 1–11; P=.02), conclusions which were similar to those of other authors.7,8
Chi has been questioned as an indicator of comorbidity because it only estimates life expectancy, as each category is associated with an adjustment based on 1-year mortality risk. Nevertheless, the classification we used takes into account the effects of comorbidity3,4,5,6,9 on the biology of the patient. In our series, we did not find any relationship between comorbidity and hospital mortality, probably due to the size of the sample and the methodology applied. It has been stated that patients referred to cardiology units suffer less comorbidity.1 Our analysis reveals a high level of comorbidity in admitted heart disease patients who were subsequently monitored as heart disease outpatients and their comorbidity had no repercussions related to long hospital stays.
Corresponding author. manuel.mora@telefonica.net