BACKGROUND: Many patients admitted to a Department of Internal Medicine have 
different degrees of heart and kidney dysfunction. Mortality, morbidity and cost 
of care greatly increase when cardiac and renal diseases coexist.
METHODS: A retrospective cohort study was conducted on 1,087 patients admitted 
from December 2009 to December 2012 to evaluate the prevalence of the 
cardiorenal syndrome (CRS) and clinical features.
RESULTS: Out of 1,087 patients discharged from our unit during the study period, 
190 (17.5%) were diagnosed as having CRS and classified into five types. CRS was 
more common in males (68.9%). CRS type 1 was associated with higher age (79.9 ± 
8.9 years) and accounted for 61.5% of all deaths (p < 0.001), representing a 
risk factor for mortality (OR 4.23, 95% CI 1.8-10). Congestive heart failure was 
significantly different among the five CRS types (p < 0.0001) with a greater 
frequency in type 1 patients. Infectious diseases were more frequent in CRS 
types 1, 3 and 5 (p < 0.05). Pneumonia presented a statistically higher 
frequency in CRS types 1 and 5 compared to other classes (p < 0.01), and 
community-acquired infections were statistically more frequent in CRS types 1 
and 5 (p < 0.05). The distribution of community-acquired pneumonia was different 
among the classes (p < 0.01) with a higher frequency in CRS types 1, 3 and 5.
CONCLUSION: CRS is a condition that is more frequently observed in the clinical 
practice. The identification of predisposing trigger factors, such as infectious 
diseases, particularly in the elderly, plays a key role in reducing morbidity 
and mortality. An early recognition can be useful to optimize therapy, encourage 
a multidisciplinary approach and prevent complications.