Risk factors for infections requiring hospitalization in renal transplant recipients: a cohort study. 
Our aim was to analyze a retrospective cohort of renal transplant recipients to determine the risk factors for infections that require hospitalization.  This was a cohort study that included patients who had received kidney transplants from January 1990 to December 2003.  The statistical analysis was performed according to the distribution of variables, and p<0.05 was considered statistically significant.  We analyzed 366 transplants in 350 patients, of whom 161 (46%) presented with an episode of infection requiring hospitalization.  These 161 patients developed 323 infections (a median of two infections per patient).  The incidence rate was 0.46 episodes per 1000 transplant-days.  Urinary tract infection, pneumonia, bacteremia, and gastroenteritis were the most common diseases.  A high incidence of infections due to Escherichia coli and Enterococcus species, as well as Candida species, was found.  By multivariate Cox model, significant risk factors for infections requiring hospitalization were systemic lupus erythematosus (relative risk (RR) 4.8, 95% confidence interval (CI) 1.64-14.1), cancer (RR 3.81, 95% CI 1.05-13.7), previous renal transplant (RR 5.6, 95% CI 1.4-22.4), history of anti-rejection therapy (RR 3.2, 95% CI 1.3-8.0), and a basal serum albumin concentration<3.5mg/dl (RR 1.77, 95% CI 1.17-2.68).  Interestingly, dyslipidemia (RR 0.5, 95% CI 0.37-0.69) and end-stage renal disease of unknown etiology (RR 0.5, 95% CI 0.3-0.8) were protective factors against hospitalization.  These data suggest that the most common infections requiring hospitalization in our cohort were those caused by microorganisms commonly related with community-acquired infections rather than those classically associated with immunosuppressant therapy.  These findings will be useful for refining medical care.