Urinary Tract Infections in Elderly Residents of a Long-Term-Care Facility: Etiology, Risk Factors and Costs

Background: In the United States, 1.6 - 3.8 million infections occur each year at long-term care facilities, and urinary tract infections are the most important, accounting for 25% to 30% of all bacterial infections and occurring at an incidence rate of 0.1 - 2.4 cases per 1,000 resident-days. Objective: To describe the characteristics of urinary tract infections in elderly residents of a long-term care facility in Brazil using epidemiologic methods, and to assess their risk factors and cost.

Methods: This cohort study was conducted at the Albert Einstein Long-Term Care Facility (São Paulo, Brazil) from June 01, 2006 to October 17, 2009. Epidemiological and clinical characteristics of the cases of urinary tract infection were described by chart review. All statistical analyses were performed using SPSS for Windows (SPSS Inc., Chicago, IL), version 10.0. Categorical variables were analyzed using chi-square or Fisher’s exact test. Continuous variables were compared using the Student t test for normally distributed variables. Univariate analysis was conducted for potential risk factors for urinary tract infection, and variables with a P value < .05 were included in the stepwise forward analysis (logistic regression model). A two-tailed P value < .05 was considered statistically significant.

Results: The incidence rate of urinary tract infections was 0.5 per 1,000 residents-day. Sixty-two percent of the residents were women and their ages ranged from 62 to 102 years (median: 85 years). Eight percent were cases of asymptomatic bacteriuria. Ten percent were polymicrobial infections, and Escherichia coli was the most frequently isolated microorganism (37.0%). We found moderate levels of antibiotic resistance, i.e. 26% of all etiologic agents were resistant to ciprofloxacin, 19% were resistant to sulfamethoxazol-trimethoprim, and 17% were resistant to nitrofurantoin. The mortality rate was 1%. The total cost was US$ 42,848.50 and the individual costs ranged from US$ 14.30 to US$ 3,107.50. Using a conditional logistic regression model, we found that age (RR, 1.02 per year; 95% CI, 1.01 – 1.03) and recurrent episodes of urinary tract infection (RR, 3.43; 95% CI, 1.24 - 9.50) were independent risk factors for urinary tract infection in this long-term care facility.

Conclusions: The analysis of risk factors, cost and etiology related to urinary tract infection in Long-Term Care Facility is important as a mean to identify vulnerable individuals and help define prevention and/or surveillance strategies.