FEBRILE URINARY-INFECTION IN THE INSTITUTIONALIZED ELDERLY

PURPOSE: Bacteriuria is common among institutionalized elderly populat ions, but the contribution of urinary infection to febrile morbidity i s unknown because of difficulties in clinical ascertainment. This stud y was undertaken to measure the contribution of urinary infection to f ebrile morbidity using both clinical and serologic criteria. METHODS: Episodes of fever in residents of two long-term care institutions were identified prospectively for 2 years. Serum and urine specimens were obtained initially and at 4 weeks. The proportion of episodes attribut able to urinary infection was determined by both standard clinical cri teria proposed for use in these populations and serum antibody respons e to uropathogens. RESULTS: For 372 fever episodes, 211 met clinical c riteria for infection: 147 (40%) of the respiratory tract; 26 (7%) of the genitourinary tract; 25 (6%) of the gastrointestinal tract; and 13 (3%) of skin and soft tissue. Of the remaining 161 fever episodes, 2 (1%) were noninfectious and 159 (43%) were of unknown origin. The prev alence of bacteriuria for residents with nongenitourinary sources of f ever varied from 32% to 75%. An antibody response meeting serologic cr iteria for urinary infection occurred in 26 (8.3%) of 314 episodes wit h paired sera obtained; 10 (43%) of 23 identified clinically as genito urinary infection, 14 (11%) of 132 unknown, 1 (4%) of 25 gastrointesti nal, and 1 (0.8%) of 122 respiratory. The positive predictive value of bacteriuria for febrile urinary infection identified by clinical crit eria was 11% (95% confidence interval [CI] 4%, 18%) and identified by serologic criteria was 12% (95% CI 7%, 17%). CONCLUSIONS: Urinary infe ction contributes to less than 10% of episodes of clinically significa nt fever in this high-prevalence bacteriuric population. A restrictive clinical definition for genitourinary infection has poor sensitivity and specificity compared with serologic criteria for identification of fever of urinary source, and bacteriuria has a low predictive value f or identifying febrile urinary infection.