EPIDEMIOLOGIC AND DIAGNOSTIC ASPECTS OF BACTERIURIA - A LONGITUDINAL-STUDY IN OLDER WOMEN

OBJECTIVE: To examine month-by-month variability of bacteriuria in a c ohort of older women and to evaluate the performance of rapid diagnost ic tests commonly used to indicate the presence of significant bacteri uria. DESIGN: Prospective, observational study. SETTING: Community hou sing sites and a long-term care institution. PARTICIPANTS: Sixty-one w omen, mean age 77.6, took part in the study. MEASUREMENTS: Midstream c lean-catch urine samples and medical information on subjects were coll ected at baseline, and then monthly for 6 months. RESULTS: Bacteriuria alone (greater than or equal to 10(5) organisms per mt) occurred in 1 7% of all urine samples (28% of patients), bacteriuria with pyuria in 15% (26% of patients), and bacteriuria with symptoms in 3% (10% of pat ients). Spontaneous clearance of bacteriuria with pyuria was common (P = .30), as were new occurrences (P = .12) over 6 months of follow-up. For the outcome of bacteriuria with symptoms, sensitivity of urinary diagnostic tests such as bacteria and pyuria on microscopic analysis, and leukocyte esterase on dipstick testing, ranged from 79 to 93%. Neg ative predictive values of these tests approached 100%. CONCLUSIONS: B acteriuria was a very common event, occurring in almost one-fifth of a ll urine samples and one-third of all subjects during 6 months of foll ow-up. Monthly-month follow-up indicates that the natural history of b acteriuria is marked by frequent spontaneous alternation between posit ive and negative events. The high negative predictive value of many si mple diagnostic tests commonly used for urinary tract disease suggests that they can quickly and cost-effectively rule out bacteriuria in th e older female patient.