Because clinicians ultimately will need to make a dichotomous (yes versus no) decision regarding the use of antibiotics, we dichotomized the obtained probabilities using a cutoff of 5% (ie, we assumed that children with a calculated probability of UTI of ≥5% are diagnosed with a UTI and treated with antibiotics). After obtaining these coefficients, we calculated, for each child in the database, the probability of UTI. We arrived at β coefficients for each predictor in these models using the data set described above. For example, for the nitrite test, we constructed 1 model that included nitrite and SG as predictors and a second model that included only the nitrite test. To do this, we constructed, for each component of the urinalysis, 2 logistic models, 1 with SG and a second without it. To give clinicians a better understanding of the implications of including SG in their diagnostic process, we calculated, for each component of the urinalysis alone and then for combinations of components, the number of children who would have been overtreated or missed with and without SG being considered in the decision-making process. Because 1 of our goals was to evaluate the accuracy of pyuria according to urine SG, we did not require pyuria for the diagnosis of UTI. 3 Cultures not meeting these criteria were categorized as having a negative result. We defined UTI as the growth of at least 100 000 colony-forming units per milliliter of a uropathogen from specimens obtained by using the clean catch method and the growth of 50 000 colony-forming units per mL from specimens obtained via catheterization. We considered the LE result to be positive if the reading was 1+, 2+, or 3+ (0 or trace was considered a negative result).
The test ordered was at the discretion of the provider. Each child either had a standard automated urinalysis, measuring LE, nitrites, white blood cell count per high-powered field (WBC/hpf), and bacteria per high-powered field (hpf), or an “enhanced” urinalysis, 2 measuring LE, nitrites, protein, blood, WBC per mm 3, and bacteria on Gram-stain (with the last 2 components performed manually by a laboratory technician). In children with multiple visits, 1 visit was randomly selected ( Supplemental Fig 1). We excluded children with major genitourinary anomalies (as defined by billing codes) and children with a missing result for the leukocyte esterase (LE) test. We included children <24 months of age who underwent bladder catheterization and who had both an automated urinalysis performed (using the Iris iQ200 Elite urine microscopic analyzer) and a urine culture obtained within a 3-hour window of each other. We conducted a retrospective analysis of data gathered in consecutive visits to the emergency department at the Children’s Hospital of Pittsburgh between 20.
0 kommentar(er)
