Predictors of ultrasound abnormalities among women treated for community-onset acute pyelonephritis: a prospective...

Acute pyelonephritis (AP) is a common but potentially severe infection. It may be complicated by pyelocaliceal dilatation which requires emergency urine drainage. In outpatient care, ultrasound (US) appears to be the easier way to diagnose pyelocaliceal dilatation, though most APs will not be complicated and do not require immediate ultrasound. We aimed to identify predictors of ultrasound abnormalities in an outpatient AP cohort.

A prospective study was conducted from April 2006 to September 2019 in an outpatient care network. Patients aged 15 and over treated for AP were included. Men, pregnant women, patients with solitary kidney, and patients without data on their management were excluded. A common algorithm ensured the same approach from diagnosis to treatment. Data were collected prospectively in an anonymized database. We described the characteristics of the patients. Univariate and then multivariate analyses were performed to identify predictors of ultrasound abnormalities.

2054 women were treated for AP. Among them, 32.5% (n = 667) had a history of urinary tract infections and 5.8% (n = 120) of uropathy. The most frequent uropathogen was E. coli (n = 1,432; 69.7%); Extended-Spectrum Beta-Lactamases (ESBLs) were found in 39 (1.9%) urine cultures. Ultrasound was abnormal in 7.3% (n = 149). Age over 55 years (OR = 2.23; 95% CI 1.58‒3.15; p < 0.0001) and uropathy (OR = 3.69; 95% CI 2.26‒6.01; p < 0.0001) were independently identified as predictors of ultrasound abnormalities. The risk increased by 1.8% (95% CI 1.0‒2.6) with each additional year of age.

This study identified age and uropathy as independent predictors of abnormal ultrasound in women treated with community-onset AP.