Obstructive pyelonephritis as a result of urolithiasis in Japan: diagnosis, treatment and prognosis.

OBJECTIVES: To study the current scenario of diagnosis, treatment and mortality of obstructive pyelonephritis secondary to urolithiasis in Japan.
METHODS: The study was a retrospective and multicenter survey for hospitalized patients with obstructive pyelonephritis as a result of urolithiasis in educational facilities for specialists by the Japanese Urological Association. Patients' characteristics including physical or laboratory examinations, treatment and prognosis were recorded, and the risk factors for disease death were analyzed.
RESULTS: A total of 1363 patients from 208 hospitals were analyzed. The median age of patients was 68 years, and there were 2.2-fold more female patients than male patients. From 844 patients, 891 species of bacteria or fungi were isolated, and Gram-negative rods accounted for 76.5% of cases. The mortality of patients was 2.3%. The risk factors related to disease death by univariate analysis were identified as older age, solitary kidney, ambulance use to visit hospital, disturbance of consciousness, severe appetite loss, higher performance status, disseminated intravascular coagulation status or systemic inflammatory response syndrome, vasopressors and anti-disseminated intravascular coagulation therapies, increased pulse rates, lower hemoglobin, lower serum albumin, and high blood urea nitrogen values. The predictive risk factors for disease death of patients' status at hospitalization were age over 80 years, systemic inflammatory response syndrome, disseminated intravascular coagulation status, disturbance of consciousness and solitary kidney by multivariate analysis.
CONCLUSIONS: Obstructive pyelonephritis as a result of urolithiasis represents an emergent disease in the urological field with relatively high mortality. Patients with older age or poor conditions should be hospitalized, and intervention by a urology specialist is likely to be required.