Objective: Diabetes mellitus has been suspected to increase mortality in acute pyelonephritis (APN) patients and the goal of this study is to verify this suspicion with a large data set based on almost the entire population of South Korea.
Methods: A nationwide cohort study was conducted using a South Korean Health Insurance Review and Assessment Service claim database. We collected demographic and clinical information including comorbidities of patients with APN as the primary discharge diagnosis during 2010-2014. Then we compared the in-hospital mortality and recurrence of APN across the diabetes and non-diabetes groups.
Results: Among 845,656 APN patients, 12.4% had diabetes mellitus. The median age was 65 in the diabetes group, which was much higher than 47 in the non-diabetes group; the female proportion was 91-92% in both groups. The in-hospital mortality rate was higher in the diabetes group (2.6/1000 events in the diabetes group vs. 0.3/1000 in the non-diabetes group, P < 0.001). When covariates (age, sex, and the modified Charlson comorbidity index) were controlled with panel logistic regression, diabetes was still associated with a higher in-hospital mortality in APN patients (OR 2.66, 95% CI 2.19-3.23). The increasing effect of diabetes on in-hospital mortality of APN patients varied greatly with age: the effect was large for age 15-49 (OR 15.06, 95% CI 5.27-43.05), slightly smaller for age 50-64 (OR 12.17, 95% CI 5.71-25.92), and much smaller for age ≥ 65 (OR 2.10, 95% CI 1.72-1.92).
Conclusions: Our data indicate that the mortality of APN is higher in the patients with diabetes and this effect becomes stronger for young patients.
Keywords: Diabetes; Mortality; Pyelonephritis.