Incidence, risk factors, and clinical outcomes of acute kidney injury associated with acute pyelonephritis in patients attending a tertiary care referral center

Abstract

Acute kidney injury (AKI) associated with acute pyelonephritis (APN) rarely has been reported. The aim of this study was to evaluate the incidence and risk factors of AKI associated with APN. We retrospectively reviewed the medical records of 403 patients over 18-year old age hospitalized for APN management from October 2009 to September 2014 in tertiary care referral center. Demographic data, clinical symptoms and signs, and laboratory findings were gathered from the medical records and analyzed. The mean age of patients was 57 years and APN commonly occurred in female (87.6%). AKI occurred in 253 patients (62.8%). As per the RIFLE classification, renal injury was graded as ‘Risk’ (62.1%), ‘Injury’ (26.5%), and ‘Failure’ (11.4%). AKI patients were more likely a male gender and had complicated APN. The AKI group had a significantly higher tendency to present with shock. The prevalence of underlying chronic kidney disease (CKD) was significantly higher in the AKI group. There was no difference in mortality between the AKI and non-AKI groups. Multivariate analysis revealed that age over 65 (OR 1.93, 95% CI 1.18–3.13, p = .008), complicated (OR 2.13, 95% CI 1.35–3.34, p = .001) and bilateral APN (OR 1.71, 95% CI 1.01–2.88, p = .045), and initial shock (OR 2.44, 95% CI 1.05–5.71, p = .039) were independent risk factors for the occurrence of AKI in patients with APN. Physicians should attempt to prevent, detect, and manage AKI associated with APN in patients with above conditions.

Preadmission kidney function and risk of acute kidney injury in patients hospitalized with acute pyelonephritis: A Danish population-based cohort study

“…Only few smaller studies with a maximum of 790 participants have evaluated the association between impaired kidney function and AKI among patients with pyelonephritis or urinary tract infections [5,6]. In a smaller study including 403 pyelonephritis patients, Jeon et al reported an AKI risk as high as 62.8% [5]. We did not find that high risk of AKI, not even among patients with eGFR < 30 ml/min/1.73 m 2 .…”

“…This is a large population-based study of pyelonephritis-related AKI, using laboratory information on pre- and post-admission creatinine. Even though the laboratory information was not complete, using laboratory data to identify reduced preadmission eGFR is known to be more accurate than using diagnostic codes, and similarly using creatinine measurements will capture more accurately incident cases of AKI [ 5 , 7 , 10 , 42 – 44 ]. The study has some limitations that should be considered when interpreting the findings.…”

“…Potential confounders were identified through existing knowledge and literature on causal mechanisms and afterwards directed acyclic graphs were constructed [ 5 – 7 , 29 – 35 ]. We therefore collected information on the following potential confounders: age, sex, diabetes, hypertension, malformation of the urinary tract, and heart failure.…”

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“…Data on AKI in patients with pyelonephritis are limited. While one in five hospitalized adults may develop AKI [4], a smaller Korean cohort study of 403 patients reported that up to 62.8% of adults hospitalized with acute pyelonephritis developed AKI [5]. Another Taiwanese cohort study of 790 patients reported a 2.63-fold (95% CI 1.53-4.56) increase in the odds of AKI in patients with pyelonephritis compared with patients admitted with lower urinary tract infection [6].…”

Untitled

“…Instead, they identified AKI from diagnostic code, used admission creatinine as baseline value or estimated baseline of creatinine assuming eGFR to be 75 ml/min/1.73m 2 [9,10]. Even though AKI and chronic kidney disease are associated conditions [11][12][13], only few studies with a small number of patients have examined if impaired kidney function increases the risk of AKI in patients with pyelonephritis [5,6]. To address the limitation of missing preadmission laboratory information on serum creatinine in the current literature, we took advantage of the nationwide Danish population-based health registries and the potential for identifying preadmission kidney function and AKI from creatinine measurements from laboratory databases.…”