Diagnostic value of urinary kidney injury molecule 1 for acute kidney injury: a meta-analysis

Abstract

Background: Urinary Kidney Injury Molecule 1 (KIM-1) is a proximal tubular injury biomarker for early detection of acute kidney injury (AKI), with variable performance characteristics depending on clinical and population settings.

Methods: Meta-analysis was performed to assess the diagnostic value of urinary KIM-1 in AKI. Relevant studies were searched from MEDLINE, EMBASE, Pubmed, Elsevier Science Direct, Scopus, Web of Science, Google Scholar and Cochrane Library. Meta-analysis methods were used to pool sensitivity and specificity and to construct summary receiver operating characteristic (SROC) curves.

Results: A total of 2979 patients from 11 eligible studies were enrolled in the analysis. Five prospective cohorts, two cross-sectional and four case-control studies were identified for meta-analysis. The estimated sensitivity of urinary KIM-1 for the diagnosis of AKI was 74.0% (95% CI, 61.0%-84.0%), and specificity was 86.0% (95% CI, 74.0%-93.0%). The SROC analysis showed an area under the curve of 0.86(0.83-0.89). Subgroup analysis suggested that population settings and detection time were the key factors affecting the efficiency of KIM-1 for AKI diagnosis.

Limitation: Various population settings, different definition of AKI and Serum creatinine level used as the standard might have influence on AKI diagnosis. The relatively small number of studies and heterogeneity between them also affected the evaluation.

Conclusion: Urinary KIM-1 may be a promising biomarker for early detection of AKI with considerable predictive value, especially for cardiac surgery patients, and its potential value needs to be validated in large studies and across a broader scope of clinical settings.

Figure 1. Flow diagram for the review process and outcomes of inclusion and exclusion.

Figure 2. Forest plots of the pooled sensitivity (A) and specificity (B) of urine kidney injury molecule 1 level in predicting acute kidney injury across all settings.

The black squares in the gray squares and the horizontal lines represent the point estimate and 95% confidence interval (CI), respectively. The dotted line represents the pooled estimate, and the diamond shape represents the 95% CI of the pooled estimate.

Figure 3. Forest plot of the pooled diagnostic odds ratio of urine kidney injury molecule 1 level in predicting acute kidney injury across all settings.

The black squares in the graysquares and the horizontal lines representthe point estimate and 95% confidence interval(CI), respectively. The dotted line represents the pooled estimate, and the diamond shape represents the 95% CI of the pooled estimate.

Figure 4. Hierarchical summary receiver perating characteristic (SROC) plots of urine kidney injury molecule 1 level to predict acute kidney injury across all settings.

The curve is represented by the straight line; each of the analyzed studies is represented by a circle; the point estimate to which summary sensitivity (SENS) and specificity (SPEC) correspond is represented by the diamond shape, and the respective 95% confidence intervals, by the dashed line, whereas the 95% confidence area in which a new study will be located is represented by the dotted line. Abbreviation: AUC, area under the curve.

Figure 5. Funnel plot for the evaluation of potential publication bias in diagnosis of KIM-1 for AKI.