Validation of EncephalApp_Stroop as screening tool for the detection of minimal hepatic encephalopathy in German patients with liver cirrhosis.

Background: In contrast to overt hepatic encephalopathy (OHE), the diagnosis of minimal HE (MHE) is challenging in patients with cirrhosis requiring elaborate, specialized testing. The EncephalApp_Stroop is a smartphone-based application established as screening tool for the diagnosis of MHE but has not yet been validated in a German cohort and country specific cut-offs are currently missing.
Methods: 93 patients with cirrhosis were enroled into this study. Psychometric hepatic encephalopathy score (PHES) was used to detect MHE, and a subset of the patients was tested with critical flicker frequency (CFF). All patients underwent testing with EncephalApp_Stroop. Cut-off thresholds for EncephalApp_Stroop were calculated according to Youden's Index and a separate cut-off was determined with focus on sensitivity.
Results: 24 (26%) patients had MHE according to PHES. EncephalApp&#95;Stroop had a strong correlation with PHES (r=-0.76, p<0.001), while there was only a modest correlation with CFF (r=-0.51, <0.001). On time as well as on+off time discriminated best between patients with and without MHE with AUROCS of 0.87 for both measures. According to Youden's index, a cut-off of >224.7 s (sec) (on+off time) discriminated best between patients with and without MHE with a sensitivity of 71% and a specificity of 88%. The adjusted cut-off value for on+off time with focus on sensitivity (sensitivity:specificity weighed 2:1) was 185.1 s, yielding an optimized sensitivity of 92% and a negative predictive value of 96%. By using this cut-off as a pre-screening test in a stepwise diagnosis algorithm, elaborate testing with PHES could have been avoided in 49% of all patients.
Conclusion: EncephalApp&#95;Stroop may be useful in a stepwise diagnosis algorithm or even as a stand-alone screening tool to detect MHE in German patients with cirrhosis.
Competing Interests: Declaration of Competing Interest The authors disclose no potential financial or non-financial conflicts of interest.
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