2. Definition of improvement of hepatic encephalopathy.

Study	Number of participants	Nomenclature of hepatic encephalopathy at inclusion	Previous episodes of overt hepatic encephalopathy	Tools for assessing hepatic encephalopathy	Definition of improvement, maintenance or worsening of hepatic encephalopathy
Ahmed 2018	120	Hepatic encephalopathy of any grade	Unknown	Mental status: West Haven criteria	Recovery from grade IV or grade III to grade I or below after 3 days of treatment
Ali 2014	126	No hepatic encephalopathy at inclusion	Yes, at least 2 episodes of hepatic encephalopathy within the last 6 months	Mental status: Conn's modification of West Haven criteria	Development of hepatic encephalopathy based on Conn score
Babar 2017	96	No hepatic encephalopathy at inclusion	Yes, at least 2 episodes of hepatic encephalopathy within the last 6 months	Mental status: Conn's modification of West Haven criteria	Development of hepatic encephalopathy based on Conn score
Bajaj 2011	42	Minimal hepatic encephalopathy	No	Two or more negative tests of the following: NCT‐A; NCT‐B; Digit Symbol Test; Block Design Test or ICT.	Improvement in mean Z‐score of the total battery of tests
Bajaj 2019	381	No hepatic encephalopathy at inclusion	Yes, within the previous 6 months	Mental status: West Haven criteria	Conn score of 2 or more
Bass 2004	96	Chronic hepatic encephalopathy grade 1 or 2	Chronic	Modified Portal‐Systemic Encephalopathy (PSE) sum/index Mental status (West Haven criteria) Asterixis NCT‐A Blood ammonia	Response was defined as change in baseline mental grade after at least 10 days of treatment.
Bass 2010	299	No hepatic encephalopathy at inclusion	Yes, at least 2 episodes within the last 6 months	Conn score Asterixis	Development of overt hepatic encephalopathy
Bucci 1993	58	Porto‐systemic encephalopathy	Unknown	Parson‐Smith semi‐quantitative scale modified according to Conn. Severity of portosystemic encephalopathy was also determined by an arbitrary score including state of consciousness, intellectual functions, behaviour and main neurological symptoms	Improvement in hepatic encephalopathy by PSE Sum
Bureau 2021	186	No hepatic encephalopathy, or below grade 2 (23 (12%))	25 (13%) people had a history of overt hepatic encephalopathy	Mental status: West Haven modified criteria Portosystemic hepatic encephalopathy score (PHES) Asterixis	Development of overt hepatic encephalopathy (grade 2 or higher by the West Haven Modified Criteria)
Butt 2018	130	Overt hepatic encephalopathy	Unknown	Mental status: Conn score	Reversal of hepatic encephalopathy
Fera 1993	40	Stage 1 portosystemic encephalopathy and hyperammonaemia	Unknown	Mental status: Conn score Ammonia levels Asterixis A‐cancellation test Trail‐making‐test (Reitan‐test) EEG Fasting serum ammonia levels	Improvement in Conn's grading evaluated by investigator. Improvement in PSE index
Festi 1993	136	Grade 1 hepatic encephalopathy	Unknown	PSE index Mental status:Conn's grading Asterixis Reitan test Electroencephalogram Blood ammonia	Reduction of neurological signs of hepatic encephalopathy (asterixis, Reitan‐test, ammonia levels, EEG)
Gill 2014	200	Hepatic encephalopathy	Unknown	Mental status: West Haven criteria	Reversal of hepatic encephalopathy based on Conn's grading assessed by investigators
Habib 2016	122	Hepatic encephalopathy	Unknown	Mental status: West Haven criteria	Reversal of hepatic encephalopathy based on Conn's grading assessed by investigators
Hasan 2018	91	Hepatic encephalopathy grades I to IV	Unknown	Mental status: West Haven criteria	Any reduction in Conn scale
Higuera‐de‐la‐Tijera 2018	88	No hepatic encephalopathy at inclusion	No previous episodes of minimal or overt hepatic encephalopathy	Mental status: West Haven criteria PSE sum CFF	Development of overt hepatic encephalopathy
Kimer 2017	54	Minimal hepatic encephalopathy	11 people had previous episodes of hepatic encephalopathy	PHES	Improvement in PHES score and continuous reaction time
Loguercio 2003	33	Overt chronic hepatic encephalopathy	Chronic encephalopathy	Mental status: Conn's grading	Improvement in mental state evaluated by investigators using Conn's grading
Maharshi 2015	120	No hepatic encephalopathy at inclusion	Unknown	Mental status: West Haven Criteria	Development of overt hepatic encephalopathy by West Haven Criteria
Majeed 2018	120	Hepatic encephalopathy; grade unknown	At least 2 episodes of overt hepatic encephalopathy in the previous 6 months	Mental status: Conn score	Breakthrough episodes of hepatic encephalopathy
Manzhalii 2022	42	Minimal, or grades 1 to 2 hepatic encephalopathy	At least 2 episodes of overt hepatic encephalopathy in the previous 6 months, with at least 1 episode in the previous 3 months	Mental status: West Haven Criteria EncephalApp Stroop Test	Improvement in EncephalApp Stroop Test
Mas 2003	103	Acute hepatic encephalopathy grade 1 to 3 > 48 hours prior to inclusion	Unknown	PSE index higher than zero Mental status: Conn's score x 3 NCT‐A EEG Venous ammonia levels	Improvement in PSE Index Improvement in hepatic encephalopathy according to Conn's grading.
Massa 1993	40	Hepatic encephalopathy	Unknown	Mental status: West Haven criteria Asterixis Neurocognitive testing 'A' ‐cancellation test Trail making test EEG Fasting venous ammonia Arbitrary hepatic encephalopathy score from 0 to 20	Improvement in hepatic encephalopathy, assessed by investigator according to West Haven criteria.
Moneim 2021	100	Grade 1 hepatic encephalopathy or less	At least 1 episode of overt hepatic encephalopathy	Mental status: Conn's score Asterixis	Increase in Conn score to a score of 2 or more
Muhammad 2016	98	Hepatic encephalopathy with a Conn score of 2 or higher	Unknown	Mental status: West Haven criteria	A Conn score < 2 after 3 months
Nawaz 2015	150	No hepatic encephalopathy at inclusion	At least 2 episodes of acute overt hepatic encephalopathy within the last 6 months	Method of assessment not stated	Acute attack of hepatic encephalopathy, diagnostics methods not stated
Paik 2005	54	Hepatic encephalopathy grade 1 to 3	Episodic	Mental status: Conn's score Asterixis NCT Serum ammonia levels > 75 ųmol/L	Improvement in hepatic encephalopathy assessed by investigators according to Conn's modifications of Parsons‐Smith classification.
Patel 2022	38	Chronic hepatic encephalopathy	Yes, all had either persistent and overt (at least grade 1) or at least 2 episodes of overt encephalopathy in the previous 6 months. 24/38 (63.2%) had overt encephalopathy at baseline.	Mental status: West Haven Criteria PHES	Recurrence of overt hepatic encephalopathy Normalisation of grade of encephalopathy from grade I to 0 Improvement in PHES
Pawar 2019	108	Minimal hepatic encephalopathy	No history of hepatic encephalopathy	PHES (‐5 or less diagnoses minimal hepatic encephalopathy) ICT (14 or more lures diagnoses hepatic encephalopathy)	Reversal of encephalopathy by PHES score more than ‐5, or ICT lures less than 14
Poudyal 2019	132	Type C acute hepatic encephalopathy of any grade	Unknown	Mental status: West Haven Criteria	Complete reversal of clinical symptoms on the basis of the West Haven Criteria
Riggio 2005	75	No hepatic encephalopathy at inclusion	Yes, overt hepatic encephalopathy in 11 cases	PSE sum /index Mental status: West Haven criteria Asterixis Trail‐making test‐A adjusted for age and education Blood ammonia	Effect evaluated as development of hepatic encephalopathy based on West Haven criteria, asterixis and trail‐making test.
Sharma 2013	120	Overt hepatic encephalopathy	Unknown	Mental status: West Haven criteria	Improvement in hepatic encephalopathy evaluated by investigators according to West Haven criteria.
Sharma 2014	124	Minimal hepatic encephalopathy	Unknown, but no overt hepatic encephalopathy 6 weeks prior to enrolment	Mental state (Clinical Hepatic Encephalopathy Staging Scale (CHESS)) Critical flicker frequency Figure‐connection‐test Digit Symbol Test NCT	Improvement in critical flocker fusion
Sidhu 2011	94	Minimal hepatic encephalopathy	Unknown	One of the 2 tests NCT‐A or Figure‐connection‐test with a standard deviation below ‐2 of a normative control group	Normalisation of the abnormal neuropsychiatric tests
Sidhu 2016	112	Minimal hepatic encephalopathy	Not reported	NCT Figure connection test Digit symbol test Picture completion test Block design test Changes in minimal hepatic encephalopathy Development of overt hepatic encephalopathy	If there was improvement in 2 or more of five neuropsychiatric tests
Suzuki 2018	172	Overt hepatic encephalopathy grade 1 to 2	Unknown	PSE index Mental status: West Haven criteia Asterixis NCT‐A and NCT‐B Digit Symbol test Electroencephalogram Blood ammonia levels	Improvement in PSE Index Improvement in asterixis, ammonia levels, number connection test and EEG Improvement in hepatic encephalopathy
Tan 2022	40	Minimal hepatic encephalopathy	Unknown, but no overt hepatic encephalopathy 3 months prior to enrolment	Mental status: MMSE to exclude overt hepatic encephalopathy Diagnosis of minimal hepatic encephalopathy by PHES and EncephalApp Stroop Test	Normalisation of the Psychometric Hepatic Encephalopathy Score or Stroop test time
Uthman 2020	84	Overt hepatic encephalopathy grade 1 to 3	Unknown	Mental status: West Haven Criteria PSE index	Improvement of PSE Index Improvement in West Haven Criteria
Vyas 2017	73	Grade III/IV hepatic encephalopathy	Unknown	Mental status:West Haven Criteria Blood Ammonia	Improvement of hepatic encephalopathy from grade III/IV to grade II/I/no encephalopathy
Wahib 2014	50	Overt hepatic encephalopathy grade 1 to 3	Unknown	Mental status: West Haven Criteria Flapping tremor PSE index Blood ammonia levels	Improvement in grading of hepatic encephalopathy based on West Haven criteria, improvement in blood ammonia levels, and improvement in hepatic encephalopathy index.
Zeng 2021	195	Decompensated liver cirrhosis, of which participants could have hepatic encephalopathy	24 (12.0%) participants had a history of hepatic encephalopathy > 1 month before the screening visit	Mental status: West Haven Criteria	Development of hepatic encephalopathy adjusted by history of encephalopathy

CCF: critical flicker fusion; EEG: electroencephalogram; ICT: inhibitory control test; MSE: mini mental state examination; NCT‐A: Number Connection Test‐A; NCT‐B: Number connection Test‐B;