Proportion of NAFLD patients with normal ALT value in overall NAFLD patients: a systematic review and meta-analysis

BACKGROUND: ALT value is often used to reflect the hepatic inflammation and injury in NAFLD patients, but many studies proved that ALT values were normal in many NAFLD patients. The aim of this study was to identify the summarized proportion of NAFLD patients with normal ALT value in the overall NAFLD patients. METHODS: Electronic databases PubMed, EMBASE, Ovid, and the Cochrane Library were searched for potential studies published from January 1, 2000 to September 30, 2019. Studies that have reported the number of NAFLD or NASH patients with normal and abnormal ALT value were included and analyzed. Abstracts, reviews, case reports, and letters were excluded. RESULTS: A total of 11 studies with 4084 patients were included for assessing the summarized proportion of NAFLD patients with normal ALT in overall NAFLD patients. As the results shown, the summarized proportion of NAFLD patients with normal ALT value in overall NAFLD patients was 25% (95%CI: 20–31%) which was calculated by the random-effects model. The summarized proportion of NASH patients with normal ALT value in overall NASH patients was 19% (95%CI: 13–27%). Subgroup analysis includes region, study type, diagnostic method, and group size were conducted to investigate the resource of heterogeneity in the summarized proportion of NAFLD and NASH patients with normal ALT value. CONCLUSIONS: 25% NAFLD patients and 19% NASH patients possess the normal ALT value in the clinical manifestation. The value of ALT in the clinical diagnosis of NAFLD and NASH remains need be further testified.