Introduction: Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, with type 2 diabetes mellitus (T2DM) as a major predictor. Insulin resistance and chronic inflammation are key pathways in the pathogenesis of T2DM leading to NAFLD and vice versa, with the synergistic effect of NAFLD and T2DM increasing morbidity and mortality risks. This meta-analysis aims to quantify the prevalence of NAFLD and the prevalence of clinically significant and advanced fibrosis in people with T2DM. Methods: MEDLINE and Embase databases were searched from inception until 13 February 2023. The primary outcomes were the prevalence of NAFLD, non-alcoholic steatohepatitis (NASH) and fibrosis in people with T2DM. A generalised linear mixed model with Clopper-Pearson intervals was used for the analysis of proportions with sensitivity analysis conducted to explore heterogeneity between studies. Results: 156 studies met the inclusion criteria, and a pooled analysis of 1 832 125 patients determined that the prevalence rates of NAFLD and NASH in T2DM were 65.04% (95% CI 61.79% to 68.15%, I²=99.90%) and 31.55% (95% CI 17.12% to 50.70%, I²=97.70%), respectively. 35.54% (95% CI 19.56% to 55.56%, I²=100.00%) of individuals with T2DM with NAFLD had clinically significant fibrosis (F2–F4), while 14.95% (95% CI 11.03% to 19.95%, I²=99.00%) had advanced fibrosis (F3–F4). Conclusion: This study determined a high prevalence of NAFLD, NASH and fibrosis in people with T2DM. Increased efforts are required to prevent T2DM to combat the rising burden of NAFLD. PROSPERO registration number: CRD42022360251.

Summary: Background: The incidence of elevated liver chemistries and the presence of pre‐existing chronic liver disease (CLD) have been variably reported in COVID‐19.Aims: To assess the prevalence of CLD, the incidence of elevated liver chemistries and the outcomes of patients with and without underlying CLD/elevated liver chemistries in COVID‐19.Methods: A comprehensive search of electronic databases from 1 December 2019 to 24 April 2020 was done. We included studies reporting underlying CLD or elevated liver chemistries and patient outcomes in COVID‐19.Results: 107 articles (n = 20 874 patients) were included for the systematic review. The pooled prevalence of underlying CLD was 3.6% (95% CI, 2.5‐5.1) among the 15 407 COVID‐19 patients. The pooled incidence of elevated liver chemistries in COVID‐19 was 23.1% (19.3‐27.3) at initial presentation. Additionally, 24.4% (13.5‐40) developed elevated liver chemistries during the illness. The pooled incidence of drug‐induced liver injury was 25.4% (14.2‐41.4). The pooled prevalence of CLD among 1587 severely infected patients was 3.9% (3%‐5.2%). The odds of developing severe COVID‐19 in CLD patients was 0.81 (0.31‐2.09; P = 0.67) compared to non‐CLD patients. COVID‐19 patients with elevated liver chemistries had increased risk of mortality (OR‐3.46 [2.42‐4.95, P < 0.001]) and severe disease (OR‐2.87 [95% CI, 2.29‐3.6, P < 0.001]) compared to patients without elevated liver chemistries.Conclusions: Elevated liver chemistries are common at presentation and during COVID‐19. The severity of elevated liver chemistries correlates with the outcome of COVID‐19. The presence of CLD does not alter the outcome of COVID‐19. Further studies are needed to analyse the outcomes of compensated and decompensated liver disease.

Immunosuppression and comorbidities increase the risk of severe coronavirus disease-2019 (COVID-19) in solid organ transplant (SOT) recipients. The outcomes of COVID-19 in liver transplant (LT) recipients remain unclear. We aimed to analyse the outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in LT recipients. The electronic databases were searched for articles published from 1 December 2019 to 20 May 2021 with MeSH terms COVID-19, SARS-CoV-2, and liver transplantation. Studies reporting outcomes in more than 10 LT recipients were included for analysis. LT vs non-LT patients with COVID-19 infection were compared for all-cause mortality, which was the primary outcome studied. We also evaluated the relation between the timing of COVID-19 infection post-LT (< one year vs > one year) and mortality. Eighteen articles reporting 1,522 COVID-19 infected LT recipients were included for the systematic review. The mean age (standard deviation [SD]) was 60·38 (5·24) years, and 68·5% were men. The mean time (SD) to COVID-19 infection was 5·72 (1·75) years. Based on 17 studies (I² = 7·34) among 1,481 LT recipients, the cumulative incidence of mortality was 17·4% (95% confidence interval [CI], 15·4–19·6). Mortality was comparable between LT (n = 610) and non-LT (n = 239,704) patients, based on four studies (odds ratio [OR], 0·8 [0·6–1·08]; P = 0·14). Additionally, there was no significant difference in mortality between those infected within one year vs after one year of LT (OR, 1·5 [0·63–3·56]; P = 0·35). The cumulative incidence of graft dysfunction was 2·3% (1·3–4·1). Nearly 23% (20·71–25) of the LT patients developed severe COVID-19 infection. Before infection, 71% and 49% of patients were on tacrolimus and mycophenolate mofetil, respectively. Immunosuppression was modified in 55·9% (38·1–72·2) patients after COVID-19 infection. LT and non-LT patients with COVID-19 have a similar risk of adverse outcomes.