Patients with diabetes are at higher risk for severe illness from COVID-19

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It is currently uncertain whether people with diabetes are at higher risk of severe illness from coronavirus disease 2019 (COVID-19).

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We found that diabetes was associated with an approximately 4-fold increased risk of having severe/critical COVID-19 illness.

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This association was independent of age, sex, obesity, hypertension and smoking.

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These findings highlight the urgent need for a multidisciplinary team-based approach to management of this patient population.

A STAT4 variant increases liver fibrosis risk in Caucasian patients with chronic hepatitis B

BACKGROUND

Host genetic modifiers of the natural history of chronic hepatitis B (CHB) remain poorly understood. Recently, a genome-wide association study (GWAS)-identified polymorphism in the STAT4 gene that contributes to the risk for hepatocellular carcinoma (HCC) was shown to be associated with the full spectrum of hepatitis B virus (HBV) outcomes in Asian patients. However, the functional mechanisms for this effect are unknown and the role of the variant in modulating HBV disease in Caucasians has not been investigated.

AIMS

To determine whether STAT4 genetic variation is associated with liver injury in Caucasian patients with CHB and to investigate potential mechanisms mediating this effect.

METHODS

STAT4 rs7574865 was genotyped in 1085 subjects (830 with CHB and 255 healthy controls). STAT4 expression in liver, PBMCs and NK cells, STAT4 phosphorylation and secretion of interferon-gamma (IFN-γ) according to STAT4 genetic variation was examined.

RESULTS

STAT4 rs7574865 genotype was independently associated with hepatic inflammation (OR: 1.42, 95% CI: 1.07-2.06, P = 0.02) and advanced fibrosis (OR: 1.83, 95% CI: 1.19-2.83, P = 0.006). The minor allele frequency of rs7574865 was significantly lower than that in healthy controls. rs7574865 GG risk carriers expressed lower levels of STAT4 in liver, PBMCs and in NK cells, while NK cells from patients with the risk genotype had impaired STAT4 phosphorylation following stimulation with IL-12/IL-18 and a reduction in secretion of IFN-γ.

CONCLUSION

Genetic susceptibility to HBV persistence, hepatic inflammation and fibrosis in Caucasians associates with STAT4 rs7574865 variant. Downstream effects on NK cell function through STAT4 phosphorylation-dependent IFN-γ production likely contribute to these effects.

IFNL3/4 genotype is associated with altered immune cell populations in peripheral blood in chronic hepatitis C infection

Single-nucleotide polymorphisms near the interferon lambda 3 (IFNL3) gene predict outcomes to infection and anti-viral treatment in hepatitis C virus (HCV) infection. To identify IFNL3 genotype effects on peripheral blood, we collected phenotype data on 400 patients with genotype 1 chronic hepatitis C (CHC). The IFNL3 responder genotype predicted significantly lower white blood cells (WBCs), as well as lower absolute numbers of monocytes, neutrophils and lymphocytes for both rs8099917 and rs12979860. We sought to define the WBC subsets driving this association using flow cytometry of 67 untreated CHC individuals. Genotype-associated differences were seen in the ratio of CD4CD45RO+ to CD4CD45RO-; CD8CD45RO+ to CD8CD45RO-, NK CD56 dim to bright and monocyte numbers and percentages. Whole blood expression levels of IFNL3, IFNLR1 (interferon lambda receptor 1), IFNLR1-mem (a membrane-associated receptor), IFNLR1-sol (a truncated soluble receptor), MxA and T- and NK (natural killer) cell transcription factors TBX21, GATA3, RORC, FOXP3 and EOMES in two subjects were also determined. CHC patients demonstrated endogenous IFN activation with higher levels of MxA, IFNLR1, IFNLR1-mem and IFNLR1-sol, and IFNL3 genotype-associated differences in transcription factors. Taken together, these data provide evidence of an IFNL3 genotype association with differences in monocyte, T- and NK cell levels in the peripheral blood of patients with CHC. This could underpin genotype associations with spontaneous and treatment-induced HCV clearance and hepatic necroinflammation.

PNPLA3 rs738409 I748M is associated with steatohepatitis in 434 non-obese subjects with hepatitis C

BACKGROUND

The PNPLA3/Adiponutrin rs738409 C/G single nucleotide polymorphism is associated with the severity of steatosis, steatohepatitis and fibrosis in patients with non-alcoholic fatty liver disease, as well as the severity of steatosis and fibrosis in patients with chronic hepatitis C (CHC).

AIM

To test in genotype 1(G1)-CHC patients, the putative association between the PNPLA3 variant and histological features of steatohepatitis, as well as their impact on the severity of fibrosis.

METHODS

Four hundred and thirty-four consecutively biopsied Caucasian G1-CHC patients were genotyped for PNPLA3 rs738409, its effect evaluated by using an additive model. Histological features of steatohepatitis in CHC were assessed using the Bedossa classification. Hepatic expression of PNPLA3 mRNA was evaluated in 63 patients.

RESULTS

The prevalence of steatohepatitis increased from 16.5% in patients with PNPLA3 CC, to 23.2% in CG and 29.2% in the GG genotype (P = 0.02). By multiple logistic regression, PNPLA3 genotype (OR 1.54, 95% CI 1.03-2.30, P = 0.03), together with age (OR 1.03, 95% CI 1.00-1.05, P = 0.02), BMI ≥ 30 (OR 2.06, 95% CI 1.04-4.10, P = 0.03) and homoeostasis model assessment (HOMA, OR 1.18, 95% CI 1.04-1.32, P = 0.006) were independently linked to steatohepatitis. When stratifying for obesity, PNPLA3 was associated with NASH in non-obese patients only (12.0% in CC vs. 18.3% in CG vs. 27.3% in GG, P = 0.01), including after correction for metabolic confounders (OR 2.06, 95% CI 1.26-3.36, P = 0.004). We showed an independent association between steatohepatitis (OR 2.05, 95% CI 1.05-4.02, P = 0.003) and severe fibrosis. Higher liver PNPLA3 mRNA was associated both with the severity of steatosis (adjusted P = 0.03) and steatohepatitis after adjusting for gender, age, BMI and HOMA (P = 0.002).

CONCLUSION

In patients with genotype 1 hepatitis C, the PNPLA3 G variant is associated with a higher risk of steatosis severity and steatohepatitis, particularly among non-obese subjects.

Peroxisome proliferator-activated receptors and hepatitis C virus

The prevalence of type 2 diabetes mellitus and insulin resistance are higher among people chronically infected with hepatitis C (CHC) when compared with the general population and people with other causes of chronic liver disease. Both insulin resistance and diabetes are associated with adverse outcomes across all stages of CHC, including the liver transplant population. CHC is also associated with the development of hepatic steatosis, a common histological feature present in approximately 55% (32-81%) of cases. There is a complex interrelationship between insulin resistance and hepatic steatosis and both are postulated to aggravate each other. The peroxisome proliferator-activated receptors (PPARs) are nuclear factors involved in the regulation of glucose, lipid homeostasis, inflammatory response, cell differentiation, and cell cycle. The relationship between hepatitis C virus replication and PPARs has been the focus of recent study. Given the availability of potent agonists, PPARs may represent a novel pharmacological target in the treatment of CHC.

Use of HOMA-IR in hepatitis C

Chronic infection with hepatitis C virus (HCV) can induce insulin resistance (IR) in a genotype-dependent manner and contributes to steatosis, progression of fibrosis and resistance to interferon plus ribavirin therapy. Our understanding of HCV-induced IR has improved considerably over the years, but certain aspects concerning its evaluation still remain elusive to clinical researchers. One of the most important issues is elucidating the ideal method for assessment of IR in the setting of hepatitis C. The hyperinsulinaemic euglycaemic clamp is the gold standard method for determining insulin sensitivity, but is impractical as it is labour intensive and time-consuming. To date, all human studies except for four where IR was evaluated in the HCV setting, an estimation of IR has been used rather than direct measurements of insulin-mediated glucose uptake. The most commonly used estimation in the HCV population is the homeostasis model assessment of insulin resistance (HOMA-IR) which is calculated from a single measurement of fasting insulin and glucose. In this article, we review the use and reporting of HOMA in the literature and provide guidance on its appropriate as well as inappropriate use in the hepatitis setting.

Meta-analysis: insulin resistance and sustained virological response in hepatitis C

BACKGROUND

A higher baseline homeostasis model assessment of insulin resistance (HOMA-IR) score has sometimes predicted a poorer sustained virological response (SVR) rate to peginterferon/ribavirin therapy in treatment-naïve chronic hepatitis C patients.

AIM

To perform a meta-analysis to evaluate the impact of HOMA-IR on SVR in hepatitis C.

METHODS

Relevant studies were identified by searching Medline and EMBASE. We identified 17 publications that addressed the influence of insulin resistance on SVR. The random effect model of Der Simonian and Laird method were used for heterogeneous studies using the Meta-Disc software 1.4, Madrid, Spain.

RESULTS

Normal insulin sensitivity was associated with a higher rate of SVR [odds ratio (OR) 2.86 (95%CI: 1.97-4.16)] in comparison with insulin resistance. Moreover, in separate analysis by genotype selecting studies that used HOMA-IR > 2 as cut-off defining insulin resistance, SVR was higher in patients with HOMA-IR < 2 in all genotypes: HCV-1 [OR: 2.16 (95%CI: 1.51-3.08)], HCV-2&3 [OR: 3.06 (95%CI: 1.06-8.82)] and HCV-4 [OR: 6.65(95%CI: 2.51-17.61)]. Studies reporting no association between HOMA and SVR included easy-to-cure cohorts, analysed variables strongly related with insulin resistance like body mass index, steatosis, hyper γGT, age and fibrosis and reported differences in handling and interpretation of HOMA-IR.

CONCLUSION

Elevated HOMA-IR was associated with a lower cure rate of patients with hepatitis C treated with Peg-IFN-α/ribavirin irrespective of genotype, and the more difficult-to-treat cohort, the better the HOMA-IR prediction. HOMA-IR is, as a surrogate marker of insulin resistance, susceptible to some biases derived from both handling and interpretation.