Banting memorial lecture 2022: 'Type 2 diabetes and nonalcoholic fatty liver disease: Partners in crime'

Mediating effect of diabetes on the relationship between nonalcoholic fatty liver disease and atherosclerotic cardiovascular disease: a prospective cohort study

OBJECTIVE

This study explored the mediating effect of diabetes on the relationship between nonalcoholic fatty liver disease (NAFLD) and atherosclerotic cardiovascular disease (ASCVD).

METHODS

In this prospective community cohort study, 82 975 participants were enrolled, with the primary outcome being the incidence of new-onset ASCVD. Using the Cox proportional hazards model, the hazard ratio (HR) and 95% confidence interval (CI) for ASCVD occurrence were computed between NAFLD and non-NAFLD groups. The correlation between NAFLD and diabetes was assessed using a binary logistic regression model, and that between NAFLD, diabetes and ASCVD using a mediation model.

RESULTS

During follow-up, 9471 ASCVD cases were observed. Compared with individuals without NAFLD, those with NAFLD showed an increased ASCVD risk (HR: 1.424; 95% CI: 1.363-1.488; P < 0.001). Stratifying NAFLD based on metabolic subphenotypes revealed a higher ASCVD risk in the NAFLD combined with diabetes subgroup than in the non-NAFLD subgroup (HR: 1.960; 95% CI: 1.817-2.115; P < 0.001). NAFLD was positively associated with baseline diabetes (odds ratio: 2.983; 95% CI: 2.813-3.163; P < 0.001). Furthermore, NAFLD severity was positively correlated with diabetes risk. Mediation analysis indicated that diabetes partially mediated the effect of NAFLD on ASCVD incidence, accounting for 20.33% of the total effect.

CONCLUSION

NAFLD is an independent predictor of increased ASCVD risk, which may be slightly mediated by diabetes in patients with NAFLD. Evaluating NAFLD and diabetes may be crucial in the early screening and prevention of ASCVD.

Investigating the Role of Non-Coding RNA in Non-Alcoholic Fatty Liver Disease

Non-coding RNAs (ncRNAs) are RNA molecules that do not code for protein but play key roles in regulating cellular processes. NcRNAs globally affect gene expression in diverse physiological and pathological contexts. Functionally important ncRNAs act in chromatin modifications, in mRNA stabilization and translation, and in regulation of various signaling pathways. Non-alcoholic fatty liver disease (NAFLD) is a set of conditions caused by the accumulation of triacylglycerol in the liver. Studies of ncRNA in NAFLD are limited but have demonstrated that ncRNAs play a critical role in the pathogenesis of NAFLD. In this review, we summarize NAFLD's pathogenesis and clinical features, discuss current treatment options, and review the involvement of ncRNAs as regulatory molecules in NAFLD and its progression to non-alcoholic steatohepatitis (NASH). In addition, we highlight signaling pathways dysregulated in NAFLD and review their crosstalk with ncRNAs. Having a thorough understanding of the disease process's molecular mechanisms will facilitate development of highly effective diagnostic and therapeutic treatments. Such insights can also inform preventive strategies to minimize the disease's future development.

MASLD, hepatic steatosis and fibrosis are associated with the prevalence of chronic kidney disease and retinopathy in adults with type 1 diabetes mellitus

AIM

We examined whether metabolic dysfunction-associated steatotic liver disease (MASLD) with or without significant fibrosis (assessed by validated non-invasive biomarkers) was associated with an increased risk of prevalent chronic kidney disease (CKD) or diabetic retinopathy in people with type 1 diabetes mellitus (T1DM).

METHODS

We performed a retrospective multicenter cross-sectional study involving 1,409 adult outpatients with T1DM, in whom hepatic steatosis index (HSI) and fibrosis (FIB)-4 index were calculated for non-invasively detecting hepatic steatosis (defined by HSI > 36), with or without coexisting significant fibrosis (FIB-4 index ≥ 1.3 or < 1.3). CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 or urine albumin/creatinine ratio ≥ 3.0 mg/mmol. The presence of diabetic retinopathy was also recorded in all participants.

RESULTS

Patients with MASLD and significant fibrosis (n = 93) had a remarkably higher prevalence of CKD and diabetic retinopathy than their counterparts with MASLD without fibrosis (n = 578) and those without steatosis (n = 738). After adjustment for sex, diabetes duration, hemoglobin A1c, hypertension, and use of antihypertensive or lipid-lowering medications, patients with SLD and significant fibrosis had a higher risk of prevalent CKD (adjusted-odds ratio 1.76, 95 % confidence interval 1.05-2.96) than those without steatosis. Patients with MASLD without fibrosis had a higher risk of prevalent retinopathy (adjusted-odds ratio 1.49, 95 % CI 1.13-1.46) than those without steatosis.

CONCLUSION

This is the largest cross-sectional study showing that MASLD with and without coexisting significant fibrosis was associated, independently of potential confounders, with an increased risk of prevalent CKD and retinopathy in adults with T1DM.

Nonalcoholic fatty liver disease without overlapping metabolic-associated fatty liver disease and the risk of incident type 2 diabetes

BACKGROUND AND AIMS

Re-classifying NAFLD as metabolic-associated fatty liver (MAFLD) has been proposed. While some people fulfil criteria for NAFLD, they do not have MAFLD; and whether NAFLD-only subjects have increased the risk of type 2 diabetes remains unknown. We compared risk of incident T2D in individuals with: (a) NAFLD-only; and (b) MAFLD, to individuals without fatty liver, considering effect modification by sex.

METHODS

246 424 Koreans without diabetes or a secondary cause of ultrasound-diagnosed hepatic steatosis were studied. Subjects were stratified into: (a) NAFLD-only status and (b) NAFLD that overlapped with MAFLD (MAFLD). Cox proportional hazards models with incident T2D as the outcome were used to estimate hazard ratios (HRs) for: (a) and (b). Models were adjusted for time-dependent covariates, and effect modification by sex was analysed in subgroups.

RESULTS

A total of 5439 participants had NAFLD-only status and 56 839 met MAFLD criteria. During a median follow-up of 5.5 years, 8402 incident cases of T2D occurred. Multivariable-adjusted HRs (95% CI) for incident T2D comparing NAFLD-only and MAFLD to the reference (neither condition) were 2.39 (1.63-3.51) and 5.75 (5.17-6.36) (women), and 1.53 (1.25-1.88) and 2.60 (2.44-2.76) (men), respectively. The increased risk of T2D in the NAFLD-only group was higher in women than in men (p for interaction by sex <0.001) and consistently observed across all subgroups. Risk of T2D was increased in lean participants regardless of metabolic dysregulation (including prediabetes).

CONCLUSIONS

NAFLD-only participants without metabolic dysregulation and the criteria for MAFLD are at increased risk of developing T2D. This association was consistently stronger in women than in men.

Metabolic-Associated Fatty Liver Disease and Diabetes: A Double Whammy

Metabolic-associated fatty liver disease (MAFLD) is the hepatic manifestation of metabolic syndrome and affects about 55% of people living with diabetes. MAFLD has been shown to be an individual risk factor for cardiovascular disease and its associated mortality. Although common, MAFLD is often underdiagnosed and not given adequate attention during clinical visits. This review highlights the most recent literature available on the evaluation and management of MAFLD in the presence of diabetes. The more recently available antidiabetic agents including glucagon-like peptide-1 analogs and sodium-glucose cotransporter-2 inhibitors have been shown to effectively manage both diabetes and MAFLD.

Long-Term Adverse Effect of Liver Stiffness on Glycaemic Control in Type 2 Diabetic Patients with Nonalcoholic Fatty Liver Disease: A Pilot Study

Currently, there are limited data regarding the long-term effect of liver stiffness on glycaemic control in patients with type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD). We prospectively followed an outpatient sample of 61 consecutive postmenopausal women with T2DM and NAFLD who had baseline data on liver ultrasonography and Fibroscan^®-assessed liver stiffness measurement (LSM) in 2017 and who underwent follow-up in 2022. Haemoglobin A1c (HbA1c) was measured both at baseline and follow-up. At baseline, 52 patients had NAFLD (hepatic steatosis) alone, and 9 had NAFLD with coexisting clinically significant fibrosis (defined as LSM ≥ 7 kPa on Fibroscan^®). At follow-up, 16 patients had a worsening of glycaemic control (arbitrarily defined as HbA1c increase ≥ 0.5% from baseline). The prevalence of NAFLD and coexisting clinically significant fibrosis at baseline was at least three times greater among patients who developed worse glycaemic control at follow-up, compared with those who did not (31.3% vs. 8.9%; p = 0.030). In logistic regression analysis, the presence of NAFLD and clinically significant fibrosis was associated with an approximately 4.5-fold increased likelihood of developing worse glycaemic control at follow-up (odds ratio 4.66, 95% confidence interval 1.07–20.3; p = 0.041), even after adjustment for baseline confounding factors, such as age, body mass index, haemoglobin A1c (or HOMA-estimated insulin resistance) and use of some glucose-lowering agents that may positively affect NAFLD and liver fibrosis. In conclusion, our results suggest that the presence of Fibroscan^®-assessed significant fibrosis was associated with a higher risk of developing worse glycaemic control in postmenopausal women with T2DM and NAFLD.