Impact of PNPLA3 and TM6SF2 polymorphisms on the prognosis of patients with MASLD and type 2 diabetes mellitus

Background/Aims: Longitudinal studies assessing the impact of genetic polymorphisms on outcomes in patients with Type 2 Diabetes Mellitus (T2DM) and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) are scarce. This study aimed to evaluate the effect of PNPLA3 and TM6SF2 risk alleles on hepatic and extrahepatic outcomes in T2DM-MASLD individuals. Methods: Patients' polymorphisms were analysed as follows: PNPLA3 CC, CG and GG; TM6SF2 CC and CT + TT; combined comparing no mutant allele, one allele G or T or <= 2 alleles G or T. Hierarchical models were built to assess associations between polymorphisms and outcomes, independently of confounding factors. Multivariate logistic regression was used for cirrhosis and its complications and extrahepatic cancer, and Cox regression for cardiovascular events (CVEs) and all-cause mortality. Results: In total, 407 T2DM-MASLD patients (62.1 +/- 10.5 years, 67.6% women) were followed for 11 (6-13) years. Having at least one G or T allele independently increased the risk of cirrhosis in the separate analysis of PNPLA3 and TM6SF2. Combined polymorphism analysis demonstrated an even higher risk of cirrhosis if two or more risk alleles were present (OR 18.48; 95% CI 6.15-55.58; p < .001). Regarding cirrhosis complications, the risk was higher in PNPLA3 GG and TM6SF2 CT + TT, also with an even higher risk when two or more risk alleles were present in the combined evaluation (OR 27.20; 95% CI 5.26-140.62; p < .001). There were no associations with CVEs or mortality outcomes. Conclusion: mIn T2DM, PNPLA3 and TM6SF2 polymorphisms, individually and additively, impact MASLD severity, with an increased risk of cirrhosis and its complications.