Liver Fibrosis Estimated Using Noninvasive Blood Biochemical Indices Is Correlated with Visit-to-Visit Glycated Hemoglobin A1c Variability in Individuals with Type 2 Diabetes.

Background/Objectives: Visit-to-visit glycated hemoglobin A1c (HbA1c) variability is associated with cardiovascular diseases (CVDs) and all-cause mortality, independent of mean HbA1c levels. Metabolic dysfunction-associated steatotic liver disease (MASLD) is associated with CVDs and mortality. We aimed to clarify the association between annual HbA1c variability and MASLD development in individuals with type 2 diabetes (T2D). Methods: A retrospective cohort study was conducted in 402 Japanese patients (219 men, 183 women) with T2D. The participants' HbA1c levels were measured every 2 months, and their HbA1c coefficient of variation (HbA1c-CV) was calculated from the HbA1c in the past year. We statistically evaluated the association between HbA1c-CV and noninvasive clinical indices of MASLD, including the hepatic steatosis index (HSI), fibrosis-4 (FIB-4) index, aspartate aminotransferase-to-platelet ratio index (APRI), and non-alcoholic fatty liver disease fibrosis score (NFS). Results: Multiple regression analysis of clinical variables and each MASLD index showed that all liver fibrosis indices, including the FIB-4 index (p < 0.001), APRI (p = 0.005), and NFS (p < 0.001), were positively correlated with HbA1c-CV, whereas the HSI was not (p = 0.148). These associations remained even after adjusting for the medications used in the participants. Conclusions: The development of liver fibrosis, estimated using noninvasive blood biochemical indices, is independently and positively associated with annual HbA1c-CV in individuals with T2D. This result suggests that a comprehensive approach, including early MASLD risk stratification, may be beneficial for optimal diabetes management.