Non-alcoholic fatty liver disease in Tanzania: prevalence, determinants, and diagnostic performance of triglycerides-glucose index and triglycerides-glucose index -body mass index compared to the hepatic ultrasound in overweight and obese individuals.

Background: Non-alcoholic fatty liver disease (NAFLD), which is closely associated with metabolic syndrome (MetS), is rarely reported in Tanzania, where MetS is prevalent. The purpose of this study was to determine the prevalence and associated factors of this condition in overweight and obese individuals and to correlate standard ultrasound diagnosis with triglyceride-glucose index (TyG) and TyG-body mass index (TyG-BMI).

Methods: A cross-sectional analysis was performed in 181 adult outpatients attending a general medical clinic. The presence of fatty liver was detected by ultrasound. Demographic, clinical, and laboratory data were collected and analyzed using STATA 15. To compare categorical variables, a chi-square test was employed, while a Student's t-test was used to compare continuous variables. Additionally, a multivariate regression analysis was conducted to identify the determinants of NAFLD. A significance level was set at p < 0.05. The discriminatory power of TyG and TyG-BMI for diagnosing NAFLD was evaluated using Receiver Operating Characteristic (ROC) Curve analysis and the Area Under the ROC Curve (AUC) was reported.

Results: The overall prevalence of NAFLD was 30.4% (55/181). The prevalence's of NAFLD in patients with class III obesity, class II obesity, class I obesity and overweight were 50.0% (12/24),, 38% (19/50), 23.7% (18/76), and 19.5% (6/31),respectively. NAFLD was strongly predicted by hyperuricemia (≥ 360 μmol/L) (p = 0.04) and TyG ≥ 8.99 (p = 0.003). The best cut-off values of TyG and TyG-BMI to predict NAFLD were 8.99 [AUC 0.735; sensitivity 70.9%, specificity 79.3%] and 312 [AUC 0.711; sensitivity 60% and specificity 75.4%] respectively.

Conclusions: The prevalence of NAFLD is high among people with overweight and obesity in Tanzania. We did not find sufficient evidence to recommend the use of TyG and TyG-BMI as surrogates for hepatic ultrasound in detecting NAFLD, and further evaluation is recommended.