Waist to height ratio in nonalcoholic fatty liver disease – Systematic review and meta-analysis

Background and aims: Current nonalcoholic fatty liver disease (NAFLD) guidelines do not provide any recommendations regarding the waist-to-height ratio (WHtR), a simple obesity metric calculated by dividing waist circumference by height. Therefore, we performed a systematic review and meta-analysis aiming to evaluate WHtR in NAFLD. Methods: We performed a systematic electronic search on PubMed, Embase, and Scopus, identifying observational studies assessing WHtR in NAFLD. QUADAS-2 tool was used to evaluate the quality of included studies. The two main statistical outcomes were the area under the curve (AUC) and the mean difference (MD). Results: We included a total of 27 studies in our quantitative and qualitative synthesis, with a total population of 93,536 individuals. WHtR was significantly higher in NAFLD patients compared to controls with an MD of 0.073 (95% CI 0.058 - 0.088). This was also confirmed after conducting a subgroup analysis according to the hepatic steatosis diagnosis method, for ultrasound (MD 0.066 [96% CI 0.051 - 0.081]) and transient elastography (MD 0.074 [96% CI 0.053 - 0.094]). Moreover, NAFLD male patients presented significantly lower WHtR compared to female patients (MD -0.022 [95% CI -0.041 - -0.004]). The AUC of WHtR for predicting NAFLD was 0.815 (95% CI 0.780 - 0.849). Conclusions: WHtR is considerably higher in NAFLD patients compared to controls. Female NAFLD patients present higher WHtR compared to NAFLD male patients. In comparison to other presently suggested scores and markers, the WHtR's accuracy in predicting NAFLD is considered acceptable.