Reply: Does reference value of “Normal Liver Stiffness” using fibroscan have a regional variation?

Abstract

We thank Kumar et al. for their interest in our article.1 We appreciate their concern and would like to reiterate that the strength of our data and its implication in liver stiffness measurements (LSMs) is the result of the inclusion of a statistically representative sample of healthy people drawn from a systemically maintained community health database, thus negating the “selection bias” inherent in any sample drawn from “free health/medical check-up” and functional dyspeptics.2, 3 We excluded the effect of social consumption of alcohol, drugs, viral hepatitis, and even ultrasound-diagnosed nonalcoholic fatty liver disease (NAFLD) in our healthy sample. Liver biopsy could not be done in these asymptomatic healthy subjects because of ethical reasons. Second, although we used World Health Organization–proposed categories for body mass index (BMI), distribution pattern of LSM remained similar (i.e., “U-shaped”), when Asian-specific categories were applied (i.e., LSM values were 6.03 ± 1.77, 5.62 ± 1.64, 5.37 ± 1.51, and 5.96 ± 1.25 kPa, respectively, in BMI categories <18.5 [n = 92], 18.5-23.0 [n = 214], 23.0-27.5 [n = 98], and >27.5 kg/m2 [n = 14], respectively). Third, the failure rate of transient elastography (4.35%) in healthy subjects was consistent with that reported in the literature.2, 3 Fourth, in our study, LSM increased in obese and underweight vis-à-vis those with healthy BMI, because, unlike other studies, our healthy cohort had a wide spectrum of BMI. We had earlier shown that nonobese people in the developing world have significant liver disease, often related to NAFLD.4 Given the intricate relationship between emerging liver diseases, lifestyle, and nutrition, it may be appropriate to view our data in a perspective for the assessment of liver diseases in the developing countries, where these determinants prevail. Finally, the 95th percentile value of LSM in the nonobese healthy men of the French cohort was 8.0 kPa.2 Efficacy of 8 kPa as the cutoff was validated in a recent community study.5 For the purpose of using LSM in the community, we need to have a trigger point that is scientifically justified and, at the same time, minimize unnecessary healthcare resource usage. We think the cut-off value of 8.5 kPa derived from our cohort is acceptable, when community application of LSM is an issue. We look forward to further studies on the validation of our data in the region. Abhijit Chowdhury M.D., D.N.B., D.M.*, Kausik Das M.D., D.M.*, * Department of Hepatology, School of Digestive and Liver Diseases, IPGME&R, Kolkata, India.