Ning W. et al., 2026: Impact of body fat content on extracorporeal shock wave lithotripsy for pancreatic duct stones: a retrospective cohort study.
Ning W, Shi Y, Ju Y, Shi Y.
PeerJ. 2026 Apr 9;14:e21112. doi: 10.7717/peerj.21112
Abstract
Background: The impact of body fat content on the treatment efficacy of extracorporeal shock wave lithotripsy (ESWL) for pancreatic duct stones (PDS) remains unclear, and there is a paucity of targeted analyses on refined body composition parameters in existing studies. This study aims to investigate the associations between body mass index (BMI), body fat percentage, visceral adipose tissue/skeletal muscle tissue (VAT/SMT) ratio, and the treatment efficiency of ESWL for PDS.
Methods: This was a single-center retrospective observational study that enrolled 147 patients with PDS who underwent ESWL and achieved complete stone clearance at Gongli Hospital, Pudong New Area, Shanghai, from January 2021 to January 2025. Measurements of VAT, subcutaneous adipose tissue (SAT), and SMT at the level of the L3/L4 intervertebral space were performed using non-contrast computed tomography (CT) combined with Adobe Photoshop software, and the VAT/SMT ratio was calculated accordingly. Hierarchical stepwise linear regression models were employed to analyze the independent effects of body fat-related parameters (including BMI, body fat percentage, and VAT/SMT ratio) on lithotripsy time and the number of lithotripsy sessions, after adjusting for confounding variables such as gender, age, and stone cross-sectional area.
Results: Pearson correlation analysis revealed that body fat percentage exhibited a strong positive correlation with the total lithotripsy time (r = 0.544, P < 0.001) and the number of lithotripsy sessions (r = 0.546, P < 0.001). Meanwhile, BMI (r = 0.354∼0.382, P < 0.001) and the VAT/SMT ratio (r = 0.352tsim0.353, P < 0.001) showed a moderate positive correlation with both outcomes. Multivariate linear regression analysis (fully adjusted model) confirmed that body fat percentage (number of lithotripsy sessions: β = 0.38, P < 0.001; total lithotripsy time: β = 0.37, P < 0.001), BMI (number of lithotripsy sessions: β = 0.27, P < 0.001; total lithotripsy time: β = 0.32, P < 0.001), and the VAT/SMT ratio (number of lithotripsy sessions: β = 0.20, P = 0.017; total lithotripsy time: β = 0.18, P = 0.035) were all independent positive predictors of lithotripsy efficiency. Additionally, stone cross-sectional area also significantly influenced the outcomes (number of lithotripsy sessions: β = 0.23, P = 0.001; total lithotripsy time: β = 0.15, P = 0.027).
Conclusion: BMI, body fat percentage, and VAT/SMT ratio exhibit a significant positive correlation with the total lithotripsy time and number of lithotripsy sessions for ESWL in PDS. Among these parameters, body fat percentage has the strongest association with lithotripsy efficiency and maintains a stable independent predictive effect in multivariate models.
Comment Hans-Göran Tiselius
There is a unanimous recommendation that for pancreatic duct stones with a diameter >5 mm, the first line treatment should be SWL.
In this report the authors examined the impact of body fat on the outcome of SWL. The following variables were studied:
BMI
Visceral adipose tissue (VAT)
Subcutaneous adipose tissue (SAT)
Skeletal muscle tissue (SMT)
The ratio VAT/SMT
The conclusion was that these different variables had an influence on the outcome of lithotripsy in terms of treatment time and number of treatment sessions. The stone cross sectional area also was of importance. Conclusions were based only on the results recorded from those patients in whom the treatment had been successful.
The authors state that SWL was carried out in supine position or in a 30o right decubitus position. This description is insufficient because it requires that the reader is familiar with the details of the lithotripter. Unfortunately, not even the type of lithotripter device is mentioned in the report.
The authors claim that knowledge of the variables on fat properties can be used for more accurate prediction of the SWL outcome, for instance in terms of number of treatment sessions.
Although that information might be of value for the individual patient it is the reviewer’s opinion that careful analysis of this kind is not worth the efforts. The data on fat is mainly of theoretical interest. Unfortunately, a precise prediction of the factors required for successful SWL cannot be made from these data only, because several factors other than those mentioned in this report play a role for the result.
Hans-Göran Tiselius
Comments