Supplementary Material for: Visual Analysis of Biomarkers Reveals Differences in Lipid Profiles and Liver Enzymes before and after Gastric Sleeve and Bypass

Introduction: Bariatric surgery results in both intentional and unintentional metabolic changes. In a high-volume bariatric center, extensive laboratory panels are used to monitor these changes pre- and postoperatively. Consecutive measurements of relevant biochemical markers allow exploration of the health state of bariatric patients and comparison of different patient groups. Objective: The objective of this study is to compare biomarker distributions over time between 2 common bariatric procedures, i.e., sleeve gastrectomy (SG) and gastric bypass (RYGB), using visual analytics. Methods: Both pre- and postsurgical (6, 12, and 24 months) data of all patients who underwent primary bariatric surgery were collected retrospectively. The distribution and evolution of different biochemical markers were compared before and after surgery using asymmetric beanplots in order to evaluate the effect of primary SG and RYGB. A beanplot is an alternative to the boxplot that allows an easy and thorough visual comparison of univariate data. Results: In total, 1,237 patients (659 SG and 578 RYGB) were included. The sleeve and bypass groups were comparable in terms of age and the prevalence of comorbidities. The mean presurgical BMI and the percentage of males were higher in the sleeve group. The effect of surgery on lowering of glycated hemoglobin was similar for both surgery types. After RYGB surgery, the decrease in the cholesterol concentration was larger than after SG. The enzymatic activity of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphate in sleeve patients was higher presurgically but lower postsurgically compared to bypass values. Conclusions: Beanplots allow intuitive visualization of population distributions. Analysis of this large population-based data set using beanplots suggests comparable efficacies of both types of surgery in reducing diabetes. RYGB surgery reduced dyslipidemia more effectively than SG. The trend toward a larger decrease in liver enzyme activities following SG is a subject for further investigation.

引言：减重代谢手术（bariatric surgery）可引发有意与无意的代谢改变。在高手术量的减重代谢中心，临床常通过全套实验室检测项目来监测术前与术后的这类代谢变化。对相关生化标志物进行连续检测，可用于探究减重代谢手术患者的健康状态，并对比不同患者群体的特征。
研究目的：本研究旨在通过可视化分析，对比两种常见减重代谢术式——袖状胃切除术（sleeve gastrectomy, SG）与胃旁路术（gastric bypass, RYGB）——随时间变化的生物标志物分布特征。
研究方法：本研究回顾性收集了所有接受初次减重代谢手术患者的术前及术后（6、12、24个月）数据。采用不对称豆图（asymmetric beanplots）对比不同生化标志物在术前与术后的分布及演变情况，以评估初次SG与RYGB的手术效果。豆图是箱线图的替代可视化方案，可便捷且全面地实现单变量数据的视觉对比。
研究结果：本研究共纳入1237例患者，其中659例接受袖状胃切除术，578例接受胃旁路术。两组患者在年龄与共病患病率方面基线可比。袖状胃切除术组患者的术前平均BMI及男性占比更高。两种术式对糖化血红蛋白的降低效果相近。接受胃旁路术后，患者的胆固醇浓度降幅大于袖状胃切除术组。术前，袖状胃切除术组患者的天冬氨酸氨基转移酶、丙氨酸氨基转移酶及碱性磷酸酶活性均高于胃旁路术组；而术后，该组的上述酶活性则低于胃旁路术组。
结论：豆图可直观实现群体分布的可视化。基于本大型群体数据集的豆图分析结果显示，两种术式在改善糖尿病方面的疗效相当。胃旁路术对血脂异常的改善效果优于袖状胃切除术。袖状胃切除术后肝酶活性降幅更大的趋势，有待进一步研究探究。