University Stone Centre, Department of Urology, University of Bonn, Bonn, Germany.
Urology. 2013 Jan;81(1):17-24. doi: 10.1016/j.urology.2012.07.107. Epub 2012 Nov 30.
To investigate the determinants of urinary stone formation in patients with fat malabsorption, because, although the prevalence of urolithiasis is greater in patients with intestinal diseases, the pathogenetic mechanisms and risk factors associated with urolithiasis in this population remain partially unsolved.
The present study retrospectively analyzed the determinants of urolithiasis in 51 patients with fat malabsorption due to different intestinal diseases. Anthropometric, clinical, blood, 24-hour urinary parameters, and dietary intake were assessed.
The resection rate (ie, pancreatic and/or bowel resection) differed significantly between stone formers (SF; n=10) and nonstone formers (NSF; n=41; 70% vs 29%; P=.027). Urinary citrate was lower (1.606±1.824 vs 3.156±1.968 mmol/24 h; P=.027), while oxalate excretion (0.659±0.292 vs 0.378±0.168 mmol/24 h; P=.002) and the relative supersaturation of calcium oxalate were greater in SF than NSF (8.16±4.61 vs 3.94±2.93; P=.003). Total cholesterol and low-density lipoprotein cholesterol, but also high-density lipoprotein cholesterol, plasma β-carotene, and vitamin E concentrations, were significantly diminished, whereas serum aspartate aminotransferase activity was significantly greater in SF compared with NSF. Binary logistic regression analysis revealed resection status as a major extrarenal risk factor for stone formation (odds ratio 5.639).
Increased urinary oxalate and decreased citrate excretion, probably resulting from pancreatic and/or bowel resection with mainly preserved colon, were identified as the most crucial urinary risk factors for stone formation in patients with fat malabsorption. The findings suggest that hyperoxaluria predominantly results from increased colonic permeability for oxalate due to disturbed bile acid metabolism. The impaired status of fat-soluble antioxidants β-carotene and vitamin E indicates severe malabsorptive states associated with an enhanced stone-forming propensity.
研究脂肪吸收不良患者尿路结石形成的决定因素，因为尽管肠病患者的尿路结石患病率更高，但该人群中尿路结石的发病机制和相关危险因素仍部分未得到解决。
本研究回顾性分析了 51 例因不同肠道疾病导致脂肪吸收不良的患者尿路结石形成的决定因素。评估了人体测量、临床、血液、24 小时尿液参数和饮食摄入情况。
结石形成者（SF；n=10）与非结石形成者（NSF；n=41）的切除率（即胰腺和/或肠道切除术）差异有统计学意义（70%比 29%；P=.027）。尿枸橼酸盐较低（1.606±1.824 比 3.156±1.968 mmol/24 h；P=.027），而 SF 的尿草酸盐排泄量（0.659±0.292 比 0.378±0.168 mmol/24 h；P=.002）和钙草酸盐相对过饱和度均大于 NSF（8.16±4.61 比 3.94±2.93；P=.003）。SF 的总胆固醇和低密度脂蛋白胆固醇以及高密度脂蛋白胆固醇、血浆β-胡萝卜素和维生素 E 浓度显著降低，而血清天冬氨酸氨基转移酶活性显著高于 NSF。二元逻辑回归分析显示，切除状态是结石形成的主要肾外危险因素（比值比 5.639）。
我们发现，尿枸橼酸盐排泄减少和草酸盐排泄增加，可能是由于胰腺和/或肠道切除，主要保留结肠，这被认为是脂肪吸收不良患者结石形成的最重要的尿危险因素。研究结果表明，高草酸尿主要是由于胆汁酸代谢紊乱导致结肠对草酸盐的通透性增加所致。脂溶性抗氧化剂β-胡萝卜素和维生素 E 的受损状态表明存在严重的吸收不良状态，与增强的结石形成倾向相关。
