Lipids play a crucial role in maintaining normal physiological functions, and cancer patients often exhibit dyslipidemia, which can affect prognosis. Phase angle (PA) is an objective index reflecting the structural integrity and function of human cell membrane, which is positively correlated with the nutritional status of the body, and is often used to predict survival and therapeutic effect. Currently, the lipid profile characteristics of digestive system cancer patients and their impact on PA remain unclear.

To analyze the lipid profile characteristics of patients with digestive system tumors and investigate their influence on PA.

A retrospective study was conducted on 142 patients admitted to the Affiliated Anqing First People's Hospital of Anhui Medical University between July 2020 and December 2023. General patient data, performance status (PS) scores and patient-generated subjective global assessment (PG-SGA) scores were collected. Lipid profile indicators and PA were measured, and patients were divided into a normal PA group and a low PA group based on PA levels. Differences in general characteristics and lipid levels between the two groups were compared. Binary logistic regression was used to analyze the influencing factors of PA. Receiver operating characteristic (ROC) curves were plotted, and the area under the ROC curve (AUC) was calculated to evaluate the predictive value of lipid indicators for PA.

Among the 142 patients, 104 (73.24%) were male, and 38 (26.76%) were female, with a mean age of (65.0±10.8) years. The low PA group comprised 64 patients (45.07%), while the normal PA group included 78 patients (54.93%). Significant differences were observed between the two groups in terms of sex, age, PS score and PG-SGA score (P<0.05). The low PA group had lower levels of total cholesterol (TC), triacylglycerol (TG) and low density lipoprotein (LDL) compared to the normal PA group (P<0.05), while no significant difference was found in high density lipoprotein (HDL) levels (P>0.05). Binary Logistic regression analysis revealed that female sex (OR=0.251, 95%CI=0.086-0.731) and age>65 (OR=0.281, 95%CI=0.108-0.727) were protective factors for PA≥4.4°, whereas TC (OR=6.142, 95%CI=2.795-13.494) was a risk factor for PA≥4.4°. The AUC for TC in predicting PA≥4.4° was 0.803 (95%CI=0.733-0.874), with a sensitivity of 75.6%, specificity of 71.9%, and an optimal cutoff value of 4.25 mmol/L. The AUC for LDL in predicting PA≥4.4°was 0.790 (95%CI=0.717-0.863), with a sensitivity of 76.9%, specificity of 67.2%, and an optimal cutoff value of 2.46 mmol/L. The AUC for TG in predicting PA≥4.4° was 0.609 (95%CI=0.517-0.702), with a sensitivity of 55.1%, specificity of 64.1%, and an optimal cutoff value of 1.05 mmol/L.

Lipid metabolism in digestive system tumor patients is influenced by multiple factors. The levels of TC and LDL have a relatively high predictive value for PA≥4.4°. Controlling both levels within an appropriate range (TC: 4.25-5.55 mmol/L, LDL: 2.46-3.91 mmol/L) is conducive to maintaining normal PA and may potentially improve prognosis.

血脂在维持机体正常生理功能中起着重要作用，肿瘤患者常存在血脂紊乱，从而影响预后。相位角（PA）是反应人体细胞膜结构完整和功能状况的客观指标，与机体营养状态呈正相关，常用于生存与疗效预测。目前消化系统肿瘤患者血脂特征及其对PA的影响尚不明确。

分析消化系统肿瘤患者血脂特征，并分析其对PA的影响。

回顾性纳入2020年7月—2023年12月安徽医科大学附属安庆第一人民医院收治的142例肿瘤患者为研究对象，收集患者一般资料、体力活动状态（PS）评分和整体营养评估量表（PG-SGA）评分，检测患者血脂指标以及PA，并根据PA分为正常PA组和低PA组，比较两组患者一般特征和血脂水平差异。采用二元Logistic回归分析PA的影响因素，绘制受试者工作特征（ROC）曲线，并计算ROC曲线下面积（AUC），评估血脂指标对PA的预测价值。

142例患者中，男性104例（73.24%），女性38例（26.76%）；平均年龄（65.0±10.8）岁。低PA组64例（45.07%），正常PA组78例（54.93%）；两组患者性别、年龄、PS评分和PG-SGA评分比较，差异均有统计学意义（P<0.05）；低PA组总胆固醇（TC）、三酰甘油（TG）、低密度脂蛋白（LDL）水平低于正常PA组（P<0.05）；两组高密度脂蛋白（HDL）比较，差异无统计学意义（P>0.05）。二元Logistic回归分析显示：女性（OR=0.251，95%CI=0.086~0.731）、年龄>65岁（OR=0.281，95%CI=0.108~0.727）是PA≥4.4°发生的保护因素，TC（OR=6.142，95%CI=2.795~13.494）是PA≥4.4°发生的危险因素。TC预测PA≥4.4°的AUC为0.803（95%CI=0.733~0.874），灵敏度为75.6%，特异度为71.9%，最佳截断值为4.25 mmol/L；LDL预测PA≥4.4°的AUC为0.790（95%CI=0.717~0.863），灵敏度为76.9%，特异度为67.2%，最佳截断值为2.46 mmol/L；TG预测PA≥4.4°的AUC为0.609（95%CI=0.517~0.702），灵敏度为55.1%，特异度为64.1%，最佳截断值为1.05 mmol/L。

消化系统肿瘤血脂受多种因素影响，TC和LDL水平对PA≥4.4°有较高预测价值，二者水平控制在合适的范围（TC：4.25~5.55 mmol/L，LDL：2.46~3.91 mmol/L ）有利于维持PA正常，并可能潜在改善预后。