Frailty is a syndrome that is closely related to age. Current assessment of frailty relies mainly on single inflammatory factors or nutritional indicators and lacks systematic diagnostic markers. Chronic inflammation and nutritional status as part of the physiopathologic mechanisms of debilitation, and platelet count and nutritional status are simple and easily accessible, whereas there are fewer studies on the correlation between mixed inflammatory markers of platelet count and nutritional status and frailties.

To investigate the correlation between preoperative platelet count/albumin ratio (PAR) and new-onset frailty at 7 d postoperatively in elderly patients undergoing elective surgery.

This is a secondary study based on the Early Warning Model Construction Study of EPAE dataset. Using cross-sectional survey method was used to select elderly patients who were hospitalized and planned to undergo surgery in 7 hospitals, including the Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Shunde Hospital of Guangzhou University of Chinese Medicine, the Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, the Eighth Clinical Medical College of Guangzhou University of Chinese Medicine, Huizhou Hospital of Guangzhou University of Chinese Medicine, Guangzhou University of Chinese Medicine Affiliated Zhongshan Hospital of Chinese Medicine and Dongguan Hospital of Guangzhou University of Chinese Medicine from February 2023 to October 2023. A total of 2 035 patients who were non-frailty before surgery were included, and the patients were divided into a non-frailty group (1 691 patients) and a new-onset frailty group (344 patients) according to the diagnostic criteria of the Chinese version of the Frail Scale at 7 d after surgery. General data and factors affecting perioperative frailty were collected and compared between the two groups. PAR was divided into four levels according to quartiles: Q1 (PAR≤4.160), Q2 (PAR: 4.161-5.339), Q3 (PAR: 5.340-6.479) and Q4 (PAR≥6.480), multi-model multifactorial Logistic regression analysis to assess the effect of different PAR levels on frailty. Analyzing the incidence of new-onset frailty 7 days after surgery in different age groups and receiver characteristic ROC curves were plotted to calculate the area under the curve (AUC) and the optimal cut-off value to assess the predictive value of preoperative PAR on new-onset frailty in elderly patients at 7 d postoperatively.

The age, caregiver, sedentary behavior, weekly hours of aerobic exercise, weekly hours of resistance training, proportion of stress history, age-corrected Charlson Comorbidity Index (ACCI) score, Athens Insomnia Scale (AIS) score, Depression Screening Scale (PHQ-9) score, Social Support Rating Scale (SSRS) score, American Society of Anesthesiologists (ASA) classification, preoperative analgesia, mode of anesthesia, proportion of type of surgery, duration of surgery and intraoperative transfusion were compared between the non-frailty group and the new-onset frailty group. The difference was statistically significant (P<0.05) and the PAR of the new-onset frailty group was significantly higher than that of the non-frailty group (P<0.001). The results of multifactorial Logistic regression analysis showed that after adjusting for all confounders, high level of PAR was a risk factor for new-onset frailty at 7 d postoperatively in elderly patients (OR=1.22, 95%CI=1.16-1.29, P<0.001). The results of multivariate Logistic regression analysis of different levels of PAR showed that compared with Q1 level PAR, Q2, Q3 and Q4 levels were the risk factors for new frailty at 7 days after surgery in elderly patients after adjusting for all confounding factors, and the risk of new frailty at 7 days after surgery was the highest in the Q4 group (OR=6.06, 95%CI=3.90-9.41, P<0.001). Stratified analysis showed that the incidence of postoperative new-onset frailty in different age groups increased significantly with higher preoperative PAR (P<0.001), and the AUC of preoperative PAR for predicting new-onset frailty at 7 d postoperatively in elderly patients was 0.635 (95%CI=0.606-0.665, P<0.001), and the optimal cut-off value was 4.345, with a sensitivity and specificity of 89.20% and 31.20%.

High level of PAR is a risk factor for new-onset frailty at 7 d postoperatively in elderly patients. Preoperative PAR has a certain predictive value for postoperative new frailty in elderly patients, and higher PAR indicates greater risk of postoperative new frailty.

衰弱是一种与年龄密切相关的综合征。目前评估衰弱主要依赖单一的炎症因子或营养指标，缺乏系统性的诊断标志物。慢性炎症和营养状况作为衰弱的病理生理机制的一部分，且血小板计数和营养状况简单易获取，而目前关于血小板计数和营养状况的混合性炎症标志物与衰弱之间的相关性研究较少。

探讨老年择期手术患者术前血小板计数/白蛋白比值（PAR）与术后7 d新发衰弱的相关性。

本研究是基于老年围手术期不良事件预警模型构建研究（EPAE）数据集进行的二次研究，采用横断面调查方法，选取2023年2—10月在广州中医药大学第二附属医院、广州中医药大学顺德医院、广州中医药大学第四临床医学院、广州中医药大学第八临床医学院、广州中医药大学惠州医院、广州中医药大学附属中山中医院、广州中医药大学东莞医院共7家医院进行住院治疗且拟行择期手术的老年患者。纳入术前无衰弱的患者共2 035例，术后7 d根据中文版Frail量表的诊断标准将患者分为无衰弱组（1 691例）和新发衰弱组（344例）。收集两组患者的一般资料及围术期衰弱的影响因素并进行比较。采用多因素Logistic回归分析评估变量之间的相关性；将术前PAR根据四分位数分为4个水平：Q1（PAR≤4.160）、Q2（PAR：4.161~5.339）、Q3（PAR：5.340~6.479）、Q4（PAR≥6.480），进行多模型多因素Logistic回归分析以评估不同PAR水平对衰弱的影响。分析不同年龄段人群术后7 d新发衰弱发生率并绘制受试者工作特征曲线（ROC曲线），计算曲线下面积（AUC）及最佳截断值，以评估术前PAR对老年患者术后7 d新发衰弱的预测价值。

无衰弱组和新发衰弱组患者的年龄、照护人员、久坐行为、每周有氧运动时长、每周抗阻训练时长、应激史比例、年龄校正查尔森合并症指数（ACCI）评分、阿森斯（Athens）失眠量表（AIS）评分、抑郁症筛查量表（PHQ-9）评分、社会支持评定量表（SSRS）评分、美国麻醉医师协会（ASA）分级、超前镇痛、麻醉方式、手术类型比例及手术时间、术中输血量比较，差异有统计学意义（P<0.05）；且新发衰弱组PAR高于无衰弱组（P<0.001）。多因素Logistic回归分析结果显示，调整全部混杂因素后，高水平PAR是老年患者术后7 d新发衰弱的危险因素（OR=1.22，95%CI=1.16~1.29，P<0.001）。不同水平PAR的多因素Logistic回归分析结果显示，调整全部混杂因素后，与Q1水平PAR相比，Q2、Q3、Q4水平PAR均是老年患者术后7 d新发衰弱的危险因素，其中Q4水平PAR老年患者术后7 d新发衰弱的风险最高（OR=6.06，95%CI=3.90~9.41，P<0.001）。分层分析结果显示，不同年龄段人群术后7 d新发衰弱发生率随着术前PAR升高而显著递增（P<0.001）；术前PAR预测老年患者术后7 d新发衰弱的AUC为0.635（95%CI=0.606~0.665，P<0.001），最佳截断值为4.345，灵敏度和特异度分别为89.20%和31.20%。

高水平PAR是老年患者术后7 d新发衰弱的危险因素。术前PAR对老年患者术后新发衰弱具有一定预测价值，PAR水平越高提示术后新发衰弱的风险越大。