Secondary outcomes of the participants (N = 207).

Background
Standardized guidelines for optimal tunnel length in tunneled peripherally inserted central catheters (PICCs) are lacking.
Objectives
The objective of this study was to evaluate the real-world impact of tunnel length on clinical outcomes.
Methods
This retrospective cohort study included 207 cancer patients who received tunneled PICCs, categorized into a control group (tunnel length > 4 cm, n = 134) and an observation group (tunnel length ≤ 4 cm, n = 73). Propensity score matching (PSM) was used to address baseline heterogeneity. Cox regression analyses were used to assess the risk of complication during a 120-day follow-up.
Results
Compared to the control group (tunnel length > 4 cm), the observation group (tunnel length ≤ 4 cm) had a significantly higher adjusted overall complication risk (HR = 2.92, 95% CI: 1.07–7.94, P = 0.036) and unplanned catheter removal rate (4.4% vs. 0.0%, P = 0.027), confirming the safety of longer tunnels despite comparable comfort levels between groups. After PSM, Cox regression analysis showed results consistent with those from the unmatched cohort. Subgroup analyses revealed a reduced risk of complications with longer tunnels in patients with BMI ≤ 25 kg/m² (HR = 0.29, 95% CI: 0.11–0.82), without hypertension (HR = 0.36, 95% CI: 0.13–1.00), without diabetes (HR = 0.38, 95% CI: 0.15–0.97), and with solid tumors (HR = 0.31, 95% CI: 0.11–0.85).
Conclusion
The results show that tunnel lengths > 4 cm reduce overall complications and prolong catheter retention, supporting the implementation of standardized protocols while advocating for personalized adjustments based on BMI, comorbidities, and cancer type.

背景
目前尚无针对隧道式经外周置入中心静脉导管（tunneled peripherally inserted central catheters, PICCs）最佳隧道长度的标准化临床指南。
目的
本研究旨在评估隧道长度对临床结局的真实世界影响。
方法
本回顾性队列研究纳入207例接受隧道式PICCs置管的癌症患者，按隧道长度分为对照组（隧道长度＞4cm，n=134）与观察组（隧道长度≤4cm，n=73）。采用倾向得分匹配（propensity score matching, PSM）校正基线异质性，并通过Cox回归分析评估120天随访期内的并发症发生风险。
结果
与对照组（隧道长度＞4cm）相比，观察组（隧道长度≤4cm）的校正后总并发症风险显著升高（风险比（Hazard Ratio, HR）=2.92，95%置信区间（Confidence Interval, CI）:1.07~7.94，P=0.036），且非计划性拔管率更高（4.4% vs. 0.0%，P=0.027）；尽管两组患者舒适度水平相当，但更长的隧道长度更具安全性。倾向得分匹配后，Cox回归分析结果与未匹配队列的结论一致。亚组分析显示，在体重指数（Body Mass Index, BMI）≤25kg/m²、无高血压、无糖尿病以及患有实体瘤的患者中，更长的隧道长度可降低并发症发生风险（HR分别为0.29、0.36、0.38、0.31，95%CI依次为0.11~0.82、0.13~1.00、0.15~0.97、0.11~0.85）。
结论
本研究结果表明，隧道长度＞4cm可降低总并发症发生率并延长导管留置时间，支持标准化置管方案的实施，同时建议结合患者体重指数、合并症情况及癌症类型进行个性化调整。