The skin-gut axis theory suggests that the gut and skin barrier, as well as the microbiota, are highly similar and have a bidirectional relationship. Gut good bacteria can reduce the permeability of the gut barrier, alter skin symbiotic bacteria, and enhance skin barrier function, which is beneficial for wound healing. How to improve wound infection and promote healing by improving gut function has become a new research hotspot in recent years.

To compare the effectiveness of two internal nurturing and external treatment for older patients with pressure injury (PI) based on the skin-gut axis theory, and explore new ideas and methods for them.

Considering the skin-gut axis theory and guidelines, we discussed and designed two internal nurturing programs including prebiotics+probiotics or traditional Chinese medicines to regulate gastrointestinal function and replenish nutrients, and the "four-step external treatment", including debridement+negative pressure wound therapy with instillation (NPWTi) +surgical closure+ follow-up with wound care. A two-arms randomized controlled trial (RCT) was adopted and 80 inpatients with fourth stage of PI,≥ 60 years old in department of Medical Aesthetics and Burns, Nanjing Hospital of Traditional Chinese Medicine Affiliated to Nanjing University of Chinese Medicine were included from August 2023 to July 2025, and were randomly divided into the trial group and the control group according to a 1∶1 ratio. The trial patients were treated by "prebiotics+probiotics" combined with "four-step external treatment". The control patients were treated by "prebiotics+traditional Chinese medicines" combined with "four-step external treatment" until 4 weeks and followed up for 3 months. Primary outcome measures included healing rate and healing time after 4 weeks of intervention and 3-month of follow-up. Secondary outcome measures included serum albumin, hemoglobin, blood glucose levels before and after intervention. Statistical analysis was applied to baseline data, primary and secondary outcomes.

Among the 80 PI patients, there were 54 males (67.5%) and 26 females (32.5%), with an average age of (71.3±11.4) years. The trial group of 40 patients completed treatment and follow-up as planned, with no dropouts or deaths; Two patients in the control group of 40 died. There was no statistically significant difference in baseline data between the two groups of patients (P>0.05). There was no statistically significant difference in the 4-week healing rate and 4-week healing time between the two groups of patients (P>0.05); The 3-month healing rate of the trial group patients was higher than that of the control group (χ² =5.952, P=0.015), and the 3-month healing time was shorter than that of the control group (t=3.440, P=0.001). Three weeks after intervention, there was no statistically significant difference in serum albumin, hemoglobin, and blood glucose levels between the two groups of patients (P>0.05). There was no statistically significant difference in hemoglobin and blood glucose levels between the two groups of patients before and after intervention (P>0.05); After intervention, the serum albumin levels of both groups of patients were higher than before intervention, and the difference was statistically significant (P<0.05).

Both internal nurturing combined with "four-step external treatment" can improve the efficacy of older patients with stage 4 PI, and the trial group showed better results after a 3-month follow-up treatment.

皮肤-肠轴理论认为，肠道和皮肤屏障及微生物群高度相似，有双向联系，肠道有益细菌可降低肠屏障通透性而改变皮肤共生细菌和增强皮肤屏障功能，利于伤口愈合，如何通过改善肠道功能来改善伤口感染和促进愈合是近年研究新热点。

比较基于皮肤-肠轴理论的两种内养结合四步外治方案用于老年压力性损伤的效果，为治疗此类患者探索新思路、新方法。

基于肠轴理论和指南，讨论设计益生元+益生菌或中成药调理胃肠道功能及补充营养的两种内养方案和清创+伤口负压结合滴注疗法+手术闭合+局部护理随访的"四步外治法"。采用双臂随机对照研究设计，纳入2023年8月—2025年7月南京中医药大学附属南京中医院医疗美容和烧伤科收治的≥60岁的4期压力性损伤患者80例为研究对象，按照1∶1比例随机分为试验组（40例）和对照组（40例），试验组采用"益生元+益生菌的内养方案"结合"四步外治法"，对照组采用"益生元+中成药的内养方案"结合"四步外治法"至4周，随访治疗3个月。主要结局指标：干预4周和随访3个月的愈合率和愈合时间。次要结局指标：干预前和干预后3周血清白蛋白、血红蛋白、血糖水平。比较2组基线资料、主要结局指标和次要结局指标。

80例压力性损伤患者中，男54例（67.5%）、女26例（32.5%），平均年龄（71.3±11.4）岁。试验组40例患者按计划完成了治疗和随访，无脱落和死亡；对照组40例中2例患者死亡。2组患者基线资料比较，差异均无统计学意义（P>0.05）。2组患者4周愈合率、4周愈合时间比较，差异无统计学意义（P>0.05）；试验组患者3个月愈合率高于对照组（χ² =5.952，P=0.015），3个月愈合时间短于对照组（t=3.440，P=0.001）。干预后3周，2组患者血清白蛋白、血红蛋白、血糖水平比较，差异均无统计学意义（P>0.05）。2组患者干预前后血红蛋白、血糖水平比较，差异均无统计学意义（P>0.05）；2组患者干预后血清白蛋白水平均高于干预前，差异有统计学意义（P<0.05）。

两种内养方案结合"四步外治法"均可改善老年4期压力性损伤患者的疗效，试验组方案随访治疗3个月的效果更优。