---
title: "Nailfold capillaroscopy shows capillary loss and venular impairment linked to renal dysfunction in"
id: "plos-one-11-assessment-of-nailfold-microcirculation-in-non-dialysis-ckd-capillaroscopic"
canonical_url: "https://medichelpline.com/clinical-feed/plos-one-11-assessment-of-nailfold-microcirculation-in-non-dialysis-ckd-capillaroscopic"
content_type: "clinical_feed_article"
specialty: "Nephrology"
source_name: "PLOS ONE (Medicine)"
source_url: "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0359419"
published_at: "2026-09-30T14:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Nailfold capillaroscopy shows capillary loss and venular impairment linked to renal dysfunction in
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/plos-one-11-assessment-of-nailfold-microcirculation-in-non-dialysis-ckd-capillaroscopic
- **Specialty:** [Nephrology](https://medichelpline.com/clinical-feed/nephrology.md)
- **Primary Source:** PLOS ONE (Medicine)
- **Source URL:** [Original Journal Publication](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0359419)
- **Published At:** 2026-09-30T14:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- The study used **nailfold capillaroscopy** to evaluate peripheral microcirculation in 63 non-dialysis chronic kidney disease (**CKD**) patients and 41 healthy controls. - Investigators recorded 20 parameterized nailfold microcirculation indexes and calculated a composite Niu Tian integral to grade abnormalities. - CKD patients had higher **capillary number integral**, output branch diameter integral, capillary top diameter integral, crossed capillary number integral, velocity of blood flow integral, erythrocyte aggregation integral, perivascular exudation integral, and capillary hemorrhage integral compared with controls. - CKD patients showed lower capillary length integral, color of blood integral, and **subpapillary venular plexus integral** versus controls. - Within the CKD group, **serum creatinine (Scr)**, cystatin C, and CKD stage correlated positively with **capillary number integral** and negatively with **subpapillary venular plexus integral**; **eGFR** correlated inversely with capillary number integral and positively with subpapillary venular plexus integral. - Multiple linear regression identified Scr, cystatin C, and CKD stage as independently and positively associated with capillary number integral; eGFR and hemoglobin were independently and negatively associated with capillary number integral. - Scr, cystatin C, and CKD stage were independently and negatively associated with subpapillary venular plexus integral, while eGFR was independently and positively associated with it. - Findings suggest renal dysfunction in non-dialysis CKD is associated with reduced capillary number and impaired subpapillary venous plexus relaxation, supporting nailfold capillaroscopy as a noninvasive tool to assess microcirculatory changes.
## Clinical Analysis & Structured Key Points
Assessment of nailfold microcirculation in non-dialysis CKD: Capillaroscopic indicators correlated with renal dysfunction | PLOS One Browse Subject Areas ? Click through the PLOS taxonomy to find articles in your field. For more information about PLOS Subject Areas, click here . Article Authors Metrics Comments Media Coverage Reader Comments Figures Figures Abstract Chronic kidney disease (CKD) is commonly associated with vascular injury. To date, efficient tools for assessing microcirculatory changes in non-dialysis CKD patients remain limited. We conducted a retrospectively registered study to employed nailfold capillaroscopy as a non-invasive method to evaluate peripheral microcirculation in CKD. A total of 104 participants were enrolled, including 63 patients with non-dialysis CKD patients (CKD group) and 41 healthy controls (control group). Renal function assessment and nailfold microcirculation examinations were performed for all participants. We analyzed 20 microcirculatory parameters and further explored their associations with serum creatinine (Scr), blood urea nitrogen (BUN), cystatin C, estimated glomerular filtration rate (eGFR), CKD stage, and hemoglobin (Hb) within the CKD group. Results showed that serum creatinine, cystatin C, and CKD stage were independently and positively associated with the capillary number integral, whereas eGFR and hemoglobin were independently and negatively associated with the capillary number integral. In addition, serum creatinine, cystatin C, and CKD stage were independently and negatively associated with the subpapillary venular plexus integral, while eGFR was independently and positively associated with the subpapillary venular plexus integral. In summary, our findings suggest that several key renal function parameters are independently associated with capillary number integral and subpapillary venular plexus integral. These findings indicate that renal dysfunction may be associated with reduced capillary number and impaired subpapillary venous plexus relaxation in patients with non-dialysis CKD. Citation: Li S, Liu Y, Yan H, Zhou X, Liu Q, Waheed YA, et al. (2026) Assessment of nailfold microcirculation in non-dialysis CKD: Capillaroscopic indicators correlated with renal dysfunction. PLoS One 21(9): e0359419. https://doi.org/10.1371/journal.pone.0359419 Editor: Diego Moriconi, University of Pisa, ITALY Received: January 25, 2026; Accepted: September 14, 2026; Published: September 30, 2026 Copyright: © 2026 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: All relevant data are within the paper. Funding: This study was supported by funding from the National Natural Science Foundation of China (82470726, 82270731, 82000703); The High-Level Hospital Construction Project of Jiangsu Province(LCZX202403);“Paired Assistance Scientific Research Project by The Affiliated Hospital of Xuzhou Medical University(SHJDBF2024104); The Open Project of Key Laboratory of Higher Education Institutions in Jiangsu Province (XZSYSKF2023019); Xuzhou Medical leading Talent training Project (XWRCHT20210038); the New Technology project of Affiliated Hospital of Xuzhou Medical University (2020301018) “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”. Competing interests: The authors have declared that no competing interests exist. Abbreviations: CKD, Chronic kidney disease; Scr, serum creatinine; BUN, blood urea nitrogen; eGFR, estimated glomerular filtration rate; Hb, hemoglobin; HTN, hypertension; RAAS, renin-angiotension-aldosterone system Introduction The kidneys, as highly vascularized organs, play a crucial role in regulating blood flow. Kidney dysfunction and renal damage for more than three months can be replicated as CKD [ 1 ]. The leading causes of CKD include diabetes, hypertension (HTN), primary or secondary glomerulopathies, obstructive nephropathy, medications, and genetic disorders. Among these, HTN and diabetes are of particular concern [ 2 , 3 ]. Most CKD patients have a vascular injury, and traditional risk factors such as hyperlipidemia and hypertension, and non-traditional ones include uremia, disordered mineral-bone disease, inflammation, and oxidative stress participate in vascular lesion [ 4 ]. Studies indicate that abnormalities in microcirculatory structure and function can impair organ function and contribute to organ damage, as seen in diabetes, HTN, and kidney disease [ 5 – 7 ]. HTN, uremic toxin, mineral metabolic disorders, and others can also cause vascular injury in CKD patients, resulting in vascular structure changes and dysfunction [ 8 – 10 ]. Microvascular rarefaction has emerged as an early marker for assessing microvascular function and tissue perfusion, including that of the kidneys [ 11 – 13 ]. Skin microcirculation can be deliberated as the representative of the structure and function of systemic microcirculation [ 14 , 15 ]. The finger nailfold is the skin wrinkle covering the root of the nail [ 16 ]. Nailfold microcirculation is the circulation pathway consisting of nailfold capillaries, a typical peripheral circulation pathway. To a certain extent, nailfold capillaries can reflect changes of microcirculatory status and can be utilized as a window to evaluate microcirculatory status. To date, nailfold microcirculation research has primarily focused on rheumatic and immune diseases, with limited attention to kidney disease. Previous studies have demonstrated altered nailfold microcirculation in CKD patients undergoing dialysis, with a strong association between these changes and dialysis treatment [ 17 , 18 ]. The present study aimed to explore the relationship between nailfold capillary indexes and renal function, and to develop a novel, non-invasive, and efficient technique for assessing the microcirculatory status of non-dialysis CKD patients. Methods Ethical approval The study was conducted at the Xuzhou Medical University Affiliated Hospital. Our study has been registered at Clinical Trials. gov (NCT03682952) and has been approved by the Clinical Trial Ethics Committee of Xuzhou Medical University Affiliated Hospital (XYFY2018-KL034–01) Helsinki and its later amendments or comparable ethical standards. All participants provided written informed consent prior to participation. Subjects We recruited 41 healthy individuals into the control group from Physical Examination Center of the Affiliated Hospital of Xuzhou Medical University. We recruited 68 non-dialysis CKD patients into the CKD group who accepted treatment in the Department of Nephrology of the Affiliated Hospital of Xuzhou Medical University. Following ethics committee approval, data were accessed for research purposes between 01/10/2018 and 31/12/2020. We had strict exclusion and inclusion criteria for CKD patients. Inclusion criteria: non-dialysis CKD patients with strict blood pressure control (systolic blood pressure ≤ 140 mmHg, diastolic blood pressure ≤ 90 mmHg). Exclusion criteria: Combined with other diseases that can affect systemic blood circulation and vascular function, including cardiovascular, cerebrovascular, respiratory, endocrine, rheumatic immune diseases, infection, shock, dehydration, urgent dialysis, and other emergencies. Among the CKD group, 5 CKD patients were excluded from the group. Those are as follows: blood pressure of 2 CKD patients did not reach up the criteria, nailfold microcirculation images of 2 CKD patients were affected by nailfold skin injury, and nailfold microcirculation result of 1 CKD patient was affected by the thickness of nailfold cutin. They were excluded from the CKD group. The remaining 63 CKD patients were included in the CKD group ( Fig 1 ). We collected the medical history of the patients together with basic information. All members accepted hematological examination, including Scr, BUN, cystatin C, Hb. Also, we calculated eGFR according to the CKD-EPI formula. The detailed information regarding CKD etiology and the distribution of CKD stages are now presented in Tables 1 and 2 . Download: PNG larger image TIFF original image Fig 1. We recruited 41 healthy individuals from Physical Examination Center of the Affiliated Hospital of Xuzhou Medical University, then we informed them of the experimental procedure, and after their informed consent, they were included in the control group. We recruited non-dialysis CKD patients who accepted treatment in the Department of Nephrology of the Affiliated Hospital of Xuzhou Medical University, we exculuded the patients who were combined with other diseases that can affect systemic blood circulation and vascular function, including cardiovascular, cerebrovascular, respiratory, endocrine, rheumatic immune diseases, infection, shock, dehydration, urgent dialysis, and other emergencies, 68 non-dialysis CKD patients were included in the CKD group after informed consent, after relevant examinations, 5 patients were excluded, and ultimately 63 non-dialysis CKD patients were included in the CKD group. https://doi.org/10.1371/journal.pone.0359419.g001 Nailfold microcirculation examination The nailfold microcirculation examination is a rapid, non-invasive, and quantitative technique to evaluate the nailfold capillary status using nailfold capillaroscopy. Before the examination, subjects were required to sit in a room for 15–20 minutes calm, their hands were needed to be warm, and the nailfold was uninjured, ensuring that we could clearly observe capillaries and blood flow. In the examination, pine and cypress oil were dripped on the skin of fourth finger nailfold. We evaluated morphology of capillaries, blood flow, and pericapillary state from the image ( Fig 2a ) pictured by nailfold capillaroscopy, which obtained 20 parameterized indexes. The 20 parameterized indexes such as clarity integral, capillary number integral, input branch diameter integral, output branch diameter integral, output branch diameter/input branch diameter, capillary top diameter integral, capillary length integral, crossed capillary number integral, abnormal capillary number integral, the velocity of blood flow integral, vascular motility integral, erythrocyte aggregation integral, white blood cell number integral, white microthrombus integral, the color of blood integral, perivascular exudation integral, capillary hemorrhage integral, subpapillary venular plexus integral, nailfold nipple integral and sweat gland catheter integral( Table 1 ). Our results showed that the image of nailfold microcirculation was clear, the nail fold capillaries were wavy, the capillary shape was normal, and the blood flow was good in the control group. However, with the progression of CKD, the image of nailfold microcirculation was blurred, the number of capillaries was reduced, the blood flow was poor, and in severe cases, the nail fold papillae were flat and the capillary morphology was abnormal in the CKD group ( Fig 2b ). Download: PNG larger image TIFF original image Table 1. 20 indexes of nailfold microcirculation examination. https://doi.org/10.1371/journal.pone.0359419.t001 Download: PNG larger image TIFF original image Fig 2. (a) Image of nailfold microcirculation pictured by nailfold capillary scopy. (b) In the control group, the image of nailfold microcirculation was clear, the nail fold capillaries were wavy, the capillary shape was normal, and the blood flow was good. In CKD group, with the progression of CKD, the image of nailfold microcirculation is blurred, the number of capillaries is reduced, the blood flow is poor, and in severe cases, the nail fold papillae are flat and the capillary morphology is abnormal. https://doi.org/10.1371/journal.pone.0359419.g002 Table 1 Nailfold microcirculation examination obtained 20 parameterized indexes, if the 20 parameterized indexes were not normal, the corresponding integral increased, resulting in abnormal comprehensive judgment. Nailfold microcirculation examination analysis methods We applied the Niu Tian integral method to assess and grade the status of nailfold microcirculation. According to the changes of the microcirculation indexes and weighted integral values, the comprehensive judgment can be divided into 5 degrees. The total integral is greater than or equal to 8, or one of the following changes occured, the comprehensive judgment is severely abnormal: a. the capillary number was reduced to 3 strips/mm, or the capillary number decreased by more than 80%; b. red blood cells accumulated heavily, the blood flow was slow or even completely stopped; c. most white microemboli in the blood flow were caused by non-local factors. d. in one nailfold, the number of capillary hemorrhage was greater than or equal to 7. The total integral is greater than or equal to 4, or two of the following changes occured, the comprehensive judgment is moderately abnormal: a. the capillary number decreased by 40% ~ 60%; b. the input branch diameter reduced by 20% to 60% or widened by 60%; c. the capillary length shortened by 80% or increased by more than 50%; d. the output branch diameter widened by more than 100%; e. perivascular exudation was obvious; f. most capillary blood flow is granular; g. in one nailfold, the number of capillary hemorrhage up to 3–6 strips; h. the color of blood was dark red; i. morphology of capillaries changed in a short time, the number of deformed and crossed capillaries up to 40%−60%; j. dermal papillae of nailfold is flat. The total integral is greater than 2, or two of the following changes occured, the comprehensive judgment is the comprehensive judgment is mildly abnormal: a. the input branch diameter, output branch diameter or capillary top diameter widened or narrowed up to 20%; b. the capillary length increased by 25%−50% or shortened by 20%; c. the number of deformed and crossed capillaries up to 40%; d. the blood flow is grained; e. in one nailfold, the number of capillary hemorrhage or perivascular exudation up to 1–2 strips; f. subpapillary venular plexus is obvious, dilated and thickened; g. the capillary is vague; h. the number of white blood cell is greater than 30 per 15 seconds or there is no white blood cell in blood flow; i. the number of sweat gland catheter in a nailfold is 3–4. The total integral is less than or equal to 2, the nailfold microcirculation is almost normal. The total integral is less than 1, the nailfold microcirculation is normal( Table 2 ). Download: PNG larger image TIFF original image Table 2. The comprehensive judgment of nailfold microcirculation examination. https://doi.org/10.1371/journal.pone.0359419.t002 Table 2 The comprehensive judgment of nailfold microcirculation examination can be divided into 5 degrees, if the total integral reached a certain level or there were abnormal changes in nail fold microcirculation, it directly affected the comprehensive judgment. Statistical analysis SPSS 22.0 statistical software was used to analyze the data. Under the normal distribution, the data were expressed by the mean ± standard deviation (x̄±s). Independent-samples t tests were used to compare the age, systolic pressure, diastolic pressure, cystatin C and Hb between the two groups. The data that do not accord with the normal distribution is expressed by the median (quartile). U tests were used to compare the Scr, BUN, and eGFR. The chi-square test was used to compare sex between the two groups. The correlations between Scr, BUN, eGFR, cystatin C, Hb, CKD stage, and meaningful indexes of nailfold microcirculation were analyzed by Spearman correlation analysis. Furthermore, adjusted multiple linear regression analyses were performed to evaluate the independent associations between renal function parameters and nailfold microcirculatory abnormalities. Separate models were constructed using the capillary number integral and subpapillary venular plexus integral as the dependent variables. Renal function parameters were entered as independent variables, with age, blood pressure, hemoglobin level, and CKD etiology included as covariates to adjust for potential confounding factors. P 0.05 for all). Download: PNG larger image TIFF original image Table 3. Comparison of general data between the two groups. https://doi.org/10.1371/journal.pone.0359419.t003 Table 3 Sex, age, systolic blood pressure, and diastolic blood pressure were not significantly different between the control group and the CKD group. While Scr, BUN and cystatin C, eGFR and Hb were different between the control group and the CKD group. Scr, BUN and cystatin C of the control group were significantly lower than in CKD group, whereas eGFR and Hb were increased in the control group ( P < 0.05). Hematological indexes We conducted statistical analysis on the scr, BUN, cystatin C, eGFR and Hb of CKD group and control group. Scr, BUN and cystatin C of the control group were significantly lower than in CKD group, whereas eGFR and Hb were increased in the control group( Table 3 , P < 0.001 for all). Nailfold microcirculation examination Nailfold microcirculation examination has 20 parameterized indexes, we also conducted statistical analysis on the 20 parameterized indexes of CKD group and control group. Compared with the control group, we found that the capillary number integral, output branch diameter integral, capillary top diameter integral, crossed capillary number integral, the velocity of blood flow integral, erythrocyte aggregation integral, perivascular exudation integral, and capillary hemorrhage integral were increased in the CKD group, whereas the capillary length integral color of blood integral, and subpapillary venular plexus integral were decreased in the CKD group ( Table 4 , P < 0.05 for all). Download: PNG larger image TIFF original image Table 4. Comparison of nailfold microcirculation examination 20 indexes between the two groups. https://doi.org/10.1371/journal.pone.0359419.t004 *Indexes of nailfold microcirculation examination mentioned above named meaningful indexes. Table 4 20 parameterized indexes of nailfold microcirculation examination were different between the control group and the CKD group. The capillary number integral, output branch diameter integral, capillary top diameter integral, crossed capillary number integral, the velocity of blood flow integral, erythrocyte aggregation integral, perivascular exudation integral, and capillary hemorrhage integral were increased in the CKD group ( P < 0.05), whereas the capillary length integral color of blood integral, and subpapillary venular plexus integral were decreased in the CKD group ( P < 0.05). Correlation between renal function indexes and meaningful indexes in the CKD group Based on the above results, we conducted statistical analysis on the correlation between renal function indexes and meaningful indexes in the CKD group. Scr, BUN, cystatin C, CKD stage had positive correlation with capillary number intergral( Table 5 , P < 0.05 for all) ( Fig 3a - d ); eGFR had negative correlation with capillary number intergral( Table 5 , P < 0.05) ( Fig 3e ); Scr, cystatin C, CKD stage had negative correlation with subpapillary venular plexus intergral( Table 5 , P < 0.05 for all) ( Fig 3f - h ); eGFR had positive correlation with subpapillary venular plexus intergral( Table 5 , P < 0.05) ( Fig 3i ). Download: PNG larger image TIFF original image Table 5. Correlation between capillary number integral,
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