Kidney Week

Abstract: SA-PO1226

Association of Skin Capillary Density with Kidney Function and Proteinuria in CKD: Results from the MAP-CKD Study

Session Information

• CKD: Biomarkers and Emerging Tools for Diagnosis and Monitoring
  November 08, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2302 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

• Malhotra, Rakesh, University of California San Diego, La Jolla, California, United States

Rakesh Malhotra, MD, MPH, FASN

• Ahmadi, Armin, University of California San Diego, La Jolla, California, United States

Armin Ahmadi, PhD

• Rahaman, Masfiqur, University of California San Diego, La Jolla, California, United States

Masfiqur Rahaman, MSc

• Harsh, Amol, University of California San Diego, La Jolla, California, United States

Amol Harsh

• Yang, Jason W., University of California San Diego, La Jolla, California, United States

Jason W. Yang, MS

• Ghanim, Basma, University of California San Diego, La Jolla, California, United States

Basma Ghanim

• Houben, Alfons Jhm, Maastricht Universitair Medisch Centrum+, Maastricht, LI, Netherlands

Alfons Jhm Houben, PhD

• Rahman, Tauhidur, University of California San Diego, La Jolla, California, United States

Tauhidur Rahman, PhD

• Ix, Joachim H., University of California San Diego, La Jolla, California, United States

Joachim H. Ix, MD, FASN

Background

Microvascular dysfunction plays a key role in the development and progression of chronic kidney disease (CKD). While skin microvascular dysfunction is linked to albuminuria in individuals without CKD, the association of skin microvascular dysfunction with eGFR severity or albuminuria in CKD remains unclear.

Methods

We have recruited 98 adults with CKD (eGFR less than 60 mL/min/1.73 m²) and 20 healthy controls. Nail-fold capillary density was assessed using a digital video microscope (Capiscope; United Kingdom) at 100x magnification. The number of erythrocyte-perfused capillaries per 1 mm² skin was quantified over 15 seconds. The association between nail-fold capillary density and CKD stage was assessed using the Kruskal-Wallis test. Spearman’s rank correlation coefficient was used to evaluate the relationship between nail-fold capillary density and both eGFR and proteinuria.

Results

The mean age of CKD participants was 64 (15) years; 54% were female, 46% had diabetes, and 88% had hypertension. The mean eGFR was 33 (15) mL/min/1.73 mm². Healthy controls had a mean age of 41 (11) years. Capillary density was significantly lower in CKD participants than healthy controls (50 [13] vs. 79 [11] per mm²; P < 0.001). Among CKD participants, capillary density positively correlated with eGFR (r = 0.53, P < 0.001) and inversely with urine protein-to-creatinine ratio (r = –0.56, P < 0.001). Nail fold capillary density declined progressively with advancing CKD stage (P for trend < 0.001) (Figure 1).

Conclusion

Skin capillary density is lower in individuals with more advanced CKD and is associated with higher proteinuria. Skin microvascular assessment may give insight to microvascular disease within the kidney.

Funding

• NIDDK Support

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025sk8wd97c