Microvascular health and frailty: nailfold capillaroscopy as a window into aging

Frailty is a prevalent geriatric syndrome characterized by diminished physiological reserves and increased vulnerability to stressors. Microvascular dysfunction and inflammaging have been proposed as key biological mechanisms underlying frailty; however, objective and practical vascular biomarkers remain limited. Nailfold capillaroscopy (NFC), a non-invasive imaging method that visualizes microcirculatory architecture, may offer novel insight into the vascular component of frailty. This study aimed to investigate the association between frailty and NFC findings in older adults.

This cross-sectional study evaluated 102 individuals aged 65 years or older (mean age 78.7 ± 8.1 years; 67% female) who underwent a comprehensive geriatric assessment. Frailty was assessed using the Clinical Frailty Scale (CFS) and the Fatigue, Resistance, Ambulation, Illnesses, and Loss of weight (FRAIL) scale. NFC was performed on eight fingers following standardized protocols. A total NFC score was derived from capillary density, giant capillaries, microhemorrhages, neoangiogenesis, tortuosity, and additional morphological features. Receiver operating characteristic (ROC) curve analysis was used to determine discriminatory performance, while multivariable logistic regression identified independent predictors of frailty.

Frail participants exhibited significantly reduced capillary density and higher frequencies of giant capillaries, microhemorrhages, morphological abnormalities, neoangiogenesis, and tortuosity (all p < 0.001). An NFC score ≥ 5 was associated with frailty, with an area under the ROC curve of 0.68.

Microvascular abnormalities detected through NFC are strongly associated with frailty in older adults. An NFC threshold of ≥ 5 may serve as a practical, non-invasive indicator of elevated frailty risk. These findings support the potential value of incorporating NFC into geriatric assessment, and prospective studies are needed to clarify its prognostic and clinical utility.