Toe brachial index measured by automated device compared to duplex ultrasonography for detecting peripheral arterial disease in older people.

Introduction To investigate the diagnostic accuracy of an automated toe blood pressure device for detecting peripheral arterial disease in older people. Methods Ninety participants underwent toe and brachial blood pressure measurements and colour duplex ultrasonography of the right lower limb. Peripheral arterial disease was diagnosed if > 50% arterial obstruction was identified in any lower limb vessel using colour duplex ultrasonography. A receiver operating characteristic curve was analysed and the sensitivity and specificity of commonly used toe brachial index and toe blood pressure values were determined. Results The optimum toe brachial index threshold value for diagnosing peripheral arterial disease was 0.72 (sensitivity 76.2%, specificity 75%). The area under the curve was 0.829 (95% CI 0.743 to 0.915, p < 0.0001) suggesting fair diagnostic accuracy. A toe blood pressure of 70 mmHg was found to have excellent specificity (97.92%) for detecting PAD but poor sensitivity (42.86%). Conclusions The accuracy of automated toe blood pressure and TBI measurements was determined to be good when using colour duplex ultrasound as the reference standard for the non-invasive diagnosis of peripheral arterial disease. Results should be interpreted in the context of all clinical signs and symptoms.

Cross-sectional correlations between the toe brachial index and lower limb complications in older people.

The aim of the study was to investigate the relationship between the toe brachial index (TBI) and foot ulceration and amputation in older people. Two hundred and sixty-one participants meeting guidelines for lower limb vascular assessment had their toe and brachial blood pressure measured, medical records audited and signs and symptoms of peripheral arterial disease (PAD) recorded. Pearson's correlation and linear regression analyses were performed to determine the strength of relationships between variables. Significant correlations were found between the TBI and painful symptoms (r = -0·35, P < 0·05) and foot complications (r = -0·31, P < 0·05). After adjusting for traditional risk factors for foot complications, participants with a TBI <0·70 were 19 times more likely to have a history of foot wounds or amputation (odds ratio = 19·20, 95% confidence interval (CI): 2·36-155·96, P < 0·001) than those with higher TBI values (>0·70). This preliminary study supports a TBI threshold of 0·70 for PAD diagnosis and indicates that lower values are associated with painful symptoms, history of ulceration and amputation. Future longitudinal investigation of the predictive capacity is now warranted.

Associations between the toe brachial index and health-related quality of life in older people.

BACKGROUND: Peripheral arterial disease is responsible for impaired health-related quality of life as a consequence of associated morbidity and mortality. The toe brachial index (TBI) provides non-invasive assessment of peripheral arterial health. Lower TBI values have been associated with foot ulceration, amputation and impaired healing, however, the relationship with health-related quality of life has not yet been investigated. The aim of this study was to explore the relationship between the TBI and health-related quality of life. METHODS: This was a cross-sectional study of 100 participants aged over 50 years recruited from podiatry clinics in New South Wales, Australia. The TBI was calculated using automated equipment and quality of life was assessed using the Short Form 36 version 2 (SF-36v2). Strength of associations was determined using Pearson and Spearman correlation coefficients. RESULTS: Lower TBI values demonstrated modest significant associations with poorer scores for the SF-36v2 domains Role Physical (r s = 0.219, p > 0.05), Social Function (r s = 0.219, p < 0.05) and the Physical Component Summary score (r s = 0.203, p < 0.05). CONCLUSIONS: The toe brachial index demonstrates limited associations with physical and social aspects of health-related quality of life in older people.

Intratester and Intertester Reliability of Toe Pressure Measurements in People with and Without Diabetes Performed by Podiatric Physicians.

BACKGROUND: Toe pressures and the toe brachial index (TBI) represent possible screening tools for peripheral arterial disease; however, limited evidence is available regarding their reliability. The aim of this study was to determine intratester and intertester reliability of toe systolic pressure and the TBI in participants with and without diabetes performed by podiatric physicians. METHODS: Two podiatric physicians performed toe and brachial pressure measurements on 80 participants, 40 with and 40 without diabetes, during two testing sessions using photoplethysmography and Doppler probe. Intraclass correlation coefficients (ICCs) and 95% limits of agreement were determined. RESULTS: In people with diabetes, intratester reliability of toe pressure measurement was excellent for both testers (ICCs, 0.84 and 0.82). Reliability of the TBI was good (ICCs, 0.72 and 0.75) and brachial pressure fair (ICCs, 0.43 and 0.55). The intertester reliability of toe pressure (ICC, 0.82) and the TBI (ICC, 0.80) was excellent. Intertester reliability of brachial pressure was reduced in people with diabetes (ICC, 0.49). In age-matched participants, intratester reliability of toe pressure measurement was excellent for both testers (ICCs, 0.83 and 0.87), and reliability of the TBI (ICCs, 0.74 and 0.80) and brachial pressure (ICCs, 0.73 and 0.78) was good to excellent. Intertester reliability of toe pressure (ICC, 0.84), the TBI (ICC, 0.81), and brachial pressure (ICC, 0.77) was excellent. CONCLUSIONS: Toe pressures and the TBI demonstrated excellent reliability in people with and without diabetes and can be an effective component of lower-extremity vascular screening. However, wide limits of agreement relative to blood pressure values for both cohorts indicate that results should be interpreted with caution.

Inter-rater reliability of automated devices for measurement of toe systolic blood pressure and the toe brachial index.

OBJECTIVES: The aim of this study was to determine the inter-rater reliability of automated devices for the measurement of toe systolic blood pressure (TSBP) and the toe brachial index (TBI). PARTICIPANTS AND METHODS: Toe and brachial systolic blood pressures were measured in 40 participants by two podiatrists using SysToe and MicroLife automated devices. Intraclass correlation coefficients (ICC) with a 95% confidence interval (CI) and 95% limits of agreement (LOA) were determined for TSBP, brachial systolic blood pressure and the TBI. RESULTS: The inter-rater reliability of all measurements was excellent, with ICCs ranging from 0.82 to 0.85. TSBP had the greatest reliability (ICC: 0.85, 95% CI: 0.74-0.92, 95% LOA: -14.4 to 21.1 mmHg) and brachial blood pressures had the lowest reliability (ICC: 0.82, 95% CI: 0.68-0.90, 95% LOA: -21.2 to 22.9 mmHg). The inter-rater reliability of the TBI fell between the TSBP and the brachial blood pressure reliability (ICC: 0.83, 95% CI: 0.70-0.90, 95% LOA: -0.16 to 0.20). CONCLUSION: We showed that automated devices for the measurement of toe and brachial systolic blood pressure and the TBI in a clinical setting produce measurements with high inter-rater reliability. These findings support the use of these automated devices for ongoing monitoring of lower extremity vascular status.