Reference value of transcutaneous oxygen measurement in diabetic patients compared with nondiabetic patients
Purpose: This study evaluated the values of transcutaneous oxygen tension (TcPo2) measurement in diabetic patients compared with nondiabetic patients and assessed its reproducibility. Methods: In 60 diabetic patients (type 1 and type 2 diabetes mellitus) without signs of peripheral arterial disease or neuropathy, we measured TcPo2at the chest and foot and compared these measurements with 60 age- and sex-matched nondiabetic patients in a cross-sectional fashion. The reproducibility of TcPo2in terms of interobserver variability was also assessed. Results: Diabetic patients had a mean ± SD TcPo2value at the foot of 50.02 ± 8.92 mm Hg, which was significantly lower compared with 56.04 ± 8.80 mm Hg in nondiabetic patients (P < .001). At the chest wall, values for TcPo2were 51.77 ± 11.15 mm Hg, and 58.22 ± 12.47 mm Hg for diabetic patients and nondiabetic patients, respectively (P = .003). Regression analysis showed that TcPo2was significantly associated with diabetes mellitus (coefficient = -0.258; P = .004), and with having a first-degree relative with diabetes mellitus (coefficient = -0.265; P = .003). Furthermore, the interobserver variability showed a substantial correlation for both measurements at the chest (P < .001; r = 0.654; intraclass correlation coefficient [ICC] = 0.79) and at the dorsum of the foot (P < .001; r = 0.426; ICC = 0.60). Conclusion: Diabetic patients without signs of peripheral disease or neuropathy had significantly lower TcPo2values compared with age- and sex-matched nondiabetic patients. The influence of the examiner on the variance in TcPo2measurements was relatively small. We advocate the use of TcPo2measurement in diabetic patients to detect subclinical microvascular impairment as an additional tool to assess peripheral vascular disease.