Hindawi Publishing Corporation Journal of Diabetes Research Volume 2016, Article ID 8029340, 7 pages http://dx.doi.org/10.1155/2016/8029340
Research Article Association between Serum Cystatin C and Diabetic Foot Ulceration in Patients with Type 2 Diabetes: A Cross-Sectional Study Jie Zhao,1 Wuquan Deng,1 Yuping Zhang,1 Yanling Zheng,1 Lina Zhou,1 Johnson Boey,2 David G. Armstrong,3 Gangyi Yang,4 Ziwen Liang,1 and Bing Chen1 1
Department of Endocrinology, Diabetic Foot Center, Southwest Hospital, Third Military Medical University, Chongqing 400038, China Department of Podiatry, Singapore General Hospital, Singapore 169608 3 Department of Surgery, Southern Arizona Limb Salvage Alliance (SALSA), University of Arizona Health Sciences Center, Tucson, AZ 85724, USA 4 Department of Endocrinology, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China 2
Correspondence should be addressed to Ziwen Liang; [email protected] and Bing Chen; [email protected] Received 9 March 2016; Revised 22 May 2016; Accepted 24 May 2016 Academic Editor: Daisuke Koya Copyright © 2016 Jie Zhao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Serum cystatin C (CysC) has been identified as a possible potential biomarker in a variety of diabetic complications, including diabetic peripheral neuropathy and peripheral artery disease. We aimed to examine the association between CysC and diabetic foot ulceration (DFU) in patients with type 2 diabetes (T2D). 411 patients with T2D were enrolled in this cross-sectional study at a university hospital. Clinical manifestations and biochemical parameters were compared between DFU group and non-DFU group. The association between serum CysC and DFU was explored by binary logistic regression analysis. The cut point of CysC for DFU was also evaluated by receiver operating characteristic (ROC) curve. The prevalence of coronary artery disease, diabetic nephropathy (DN), and DFU dramatically increased with CysC (𝑃 < 0.01) in CysC quartiles. Multivariate logistic regression analysis indicated that the significant risk factors for DFU were serum CysC, coronary artery disease, hypertension, insulin use, the differences between supine and sitting TcPO2 , and hypertension. ROC curve analysis revealed that the cut point of CysC for DFU was 0.735 mg/L. Serum CysC levels correlated with DFU and severity of tissue loss. Our study results indicated that serum CysC was associated with a high prevalence of DFU in Chinese T2D subjects.
1. Introduction Diabetes mellitus is a complex metabolic disease that poised huge challenge to healthcare systems across the globe. Despite increased efforts in prevention and improved understanding of the condition, there is still an upward spike in prevalence rate and a paradigm shift towards developing countries in the recent decades [1]. Complications of tissue loss in people with diabetes have been identified as a major cause of hospitalization and nontraumatic lower extremity amputation [2, 3]. Diabetic foot ulceration (DFU) correlated to failure of healing, longer length of inpatient stay, and increased mortality, with adjusted relative ratio for length of stay and adjusted odds ratio for inpatient mortality was 2.01 and 1.31,
respectively [4, 5]. Therefore, early diagnosis and appropriate management of DFU play a crucial role in amputation prevention and reduction of mortality in diabetic population. Moreover, the underlying mechanism of DFU is poorly comprehended with few possible biomarkers associating DFU prediction. A reliable predictive biomarker to identify and diagnose risk for DFU and its potential severity remains elusive yet. The severity and prognosis of DFU have a close relationship with renal insufficiency, peripheral artery disease (PAD), and neuropathy [6], consequently making it possible for early screening and identification of DFU biomarker related to above diseases. Serum cystatin C (CysC) is a small molecular protein that produced by human nucleated cells and belongs to type 2
2 cystatin superfamily that functions as reversible competitive inhibitors of cysteine proteinase. CysC is freely filtered by the glomerulus and almost completely reabsorbed in the distal tubule without tubular secretion. Based on these reasons, CysC has been shown to be more reliable biomarker of renal function assessment compared with creatinine. It has been recognized as endogenous marker and noninvasive risk predictor of DN [7]. Apart from renal function, CysC was found to have an associative relationship and strong potential predictors, with PAD and diabetic peripheral neuropathy (DPN) [8, 9]. In our previous study, CysC level was higher in type 2 diabetes (T2D) with DPN than non-DPN, but no significant difference to blood creatinine or 24-hour urinary protein (24 h UP) between different groups was found [10]. Whether CysC has association for DFU in T2D subjective is still unknown. Therefore, in this study, we investigate the association between serum CysC and T2D patients with DFU.
2. Methods In this study, we enrolled a total of 411 subjects with T2D admitted to a university hospital, between October 2011 to September 2012. The diagnosis of diabetes and its complications including DPN, DN, and diabetic retinopathy (DR) were based on the diagnostic criteria recommended by the ADA in 2010 [11]. DFU is defined as “ulceration of the foot (distally from the ankle and including the ankle) associated with neuropathy and different grades of ischemia and infection” according to the World health Organization [12]. DFU was categorized with the Wagner grade (from grade 0 to grade 5) and the society for vascular surgery lower extremity threatened limb classification system based on Wound, Ischemia, and Foot Infection (WIfI) [13, 14]. The diagnosis of hypertension was based on the diagnostic criteria recommended by the World Health Organization and the International Society of Hypertension in 1999 [15]. The patients with type 1 diabetes, other specific types of diabetes, and acute non-DFU diabetic complications were excluded from participation in the study. The study was approved by the ethics committee of the Southwest Hospital, and all of the subjects provided written informed consent. All enrolled patients received ongoing medications for diabetes, hypertension, and hyperlipidemia throughout the duration of the study, except when overnight fasting blood samples were collected. Demographic information on age, sex, diabetes duration, hereditary history, systolic and diastolic blood pressure, smoking and drinking history, hypertension, coronary artery disease (CAD), and other diabetic complications was recorded for all participants. The systolic ankle and arm pressures were measured three times using the Doppler technique (Diabetic Foot Assessment Kit, Huntleigh Healthcare, UK). Ankle/brachial index (ABI) was determined by dividing the average of three systolic ankle pressures by the systolic brachial pressure. The transcutaneous oxygen pressure (TcPO2 ) was measured with the TCM 400 system (Radiometer, Copenhagen, Denmark) at an electrode temperature of 44∘ C. TcPO2 measurements were performed at the dorsum of the right foot proximal to
Journal of Diabetes Research the first and second toes, in both supine and sitting position with their legs hanging down. The average calibration period was 20 min. Measurements of TcPO2 in both supine and sitting positions and difference between sitting and supine position were expressed in mmHg, and the average of the last 5 min was used in the analysis. Overnight fasting blood samples were collected and transported to the medical laboratory of Southwest Hospital. Fasting blood glucose (FBG) was assayed using the glucose oxidase method. Glycated hemoglobin (HbA1c) was measured by chromatography. Hemoglobin level was obtained using a hematology analyser. Serum uric acid (UA), creatinine, potassium, calcium, albumin, total cholesterol (TC), triglycerides (TG), low-density lipoprotein C (LDLC), and high-density lipoprotein C (HDL-C) concentrations were determined with enzymatic method. 24 h UP, 24hour urinary microalbumin (24 h UM), and serum CysC concentration were measured by immunoturbidimetry. The experimental data were analyzed using SPSS software version 19.0 (IBM, IL, USA). Continuous variables are presented as the means ± standard deviations, and differences between groups were evaluated by Student’s 𝑡-test or Analysis of Variance. Categorical variables are presented as frequency percentage and intergroup comparison using the chi-square test. The data were subjected to normal distribution analysis using the Kolmogorov-Smirnov test before statistical analysis. The association between CysC and clinical characteristics was performed by Spearman’s correlation analysis. For multivariate analysis, we used a forward likelihood ratio logistic regression to identify the independent risk factors for DFU. Receiver operating characteristic (ROC) curve analyses were performed to determine the sensitivity and specificity of CysC for predicting DFU. The cut-off values were obtained from the ROC curves. A 𝑃 value of 0.05). Spearman’s correlation analysis showed that serum CysC was closely associated with DFU (𝑟 = 0.347; 𝑃 < 0.001), diabetes duration (𝑟 = 0.156; 𝑃 = 0.002), gender (𝑟 = 0.189; 𝑃 < 0.001), smoking (𝑟 = 0.118; 𝑃 = 0.016), CAD (𝑟 = 0.166; 𝑃 = 0.001), DBP (𝑟 = −0.224; 𝑃 < 0.001), hemoglobin (𝑟 = −0.264; 𝑃 < 0.001), UA (𝑟 = 0.360; 𝑃 < 0.001), creatinine
Journal of Diabetes Research
3 60
With DFU 𝑁 (male/female) 92 (55/37) Age (ys) 66.42 ± 11.64 Duration (ys) 9.45 ± 7.69 Smoking (%) 35.87 Drinking (%) 22.83 Hereditary (%) 22.83 IU (%) 77.55 DPN (%) 70.65 DR (%) 38.00 DN (%) 36.46 HTN (%) 56.52 CAD (%) 29.35 SBP (mmHg) 134.52 ± 19.74 DBP (mmHg) 77.07 ± 12.01 Hemoglobin (g/L) 113.13 ± 17.17 UA (𝜇mol/L) 283.08 ± 108.83 Cr (𝜇mol/L) 82.22 ± 51.49 Potassium (mmol/L) 3.89 ± 0.57 Calcium (mmol/L) 2.18 ± 0.20 Albumin (g/L) 34.40 ± 6.13 TC (mmol/L) 4.49 ± 1.25 TG (mmol/L) 1.56 ± 0.93 LDL-C (mmol/L) 2.67 ± 0.79 HDL-C (mmol/L) 1.07 ± 0.38 24 h UP (mg) 1117.62 ± 652.22 24 h UM (mg) 47.73 ± 28.25 ABI 1.01 ± 0.26 47.11 ± 15.81 SiTcPO2 SuTcPO2 27.29 ± 13.63 20.24 ± 10.08 DSS TcPO2
Without DFU 319 (181/138) 60.13 ± 10.60 8.07 ± 5.92 27.59 19.44 31.35 49.40 76.49 25.58 22.92 57.68 11.60 131.62 ± 17.70 80.26 ± 11.44 128.16 ± 17.11 286.18 ± 89.47 63.32 ± 26.39 3.87 ± 0.40 2.25 ± 0.13 39.88 ± 4.77 4.63 ± 1.09 1.89 ± 1.34 2.74 ± 0.71 1.16 ± 0.31 337.21 ± 189.57 15.62 ± 8.25 1.09 ± 0.11 64.81 ± 10.29 44.18 ± 11.83 20.62 ± 7.36
𝑃 value 0.603
Research Article Association between Serum Cystatin C and Diabetic Foot Ulceration in Patients with Type 2 Diabetes: A Cross-Sectional Study Jie Zhao,1 Wuquan Deng,1 Yuping Zhang,1 Yanling Zheng,1 Lina Zhou,1 Johnson Boey,2 David G. Armstrong,3 Gangyi Yang,4 Ziwen Liang,1 and Bing Chen1 1
Department of Endocrinology, Diabetic Foot Center, Southwest Hospital, Third Military Medical University, Chongqing 400038, China Department of Podiatry, Singapore General Hospital, Singapore 169608 3 Department of Surgery, Southern Arizona Limb Salvage Alliance (SALSA), University of Arizona Health Sciences Center, Tucson, AZ 85724, USA 4 Department of Endocrinology, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China 2
Correspondence should be addressed to Ziwen Liang; [email protected] and Bing Chen; [email protected] Received 9 March 2016; Revised 22 May 2016; Accepted 24 May 2016 Academic Editor: Daisuke Koya Copyright © 2016 Jie Zhao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Serum cystatin C (CysC) has been identified as a possible potential biomarker in a variety of diabetic complications, including diabetic peripheral neuropathy and peripheral artery disease. We aimed to examine the association between CysC and diabetic foot ulceration (DFU) in patients with type 2 diabetes (T2D). 411 patients with T2D were enrolled in this cross-sectional study at a university hospital. Clinical manifestations and biochemical parameters were compared between DFU group and non-DFU group. The association between serum CysC and DFU was explored by binary logistic regression analysis. The cut point of CysC for DFU was also evaluated by receiver operating characteristic (ROC) curve. The prevalence of coronary artery disease, diabetic nephropathy (DN), and DFU dramatically increased with CysC (𝑃 < 0.01) in CysC quartiles. Multivariate logistic regression analysis indicated that the significant risk factors for DFU were serum CysC, coronary artery disease, hypertension, insulin use, the differences between supine and sitting TcPO2 , and hypertension. ROC curve analysis revealed that the cut point of CysC for DFU was 0.735 mg/L. Serum CysC levels correlated with DFU and severity of tissue loss. Our study results indicated that serum CysC was associated with a high prevalence of DFU in Chinese T2D subjects.
1. Introduction Diabetes mellitus is a complex metabolic disease that poised huge challenge to healthcare systems across the globe. Despite increased efforts in prevention and improved understanding of the condition, there is still an upward spike in prevalence rate and a paradigm shift towards developing countries in the recent decades [1]. Complications of tissue loss in people with diabetes have been identified as a major cause of hospitalization and nontraumatic lower extremity amputation [2, 3]. Diabetic foot ulceration (DFU) correlated to failure of healing, longer length of inpatient stay, and increased mortality, with adjusted relative ratio for length of stay and adjusted odds ratio for inpatient mortality was 2.01 and 1.31,
respectively [4, 5]. Therefore, early diagnosis and appropriate management of DFU play a crucial role in amputation prevention and reduction of mortality in diabetic population. Moreover, the underlying mechanism of DFU is poorly comprehended with few possible biomarkers associating DFU prediction. A reliable predictive biomarker to identify and diagnose risk for DFU and its potential severity remains elusive yet. The severity and prognosis of DFU have a close relationship with renal insufficiency, peripheral artery disease (PAD), and neuropathy [6], consequently making it possible for early screening and identification of DFU biomarker related to above diseases. Serum cystatin C (CysC) is a small molecular protein that produced by human nucleated cells and belongs to type 2
2 cystatin superfamily that functions as reversible competitive inhibitors of cysteine proteinase. CysC is freely filtered by the glomerulus and almost completely reabsorbed in the distal tubule without tubular secretion. Based on these reasons, CysC has been shown to be more reliable biomarker of renal function assessment compared with creatinine. It has been recognized as endogenous marker and noninvasive risk predictor of DN [7]. Apart from renal function, CysC was found to have an associative relationship and strong potential predictors, with PAD and diabetic peripheral neuropathy (DPN) [8, 9]. In our previous study, CysC level was higher in type 2 diabetes (T2D) with DPN than non-DPN, but no significant difference to blood creatinine or 24-hour urinary protein (24 h UP) between different groups was found [10]. Whether CysC has association for DFU in T2D subjective is still unknown. Therefore, in this study, we investigate the association between serum CysC and T2D patients with DFU.
2. Methods In this study, we enrolled a total of 411 subjects with T2D admitted to a university hospital, between October 2011 to September 2012. The diagnosis of diabetes and its complications including DPN, DN, and diabetic retinopathy (DR) were based on the diagnostic criteria recommended by the ADA in 2010 [11]. DFU is defined as “ulceration of the foot (distally from the ankle and including the ankle) associated with neuropathy and different grades of ischemia and infection” according to the World health Organization [12]. DFU was categorized with the Wagner grade (from grade 0 to grade 5) and the society for vascular surgery lower extremity threatened limb classification system based on Wound, Ischemia, and Foot Infection (WIfI) [13, 14]. The diagnosis of hypertension was based on the diagnostic criteria recommended by the World Health Organization and the International Society of Hypertension in 1999 [15]. The patients with type 1 diabetes, other specific types of diabetes, and acute non-DFU diabetic complications were excluded from participation in the study. The study was approved by the ethics committee of the Southwest Hospital, and all of the subjects provided written informed consent. All enrolled patients received ongoing medications for diabetes, hypertension, and hyperlipidemia throughout the duration of the study, except when overnight fasting blood samples were collected. Demographic information on age, sex, diabetes duration, hereditary history, systolic and diastolic blood pressure, smoking and drinking history, hypertension, coronary artery disease (CAD), and other diabetic complications was recorded for all participants. The systolic ankle and arm pressures were measured three times using the Doppler technique (Diabetic Foot Assessment Kit, Huntleigh Healthcare, UK). Ankle/brachial index (ABI) was determined by dividing the average of three systolic ankle pressures by the systolic brachial pressure. The transcutaneous oxygen pressure (TcPO2 ) was measured with the TCM 400 system (Radiometer, Copenhagen, Denmark) at an electrode temperature of 44∘ C. TcPO2 measurements were performed at the dorsum of the right foot proximal to
Journal of Diabetes Research the first and second toes, in both supine and sitting position with their legs hanging down. The average calibration period was 20 min. Measurements of TcPO2 in both supine and sitting positions and difference between sitting and supine position were expressed in mmHg, and the average of the last 5 min was used in the analysis. Overnight fasting blood samples were collected and transported to the medical laboratory of Southwest Hospital. Fasting blood glucose (FBG) was assayed using the glucose oxidase method. Glycated hemoglobin (HbA1c) was measured by chromatography. Hemoglobin level was obtained using a hematology analyser. Serum uric acid (UA), creatinine, potassium, calcium, albumin, total cholesterol (TC), triglycerides (TG), low-density lipoprotein C (LDLC), and high-density lipoprotein C (HDL-C) concentrations were determined with enzymatic method. 24 h UP, 24hour urinary microalbumin (24 h UM), and serum CysC concentration were measured by immunoturbidimetry. The experimental data were analyzed using SPSS software version 19.0 (IBM, IL, USA). Continuous variables are presented as the means ± standard deviations, and differences between groups were evaluated by Student’s 𝑡-test or Analysis of Variance. Categorical variables are presented as frequency percentage and intergroup comparison using the chi-square test. The data were subjected to normal distribution analysis using the Kolmogorov-Smirnov test before statistical analysis. The association between CysC and clinical characteristics was performed by Spearman’s correlation analysis. For multivariate analysis, we used a forward likelihood ratio logistic regression to identify the independent risk factors for DFU. Receiver operating characteristic (ROC) curve analyses were performed to determine the sensitivity and specificity of CysC for predicting DFU. The cut-off values were obtained from the ROC curves. A 𝑃 value of 0.05). Spearman’s correlation analysis showed that serum CysC was closely associated with DFU (𝑟 = 0.347; 𝑃 < 0.001), diabetes duration (𝑟 = 0.156; 𝑃 = 0.002), gender (𝑟 = 0.189; 𝑃 < 0.001), smoking (𝑟 = 0.118; 𝑃 = 0.016), CAD (𝑟 = 0.166; 𝑃 = 0.001), DBP (𝑟 = −0.224; 𝑃 < 0.001), hemoglobin (𝑟 = −0.264; 𝑃 < 0.001), UA (𝑟 = 0.360; 𝑃 < 0.001), creatinine
Journal of Diabetes Research
3 60
With DFU 𝑁 (male/female) 92 (55/37) Age (ys) 66.42 ± 11.64 Duration (ys) 9.45 ± 7.69 Smoking (%) 35.87 Drinking (%) 22.83 Hereditary (%) 22.83 IU (%) 77.55 DPN (%) 70.65 DR (%) 38.00 DN (%) 36.46 HTN (%) 56.52 CAD (%) 29.35 SBP (mmHg) 134.52 ± 19.74 DBP (mmHg) 77.07 ± 12.01 Hemoglobin (g/L) 113.13 ± 17.17 UA (𝜇mol/L) 283.08 ± 108.83 Cr (𝜇mol/L) 82.22 ± 51.49 Potassium (mmol/L) 3.89 ± 0.57 Calcium (mmol/L) 2.18 ± 0.20 Albumin (g/L) 34.40 ± 6.13 TC (mmol/L) 4.49 ± 1.25 TG (mmol/L) 1.56 ± 0.93 LDL-C (mmol/L) 2.67 ± 0.79 HDL-C (mmol/L) 1.07 ± 0.38 24 h UP (mg) 1117.62 ± 652.22 24 h UM (mg) 47.73 ± 28.25 ABI 1.01 ± 0.26 47.11 ± 15.81 SiTcPO2 SuTcPO2 27.29 ± 13.63 20.24 ± 10.08 DSS TcPO2
Without DFU 319 (181/138) 60.13 ± 10.60 8.07 ± 5.92 27.59 19.44 31.35 49.40 76.49 25.58 22.92 57.68 11.60 131.62 ± 17.70 80.26 ± 11.44 128.16 ± 17.11 286.18 ± 89.47 63.32 ± 26.39 3.87 ± 0.40 2.25 ± 0.13 39.88 ± 4.77 4.63 ± 1.09 1.89 ± 1.34 2.74 ± 0.71 1.16 ± 0.31 337.21 ± 189.57 15.62 ± 8.25 1.09 ± 0.11 64.81 ± 10.29 44.18 ± 11.83 20.62 ± 7.36
𝑃 value 0.603
