Plantar pressures are elevated in the neuroischemic and the neuropathic diabetic foot

OBJECTIVE: Clinical observation has noted that diabetic neuropathic ulcers occur frequently on the plantar surface, whereas neuroischemic ulcers seem to occur often on the foot margins. The reason for this difference in the site of ulceration is unknown, but it may be related to differences in pressure loading. The aim of the study was to compare vertical in-shoe foot pressures measured during walking (using the F-SCAN system) in four groups of patients whose degree of neuropathy was measured by vibration perception threshold (VPT). RESEARCH DESIGN AND METHODS: Subjects included 14 neuroischemic diabetic patients (VPT 29.3 +/- 13.5 V) with history of ulceration on the margins of the foot, 18 patients with neuropathy alone (VPT 38.7 +/- 12.7 V) and previous history of ulceration on the plantar surface, 10 diabetic control patients (VPT 9.9 +/- 2.7 V), and 15 nondiabetic control subjects (VPT 7.0 +/- 0.5 V). RESULTS: When compared with the other three groups, neuroischemic patients had higher foot pressures when measured as mean peak pressures and highest peak pressures under four areas of the foot: medial and lateral forefoot, hallux, and heel. Furthermore, when measuring the maximum pressures developed at any point under the plantar surface, the neuroischemic patients also had the most elevated pressures (757.6 +/- 135.9 kPa), significantly higher than those found in the neuropathic group (482.8 +/- 68.6 kPa, P = 0.04) and in both diabetic control patients (310.2 +/- 34.7 kPa, P = 0.008) and nondiabetic controls subjects (365.1 +/- 49.8 kPa, P = 0.007). CONCLUSIONS: Despite having increased plantar pressures and a comparable degree of neuropatny, the neuroischemic patients did not have a history of ulceration on the plantar surface. These observations may have relevance to different mechanisms of ulcer formation in the neuroischemic and neuropathic foot.     

Foot pressure measurements in diabetic and nondiabetic amputees.

OBJECTIVE--Foot problems are common in the remaining foot of diabetic amputees. Because high foot pressures are associated with foot ulceration, we studied foot pressures of the remaining foot of diabetic and nondiabetic unilateral amputees. RESEARCH DESIGN AND METHODS--Four age-matched groups of 11 subjects were studied. The groups were comprised of diabetic subjects with previous major amputation, nondiabetic nonneuropathic amputees, diabetic nonamputee patients with similar peripheral nerve involvement as the diabetic amputees, and nondiabetic control subjects. Vibration perception threshold (VPT) was assessed by biothesiometry and foot pressures with an optical pedobarograph. RESULTS--Mean +/- SE VPT in the diabetic amputees was significantly higher than the nondiabetic amputees (40.2 +/- 3.7 vs. 17.7 +/- 2.8 V, P less than 0.002) and similar to diabetic nonamputees (43.4 +/- 3.3 V, NS). VPT was abnormal in 9 (82%) diabetic amputees, 2 (18%) nondiabetic amputees, and 10 (91%) nonamputee diabetic patients. The mean peak foot pressure in the diabetic amputees was higher compared with nondiabetic amputees (18.3 +/- 2.2 vs. 11.3 +/- 1.4 kg/cm2, P less than 0.05) and control subjects (10.0 +/- 1.5 kg/m2, P less than 0.01), but no difference existed with diabetic nonamputees. Abnormally high foot pressures (greater than 12.3 kg/cm2) were present in 8 (73%) diabetic amputees, 3 (27%) nondiabetic amputees, 8 (73%) diabetic nonamputees, and 4 (36%) healthy subjects. CONCLUSIONS--We conclude that high pressures are present under the remaining foot in diabetic amputees, and that these pressures are associated with diabetic neuropathy. Prosthetic usage does not increase the pressures under the remaining foot in nondiabetic amputees.     

Atrophy of foot muscles: a measure of diabetic neuropathy

OBJECTIVE: Diabetic neuropathy is a length-dependent process that leads to reduced muscle strength and atrophy of leg muscles in some patients. We hypothesized that intrinsic foot muscles are atrophied in diabetic neuropathy and that the degree of atrophy is a measure of motor dysfunction closely related to the neuropathic process. RESEARCH DESIGN AND METHODS: Consecutive cross-sectional magnetic resonance images of the nondominant foot were obtained for stereological determination of the total volume of the intrinsic foot muscles (VFM) in 23 long-term diabetic patients with (n = 15) and without (n = 8) chronic neuropathy and in 23 matched healthy nondiabetic control subjects. Based on clinical examination, nerve conduction studies, and quantitative sensory examination, a neuropathy rank-sum score was calculated for each patient. RESULTS: Total VFM was 86 +/- 52, 165 +/- 34, and 168 +/- 42 cm3 in neuropathic patients, nonneuropathic patients, and healthy control subjects, respectively (P < 0.001). There was a close inverse relationship between the neuropathy rank-sum score and the VFM (r = -0.75, P < 1 x 10(-5)). CONCLUSIONS: Total volume of the foot muscles is halved in patients with diabetic neuropathy. Atrophy of foot muscles is closely related to the severity of neuropathy and reflects motor dysfunction.     

Effects of leg and body position on transcutaneous oxygen measurements in healthy subjects and subjects with peripheral artery disease after lower-extremity arterial revascularization: A pilot study

Transcutaneous oxygen (TcPO(2)) measurements provide a noninvasive, objective determination of the oxygen level at the skin surface. This offers a means of estimating the underlying circulation and tissue oxygenation. The purpose of the pilot study was to measure the TcPO(2) value of the lower extremity of healthy men and women and of patients with peripheral arterial disease (PAD) in 4 different body and leg positions 24 hours after peripheral vascular surgery reconstruction. The specific aim was to determine if lower-extremity TcPO(2) measurements were affected by changes in extremity position in these subject populations. A convenience sample of 4 healthy health care professionals and 4 patients who had peripheral vascular reconstruction surgery 24 hours before the measurements were studied. Subjects were studied in 4 different leg and body positions: supine with legs extended, sitting with legs dependent, a 5 degrees head-up reverse Trendelenburg, and supine with legs elevated 10 in. The Radiometer TCM30 TcPO(2) monitor was used to carry out these measures. Findings revealed a statistically significant difference in TcPO(2) measurements between the 2 groups, with the healthy subjects having a significantly higher TcPO(2) measurement in all extremity positions compared with the revascularized subjects with PAD (P =.02-.05). Significant changes were noted in both the foot temperature (P =.03) and TcPO(2) measurements with extremity positions within the healthy subject group (P =.001). The foot and leg TcPO(2) measurements affect from leg and body position did not reach significance (P =.09) in the subjects with PAD. No change in foot temperature with extremity positioning (P =.42) was noted in the subjects with PAD. This pilot study provides a base in which additional research will be performed with TcPO(2) measurements in both the healthy and revascularized person.     

Transcutaneous oxygen tension and toe blood pressure as predictors for outcome of diabetic foot ulcers.

OBJECTIVE: The present study was undertaken to compare the predictive values of transcutaneous oxygen tension (TcPO2) and toe blood pressure (TBP) measurements for ulcer healing in patients with diabetes and chronic foot ulcers. RESEARCH DESIGN AND METHODS: Investigated prospectively were 50 diabetic patients (37 men) with chronic foot ulcers. The age was 61 +/- 12 (mean +/- SD), and the diabetes duration was 26 +/- 14 years. TBP (mmHg) was measured in dig I and TcPO2 (mmHg) at the dorsum of the foot. Ulcer healing was continuously evaluated by measuring the ulcer area every 4-6 weeks. After a follow-up time of 12 months, the patients were divided into three groups according to clinical outcome: healed with intact skin, improved ulcer healing, or impaired ulcer healing. RESULTS: Of the 13 patients who deteriorated, 11 had TcPO2 < 25 mmHg, while 34 of the 37 patients who improved had TcPO2 > or = 25 mmHg. The sensitivity and specificity for TcPO2 were 85 and 92%, respectively, when a cutoff level of 25 mmHg was used for determination of outcome of ulcer healing (healing or nonhealing). The corresponding values for TBP at 30 mmHg were 15 and 97%. Measurement of TcPO2 provided a higher positive predictive value (79%) than TBP (67%). CONCLUSIONS: The results indicate that TcPO2 is a better predictor for ulcer healing than TBP in diabetic patients with chronic foot ulcers, and that the probability of ulcer healing is low when TcPO2 is < 25 mmHg.     

Intrinsic muscle atrophy and toe deformity in the diabetic neuropathic foot: a magnetic resonance imaging study

OBJECTIVE: The objectives of this study were to compare intrinsic foot muscle cross-sectional area (CSA) in patients with diabetic polyneuropathy and nondiabetic control subjects and to examine the association between intrinsic muscle CSA and clawing/hammering of the toes in neuropathic feet. RESEARCH DESIGN AND METHODS: High-resolution T2-weighted fast spin-echo images and parametric T2 multiple spin-echo images were acquired using multiple spin-echo magnetic resonance imaging (MRI) of frontal plane sections of the metatarsal region of the foot in a sample of eight individuals with diabetic polyneuropathy and eight age- and sex-matched nonneuropathic nondiabetic control subjects. The configuration of joints of the second toe was obtained using a three-dimensional contact digitizer. RESULTS: Remarkable atrophy was found in all the intrinsic muscles of neuropathic subjects as compared with nondiabetic control subjects. Quantitative T2 analysis showed a 73% decrease in muscle tissue CSA distally in the neuropathic subjects. Muscle comprised only 8.3 +/- 2.9% (means +/- SD) of total foot CSA compared with 30.8 +/- 3.9% in control subjects. No significant differences were found between the groups in the metatarso-phalangeal and proximal and distal interphalangeal joint angles of the second ray. Moreover, clawing/hammering of the toes was found in only two of eight neuropathic subjects. CONCLUSIONS: Although sensory neuropathy is often emphasized in considerations of diabetic foot pathology, our results show that the consequences of motor neuropathy in the feet are profound in people with diabetes. This has implications for foot function and may play a significant role in postural instability. However, intrinsic muscle atrophy does not necessarily appear to imply toe deformity.     

Hyperbaric oxygenation accelerates the healing rate of nonischemic chronic diabetic foot ulcers: a prospective randomized study

OBJECTIVE: To study the effect of systemic hyperbaric oxygenation (HBO) therapy on the healing course of nonischemic chronic diabetic foot ulcers. RESEARCH DESIGN AND METHODS: From 1999 to 2000, 28 patients (average age 60.2 +/- 9.7 years, diabetes duration 18.2 +/- 6.6 years), of whom 87% had type 2 diabetes, demonstrating chronic Wagner grades I-III foot ulcers without clinical symptoms of arteriopathy, were studied. They were randomized to undergo HBO because their ulcers did not improve over 3 months of full standard treatment. All the patients demonstrated signs of neuropathy. HBO was applied twice a day, 5 days a week for 2 weeks; each session lasted 90 min at 2.5 ATA (absolute temperature air). The main parameter studied was the size of the foot ulcer measured on tracing graphs with a computer. It was evaluated before HBO and at day 15 and 30 after the baseline. RESULTS: HBO was well tolerated in all but one patient (barotraumatic otitis). The transcutaneous oxygen pressure (TcPO(2)) measured on the dorsum of the feet of the patients was 45.6 +/- 18.1 mmHg (room air). During HBO, the TcPO(2) measured around the ulcer increased significantly from 21.9 +/- 12.1 to 454.2 +/- 128.1 mmHg (P < 0.001). At day 15 (i.e., after completion of HBO), the size of ulcers decreased significantly in the HBO group (41.8 +/- 25.5 vs. 21.7 +/- 16.9% in the control group [P = 0.037]). Such a difference could no longer be observed at day 30 (48.1 +/- 30.3 vs. 41.7 +/- 27.3%). Four weeks later, complete healing was observed in two patients having undergone HBO and none in the control group. CONCLUSIONS: In addition to standard multidisciplinary management, HBO doubles the mean healing rate of nonischemic chronic foot ulcers in selected diabetic patients. The time dependence of the effect of HBO warrants further investigations.     

The effects of leg/body position on transcutaneous oxygen measurements after lower-extremity arterial revascularization.

A postoperative nursing goal in a patient with peripheral artery disease requiring lower-extremity arterial reconstruction surgery is to maintain blood flow and tissue oxygenation to the revascularized extremity. This may be achieved through extremity positioning. Transcutaneous oxygen (TcPO(2)) measurements provide a noninvasive objective determination of oxygen at the skin surface and assessment of underlying circulation and tissue oxygenation. The purpose of this study was to determine which lower-extremity position afforded the highest TcPO(2) in 10 subjects with a lower-extremity arterial revascularization procedure preoperatively and 24 and 48 hours postoperatively. Hypotheses included comparing preoperative and postoperative TcPO(2) measurements, leg skin temperatures, and limb volumes. The subjects were studied in three different leg/body positions: supine with legs extended, sitting with legs extended, and supine with legs-elevated 20 degrees using the Radiometer TCM30 (Radiometer; Copenhagen) and PhysitempTH-5 Thermalert (Physitemp; Clifton, NJ) monitors. There was no change in the postoperative leg TcPO(2) measurements or limb volumes compared with preoperative measurements (P = .12-.92). A small sample size and lack of peripheral artery disease stratification were among study limitations. Significant to the nursing care of patients with vascular dsease is the finding that any of the leg/body positions in this study could be used postoperatively on the revascularized extremity without decreasing TcPO(2) measurements.     

Relationship of limited joint mobility to abnormal foot pressures and diabetic foot ulceration

OBJECTIVE: To investigate the role of limited joint mobility (LJM) in causing abnormal foot pressures and foot ulceration. RESEARCH DESIGN AND METHODS: The subjects were recruited from a general diabetes clinic where patients were screened for neuropathy, retinopathy, and elevated plantar foot pressure. Sixty-four patients in five groups were matched by age and sex in the following groups: group 1, patients with LJM and neuropathy; group 2, nonneuropathic diabetic patients with LJM; group 3, patients with neuropathy and no LJM; group 4, diabetic control subjects; and group 5, nondiabetic control subjects. Joint mobility was assessed in the foot at subtalar and metatarsophalangeal joints; plantar foot pressures were assessed by optical pedobarography and neuropathic status by a Biothesiometer and electrophysiology. RESULTS: Joint mobility was reduced at both sites in groups 1 and 2 compared with groups 3, 4, and 5 (P less than 0.001). Plantar foot pressures were significantly higher in groups 1 and 2 compared with groups 3, 4, and 5 (P less than 0.001). No differences in plantar foot pressures were observed between groups 1 and 2. There were strong correlations between plantar foot pressures and joint mobility in the foot (r = -0.7, P less than 0.001). Previous foot ulceration was present in 65% of patients in group 1, none in group 2, and 5% in group 3. CONCLUSIONS: 1) LJM may be a major factor in causing abnormally high plantar foot pressures, 2) abnormal plantar foot pressures alone do not lead to foot ulceration, and 3) LJM contributes to foot ulceration in the susceptible neuropathic foot.     

The role of limited joint mobility in diabetic patients with an at-risk foot

OBJECTIVE: To assess the role of limited joint mobility (LJM) in causing abnormal high plantar pressures in the forefoot of diabetic patients with an at-risk foot. RESEARCH DESIGN AND METHODS: A total of 70 type 1 or type 2 diabetic patients and 30 control subjects participated in this cross-sectional study. Thirty-five diabetic patients with an at-risk foot, defined as a foot with neuropathy but without ulceration or previous ulceration, and 35 diabetic control subjects without neuropathy were selected for the subgroups. Joint mobility was assessed in the foot at the ankle and metatarsophalangeal I (first MTP) joints. Using the FastScan plantar pressure analyzer, the pressure-time integrals (PTIs) as dynamic variables were measured in each foot. The clinical assessment included standard measures of peripheral neuropathy. RESULTS: The mobility at the ankle and first MTP joint were significantly reduced in the foot-at-risk group compared with the diabetic control group and the control subjects (P < 0.0001). The PTIs were significantly higher in the foot-at-risk group compared with the two other groups (P < 0.0001). There was a strong inverse correlation between the mobility of the ankle or first MTP joint and the PTI of the diabetic patients (r = -0.67, P < 0.0001, and r = -0.71, P < 0.0001, respectively). The vibration perception threshold was positively correlated with the PTI of the diabetic patients (r = 0.44, P = 0.0001). CONCLUSIONS: Diabetic patients with an at-risk foot have reduced joint mobility and elevated PTIs on the plantar forefoot, placing them at risk for subsequent ulceration. Therefore, LJM may be a possible factor in causing high plantar pressures and may contribute to foot ulceration in the susceptible neuropathic at-risk foot.     

The impact of the Micro-Lightguide O2C for the quantification of tissue ischemia in diabetic foot ulcers

OBJECTIVE: Tissue oxygen supply is crucial for wound healing. Especially in diabetic foot lesions, the chances for healing are mainly dependent on the presence or absence of ischemia. This study investigates the impact of the tissue O2 analysis system "O2C" for noninvasive quantification of tissue oxygenation in diabetic foot ulcer patients. RESEARCH DESIGN AND METHODS: O2C assessed relative blood flow (flow), flow velocity (velo), and hemoglobin concentration (rHb) and hemoglobin oxygenation (SO2) at 2 and 6 mm depth (means +/- SE). 1) Measurements were performed on intact skin of the forefoot and forearm of 20 healthy volunteers on 2 consecutive days. 2) Parameters were assessed on intact skin of the forefoot of diabetic foot ulcer patients (n=14). 3) Measurements were performed directly at the wound site in diabetic patients (n = 14). RESULTS: 1) Flow, velo, rHb, and SO2 at 2 and 6 mm depth were not significantly different when measured at 2 consecutive days. 2) There were no significant differences between diabetic subjects and healthy volunteers. Only flow in 6 mm depth was significantly higher in diabetic subjects (75 +/- 13 vs. 51 +/- 0.4 arbitrary units [AU], P <0.05). When diabetic foot ulcer patients were split into healers and nonhealers, initial readings of SO2 at 2 mm (32 +/- 6 vs. 44 +/- 3%, P <0.05) and flow in 6 mm (28 +/- 1 vs. 51 +/- 0.6 AU, P <0.05) were significantly reduced in nonhealers compared with control subjects, whereas in healers flow in 6 mm (70 +/- 0.6 vs. 51 +/- 0.6 AU, P <0.05) was significantly higher than that in control subjects. 3) Initial SO2, rHb, flow, and velo were significantly lower in nonhealing compared with healing wounds. CONCLUSIONS: O2C is a new reliable and valid method for noninvasive measurement of tissue oxygenation and microvascular blood flow in patients with diabetic foot ulcers.     

Cortisol secretion in patients with type 2 diabetes: relationship with chronic complications

OBJECTIVE: The presence of an enhanced cortisol secretion in patients with type 2 diabetes is debated. In type 2 diabetic subjects, cortisol secretion was found to be associated with the complications and metabolic control of diabetes. We evaluated cortisol secretion in 170 type 2 diabetic subjects and in 71 sex-, age-, and BMI-matched nondiabetic subjects. RESEARCH DESIGN AND METHODS: In all subjects, we evaluated ACTH at 8:00 a.m. in basal conditions and serum cortisol levels at 12:00 p.m. (F24) and at 9:00 a.m. after a 1-mg overnight dexamethasone suppression test and 24-h urinary free cortisol (UFC). In diabetic patients, we evaluated the presence of chronic complications (incipient nephropathy, asymptomatic neuropathy, background retinopathy, and silent macroangiopathy). Patients were subdivided according to the absence (group 1, n = 53) or presence (group 2, n = 117) of diabetes complications. RESULTS: In group 2, UFC (125.2 +/- 4.6 nmol/24 h) and F24 (120.6 +/- 4.1 nmol/l) were higher than in group 1 (109.2 +/- 6.8 nmol/24 h, P = 0.057, and 99.7 +/- 6.1 nmol/l, P = 0.005, respectively) and in nondiabetic patients (101.7 +/- 5.9 nmol/24 h, P = 0.002, and 100.3 +/- 5.3 nmol/l, P = 0.003, respectively). In diabetic patients, the number of complications was associated with F24 (R = 0.345; P < 0.0001) and diabetes duration (R = 0.39; P < 0.0001). Logistic regression analysis showed that the presence of diabetes complications was significantly associated with F24, sex, duration of diabetes, and glycated hemoglobin. CONCLUSIONS: In type 2 diabetic subjects, hypothalamic-pituitary-adrenal activity is enhanced in patients with diabetes complications and the degree of cortisol secretion is related to the presence and number of diabetes complications.     

Contact thermography of painful diabetic neuropathic foot.

OBJECTIVE: To investigate regional differences in skin blood flow (measured by contact thermography) in the diabetic neuropathic foot and to examine the effect of foot temperature on the severity of neuropathic pain. RESEARCH DESIGN AND METHODS: Thirty-five diabetic patients with painful polyneuropathy (PPN) and 33 healthy age- and sex-matched control subjects comprised the study. Mean foot temperature (MFT) in PPN (mean +/- SE 28.3 +/- 0.3 degrees C) was significantly higher (P less than 0.001) than in the control subjects (25.9 +/- 0.5 degrees C), with the highest temperatures over the metatarsal areas and heel. Visual analogue scale pain score (mean +/- SD 5.3 +/- 1.9 cm) did not correlate with MFT (r = -0.14, P = 0.52). In 10 patients with PPN followed for 2-8 mo (mean 4.6), MFT fell by 1.6 degrees C (P = 0.05), but pain scores did not alter. CONCLUSIONS: Neuropathic pain is unaffected by alterations in skin temperature. Elevated skin temperatures at recognized sites of weight bearing (metatarsal heads and heels) are common in the diabetic neuropathic foot and may indicate tissue injury or inflammation induced by pressure trauma or increased arteriovenous shunting. Follow-up studies will determine whether thermographic hot spots are more susceptible to ulceration.     

Hand skin blood flow in diabetic patients with autonomic neuropathy and microangiopathy.

OBJECTIVE: To determine whether changes in hand skin blood flow in diabetic men could be demonstrated with liquid crystal contact thermography and to assess the relative effects of autonomic neuropathy and microangiopathy on these changes. RESEARCH DESIGN AND METHODS: Thirty-four diabetic and 12 age-matched nondiabetic men comprised the study. The diabetic men were categorized according to standard cardiovascular autonomic function tests and the presence or absence of background or proliferative retinopathy and/or proteinuria. Bilateral hand thermograms were measured at rest and after immersion of the right hand in ice-cold water. RESULTS: Diabetic men with definite or severe autonomic neuropathy (n = 13) had a high frequency of anisothermal baseline thermograms (77 vs. 25% in nondiabetic subjects, P less than 0.05). After ice-cold water immersion, right-hand recovery was abnormally slow (514 +/- 157 arbitrary U, area under the curve) compared with nondiabetic men (685 +/- 135 arbitrary U, P less than 0.01). Diabetic men with proliferative retinopathy (n = 8) all had definite or severe autonomic neuropathy and showed the same abnormalities. Diabetic men with nor or early autonomic changes showed normal thermographic patterns. CONCLUSIONS: These results are consistent with increased palmar arteriovenous shunt blood flow or capillary closure in the hands of diabetic patients with definite or severe autonomic neuropathy. They indicate that thermoregulatory reflex changes in hand skin blood flow are controlled by the autonomic nervous system. It is possible, however, that diabetic microangiopathy, associated with the presence of proliferative retinopathy, also independently affects hand skin blood flow.     

Orthostatic hypertension in patients with type 2 diabetes

OBJECTIVE: The prevalence and clinical importance of orthostatic hypertension (OHT) in diabetic patients has not been elucidated, in contrast to orthostatic hypotension, which is occasionally found in diabetic patients with autonomic neuropathy. RESEARCH DESIGN AND METHODS: The prevalence and severity of orthostatic hypertension was investigated in 277 Japanese male patients with type 2 diabetes, including 90 hypertensive patients and 128 nondiabetic age-matched male subjects. Patients treated with antihypertensive drugs were excluded from the study. OHT was defined as an increase in diastolic blood pressure (DBP) from <90 to >or=90 mmHg and/or an increase in systolic blood pressure (SBP) from <140 to >or=140 mmHg after standing from supine position. Clinical profiles and several serum biochemical parameters were determined in addition to chest X-rays and electrocardiograms. RESULTS: The prevalence of OHT in normotensive and hypertensive diabetic patients was significantly higher than in control subjects (12.8 vs. 1.8%, P < 0.01, for normotensive patients; 12.6 vs. 11.1%, not significant, for hypertensive patients). Orthostasis induced a mean increase of 6.8 +/- 11.4 mmHg in SBP and 9.1 +/- 5.2 mmHg in DBP in diabetic patients with OHT compared with those without OHT (-1.0 +/- 9.0 and 3.8 +/- 6.6 mmHg, respectively). Vibration sensation in the lower limb was reduced in diabetic patients with OHT, but the percent coefficient of variation of RR interval, cardio-to-thoracic ratio on chest X-ray, and serum triglyceride levels were higher in these patients compared with normotensive diabetic patients without OHT. CONCLUSIONS: Orthostatic hypertension is a novel complication in normotensive diabetic patients and may associate with early stage neuropathy and development of sustained hypertension.     

A foot care program for diabetic unilateral lower-limb amputees

OBJECTIVE: To assess the efficacy of a specialist foot care program designed to prevent a second amputation and to assess peripheral vascular disease (PVD) and peripheral neuropathy in diabetic unilateral lower-limb amputees. RESEARCH DESIGN AND METHODS: Investigations were carried out in 143 diabetic lower-limb unilateral amputees referred to a subregional rehabilitation center for prosthetic care from a catchment area of approximately 3 million people. Peripheral vascular and nerve assessment, education, and podiatry were provided for each patient. RESULTS: For the patients referred to the foot care program, there were no baseline differences between the patients who proceeded to a bilateral amputation (n = 22) and those who remained as unilateral amputees (n = 121) in their level of foot care knowledge and mean neuropathy scores. Mean ankle-brachial pressure index was significantly lower for the bilateral amputees (0.75 +/- 0.04) compared with the unilateral amputees (0.90 +/- 0.03, mean +/- SEM, P < 0.05), but there was no difference in the level of oxygen in the skin. However, the level of carbon dioxide was significantly lower in patients with bilateral amputation (24.21 +/- 2.16 vs. 31.20 +/- 0.85 mmHg, P < 0.03). Overall, the establishment of a specialist foot care program made no impact on contralateral limb amputation (22 of 143, 15.4%) compared with matched patients without the program (21 of 148, 14%) over a 2-year outcome period for each patient. CONCLUSIONS: PVD is more closely associated with diabetic bilateral amputation than neuropathy or level of foot care knowledge. Preventative foot care programs for diabetic unilateral amputees should therefore place greater emphasis on peripheral vascular assessment to identify patients at risk and on the development of timely intervention strategies.     

Muscle weakness and foot deformities in diabetes: relationship to neuropathy and foot ulceration in caucasian diabetic men

OBJECTIVE: To examine the relationships among muscle weakness, foot deformities, and peroneal and tibial nerve conduction velocity in diabetic and nondiabetic men. RESEARCH DESIGN AND METHODS: A neuropathic and foot evaluation was undertaken in 10 nondiabetic control subjects (group C) and in 36 consecutive diabetic patients attending Diabetes Centre clinics, including 10 diabetic control subjects (group D), 15 diabetic neuropathic patients (group DN), and 11 diabetic patients with a history of ulceration (group DU). Neuropathy was defined as a peroneal motor nerve conduction <40 m/s. Muscle weakness was assessed in seven intrinsic and seven extrinsic muscles of the foot using a semiquantitative score (max score per muscle = 3). Foot deformities were assessed using a foot deformity score (max score = 3). A higher score indicated increased muscle weakness or more severe foot deformities. Muscle weakness and foot deformities were assessed without prior knowledge of patient and neuropathy status. RESULTS: Peroneal and tibial nerve conduction velocity were associated with weakness in muscles innervated by, respectively, the peroneal and tibial nerve (r = -0.70 and r = -0.51, P < 0.01) and foot deformities (r = -0.60 and r = -0.59, P < 0.001). The DN and DU groups had more weakness in intrinsic and extrinsic muscles compared with the C and D groups. Muscles innervated by the tibial nerve had a greater proportional muscle weakness than those innervated by the peroneal nerve in the DN and DU groups. The DN and DU patients had more foot deformities (median food deformity score [interquartile range]) (3 [2-3] and 2 [2-3]) compared with D and C patients (0 [0-0.75] and 0 [0-0]). CONCLUSIONS: Important relationships have been shown between motor nerve conduction deficit and muscle weakness; however, it is still not clear whether abnormal nerve function, leading to a decrease in muscle strength, could be responsible for the development of foot deformities.     

Sensitivity of R-R variation and Valsalva ratio in assessment of cardiovascular diabetic autonomic neuropathy

R-R variation and the Valsalva ratio are commonly used to quantitatively assess diabetic autonomic neuropathy (DAN). To assess the sensitivity of these two measures to parasympathetic ablation, 12 nondiabetic subjects were tested before and after graded doses (0.3-4.0 mg i.v.) of atropine. R-R variation was significantly reduced at 0.7 mg, whereas Valsalva ratio was not significantly smaller until the 2.0-mg dose of atropine. R-R variation continued to become progressively smaller during the 0.85-, 1.0-, and 2.0-mg doses. Valsalva ratio, but not R-R variation, was further reduced by the 4.0-mg dose. To further compare these two measures, two groups of diabetic subjects were compared with a group of nondiabetic subjects (n = 22). One group of diabetic subjects had symptoms of DAN (n = 22), and the other diabetic group had no symptoms of DAN (n = 19). In DAN subjects, both R-R variation (nondiabetic 33.2 +/- 4.3 vs. DAN 9.8 +/- 1.2, P less than .001) and the Valsalva ratio (nondiabetic 1.98 +/- 0.07 vs. DAN 1.55 +/- 0.07, P less than .001) were reduced. However, in asymptomatic subjects, R-R variation (23.2 +/- 3.9, P less than .05), but not Valsalva ratio (1.94 +/- 0.13, NS), was less than nondiabetic subjects. Even after beta-blockade, R-R variation was still less in both groups of diabetic subjects (nondiabetic 34.4 +/- 4.2 vs. DAN 7.4 +/- 1.3, P less than .001; asymptomatic 21.8 +/- 3.3, P less than .02).(ABSTRACT TRUNCATED AT 250 WORDS)     

Value of coronary artery calcium scanning by computed tomography for predicting coronary heart disease in diabetic subjects

OBJECTIVE: The South Bay Heart Watch is a cohort study designed to determine the significance of coronary calcium in high-risk asymptomatic patients. This is a report of the relative risk (RR) for outcomes of coronary artery calcium in diabetic and nondiabetic subjects. RESEARCH DESIGN AND METHODS: A total of 1312 diabetic and nondiabetic subjects underwent risk factor screening and computed tomography testing for coronary calcium at baseline and were followed clinically for 6.3 +/- 1.4 years. End points were either 1). hard events of nonfatal myocardial infarction (MI) or coronary death or 2). any cardiovascular event (nonfatal MI, coronary death, coronary revascularization, or stroke). RESULTS: The incidence rates of a hard event and any cardiovascular event for diabetic and nondiabetic subjects were 14.5 and 6.1% and 23.8 and 12.2%, respectively (P < 0.001). Cox regression analyses of the combined risk relationship of diabetes status and calcium score demonstrated that relative to nondiabetic subjects with low calcium scores (<2.8), diabetic subjects with calcium scores >or=2.8 exhibited at least a fourfold increase in the risk of either a hard or any cardiovascular event (P < 0.001). Cox regression analyses conducted separately for nondiabetic and diabetic subjects revealed that coronary calcium score risk groups were significantly associated with events in nondiabetic subjects (RR >or= 2.6, P 0.05). CONCLUSIONS: The risk of coronary heart disease increases with increasing calcium scores and diabetes status. Calcium scores have less prognostic value in diabetic subjects.