Predictors of transcutaneous oxygen tension in the lower limbs of diabetic subjects.

We examined neuropathy, ankle pressure index (API), and other factors as predictors of transcutaneous oxygen (TcPO2) in the lower limbs of 657 diabetic subjects. Eligible subjects underwent a clinical assessment that included three standard measures of autonomic neuropathy. TcPO2 measurements were performed at 37 degrees C and 44 degrees C at four lower limb locations. Associations between potential predictors and TcPO2 were tested using univariate and multivariate statistics. Mean TcPO2 at any site did not differ by presence of autonomic neuropathy at either temperature, except for a significantly lower value at 44 degrees C below the knee (56.5 versus 59.2 mmHg, p = 0.021). In multivariate analysis, autonomic neuropathy was significantly and independently related to leg 44 degrees C TcPO2 only (coefficient = -2.6734, p = 0.0182). Much stronger associations were seen between TcPO2 and age, ankle blood pressure, and relative body weight on the plantar foot; and between API, glycosylated haemoglobin, ankle blood pressure, and pedal oedema on the dorsal foot and leg. We conclude that factors related to lower limb TcPO2 vary depending on measurement site. Autonomic neuropathy is not an important determinant of TcPO2 in the feet of diabetic subjects. Although several predictors of TcPO2 were identified, most of the variance of this measurement remains unexplained.

Paradoxical transcutaneous oxygen response to cutaneous warming on the plantar foot surface: a caution for interpretation of plantar foot TcPO2 measurements.

We examined the effect of cutaneous warming on the transcutaneous oxygen measurement (TcPO2) at standard locations below the knee, on the dorsal foot, on the plantar right great toe, and on the plantar surface under the second metatarsal head of 656 diabetic and 16 nondiabetic subjects. All subjects underwent a directed medical history, physical examination, and neurovascular lower extremity evaluation and assessment of autonomic neuropathy. Associations between autonomic neuropathy and TcPO2 were tested using two-way analysis of variance and multiple linear regression. An unexpected, statistically significant fall in TcPO2 occurred with cutaneous warming from 37 degrees C to 44 degrees C on the plantar great toe surface that did not differ by presence of autonomic neuropathy, or the presence of diabetes (mean change: -8.82 mmHG, 95% confidence interval [CI]: -7.70 to -9.93). The TcPO2 measured at the plantar metatarsal head site also fell with cutaneous warming from 37 degrees C to 44 degrees C (mean change: -9.67 mmHG, 95% CI: -7.75 to -11.59). As expected, the TcPO2 increased with cutaneous warming from 37 degrees C to 44 degrees C on the dorsal foot site (mean rise:= 35.61 mmHg, 95% CI: 34.18 to 37.04). The mean TcPO2 at any site did not differ by presence of autonomic neuropathy at either 37 degrees C or 44 degrees C. We conclude that cutaneous warming leads to a paradoxical fall in TcPO2 on the plantar foot surface that does not depend on the presence of autonomic neuropathy or diabetes. Caution in interpretation of ambient versus warmed plantar TcPO2 values is recommended.

The health and functional status of veterans with diabetes.

OBJECTIVE: To determine the extent of functional impairment among veterans with diabetes and investigate whether such functional impairment is associated with measures of glycemic control, sensory neuropathy, lower extremity macrovascular disease, or other comorbid conditions. RESEARCH DESIGN AND METHODS: A 20-item general health survey (SF-20) developed by the Medical Outcomes Study (MOS) Group, was administered to 577 subjects participating in a prospective study of risk factors for diabetic foot ulceration. Measures of glycemic control and neurovascular disease included GHb, sensory lower extremity neuropathy assessed by aesthesiometry, and segmental lower extremity doppler blood pressures. RESULTS: Veterans with diabetes have major decreases in all domains of functional status; 87% were in poor health in terms of physical functioning and 86% in terms of health perceptions. Those with advancing age, symptoms of neuropathy and claudication, and a medical history of complications associated with diabetes had significantly more impairment of health status than those without. GHb values did not correlate with functional status measures. Subjects with neuropathy had statistically significant functional impairment. Subjects with vasculopathy had only two significantly low health status measures. CONCLUSIONS: In summary, the findings from this survey reveal that veterans with diabetes have low functional status scores. The presence of symptoms and complications accounts for only part of the impairments experienced by this group.

Definitions and guidelines for assessment of wounds and evaluation of healing.

BACKGROUND: Chronic wounds represent a worldwide problem. For laboratory and clinical research to adequately address this problem, a common language needs to exist. OBSERVATION: This language should include a system of wound classification, a lexicon of wound descriptors, and a description of the processes that are likely to affect wound healing and wound healing end points. CONCLUSIONS: The report that follows defines wound, acute wound, chronic wound, healing and forms of healing, wound assessment, wound extent, wound burden, and wound severity. The utility of these definitions is demonstrated as they relate to the healing of a skin wound, but these definitions are broadly applicable to all wounds.

Underreporting of diabetes on death certificates, King County, Washington.

We estimated the reporting of diabetes on death certificates for persons known to have diabetes. Surveillance of 19 hospitals and two paramedic emergency medical services during 12 months in Seattle and King County, Washington, ascertained acute ischemic heart disease events for persons with diabetes and yielded 1235 persons with suspected ischemic heart disease. Mortality was 23.6%, and 41% of death certificates listed diabetes. The reporting of diabetes on the death certificate was not random, and it varied by patient and physician characteristics. Diabetes is strongly linked to fatal ischemic heart disease, but its importance is underrepresented by death certificates for some subgroups.

Risk factors for amputation in patients with diabetes mellitus. A case-control study.

OBJECTIVE: To identify and quantify risk factors for lower extremity amputation in persons with diabetes mellitus. DESIGN: Case-control study. SETTING: A Veterans Affairs medical center. PATIENTS: Eighty patients having amputation associated with diabetes and 236 diabetic controls without limb lesions were enrolled before surgery from the 21,167 inpatient care and outpatient surgical patients seen at the Seattle Veterans Affairs Medical Center during a 30-month period. MEASUREMENTS: Selected vascular, neuropathic, environmental, health care, self care, nutritional, metabolic, lifestyle, and psychosocial risk factors were measured in all patients before surgery. RESULTS: Statistically significant risk factors identified from analysis included insufficient mean below-knee and foot cutaneous circulation (odds ratio, 161; 95% CI, 55.1 to 469); ankle-arm blood pressure index less than 0.45 (odds ratio, 55.8; CI, 14.9 to 209); absence of lower leg vibratory perception (odds ratio, 15.5; CI, 8.3 to 28.7); low levels of high-density lipoprotein (HDL) subfraction 3 less than or equal to 0.7 mumol/L (odds ratio, 4.9; CI, 2.9 to 8.3); and no previous outpatient diabetes education (odds ratio, 3.2; CI, 1.6 to 6.6). A logistic regression analysis done to control for the potentially confounding effects of age; race; socioeconomic status; diabetes duration, type, and severity confirmed these findings and added a statistically significant interaction between foot transcutaneous oxygen tension and peripheral vascular disease history. Clinical interventions to alter these risk factors were identified, including aggressive treatment of infection, diabetes education, protective footwear, and preventive footcare. CONCLUSIONS: Multiple risk factors exist along the continuum of conditions and events leading to lower extremity amputation in diabetes. Modification of certain risk factors by patients and health professionals may reduce the risk for amputation and thus decrease the human and dollar costs that accompany limb loss in this prevalent chronic disease.

Immediate and long-term efficacy of systemic antibiotics for eradicating nasal colonization with Staphylococcus aureus.

The efficacy of nine antibiotics used in different nonrandomized regimens for eradicating nasal colonization with Staphylococcus aureus was investigated in 72 patients. Dicloxacillin, erythromycin and three cephalosporins had eradicated colonization in about 75% of cases at early follow-up (less than or equal to 20 days) and in less than or equal to 50% at late follow-up (greater than or equal to 20 days). Clindamycin had eradicated colonization in all 13 patients at both follow-up times. One of two patients was successfully treated with fleroxacin, as were three of five with enoxacin. Among 21 patients treated with ofloxacin, colonization was eradicated in 20 (95%) at early follow-up and in all six of those from whom late follow-up cultures were obtained. Thus, clindamycin and ofloxacin appear to be useful systemic antibiotics for eradicating nasal colonization with Staphylococcus aureus.

Chronology and determinants of tissue repair in diabetic lower-extremity ulcers.

The natural history of tissue repair and the critical determinants of faulty healing of diabetic ulcers remain obscure despite recent advances in our knowledge of the cellular physiology of normal cutaneous healing. To characterize the chronology and identify important factors affecting healing, we applied an objective method to quantify the rate of wound healing of full-thickness lower-extremity ulcers in 46 diabetic outpatients who received local wound care under a standardized clinical protocol. The initial ulcer healing rate, eventual status of tissue repair, and definitive clinical outcome were not significantly associated with age; diabetes type, duration, or treatment; level or change in glycosylated hemoglobin; current smoking; presence of sensory neuropathy; ulcer location or class; initial infection; or frequency of recurrent infections. However, direct measures of local cutaneous perfusion, estimated by periwound measurements of transcutaneous O2 tension (TcPo2) and transcutaneous CO2 tension (TcPco2), were significantly associated with the initial rate of tissue repair (P = 0.003 and 0.005, respectively). The strong prediction of early healing by these parameters of local skin perfusion was independent from the effects of segmental Doppler arterial blood pressure at the dorsalis pedis, although eventual ulcer reepithelialization was significantly related to foot blood pressure and periwound TcPo2 and TcPco2. We conclude that periwound cutaneous perfusion is the critical physiological determinant of diabetic ulcer healing, indicating a 39-fold increased risk of early healing failure when the average periwound TcPo2 is less than 20 mmHg.

Diagnosis of osteomyelitis in the presence of soft-tissue infection and radiologic evidence of osseous abnormalities: value of leukocyte scintigraphy.

To evaluate the usefulness of 111In-leukocyte scintigraphy for identifying osteomyelitis in the presence of soft-tissue infection, we prospectively studied 45 bone sites adjacent to soft-tissue infection in patients with abnormal findings on radiographs and 99mTc bone scans that were suggestive of osteomyelitis. 111In-leukocyte scans were analyzed in terms of the intensity of abnormal uptake and its location relative to bone. The diagnosis of osteomyelitis was established from results of percutaneous bone biopsy culture (n = 35), histologic examination of surgical specimens (n = 8), and clinical follow-up (n = 2). Osteomyelitis was present at 22 sites, including 16 of 18 sites with increased leukocyte uptake in bone, resulting in a sensitivity of 73%, specificity of 91%, and positive predictive value of 89% for this finding. Osteomyelitis was present at four of 17 sites with predominantly soft-tissue localization of leukocyte activity in the region of bone, none of seven sites with normal leukocyte scans, and two of three sites with diminished leukocyte uptake in bone. Although not helpful in distinguishing infectious from noninfectious bone abnormalities, 3- and especially 24-hr bone scans viewed in conjunction with leukocyte studies provided important correlation to aid in estimating the location of focal abnormal leukocyte uptake. The finding of soft-tissue infection with increased uptake of labeled leukocytes that extends to involve adjacent bone strongly suggests concurrent osteomyelitis. When the presence of abnormal leukocyte uptake in bone is uncertain, additional imaging and possibly biopsy may be required to establish or exclude the diagnosis of osteomyelitis.

Treatment of lower respiratory infections in outpatients with ofloxacin compared with erythromycin.

To assess the safety and efficacy of a ten-day oral course of ofloxacin (400 mg 12 hourly) as compared with erythromycin (400 mg every 6 hours) for treatment of lower respiratory tract infections, fifty-two adult outpatients with pulmonary infiltrates (pneumonia) or with a cough and purulent sputum (bronchitis) were evaluated. Expectorated sputum specimens were Gram-stained and cultured, and antibody titres to Mycoplasma pneumoniae, Legionella pneumophilia, and in most cases Chlamydia pneumoniae were measured on acute and convalescent serum samples. Patients were evaluated clinically, microbiologically and radiographically three to five days after concluding therapy; the incidence of adverse reactions was monitored throughout the study period. The ofloxacin group (N = 25) was comprised of nineteen patients with pneumonia and six patients with bronchitis. The erythromycin group (N = 27) was comprised of thirteen patients with pneumonia and fourteen patients with bronchitis. All fifty-two patients were either clinically improved or cured after therapy. Microbiological cure was documented in all fourteen cases (27%) in which causative pathogens were identified. Clinical cure was achieved with ofloxacin in 68% of patients with pneumonia and in 83% of patients with bronchitis, while clinical cure with erythromycin was achieved in 46% of patients with pneumonia and 54% of patients with bronchitis. Adverse reactions (mostly mild gastrointestinal or central nervous system symptoms) were reported by eight patients receiving ofloxacin and four patients receiving erythromycin. While the types of adverse effects were similar, ofloxacin showed a trend toward a higher rate of cure than erythromycin. Ofloxacin is a promising new antibiotic for the treatment of acute lower respiratory infections.

Foot ulceration and infections in elderly diabetics.

Foot lesions occur commonly among patients with diabetes, particularly the elderly and those with sensory neuropathy. Because of serious or recurrent infections and impaired healing processes, initially trivial lesions may progress to chronic nonhealing wounds, gangrene, or untreatable infections that can lead to limb amputation. Strategies to prevent amputation depend on understanding the multifactorial nature of diabetic foot disease; providing effective ongoing preventive care, including patient education; and prompt and aggressive treatment of foot lesions when they occur. The approach to treatment of infections depends on many factors, including the severity of the soft tissue infection, whether or not underlying bone or joints are involved, the types of infecting organisms, the patient's social situation, and his other medical problems. Proper diagnostic studies followed by appropriate antimicrobial therapy and local wound care can usually lead to resolution of these potentially serious infections.

The diabetic foot. Soft tissue and bone infection.

Diabetic patients, as a consequence of various neurologic, vascular, and metabolic perturbations, are at high risk for developing infections of the soft tissue and bones of the feet. The microbial etiology of soft tissue in infections is best determined by cultures of a tissue curetting or aspiration, rather than a swab. Aerobic gram-positive cocci are the major pathogens in diabetic foot infections; these may be the sole isolate(s) in acute uncomplicated infections, but they are usually accompanied by aerobic gram-negative bacilli or anaerobes in chronic or previously treated infections. Carefully selected patients with mild infections can be treated as outpatients with oral antibiotics, but others require hospitalization and broad-spectrum parenteral antibiotics. Bone infections are frequently diagnosed on the basis of roentgenographs and nuclear medicine scans, but these methods are often inaccurate, and bone cultures should be obtained whenever possible.

Pathways to diabetic limb amputation. Basis for prevention.

We defined the causal pathways responsible for 80 consecutive initial lower-extremity amputations to an extremity in diabetic patients at the Seattle Veterans Affairs Medical Center over a 30-mo interval from 1984 to 1987. Causal pathways, either unitary or composed of various combinations of seven potential causes (i.e., ischemia, infection, neuropathy, faulty wound healing, minor trauma, cutaneous ulceration, gangrene), were determined empirically after a synthesis by the investigators of various objective and subjective data. Estimates of the proportion of amputations that could be ascribed to each component cause were calculated. Twenty-three unique causal pathways to diabetic limb amputation were identified. Eight frequent constellations of component causes resulted in 73% of the amputations. Most pathways were composed of multiple causes, with only critical ischemia from acute arterial occlusions responsible for amputations as a singular cause. The causal sequence of minor trauma, cutaneous ulceration, and wound-healing failure applied to 72% of the amputations, often with the additional association of infection and gangrene. We specified precise criteria in the definition of causal pathway to permit estimation of the cumulative proportion of amputations due to various causes. Forty-six percent of the amputations were attributed to ischemia, 59% to infection, 61% to neuropathy, 81% to faulty wound healing, 84% to ulceration, 55% to gangrene, and 81% to initial minor trauma. An identifiable and potentially preventable pivotal event, in most cases an episode involving minor trauma that caused cutaneous injury, preceded 69 to 80 amputations. Defining causal pathways that predispose to diabetic limb amputation suggests practical interventions that may be effective in preventing diabetic limb loss.

Outpatient management of uncomplicated lower-extremity infections in diabetic patients.

Most diabetic foot infections are believed to be caused by both aerobic and anaerobic bacteria and to require hospitalization and parenteral antimicrobial therapy. We prospectively evaluated diabetic patients with non-limb-threatening lower-extremity infections not yet treated with antibiotics. The patients were randomized to outpatient treatment with oral clindamycin hydrochloride or cephalexin for 2 weeks and evaluated every 3 to 7 days. In 56 assessable patients, curettage yielded a mean of 2.1 microorganisms. Aerobic gram-positive cocci were isolated in 50 cases (89%), and were the sole pathogen in 21 (42%) of these. Aerobic gram-negative bacilli and anaerobes were isolated in 20 (36%) and 7 (13%) cases, respectively, and almost always in polymicrobial infections. Fifty-one infections (91%) were eradicated, 42 (75%) after 2 weeks of treatment; only 5 (9%) were initially treatment failures, and 3 (5%) were subsequently cured with further outpatient oral antibiotic treatment. After a mean follow-up of 15 months, no further treatment was required in 43 (84%) of the cured patients. Previously untreated lower-extremity infections in diabetic patients are usually caused by aerobic gram-positive cocci, and generally respond well to outpatient management with oral antibiotic therapy.

NIDDM and prevalence of nasal Staphylococcus aureus colonization. San Luis Valley Diabetes Study.

Previous studies of hospitalized and ambulatory patients have found a higher prevalence of Staphylococcus aureus nasal colonization in diabetic than nondiabetic subjects. We examined this association in a geographically based study among 551 residents of the San Luis Valley of Colorado and found no statistically significant increase in the relative risk of nasal S. aureus colonization in 188 non-insulin-dependent diabetic (NIDDM) versus 363 nondiabetic subjects (relative risk 1.3, 95% confidence limits 0.9-1.8). Adjustment for confounding by age, sex, ethnicity, county of residence, and frequency of hospitalizations or physician visits in the previous year did not affect the results. Among the diabetic subjects, S. aureus colonization was not associated with type of treatment for diabetes, level of glucose control, clinical duration of diabetes, or frequency of hospitalizations or physician visits in the previous year. In this population-based study, diabetes mellitus did not increase S. aureus nasal colonization, suggesting that factors other than diabetes mellitus may have caused the higher colonization rate found in previous clinic-based studies.

Relationship of patient request fulfillment to compliance, glycemic control, and other health care outcomes in insulin-dependent diabetes.

Patients' perceptions of the extent to which their health care needs have been met may affect compliance with prescribed health behaviors and related health outcomes. The authors examined the relationships of "patient request fulfillment" to patient compliance, glycemic control, and several other health care outcomes in 51 adult outpatients with insulin-dependent diabetes mellitus. On average, patients retrospectively cited 4.5 long-term requests, of which over three-fourths were fulfilled. Fulfillment of these requests was significantly associated with patient satisfaction, perceived health status, fewer insulin reactions, and greater insulin injection time reliability (p less than 0.05), but not with several other measures of compliance. Higher patient request fulfillment at single visits was correlated, as hypothesized, with subsequent reduction in glycosylated hemoglobin, but this association was not statistically significant. These results suggest that patient request fulfillment is associated with several aspects of health behavior and health status in adults with insulin-dependent diabetes. Further studies are needed to confirm these observations and determine whether strategies to enhance patient request fulfillment can enhance health care outcomes.

Reliability of transcutaneous oxygen tension (TcPO2) measurements in elderly normal subjects.

This study was conducted to evaluate the reliability of TcPO2 measurements in a well characterized group of 10 elderly normal subjects with an age distribution typical for the population with peripheral vascular disease (PVD) and amputation. The TcPO2 values were obtained on three separate occasions at 2-week intervals at seven anatomic sites commonly measured in patients with PVD. The TcPO2 values were comparable to those previously reported for similar sites in normal elderly subjects. Measurement to measurement variation averaged 1.1 kPa (8 mmHg) for a coefficient of variation (CV) of 14.4%. Confidence intervals ranging from 2.1 kPa (16 mmHg) above a single TcPO2 value to 2.1 kPa (16 mmHg) below were necessary to contain the true value 95% of the time. While TcPO2 measurement is assuming an important role in the evaluation of disease states in both paediatric and adult medicine, our observations emphasize the importance of using such measurements as an adjunct in clinical decision making and not basing such decisions on a single TcPO2 value alone. The size of the confidence intervals can be reduced substantially for a given site by taking the mean of two or more TcPO2 measurements taken at separate times.

Factors affecting staphylococcal colonization among NIDDM outpatients.

Because colonization with Staphylococcus aureus probably predisposes to staphylococcal infections, we examined several factors that may be associated with staphylococcal carriage in outpatients with non-insulin-dependent diabetes mellitus and in nondiabetic controls. Nose and skin carrier rates for 59 diabetic patients were significantly greater (30.5%) than for 44 controls (11.4%) (P = .02), but rates did not differ significantly between diabetic patients who injected insulin (31.0%) and those who did not (30.0%). Among the diabetic patients, staphylococcal colonization was not significantly correlated (P greater than .05) with recent antibiotic treatment, age, race, or clinical duration of diabetes but was inversely correlated (P less than .03) with glycemic control, as measured by fasting plasma glucose and glycosylated hemoglobin levels. Hospitalization in the previous year was also associated with staphylococcal colonization, and it was significantly more common among the diabetic patients than the controls; however, this did not account for the increased colonization rates observed. Our results in a well-characterized population confirm an increased rate of staphylococcal colonization among diabetic as compared with nondiabetic outpatients but demonstrate that neither injections of insulin nor various pertinent demographic factors explain this finding.