Confirming glycemic status in the Diabetes Prevention Program: implications for diagnosing diabetes in high risk adults.

AIMS: To examine the ability of fasting plasma glucose (FPG) and/or 2-h glucose to confirm diabetes and to determine the proportion of participants with HbA1c ≥6.5%. METHODS: Diabetes confirmation rates were calculated after a single elevated FPG and/or 2-h glucose on an oral glucose tolerance test (OGTT) using a confirmatory OGTT performed within 6 weeks. RESULTS: 772 (24%) participants had elevated FPG or 2-h glucose on an OGTT that triggered a confirmation visit. There were 101 triggers on FPG alone, 574 on 2-h glucose alone, and 97 on both. Only 47% of participants who triggered had confirmed diabetes. While the confirmation rate for FPG was higher than that for 2-h glucose, the larger number of 2-h glucose triggers resulted in 87% of confirmed cases triggering on 2-h glucose. Confirmation rates increased to 75% among persons with FPG ≥126 mg/dl and HbA1c ≥6.5%. CONCLUSIONS: Only half of the persons with elevated FPG and IGT were subsequently confirmed to have diabetes. At current diagnostic levels, more persons trigger on 2-h glucose than on FPG, but fewer of these persons have their diagnoses confirmed. In individuals with FPG ≥126 mg/dl and HbA1c ≥6.5%, the confirmation rate was increased.

Troglitazone amplifies counterregulatory responses to hypoglycemia in nondiabetic subjects.

As insulin sensitizers, thiazolidinediones could affect the hormonal counterregulatory response to hypoglycemia via the modulatory effect of insulin on counterregulation. In addition, recent studies suggest that thiazolidinediones may influence key steps in glucose sensing and glucoregulatory hormone secretion. We therefore evaluated the effects of a short course of troglitazone on counterregulatory hormones in response to mild hypoglycemia in eight lean nondiabetic subjects. Subjects received either troglitazone (400 mg/day) or placebo for 7 days before stepped hypoglycemia clamp studies (5.0, 4.4, 3.9, and 3.3 mmol/L target plasma glucose steps, 50 min each). The glycemic thresholds for secretion of epinephrine (3.77 +/- 0.05 mmol/L) and glucagon (3.83 +/- 0.11 mmol/L) were reset to a higher plasma glucose concentration after troglitazone [4.05 +/- 0.05 mmol/L (P = 0.003) and 4.10 +/- 0.05 mmol/L (P = 0.03), respectively]. In addition, the magnitude of the rise in epinephrine and glucagon concentrations was higher with troglitazone (28% and 11%, respectively; P < 0.05 for both), whereas plasma norepinephrine, GH, and cortisol were comparable in both sets of studies. Endogenous glucose production, measured with [3-(3)H]glucose, rose by 33% (P < 0.05) in the troglitazone studies compared with 17% (P = NS) after placebo. We conclude that thiazolidinediones may induce an amplification of the counterregulatory response to hypoglycemia characterized by a shift in the glycemic threshold for and an increase in the magnitude of glucagon and epinephrine secretion, and subsequent activation of glucose production.

Hormone-independent activation of EGP during hypoglycemia is absent in type 1 diabetes mellitus.

It has been suggested that insulin-induced suppression of endogenous glucose production (EGP) may be counteracted independently of increased epinephrine (Epi) or glucagon during moderate hypoglycemia. We examined EGP in nondiabetic (n = 12) and type 1 diabetic (DM1, n = 8) subjects while lowering plasma glucose (PG) from clamped euglycemia (5.6 mmol/l) to values just above the threshold for Epi and glucagon secretion (3.9 mmol/l). Individualized doses of insulin were infused to maintain euglycemia during pancreatic clamps by use of somatostatin (250 microg/h), glucagon (1.0 ng. kg(-1). min(-1)), and growth hormone (GH) (3.0 ng. kg(-1). min(-1)) infusions without need for exogenous glucose. Then, to achieve physiological hyperinsulinemia (HIns), insulin infusions were fixed at 20% above the rate previously determined for each subject. In nondiabetic subjects, PG was reduced from 5.4 +/- 0.1 mmol/l to 3.9 +/- 0.1 mmol/l in the experimental protocol, whereas it was held constant (5. 3 +/- 0.2 mmol/l and 5.5 mmol/l) in control studies. In the latter, EGP (estimated by [3-(3)H]glucose) fell to values 40% of basal (P < 0.01). In contrast, in the experimental protocol, at comparable HIns but with PG at 3.9 +/- 0.1 mmol/l, EGP was activated to values about twofold higher than in the euglycemic control (P < 0.01). In DM1 subjects, EGP failed to increase in the face of HIns and PG = 3.9 +/- 0.1 mmol/l. The decrease from basal EGP in DM1 subjects (4.4 +/- 1.0 micromol. kg(-1). min(-1)) was nearly twofold that in nondiabetics (2.5 +/- 0.8 micromol. kg(-1). min(-1), P < 0.02). When PG was lowered further to frank hypoglycemia ( approximately 3.1 mmol/l), the failure of EGP activation in DM1 subjects was even more profound but associated with a 50% lower plasma Epi response (P < 0. 02) compared with nondiabetics. We conclude that glucagon- or epinephrine-independent activation of EGP may accompany other counterregulatory mechanisms during mild hypoglycemia in humans and is impaired or absent in DM1.

The effect of health education on the rate of ophthalmic examinations among African Americans with diabetes mellitus.

OBJECTIVES: This study evaluated a multicomponent educational intervention to increase ophthalmic examination rates among African Americans with diabetes. METHODS: A randomized trial was conducted with 280 African Americans with diabetes, enrolled from outpatient departments of 5 medical centers in the New York City metropolitan area, who had not had a dilated retinal examination within 14 months of randomization (65.7% female, mean age = 54.7 years [SD = 12.8 years]). RESULTS: After site differences were controlled, the odds ratio for receiving a retinal examination associated with the intervention was 4.3 (95% confidence interval = 2.4, 7.8). The examination rate pooled across sites was 54.7% in the intervention group and 27.3% in the control group. CONCLUSIONS: The intervention was associated with a rate of ophthalmic examination double the rate achieved with routine medical care.

Transcutaneous glucose measurement using near-infrared spectroscopy during hypoglycemia.

OBJECTIVE: To analyze a transcutaneous near-infrared spectroscopy system as a technique for in vivo noninvasive blood glucose monitoring during euglycemia and hypoglycemia. RESEARCH DESIGN AND METHODS: Ten nondiabetic subjects and two patients with type 1 diabetes were examined in a total of 27 studies. In each study, the subject's plasma glucose was lowered to a hypoglycemia level (approximately 55 mg/dl) followed by recovery to a glycemic level of approximately 115 mg/dl using an intravenous infusion of insulin and 20% dextrose. Plasma glucose levels were determined at 5-min intervals by standard glucose oxidase method and simultaneously by a near-infrared spectroscopic system. The plasma glucose measured by the standard method was used to create a calibration model that could predict glucose levels from the near-infrared spectral data. The two data sets were correlated during the decline and recovery in plasma glucose, within 10 mg/dl plasma glucose ranges, and were examined using the Clarke Error Grid Analysis. RESULTS: Two sets of 1,704 plasma glucose determinations were examined. The near-infrared predictions during the fall and recovery in plasma glucose were highly correlated (r = 0.96 and 0.95, respectively). When analyzed during 10 mg/dl plasma glucose segments, the mean absolute difference between the near-infrared spectroscopy method and the chemometric reference ranged from 3.3 to 4.4 mg/dl in the nondiabetic subjects and from 2.6 to 3.8 mg/dl in the patients with type 1 diabetes. Using the Error Grid Analysis, 97.7% of all the near-infrared predictions were assigned to the A-zone. CONCLUSIONS: Our findings suggest that the near-infrared spectroscopy method can accurately predict plasma glucose levels during euglycemia and hypoglycemia in humans.

Regulation of endogenous glucose production by glucose per se is impaired in type 2 diabetes mellitus.

We examined the ability of an equivalent increase in circulating glucose concentrations to inhibit endogenous glucose production (EGP) and to stimulate glucose metabolism in patients with Type 2 diabetes mellitus (DM2). Somatostatin was infused in the presence of basal replacements of glucoregulatory hormones and plasma glucose was maintained either at 90 or 180 mg/dl. Overnight low-dose insulin was used to normalize the plasma glucose levels in DM2 before initiation of the study protocol. In the presence of identical and constant plasma insulin, glucagon, and growth hormone concentrations, a doubling of the plasma glucose levels inhibited EGP by 42% and stimulated peripheral glucose uptake by 69% in nondiabetic subjects. However, the same increment in the plasma glucose concentrations failed to lower EGP, and stimulated glucose uptake by only 49% in patients with DM2. The rate of glucose infusion required to maintain the same hyperglycemic plateau was 58% lower in DM2 than in nondiabetic individuals. Despite diminished rates of total glucose uptake during hyperglycemia, the ability of glucose per se (at basal insulin) to stimulate whole body glycogen synthesis (glucose uptake minus glycolysis) was comparable in DM2 and in nondiabetic subjects. To examine the mechanisms responsible for the lack of inhibition of EGP by hyperglycemia in DM2 we also assessed the rates of total glucose output (TGO), i.e., flux through glucose-6-phosphatase, and the rate of glucose cycling in a subgroup of the study subjects. In the nondiabetic group, hyperglycemia inhibited TGO by 35%, while glucose cycling did not change significantly. In DM2, neither TGO or glucose cycling was affected by hyperglycemia. The lack of increase in glucose cycling in the face of a doubling in circulating glucose concentrations suggested that hyperglycemia at basal insulin inhibits glucose-6-phosphatase activity in vivo. Conversely, the lack of increase in glucose cycling in the presence of hyperglycemia and unchanged TGO suggest that the increase in the plasma glucose concentration failed to enhance the flux through glucokinase in DM2. In summary, both lack of inhibition of EGP and diminished stimulation of glucose uptake contribute to impaired glucose effectiveness in DM2. The abilities of glucose at basal insulin to both increase the flux through glucokinase and to inhibit the flux through glucose-6-phosphatase are impaired in DM2. Conversely, glycogen synthesis is exquisitely sensitive to changes in plasma glucose in patients with DM2.

Persistent alterations of the autonomic nervous system after noncardiac surgery.

UNLABELLED: BACKGROUND. Changes in the sympathetic nervous system may be a cause of postoperative cardiovascular complications. The authors hypothesized that changes in both beta-adrenergic receptor (betaAR) function (as assessed in lymphocytes) and in sympathetic activity (assessed by plasma catecholamines and by heart rate variability [HRV] measurements obtained from Holter recordings) occur after operation. METHODS: The HRV parameters were measured in 28 patients having thoracotomy (n = 14) or laparotomy (n = 14) before and for as long as 6 days after operation. Transthoracic echocardiography was performed before and on postoperative day 2. Lymphocytes were also isolated from blood obtained before anesthesia and again on postoperative days 1, 2, 3, and 5 (or 6). They were used to examine betaAR number (Bmax) and cyclic adenosine monophosphate (cAMP) production after stimulation with isoproterenol and prostaglandin E1. In addition, plasma epinephrine, norepinephrine, and cortisol concentrations were determined at similar intervals. RESULTS: After abdominal and thoracic surgery, most time and all frequency indices of HRV decreased significantly, as did Bmax and basal and isoproterenol-stimulated cAMP production. The decrements in HRV correlated with those of Bmax and isoproterenol-stimulated cAMP throughout the first postoperative week and inversely correlated with the increase in heart rate. Plasma catecholamine concentrations did not change significantly from baseline values, but plasma cortisol levels did increase after operation in both groups. Left ventricular ejection fraction was normal in both groups and unaffected by surgery. CONCLUSIONS: Persistent downregulation and desensitization of the lymphocyte betaAR/adenylyl cyclase system correlated with decrements in time and frequency domain indices of HRV throughout the first week after major abdominal or thoracic surgery. These physiologic alterations suggest the continued presence of adaptive autonomic regulatory mechanisms and may explain why the at-risk period after major surgery appears to be about 1 week or more.

Efficacy, safety, and dose-response characteristics of glipizide gastrointestinal therapeutic system on glycemic control and insulin secretion in NIDDM. Results of two multicenter, randomized, placebo-controlled clinical trials. The Glipizide Gastrointestinal Therapeutic System Study Group.

OBJECTIVE: To investigate the efficacy, safety, and dose-response characteristics of an extended-release preparation of glipizide using the gastrointestinal therapeutic system (GITS) on plasma glucose, glycosylated hemoglobin (HbA1c), and insulin secretion to a liquid-mixed meal in NIDDM patients. RESEARCH DESIGN AND METHODS: Two prospective, randomized, double-blind, placebo-controlled, multicenter clinical trials were performed in 22 sites and 347 patients with NIDDM (aged 59 +/- 0.6 years; BMI, 29 +/- 0.3 kg/m2; known diabetes duration, 8 +/- 0.4 years) were studied. Each clinical trial had a duration of 16 weeks with a 1-week washout, 3-week single-blind placebo phase, 4-week titration to a fixed dose, and 8-week maintenance phase at the assigned dose. In the first trial, once-daily doses of 5, 20, 40, or 60 mg glipizide GITS were compared with placebo in 143 patients. In the second trial, doses of 5, 10, 15, or 20 mg of glipizide GITS were compared with placebo in 204 patients. HbA1c, fasting plasma glucose (FPG), insulin, C-peptide, and glipizide levels were determined at regular intervals throughout the study. Postprandial plasma glucose (PPG), insulin, and C-peptide also were determined at 1 and 2 h after a mixed meal (Sustacal). RESULTS: All doses of glipizide GITS in both trials produced significant reductions from placebo in FPG (range -57 to -74 mg/dl) and HbA1c (range -1.50 to -1.82%). Pharmacodynamic analysis indicated a significant relationship between plasma glipizide concentration and reduction in FPG and HbA1c over a dose range of 5-60 mg, with maximal efficacy achieved at a dose of 20 mg for FPG and at 5 mg for HbA1c. PPG levels were significantly lower, and both postprandial insulin and C-peptide levels significantly higher in patients treated with glipizide GITS compared with placebo. The percent reduction in FPG was comparable across patients with diverse demographic and clinical characteristics, including those with entry FPG > or = 250 mg/dl, resulting in greater absolute decreases in FPG and HbA1c in patients with the most severe hyperglycemia. Despite the forced titration to a randomly assigned dose, only 11 patients in both studies discontinued therapy because of hypoglycemia. Glipizide GITS did not alter lipids levels or produce weight gain. CONCLUSIONS: The once-daily glipizide GITS 1) lowered HbA1c, FPG, and PPG over a dose range of 5-60 mg, 2) was maximally effective at 5 mg (using HbA1c) or 20 mg (using FPG) based on pharmacokinetic and pharmacodynamic relationships, 3) maintained its effectiveness in poorly controlled patients (those with entry FPG > or = 250 mg/dl), 4) was safe and well tolerated in a wide variety of patients with NIDDM, and 5) did not produce weight gain or adversely affect lipids.

Incentives and barriers to retinopathy screening among African-Americans with diabetes.

Diabetes-related ophthalmic complications are the leading cause of newly diagnosed blindness among adults. These eye complications are often asymptomatic in the early stages, yet the majority of diabetes patients are not screened yearly. To develop a health promotion intervention to increase the rate of screening for diabetic retinopathy by dilated fundus exam (DFE), we assessed the knowledge and health beliefs related to preventing diabetic eye complications among a sample of African-Americans with diabetes. The study design was cross-sectional, using a telephone interview to collect data. From a random sample of 104 African-Americans with diabetes, 67 (64%) were completed: 54 women; mean age of 58 years. The telephone interview schedule contained items grouped into subscales for Perceived Incentives, Perceived Barriers to getting a DFE, Causes of Eye Problems, Risk of Eye Problems, and Effective Treatments for Eye Problems. Descriptive statistics were used to analyze the quantitative data. Transcribed qualitative responses to the open-ended questions were analyzed for themes. The incentives "having eye problems" and "doctor said it was important to go" each had 91% responding it was an incentive to go for a DFE. Only about one-third agreed that any particular item was a barrier to receiving a DFE (e.g., economic factors). In the subscale for Risk of Eye Problems, "retinopathy" had the lowest level of perceived risk (30%). Only 21% of the sample reported there were effective treatments for retinopathy. Eighty-seven percent reported the faulty belief that "diabetic eye problems have symptoms." Only 36% of the sample said they had heard of retinopathy and of those, only 8% could describe it correctly. Among general response themes were: fear, spirituality (faith and hope), priorities, economic or logistical factors, and external/internal motivation. Perceived incentives for receiving a DFE were acknowledged at far greater rates than perceived barriers. Having a yearly DFE in the absence of symptoms must be emphasized in health promotion materials. There are effective, early treatments for diabetic eye problems, and this information should be used to counter the fear of a dreaded diagnosis with the hope of treatment and cure. Ways of coping with fear of having the exam should be included in health education. DFEs must become a routine yearly exam and not just a reaction to recognized problems. Health education must address the specific needs of high-risk minority populations.

Increased lipid oxidation but normal muscle glycogen response to epinephrine in humans with IDDM.

The effects of physiological increments in epinephrine and insulin on glucose production (GP), skeletal muscle glycogen metabolism, and substrate oxidation were studied in eight insulin-dependent diabetes mellitus (IDDM) and nine control subjects. Epinephrine was coinfused for the final 120 min of a 240-min euglycemic, hyperinsulinemic clamp. In both groups, insulin increased glucose uptake, glycogen synthesis, and whole body carbohydrate (CHO) oxidation and inhibited GP (by 70-80%) and lipid oxidation (by approximately 50%), whereas epinephrine antagonized the effect of insulin on glucose uptake and glycogen synthesis. In contrast, GP increased in IDDM subjects (P < 0.02) but remained suppressed by insulin in controls. CHO oxidation fell (1.37 +/- 0.25 vs. 2.08 +/- 0.32 mg.kg-1.min-1) and lipid oxidation increased to baseline in IDDM subjects, with increments in plasma free fatty acids (FFA) and glycerol. In contrast, in controls, plasma FFA and glycerol remained suppressed and lipid oxidation decreased further with epinephrine (P < 0.005). Epinephrine completely reversed insulin's activation of muscle glycogen synthase in both groups. Thus, during hyperinsulinemia, the hepatic response to epinephrine in IDDM subjects may be dependent on activation of lipid oxidation. Skeletal muscle glycogen metabolism is exquisitely sensitive to epinephrine despite the presence of hyperinsulinemia.

Oral vanadyl sulfate improves insulin sensitivity in NIDDM but not in obese nondiabetic subjects.

We compared the effects of oral vanadyl sulfate (100 mg/day) in moderately obese NIDDM and nondiabetic subjects. Three-hour euglycemic-hyperinsulinemic (insulin infusion 30 mU / m / min) clamps were performed after 2 weeks of placebo and 3 weeks of vanadyl sulfate treatment in six nondiabetic control subjects (age 37 +/- 3 years; BMI 29.5 +/- 2.4 kg/m2 ) and seven NIDDM subjects (age 53 +/- 2 years; BMI 28.7 +/-1.8 kg/m2). Glucose turnover ([3-3 H]glucose), glycolysis from plasma glucose, glycogen synthesis, and whole-body carbohydrate and lipid oxidation were evaluated. Decreases in fasting plasma glucose (by approximately 1.7 mmol/l) and HbAlc (both P < 0.05) were observed in NIDDM subjects during treatment; plasma glucose was unchanged in control subjects. In the latter, the glucose infusion rate (GIR) required to maintain euglycemia (40.1 +/- 5.7 and 38.1 +/- 4.8 micromol / kg fat-free mass FFM / min) and glucose disposal (Rd) (41.7 +/- 5.7 and 38.9 +/-4.7 micromol / kg FFM / min were similar during placebo and vanadyl sulfate administration, respectively. Hepatic glucose output (HGO) was completely suppressed in both studies. In contrast, in NIDDM subjects, vanadyl sulfate increased GIR approximately 82% (17.3 +/- 4.7 to 30.9 +/- 2.7 micromol / kg FFM / min, P < 0.05); this improvement in insulin sensitivity was due to both augmented stimulation of Rd (26.0 +/-4.0 vs. 33.6 +/- 2.22 micromol / kg FFM / min, P < 0.05) and enhanced suppression of HGO (7.7 +/- 3.1 vs. 1.3 +/- 0.9 micromol / kg FFM / min, P < 0.05). Increased insulin-stimulated glycogen synthesis accounted for >80% of the increased Rd with vanadyl sulfate (P < 0.005), but plasma glucose flux via glycolysis was unchanged. In NIDDM subjects, vanadyl sulfate was also associated with greater suppression of plasma free fatty acids (FFAs) (P < 0.01) and lipid oxidation (P < 0.05) during clamps. The reduction in HGO and increase in Rd were both highly correlated with the decline in plasma FFA concentrations during the clamp period (P < 0.001). In conclusion, small oral doses of vanadyl sulfate do not alter insulin sensitivity in nondiabetic subjects, but it does improve both hepatic and skeletal muscle insulin sensitivity in NIDDM subjects in part by enhancing insulin's inhibitory effect on lipolysis. These data suggest that vanadyl sulfate may improve a defect in insulin signaling specific to NIDDM.

Increased norepinephrine variability in patients with sleep apnea syndrome.

OBJECTIVE: To assess the plasma arterial catecholamine response to nocturnal desaturation in a group of patients with a history suggestive of sleep apnea. PATIENTS AND METHODS: At a Veterans Affairs hospital, 10 patients who had a history consistent with sleep apnea syndrome were involved in the study. Arterial plasma catecholamines were measured at varying intervals during a 5 1/2-hour sleep study. Eighteen samples per patient were analyzed. RESULTS: As the hemoglobin saturation decreased, the variability in plasma norepinephrine increased significantly (r = -.78, P = 0.004). As the hemoglobin saturation fell, there was a trend towards higher concentrations of plasma norepinephrine (r = -.53, P = 0.06). As the hemoglobin saturation decreased, the variability in plasma epinephrine concentration was not significant (r = .42). CONCLUSION: The association between the degree of desaturation and the variability in norepinephrine suggests that norepinephrine is released in response to nocturnal desaturation.

Components of variance for vibratory and thermal threshold testing in normal and diabetic subjects.

Quantitative sensory testing (QST) is commonly used in the assessment of diabetic neuropathy. However, little data are available on the reliability of tactile and thermal testing devices. Reproducibility of QST measures between centers has not been previously reported. This study was designed to validate QST testing procedures and determine if these devices are suitable for large scale multicenter clinical trials. Finger and toe vibratory (Vf, Vt) and thermal (Tf, Tt) thresholds were determined for ten normal individuals by a two-alternative forced-choice procedure using the Optacon Tactile Tester (OTT) and Thermal Sensitivity Tester (TST). Threshold measurements were reproducible between technologists and had a day-to-day coefficient of variation of Vf 20%, Vt 23%, Tf 41%, and Tt 95%. Thresholds were determined for 140 normal individuals at six centers. Mean threshold values between centers were not significantly different. Center-to-center coefficients of variation (CV) were Vf 44%, Vt 45%, Tf 47%, and Tt 87%. There was no significant difference in threshold measures with regard to sex, side studied, presence of calluses, or skin temperature. Vf thresholds significantly correlated with age (p < 0.01). There was no correlation between either vibratory or thermal thresholds in normal individuals, and nerve conduction velocities (NCV). Thermal and vibratory thresholds were determined for 98 diabetic patients. Diabetic subjects without clinical evidence of neuropathy were not significantly different from normal individuals, but diabetic patients with neuropathy had increased thresholds compared to normals (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Oral vanadyl sulfate improves hepatic and peripheral insulin sensitivity in patients with non-insulin-dependent diabetes mellitus.

We examined the in vivo metabolic effects of vanadyl sulfate (VS) in non-insulin-dependent diabetes mellitus (NIDDM). Six NIDDM subjects treated with diet and/or sulfonylureas were examined at the end of three consecutive periods: placebo for 2 wk, VS (100 mg/d) for 3 wk, and placebo for 2 wk. Euglycemic hyperinsulinemic (30 mU/m2.min) clamps and oral glucose tolerance tests were performed at the end of each study period. Glycemic control at baseline was poor (fasting plasma glucose 210 +/- 19 mg/dl; HbA1c 9.6 +/- 0.6%) and improved after treatment (181 +/- 14 mg/dl [P < 0.05], 8.8 +/- 0.6%, [P < 0.002]); fasting and post-glucose tolerance test plasma insulin concentrations were unchanged. After VS, the glucose infusion rate during the clamp was increased (by approximately 88%, from 1.80 to 3.38 mg/kg.min, P < 0.0001). This improvement was due to both enhanced insulin-mediated stimulation of glucose uptake (rate of glucose disposal [Rd], +0.89 mg/kg.min) and increased inhibition of HGP (-0.74 mg/kg.min) (P < 0.0001 for both). Increased insulin-stimulated glycogen synthesis (+0.74 mg/kg.min, P < 0.0003) accounted for > 80% of the increased Rd after VS, and the improvement in insulin sensitivity was maintained after the second placebo period. The Km of skeletal muscle glycogen synthase was lowered by approximately 30% after VS treatment (P < 0.05). These results indicate that 3 wk of treatment with VS improves hepatic and peripheral insulin sensitivity in insulin-resistant NIDDM humans. These effects were sustained for up to 2 wk after discontinuation of VS.

Counterregulation of hypoglycemia. Skeletal muscle glycogen metabolism during three hours of physiological hyperinsulinemia in humans.

We examined the role of skeletal muscle in counterregulation of hypoglycemia (3.4 +/- 0.1 mmol/l) in 12 nondiabetic individuals (age 26 +/- 1 years, body mass index 24.2 +/- 0.7 kg/m2) during physiological hyperinsulinemia (280 +/- 25 pmol/l) compared with euglycemia (4.8 +/- 0.1 mmol/l). During hypoglycemia, hepatic glucose output (3-[3H]-glucose) was greater (7.72 +/- 2.72 mumol.kg-1.min-1, P < 0.01), glucose uptake was approximately 49% lower (21.20 +/- 3.55 mumol.kg-1.min-1, P < 0.005), and glucose clearance was reduced (P < 0.002) compared with euglycemia. Rates of flux of plasma-derived glucosyl units through glycolysis were similar in the two experiments, while glycogen synthetic rates were significantly reduced during hypoglycemia (P < 0.01) and accounted entirely for the reduction in glucose disposal. The insulin-induced activation of skeletal muscle glycogen synthase (reflected by Km decline by approximately 50% from 0.408 +/- 0.056 mmol/l and fractional velocity increase by approximately twofold from 21.8 +/- 2.7%) was completely abolished in hypoglycemia. In concert, glycogen phosphorylase activity increased during hypoglycemia by approximately 40% (P = 0.0001). Hypoglycemia resulted in seven- to eightfold increments in plasma epinephrine (P < 0.0001) and growth hormone (P < 0.001) and 40-60% increments in plasma glucagon (P < 0.005) and cortisol (P < 0.05). We conclude that, in this model of mild hypoglycemia of moderate duration, the majority of the glucose made available during the counterregulatory process (approximately 60-70%) is due to the limitation of glucose disposal, mostly via decreased glycogen synthetic activity in skeletal muscle.

Diabetes care needs of Hispanic patients treated at inner-city neighborhood clinics in New York City.

The charts of 254 Hispanic patients were selected from a sample of 321 patients with diabetes in four urban clinics that received federal funding to provide medical care in underserved communities. A standardized chart-audit protocol was used to assess the process of healthcare delivery and the presence of diabetes-associated comorbidities and complications in patients. Inconsistent recognition of obesity (11% identified vs 59% present), hyperlipidemia (17% identified vs 69% present), and renal dysfunction (3.5% identified vs 16% present) was evident on chart review. We also found inadequate compliance with current recommendations for diabetes care with respect to routine health screenings for diabetes-related complications, recognition of comorbid diagnoses, and referral of patients for recommended specialty consultations. Issues specific to the varied Hispanic populations may need to be considered to improve the delivery of diabetes care for the growing Hispanic population with diabetes.

Assessment of documented foot examinations for patients with diabetes in inner-city primary care clinics.

BACKGROUND: The established guidelines for a diabetes foot examination include assessing circulatory, skin, and neurological status to detect problems early and reduce the likelihood of amputation. OBJECTIVE: To determine documented adherence with guidelines for foot examinations. SETTING: Four clinics in underserved areas. METHODS: Charts of 350 diabetic patients, identified by billing code, were reviewed for foot examination documentation. A documented foot examination was defined as assessing at least two of the three components of a foot examination. The review determined the periodicity and prevalence of foot examinations, referrals to a podiatrist or vascular surgeon during a 2-year period, and risk factors for foot complications. Stepwise logistic regression was used to determine whether risk factors for foot complications predicted foot examination status. RESULTS: The patients had a mean age and duration of diabetes of 57.7 and 8.8 years, respectively; 86% were black or Hispanic. There was no indication of foot examination or referral for 55.7% of the patients during the 2-year period. Patients with foot care referrals were more likely to have foot examinations by their primary care providers (P = .0001). There was almost a fourfold increase in the odds that patients with diagnosed peripheral vascular disease had foot examinations, with twofold greater odds for each 25-year increase in age. CONCLUSIONS: Populations at risk of diabetic complications are unlikely to have foot examinations in their primary medical care, but having peripheral vascular disease increases the likelihood. Efforts are needed to improve adherence to foot examination guidelines for patients with diabetes from underserved populations.