Comparison of CT and dual-energy DEXA using a modified trunk compartment in the measurement of abdominal fat.

The quantification of abdominal fat is a marker of health risk. While dual-energy x-ray absorptiometry (DEXA) is easily applied, it measures overall fat, although abdominal fat may be a better indicator of health risk from obesity. We have evaluated whether a subcomponent of DEXA measurements correlates better with computed tomography (CT) for body fat than those traditionally used. Forty-seven healthy adults (22 M/25 F), aged 54.5+/-15.8 yr (mean+/-SD), with BMI of 27.1+/-4.6 kg/m2 participated in a cross-sectional study. Body fat was measured using abdominal CT and DEXA for total fat, trunk fat, and a modified trunk measurement that excludes the chest, termed "lower trunk," and compared. The coefficient of variation for DEXA measurements for trunk, lower trunk, and total body were 1.98, 3.12, and 0.85%, respectively. Mean DEXA for percentage fat ranged from 31.7% to 34.1% for trunk, lower trunk, and total body, compared to 54.2% for abdominal CT (p<0.003 for each pairwise comparison). Lower trunk, whole trunk, and total body DEXA measurements were not different. Measurement of subcomponents of fat content by DEXA is not superior to whole body measurements and remains consistently lower than measurements by CT.

Greater early pancreas graft loss in women compared with men after simultaneous pancreas-kidney transplantation.

BACKGROUND: Gender differences in graft survival has been reported after some types of organ transplantation, but not after pancreas transplantation. This study compares graft survival between women and men after simultaneous pancreas-kidney transplantation (SPK). METHODS: All first time SPK (n = 163) transplants (109 M/54 F) performed between 1989 and 2000 at University of Nebraska Medical Center, where data was available, were analyzed for overall graft and patient survival. Graft failure was then subdivided into early (<6 months), and late (>6 months), and compared between women and men. RESULTS: The 5-yr pancreas and kidney graft survival rates for all SPK recipients was 86% [95% confidence interval (CI) = 81-92%] and 87% (95% CI = 82-93%), respectively. While overall pancreas graft survival in women was similar to men (p = 0.16), early pancreas graft failure was greater in women than men (p = 0.010) with no one cause for failure predominant. There was no gender difference in late pancreas graft failure or in early, or late kidney graft failure in the same recipients. The gender difference was unexplained by differences in age, immunosuppression, body mass index (BMI), or diabetes duration between women and men. CONCLUSIONS: This is the first report of a gender difference in pancreas graft survival after SPK with greater early (<6 months) pancreas graft failure in women than men. With no gender difference in kidney graft failure in the same individuals, gender differences in immune responses are unlikely to be the cause. Multiple variables likely contribute.

Heel ultrasonography is not a good screening tool for bone loss after kidney and pancreas transplantation.

BACKGROUND: Solid organ transplant recipients, particularly simultaneous pancreas kidney recipients, are at high fracture risk. We tested whether quantitative ultrasonography (QUS) of the heel predicts bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) in solid organ transplant recipients. METHODS: Thirty-eight transplant recipients (22 Female/16 Male) were studied. Spine and hip BMD was measured with a Hologic DXA scanner. 'Stiffness' of the heel was measured with a Lunar Ultrasound densitometer and compared with BMD by DXA. Contributing factors to bone loss were also assessed. RESULTS: Mean age was 43.1 +/- 1.3 yr. Simultaneous pancreas-kidney, kidney, and pancreas alone transplant recipients were assessed. Mean time post-transplantation was 3.0 +/- 0.6 yr. Mean DXA spine T-score was -1.15 +/- 0.22 (mean +/- SEM) and hip T-score was -1.22 +/- 0.20. There was no difference in mean T-score between women and men at the hip or spine. Mean right heel stiffness T-score was -0.97 +/- 0.25. There was no correlation between QUS and DXA at either the hip or spine in women or men. QUS had a false negative rate for identifying osteopenia or osteoporosis of 17% compared with DXA. The false positive rate for identifying osteopenia was 61%. CONCLUSIONS: The QUS is an unacceptable tool for identifying those at risk for bone loss after kidney or pancreas transplantation.

Pancreas transplantation improves vascular disease in patients with type 1 diabetes.

OBJECTIVE: Pancreas transplantation (PTX) normalizes glucose and improves microvascular complications, but its impact on macrovascular disease is still debated. RESEARCH DESIGN AND METHODS: Carotid intima-media thickness (IMT), shown to correlate with cardiovascular disease (CVD) risk and events, was determined prospectively by ultrasonography in successful pancreas transplant recipients to evaluate the effect of PTX on CVD risk. Carotid IMT and CVD risk factors of pancreas transplant recipients (n = 25) were compared with three groups: individuals with type 1 diabetes without significant nephropathy (n = 20), nondiabetic kidney transplant recipients (n = 16), and normal control subjects (n = 32). Mean age of pancreas transplant recipients at the time of transplantation was 42.4 +/- 1.2 years (mean +/- SE) and duration of diabetes was 25.9 +/- 1.4 years. RESULTS: After PTX, HbA(1c) level (P < 0.0001) decreased to normal and, whereas creatinine level (P = 0.0002) decreased, it remained elevated compared with normal control subjects (P < 0.05). Blood pressure, BMI, fasting lipid levels, smoking frequency, and use of hypolipidemic agents were unchanged. Mean carotid IMT was increased in pancreas transplant candidates but decreased by 1.8 +/- 0.1 year after PTX (P = 0.0068), no longer different from that in normal control subjects or patients with type 1 diabetes. CONCLUSIONS: Carotid IMT improves after successful PTX within 2 years of the procedure, with normalization of HbA(1c) and improved renal function, independent of changes in lipid levels, BMI, blood pressure, smoking, or use of hypolipidemic agents. This study suggests that CVD risk, future events, and mortality should improve after PTX in the absence of other significant, untreated CVD risk factors.

What is hypoglycemia in patients with well-controlled type 1 diabetes treated by subcutaneous insulin pump with use of the continuous glucose monitoring system?

OBJECTIVE: To analyze 72-hour interstitial glucose concentrations measured by a glucose sensor in adult subjects. METHODS: We compared glucose levels in 10 patients with type 1 diabetes mellitus (DM-1) and 10 normal control subjects with use of the Medtronic Continuous Glucose Monitoring System (CGMS). Hypoglycemic events identified by the CGMS, the patients, or both were compared in the patients with DM-1. In addition, the results between two glucose sensors placed at similar sites in the same subject were evaluated. RESULTS: Hemoglobin A1c and mean glucose values were higher in the DM-1 group than in the control group (P<0.01), whereas time spent at glucose levels of less than 60, 60 to 79, and 121 to 150 mg/dL were similar between the two study groups. Time spent at glucose levels above 150 mg/dL was greater in the DM-1 group than in the control group (P<0.05). Of the 74 total hypoglycemic events in the patients with DM-1, the sensor and the patient recognized 14%, only the patient recognized 9% (confirmed by readings of <55 mg/dL on a glucose meter), and only the sensor detected 77%. Of note, 41% of the patient-identified symptomatic hypoglycemic events were missed by the CGMS. When one patient with DM-1 and one control subject wore two glucose sensors simultaneously, one and not the other sensor often identified "hypoglycemia," and the correlation was only fair to good by intraclass correlation analysis. CONCLUSION: Many asymptomatic "hypoglycemic events" identified by the CGMS may not be actual hypoglycemia. Hypoglycemia is both overreported and underreported with use of the CGMS. Thus, adjustment of insulin doses to reduce asymptomatic hypoglycemia identified by the CGMS alone may not be warranted.

Apolipoprotein E gene polymorphism alters lipids before pancreas transplantation.

BACKGROUND: Pancreas transplantation (PTX) improves lipids in patients with type 1 diabetes mellitus. However, there are patients who have persistent abnormal lipids or develop new hyperlipidemia despite PTX. One factor that may influence the lipid profile is apolipoprotein E (Apo E) genotype. Apo E polymorphism, particularly E2 and E4 alleles, increases the risk of dyslipidemia. Apo E2 has also been found to increase risk of diabetic nephropathy and so may be more prevalent in PTX candidates. METHODS: This study evaluated fasting-lipid profiles in type 1 diabetes patients who were pancreas transplant candidates to prospectively evaluate the impact of Apo E genotype on dyslipidemia before and after PTX. RESULTS: Presence of one or more E4 alleles resulted in higher triglycerides ( =0.0446), lower HDL ( =0.0247), and a higher cholesterol-to-HDL (C/H) ratio ( =0.0405) before PTX when compared with those with E3/3 genotype. After PTX, lipids improved so there was no longer a difference in fasting lipids between patients with an E4 allele and E3/3 genotype. Presence of an E2 allele had no significant impact on fasting lipids before or after PTX. CONCLUSIONS: Presence of an Apo E4 allele worsened HDL, triglycerides, and C/H ratio before PTX compared with those with E3/3 genotype, whereas the presence of an Apo E2 allele had no significant effect on lipids before or after PTX. Thus, Apo E4 has a larger impact than Apo E2 on fasting-lipid profile in PTX candidates, and Apo E gene polymorphism does not worsen lipid dyslipidemia after PTX, despite introduction of immunosuppressant medications known to cause dyslipidemia.

Carotid intima media thickness decreases after pancreas transplantation.

BACKGROUND: Pancreas transplantation (PTX) improves diabetic microvascular complications, but it is unknown whether PTX alters macrovascular disease. Carotid intima media thickness (IMT) has been shown to correlate with cardiovascular events, so this study was designed to evaluate changes in carotid IMT after PTX. METHODS: Four groups were studied: PTX candidates (n=60); successful PTX recipients (n=89; mean time since PTX=4.0+/-0.3 years); patients with type 1 diabetes but without nephropathy (n=20); and normal controls (n=32). Mean IMT and mean of maximum carotid IMT measurements (mean-max IMT), hemoglobin A1C, serum creatinine, body mass index (BMI), blood pressure, smoking status, use of hypolipidemic medications, and fasting lipids were determined in all groups. RESULTS: Age, gender distribution, and BMI were not different among the groups. Duration of diabetes was also equal between pre- and post-PTX groups. Mean and mean-max IMT were greatest pre-PTX and decreased after PTX (P<0.05) to a value that was not different from controls. Hemoglobin A1C and creatinine decreased, and high density lipoprotein (HDL) increased after PTX (P<0.05), but there were no significant differences in other lipids, BMI, use of lipid lowering agents, blood pressure, or smoking status. CONCLUSIONS: Carotid IMT is lower after PTX, suggesting a reduction in overall cardiovascular risk independent of changes in use of hypolipidemic agents, smoking, blood pressure, BMI, or lipids, except HDL. Improved carotid IMT after successful PTX predicts a reduction in future vascular disease events and suggests that the macrovascular disease of type 1 diabetes is at least partially reversible with improved glucose control.

Pancreas and kidney transplantation.

Kidney transplantation is preferred over dialysis for management of end-stage renal disease complicating type I or type 2 diabetes, for those who are eligible. Simultaneous pancreas-kidney (SPK) or pancreas after kidney transplantation (PAK) is an important alternative to kidney transplantation alone for type I diabetes patients if the patient is able to withstand the additional risks of these procedures, because of the benefits of glucose control on other diabetic complications. Pancreas transplantation alone (PTA) is most useful for the treatment of debilitating, frequent hypoglycemia complicating type I diabetes, if renal function is adequate. One-year pancreas graft survival is best after SPK (82%) but has significantly improved after both PAK (74%) and PTA (76%). The I-year kidney graft and patient survival rates after SPK are similar to kidney transplantation alone. Pancreas transplantation normalizes glucose beyond what can be achieved with insulin therapy and has been shown to decrease progression of or improve most, if not all, diabetic end-organ complications using current immunosuppression regimens. However, the diabetologist and endocrinologist should remain involved in the care of the pancreas or kidney transplant recipient for treatment of vascular disease risk factors such as dyslipidemia, surveillance of other diabetic complications including foot ulcers, surveillance and treatment of bone loss, and management of hyperglycemia if it recurs.