Metabolic syndrome, insulin resistance and kidney function in non-diabetic individuals.

BACKGROUND: Metabolic syndrome has been recently identified as a risk factor for chronic kidney disease (CKD). Since the five individual components of the metabolic syndrome have also been identified as risk factors for CKD, the metabolic syndrome diagnosis may represent an aggregate of CKD risk factors. On the other hand, the components of the metabolic syndrome are also associated with insulin resistance, which may directly mediate the increased CKD risk. METHODS: This study was a cross-sectional evaluation of the relationship between metabolic syndrome, insulin resistance and estimated glomerular filtration rate (eGFR) in 574 non-diabetic individuals. Insulin resistance was directly quantified using the insulin suppression test, and the metabolic syndrome components were measured. eGFR was calculated using the three validated estimation equations: the Chronic Kidney Disease Epidemiology Collaboration equation, the Mayo quadratic equation and the Modification of Diet in Renal Disease study equation. RESULTS: While CKD prevalence was higher and mean eGFR was lower in individuals who met the metabolic syndrome criteria compared with those who did not, we did not observe a significant relationship between insulin resistance and eGFR. Of all of the components of the metabolic syndrome, only hypertension was significantly associated with CKD prevalence [odds ratio (95% confidence interval), 3.5 (1.2-10.1), P=0.02]. CONCLUSION: Although CKD is more common among individuals with the metabolic syndrome, insulin resistance is not a common factor.

Estimates of insulin secretory function in apparently healthy volunteers vary as a function of how the relevant variables are quantified.

BACKGROUND: Several surrogate estimates have been used to define relationships between insulin action and pancreatic ß-cell function in healthy individuals. Because it is unclear how conclusions about insulin secretory function depend on specific estimates used, we evaluated the effect of different approaches to measurement of insulin action and secretion on observations of pancreatic ß-cell function in individuals whose fasting plasma glucose (FPG) was <7.0 mmol/L (126 mg/dL). METHODS: We determined 2 indices of insulin secretion [homeostasis model assessment of ß-cell function (HOMA-ß) and daylong insulin response to mixed meals], insulin action [homeostasis model assessment of insulin resistance (HOMA-IR) and steady-state plasma glucose (SSPG) concentration during the insulin suppression test], and degree of glycemia [fasting plasma glucose (FPG) and daylong glucose response to mixed meals] in 285 individuals with FPG <7.0 mmol/L. We compared the relationship between the 2 measures of insulin secretion as a function of the measures of insulin action and degree of glycemia. RESULTS: Assessment of insulin secretion varied dramatically as a function of which of the 2 methods was used and which measure of insulin resistance or glycemia served as the independent variable. For example, the correlation between insulin secretion (HOMA-ß) and insulin resistance varied from an r value of 0.74 (when HOMA-IR was used) to 0.22 (when SSPG concentration was used). CONCLUSIONS: Conclusions about ß-cell function in nondiabetic individuals depend on the measurements used to assess insulin action and insulin secretion. Viewing estimates of insulin secretion in relationship to measures of insulin resistance and/or degree of glycemia does not mean that an unequivocal measure of pancreatic ß-cell function has been obtained.

Interferon Alfa-2b or not 2b? Significant differences exist in the decision-making process between melanoma patients who accept or decline high-dose adjuvant interferon Alfa-2b treatment.

BACKGROUND: Patients with thick (Breslow>4 mm) primary melanoma and/or regional nodal metastasis have a high risk of tumor recurrence. High-dose adjuvant interferon (IFN) alfa-2b offers/=50% risk of recurrence/disease-related mortality and offered IFN. Telephone surveys delineated reasons behind patients' decisions to accept IFN. RESULTS: Acceptors, 60 of 135 (45%), decided to take IFN alfa-2b whereas 75 of 135 (55%) declined. Being female (OR, 2.4; 95% CI, 1.17-5.03; p=.017) and positive SLN status (OR, 2.2; 95% CI, 1.01-4.97; p=.048) were strongly associated with patients who chose IFN. Acceptors of IFN were younger, more influenced by physicians, and less affected by depression and side effect profile (p<.05 for all). Decliners were more concerned by strained relationships with family and social life (p<.05). CONCLUSIONS: Gender and positive SLN were predictive of high-risk melanoma patients' acceptance of IFN treatment. Physician insight into melanoma patients' therapeutic decision-making process can guide patients through this difficult disease.