Avaliação da secreção e resistência insulínica em indivíduos com diferentes graus de tolerância à glicose - do metabolismo normal ao diabetes mellitus / Insulin resistance and secretion assessment across a range of glucose tolerance from normal individuals through diabetes

OBJETIVO: Os principais objetivos são determinar a associação entre os parâmetros clínicos e demográficos e os diferentes índices de secreção e resistência insulínica em indivíduos aparentemente saudáveis, sem conhecimento prévio de seu grau de tolerância à glicose. PACIENTES E MÉTODOS: Submetemos ao teste oral de tolerância à glicose (TOTG), no período de fevereiro a agosto de 2003, 105 indivíduos com média de idade de 33,4 ± 1,4 anos, sendo 57,1 por cento do sexo feminino, subdividindo-os em 4 grupos: grupo 0 (normais): indivíduos com IMC < 25 e metabolismo glicídico normal, grupo 1 (obesos): IMC > 25 e metabolismo glicídico normal, grupo 2 (IFG): glicemia de jejum alterada e grupo 3 (IOG): intolerância oral à glicose. RESULTADOS: Encontramos diferença estatística para todas as variáveis analisadas durante o TOTG dentre os 4 grupos de indivíduos: glicemias de jejum e em 2 horas (p < 0,05; p < 0,05), valor de pico (p < 0,05), delta (p = 0,02), percentual de incremento (p = 0,047), área sob a curva (p < 0,05) e tempo de pico da glicose (p = 0,022). Não encontramos diferença para a velocidade de incremento da glicose, assim como para nenhuma variável da curva de insulina. Em relação aos índices de secreção insulínica, não houve significância estatística para os índices insulinogênico ou delta, porém estes tornaram-se significantes após correção da secreção pela resistência insulínica (p = 0,008). Quanto aos índices de resistência insulínica, os índices HOMA e QUICKI foram estatisticamente significativos (p = 0,005; p = 0,005, respectivamente), assim como a relação glicose/insulina em jejum (p = 0,053). CONCLUSÃO: Apesar do tamanho limitado da amostra, podemos inferir que indivíduos com intolerância à glicose em jejum e pós-prandial possivelmente estão em momentos diferentes da história natural da doença. Nossos dados demonstram que os melhores índices para a avaliação de resistência insulínica são o HOMA e o QUICKI, e que os...

AIM AND METHODS: Our main aim was to determine the association between clinical, demographical parameters and different insulin resistance and secretion indices in apparently healthy subjects, without previous knowledge of their own level of glucose tolerance. For that purpose, we evaluated 105 individuals from February to August 2003 by means of OGTT, aged 33.4 ± 1.4 years old, 57.1 percent female. We allocated them in four groups: group 0 (normal): individuals with BMI < 25 Kg/m² and normal glucose metabolism, group 1 (obese): BMI > 25 Kg/m² and normal glucose metabolism, group 2 (IFG): impaired fasting glucose and group 3 (IGT): impaired glucose tolerance. RESULTS: We have found statistical difference on all variables during OGTT between all groups: fasting glucose (p < 0.05), 2-hour glucose (p < 0.05), glucose peak value (p < 0.05), glucose delta (p = 0.02), glucose incremental percentage (p = 0.047), area under curve (p < 0.05), and glucose peak time (p = 0.022). We have not found difference on any variable in insulin curves or on glucose incremental velocity. Regarding insulin secretion indices there were no statistical significance in insulinogenic or delta indices, but they became significant after being corrected by insulin resistance (p = 0.008). When we evaluated insulin resistance alone, by using HOMA and QUICKI indices and the fasting glucose to insulin index, we have found statistical significance (p = 0.005; p = 0.005; p = 0.053). CONCLUSION: Although studying a small sample, we could suggest that individuals with impaired fasting glucose and impaired glucose tolerance are in different stages of diabetes natural history disease. We found out that the best indices of insulin resistance are both HOMA and QUICKI. We also suggest that pancreatic secretion indices should be corrected by the insulin resistance, which could best reflect type 2 diabetes natural history.

[Insulin resistance and secretion assessment across a range of glucose tolerance from normal individuals through diabetes]. / Avaliação da secreção e resistência insulínica em indivíduos com diferentes graus de tolerância à glicose--do metabolismo normal ao diabetes mellitus.

AIM AND METHODS: Our main aim was to determine the association between clinical, demographical parameters and different insulin resistance and secretion indices in apparently healthy subjects, without previous knowledge of their own level of glucose tolerance. For that purpose, we evaluated 105 individuals from February to August 2003 by means of OGTT, aged 33.4+/-1.4 years old, 57.1% female. We allocated them in four groups: group 0 (normal): individuals with BMI < 25 Kg/m(2) and normal glucose metabolism, group 1 (obese): BMI >or= 25 Kg/m(2) and normal glucose metabolism, group 2 (IFG): impaired fasting glucose and group 3 (IGT): impaired glucose tolerance. RESULTS: We have found statistical difference on all variables during OGTT between all groups: fasting glucose (p < 0.05), 2-hour glucose (p < 0.05), glucose peak value (p < 0.05), glucose delta (p = 0.02), glucose incremental percentage (p = 0.047), area under curve (p < 0.05), and glucose peak time (p = 0.022). We have not found difference on any variable in insulin curves or on glucose incremental velocity. Regarding insulin secretion indices there were no statistical significance in insulinogenic or delta indices, but they became significant after being corrected by insulin resistance (p = 0.008). When we evaluated insulin resistance alone, by using HOMA and QUICKI indices and the fasting glucose to insulin index, we have found statistical significance (p = 0.005; p = 0.005; p = 0.053). CONCLUSION: Although studying a small sample, we could suggest that individuals with impaired fasting glucose and impaired glucose tolerance are in different stages of diabetes natural history disease. We found out that the best indices of insulin resistance are both HOMA and QUICKI. We also suggest that pancreatic secretion indices should be corrected by the insulin resistance, which could best reflect type 2 diabetes natural history.

[Evaluation of microalbuminuria in non-diabetic individuals]. / Avaliação da microalbuminúria em indivíduos não diabéticos.

AIM: To evaluate the presence of microalbuminuria in non-diabetic subjects, associating it to the presence of cardiovascular risk factors like hypertension, smoking, dislipidemia and obesity. The urinary albumin excretion rate (UAE) was also evaluated regarding to insulin secretion and resistance indices. DESIGN AND METHODS: 105 subjects aged 33.4 +/- 1.4 years (57.1% women), received 75 g dextrose for an OGTT, and the following variables were evaluated for glucose and insulin curves: basal and 2 hours values, peak values (PV) and area under the curves (AUC). To evaluate insulin secretion and resistance, we used the insulinogenic, delta, HOMA, QUICKI, glucose to insulin ratio and the relation between insulinogenic and HOMA indices. A urine sample was collected overnight for albuminuria. Individuals were allocated in two groups: 1) normal, and 2) altered glucose metabolism. RESULTS: The two groups differed in age, BMI, BP, abdominal circumference (AC), WHR, cholesterol, triglycerides (TG), glycemias (basal and 2h), AUCg, HOMA and QUICKI indices and the relation between insulinogenic and HOMA. Mean UAE was 4.28 +/- 2.73 microg/mL, correlating to DBP, glycemias, AUCg, GPV, HOMA, 2h insulin, IPV e AUCi. By stepwise multiple-regression analysis, only AUCg was predictive of UAE. By comparing interquartile intervals of UAE, we found statistical significance between the 1st and 4th quartile for: BMI, SBP, DBP, AC, waist, 2h glucose, TG, LDL, AUCg, AUCi, GPV and HOMA and QUICKI indices. CONCLUSION: Although in the absence of microalbuminuric individuals, we found differences among UAE in individuals across a range of glucose tolerance and differences between clinical and laboratorial variables in the interquartile analysis. Our findings suggest that in non-diabetic individuals, UAE is associated to some characteristics of the metabolic syndrome, probably predisposing to greater atherogenic susceptibility.

Avaliação da microalbuminúria em indivíduos não diabéticos / Evaluation of microalbuminuria in non-diabetic individuals

OBJETIVO: Avaliar a presença de microalbuminúria em indivíduos não diabéticos, associando-a à presença de fatores de risco cardiovasculares como hipertensão arterial, tabagismo, dislipidemia e obesidade. A taxa de excreção urinária de albumina (EUA) foi avaliada em relação aos índices de secreção e resistência insulínica (RI). PACIENTES E MÉTODOS: 105 indivíduos com idade de 33,4 ± 1,4 anos (57,1 por cento mulheres) foram submetidos ao TOTG com 75 g de dextrose, sendo avaliadas as curvas de glicose e insulina: valores basais e em 2h, valores de pico e áreas sob a curva (ASC). Para a avaliação da secreção e RI, utilizamos os índices: insulinogênico, delta, HOMA, QUICKI, relação glicose/insulina e relação entre os índices insulinogênico e HOMA. As amostras para avaliação da albuminúria foram colhidas overnight. Os indivíduos foram divididos em dois grupos: 1) tolerância normal à glicose e 2) alteração do metabolismo glicídico. RESULTADOS: Houve diferença entre os 2 grupos para idade, IMC, PA, cintura, RCQ, colesterol, triglicerídeos (TG), glicemias (GJ e G2h), ASCg, índices HOMA e QUICKI, e relação entre os índices insulinogênico e HOMA. A EUA foi de 4,28 ± 2,73 æg/mL, apresentando correlação com PAD, GJ, G2h, ASCg, VPG, HOMA, I2h, VPI e ASCi. Após regressão em stepwise, apenas ASCg foi preditora de EUA. Na comparação da amostra estratificada em quartis de EUA, o 1° e o 4° quartis foram estatisticamente diferentes para IMC, PAS, PAD, cintura, quadril, G2h, TG, LDL, ASCg, ASCi, VPG e índices HOMA e QUICKI. CONCLUSÃO: Embora não houvesse nenhum indivíduo com microalbuminúria, encontramos diferença entre a EUA em indivíduos com diferentes graus de tolerância à glicose e diferenças entre as variáveis clínicas e laboratoriais entre o 1° e o 4° quartis de EUA. Nossos achados sugerem que em indivíduos não diabéticos o aumento da EUA está relacionado a algumas características da síndrome metabólica, o que pode conferir uma maior suscetibilidade aterogênica.

Acute-phase proteins and microalbuminuria among patients with type 2 diabetes.

OBJECTIVE: to determine the relationship between acute-phase proteins and microalbuminuria in type 2 diabetic patients without clinical evidence of macrovascular disease. RESEARCH DESIGN AND METHODS: We studied cross-sectionally 64 non-smoking outpatients with type 2 diabetes mellitus without clinical evidence of cardiovascular disease attended at Brazilian University General Hospital aged 59.5 +/- 8.1 years and with a known duration of diabetes of 11.5 +/- 8 years. Urinary albumin excretion rate (AER) was determined in timed overnight urine samples. Serum alpha(1)-acid glycoprotein (AGP) and plasma fibrinogen were determined by immunoturbidimetry assay and serum C-reactive protein (CRP) was measured by a high-sensitive immunonephelometry assay. RESULTS: A higher levels of AGP (P = 0.0000), CRP (P= 0.003) and fibrinogen ( P = 0.0001) were found in microalbuminuric (n = 26) than in normoalbuminuric patients ( n = 38). All the acute-phase proteins were correlated with each other and with AER, respectively (r = 0.67 for AGP; 0.35 for fibrinogen, and 0.41 for CRP, P < 0.01 for all). Stepwise multiple regression analysis showed that AGP was independently associated with AER along with systolic blood pressure (r2 = 0.49, P = 0.000). Logistic regression analysis showed that AGP was independently related to microalbuminuria with an odds ratio (95% CI) of 1.16 ((1.08-1.24), P = 0.000). CONCLUSIONS: According to our results acute-phase proteins a known markers of chronic inflammation were associated with microalbuminuria independently of clinical cardiovascular disease. The influence of AGP on AER and microalbuminuria needs to be confirmed in prospective studies. Intervention studies are necessary to assess whether anti-inflammatory treatment would have a beneficial effect on this chronic complication of diabetes.