RELATIONSHIPS OF C-PEPTIDE LEVELS AND THE C-PEPTIDE BLOODSUGAR RATIO WITH CLINICAL/BIOCHEMICAL VARIABLES ASSOCIATED WITH INSULIN-RESISTANCEIN ORALLY-TREATED, WELL-CONTROLLED TYPE-2 DIABETIC-PATIENTS/

The aim of the present study was to evaluate the relationship of C-pep tide and the C-peptide/bloodsugar ratio with clinical/biochemical vari ables presenting a well-known association with insulin resistance in N IDDM patients in acceptable control, obtained without the use of exoge nous insulin. A total of 118 non insulin dependent diabetes mellitus ( NIDDM) patients treated with diet/oral drugs and having a HbA(1c) leve l <7.5% have been studied. Non-stimulated C-peptide levels (RIA) and t he C-peptide/bloodsugar ratio have been determined and their relation ships with the blood pressure status, blood pressure figures, estimate s of adiposity, age, known duration of diabetes, current therapies, pl asma lipids, glycaemic control, urinary albumin excretion rate, uric a cid and creatinine have been ascertained. C-peptide levels were signif icantly (P < 0.05) correlated with systolic (r = 0.21) and diastolic b lood pressure (r = 0.19), BMI (r = 0.21), high density lipoprotein (HD L) (r = -0.22), non-HDL-cholesterol (r = 0.23), apolipoprotein B (r = 0.29), log of triglycerides (r = 0.39) and uric acid (r = 0.35). The C -peptide/bloodsugar ratio had statistically significant correlations w ith known duration of diabetes (r = -0.23), diastolic blood pressure ( r = 0.21), body mass index (BMI) (r = 0.22), log of triglycerides (r = 0.23) and uric acid (r = 0.36). Hypertensives had higher C-peptide le vels than normotensives (1.04 +/- 0.04 versus 0.88 +/- 0.04 nmol/ml, r espectively (mean +/- S.E.), P < 0.05) and this statistically signific ant difference remained after adjustment for age and known duration of diabetes. In well-controlled NIDDM patients not receiving exogenous i nsulin, both C-peptide levels and the C-peptide/bloodsugar ratio have statistically significant relationships with clinical/biochemical vari ables presenting a well-known association with insulin resistance. (C) 1997 Elsevier Science Ireland Ltd.