Lack of effect of improved glycemic control on C-peptide secretion in patients without residual B-cell function

The patient's experience of diabetes and its treatment: construction of an attitude scale by a semantic differential technique

An instrument for measuring attitudes towards diabetes and self-care was constructed by a semantic differential technique. The instrument contained nine adjective pairs. Factor analysis classified these into four factors: self-esteem/autonomy, object evaluation, quality of life supporting factor and self-strength/vulnerability. The reliability coefficient of test-retest by 28 nurses/nurse tutors was 0.93. Fifty diabetic patients completed the attitude scale for testing the validity of the instrument. Male patients had a more positive attitude towards diabetes than females. Those who had had diabetes for less than 10 years were more positive than those with a longer duration of the disease. A higher degree of education, well-performed self-monitoring of blood glucose and achievement of good metabolic control were all associated with a more negative attitude towards diabetes. A group of nurses/nurse tutors who also completed the attitude scale had a more negative attitude towards diabetes than the investigated groups of patients.

Fasting plasma C-peptide, glucagon stimulated plasma C-peptide, and urinary C-peptide in relation to clinical type of diabetes

Many patients with Type 2 (non-insulin-dependent) diabetes mellitus are treated with insulin in order to control hyperglycaemia. We studied fasting plasma C-peptide, glucagon stimulated plasma C-peptide, and 24 h urinary C-peptide in relation to clinical type of diabetes in 132 insulin treated diabetic subjects. Patients were classified clinically as Type 1 (insulin-dependent) diabetic subjects in the presence of at least two of the following criteria: 1) significant ketonuria, 2) insulin treatment started within one year after diagnosis, 3) age of diagnosis less than or equal to 40 years, and 4) weight below 110% of ideal weight of the same age and sex. Eighty patients were classified as Type 1 and 52 as Type 2 diabetic subjects. A second classification of patients into 6 C-peptide classes was then performed. Class I consisted of patients without islet B-cell function. Class II-VI had preserved islet B-cell function and were separated according to the 20%, 40%, 60% and 80% C-peptide percentiles. The two classifications of patients were compared by calculating the prevalence of clinical Type 1 and Type 2 diabetes in each of the C-peptide classes. This analysis showed that patients with a fasting plasma C-peptide value less than 0.20 nmol/l, a glucagon stimulated plasma C-peptide value less than 0.32 nmol/l, and a urinary C-peptide value less than 3.1 nmol/l, or less than 0.54 nmol/mmol creatinine/24 h, or less than 5.4 nmol/24 h mainly were Type 1 diabetic patients; while patients with C-peptide levels above these values mainly were Type 2.(ABSTRACT TRUNCATED AT 250 WORDS)

The beta-cell response to glucagon and mixed meal stimulation in non-insulin dependent diabetes

The aim of this study was to evaluate the correlations of the C-peptide and insulin responses after stimulation with glucagon intravenously as well as the 24-h urinary excretion of C-peptide to the C-peptide response to a standard mixed meal in 30 patients with non-insulin dependent diabetes mellitus (NIDDM). Fasting plasma C-peptide as well as the C-peptide and insulin responses to glucagon, showed similar but only modest correlations with the C-peptide response to the meal. Urinary C-peptide showed no correlation with the C-peptide response to the meal, but correlated modestly with fasting plasma C-peptide (r = 0.55, p less than 0.01). The C-peptide and insulin responses after meal stimulation correlated modestly inversely with HbA1. In conclusion, measurement of C-peptide in fasting state, as well as measurements of C-peptide and insulin after glucagon stimulation, only modestly predict the C-peptide response to physiologic stimulation in NIDDM. Twenty-four-hour urinary C-peptide excretion does not predict this response. Patients with NIDDM seem to show a better metabolic control if they have a more pronounced beta-cell response to physiologic stimulation.