Insulin pump therapy vs. multiple daily injections in obese Type 2 diabetic patients

AIMS

To compare the efficacy of insulin pump treatment with multiple daily injections in the treatment of poorly controlled obese Type 2 diabetic patients already receiving two or more daily injections of insulin plus metformin.

METHODS

Forty obese Type 2 diabetic subjects (using insulin) were randomized to treatment with continuous subcutaneous infusion pump (CSII) (Minimed) or multiple daily insulin injections (MDI). At the end of the first 18-week treatment period, patients underwent a 12-week washout period during which they were treated with MDI plus metformin. They were then crossed-over to the other treatment for an 18-week follow-up period. Patients performed 4-point daily self blood-glucose monitoring (SBGM) on a regular basis and 7-point monitoring prior to visits 2, 8, 10 and 16. A subset of patients underwent continuous glucose monitoring using the Minimed(R) continuous glucose monitoring system (CGMS) at visits 2, 8, 10 and 16. A standard meal test was performed in which serum glucose was tested at fasting and once each hour for 6 h following a test meal. Glucose levels were plotted against time and the area under the curve (AUC) was calculated. HbA(1c), weight, daily insulin dose and hypoglycaemic episodes were recorded.

RESULTS

In obese Type 2 diabetic patients already treated with insulin, treatment with CSII significantly reduced HbA(1c) levels compared with treatment with MDI. An additional CSII treatment benefit was demonstrated by reduced meal-test glucose AUC. Initial reduction of daily insulin requirement observed in CSII-treated subjects during the first treatment period was attributable to a period effect and did not persist over time.

CONCLUSIONS

In the intent-to-treat analysis, CSII appeared to be superior to MDI in reducing HbA(1c) and glucose AUC values without significant change in weight or insulin dose in obese, uncontrolled, insulin-treated Type 2 diabetic subjects.

Homogeneity of the age at diagnosis in sibs with Type 2 diabetes: implications for sib-pair analysis

Homogeneity of the age at diagnosis of Type 2 diabetes was studied in 1,228 sibs in 300 unrelated families: 100 consecutive single-affected and 200 consecutive multiple-affected ones. There were 635 diabetic sibs. The mean and median age at diagnosis in all affected individuals was 50 years (range, 19-75 years). The mean age at diagnosis in the multiply affected families was 49 years (median 50); the between-sibs range of age at diagnosis within multiple-affected families was (mean and median) 17 years (range, 0-55), with 42% of these diagnosed within a 5-year age span, 66% within 10 years, and 90% within 13 years. When one parent had diabetes, it was more often the mother (79% P = 0.0023). In order to examine this apparent tendency toward homogeneity of age at diagnosis within families, with full regard for and parsimonious to right-censored data, we employed a Cox proportional-hazards survival analysis, with family as the explanatory variable. Deviance residuals resulting from that model were analyzed in a variance components, random effects model ANOVA which indicated a significant (P << 0.001) effect of family on age of diagnosis, with an intraclass correlation of 0.29. In many families the clustering of age at diagnosis appeared very tight, with single outliers, and in 20 families with the longest history, diabetes was diagnosed in 68 sibs within the span of 8 +/- 7 years, whereas 38 unaffected sibs remain free of diabetes 25 +/- 8 years later. The wide differences of the age at diagnosis between families and its intrafamilial homogeneity should be considered in planning genetic analysis of Type 2 diabetes.

In most poorly controlled glyburide-treated type 2 diabetic patients drug withdrawal causes further increase in glycemia not accompanied by changes in insulin secretion

To find out whether the secondary failure of glyburide in type 2 diabetes is complete or partial, we studied 38 patients, age (M +/- SD) 69 +/- 9 years, suffering from diabetes from 13.5 +/- 8.4 years and treated with glyburide for 5-13 years, with poor glycemic control (glycohemoglobin 10.6 +/- 2.6%). Serum glucose, insulin and C-peptide were assayed before and 1 h and 2 h after a simulated meal load (355 Cal), after which the drug was replaced with placebo for 4 weeks, and the test repeated. After glyburide withdrawal, fasting glycemia increased from 10.3 +/- 3.3 to 15.1 +/- 4.4 mmol/L (p < 0.001), but in 3/38 patients, it even decreased and in five others the changes were less than +/- 2 mmol/L. These changes negatively but only weakly correlated with initial glycemia: r = 0.4123, p < 0.010. The mean post-meal glycemia at 1 h and 2 h increased respectively by 3.3 and 5.9 mmol/L (both p < 0.001). Neither the levels of glycemia nor its changes after the glyburide withdrawal correlated with the levels of, or changes in, insulin or C-peptide. We conclude that in most but not all type-2 diabetic patients, poorly controlled with glyburide, the drug still retains some limited therapeutic effectiveness, and therefore its withdrawal causes further deterioration of control with the almost equal increases in fasting and post-meal levels of glycemia. These changes are not accompanied by decrease in insulin secretion.

Plasma neurotransmitter profile during different phases of the ovulatory cycle

The influence of the different phases of the menstrual cycle on platelet-poor plasma norepinephrine (NE) and serotonin (5HT) was examined in 17 normal volunteers. The examinations were performed consecutively during 3 phases of the ovulatory cycle: 1) follicular phase, 2) ovulation, and 3) luteal phase. This investigation was initiated after a preliminary study in 51 volunteers showed wide and consistent variations of plasma NE and 5HT during the different phases of the cycle. Since in this first group the determinations had not been performed consecutively in the same subjects, and the changes observed in the different phases of the cycle could reflect interpersonal variations, the determinations were performed consecutively in a second group, concomitantly with serum estradiol (E2) and LH measurements. The results showed a decrease in plasma 5HT from the follicular phase [144.3 +/- 69.3 nmol/L (+/- SD)] to ovulation (55.7 +/- 41.4; P less than 0.001) and a subsequent increase in the luteal phase (141.3 +/- 96.4; P less than 0.01). The nadir in plasma 5HT showed an inverse correlation with serum LH (r = -0.07). Plasma NE increased from the follicular phase (1226.5 +/- 475.1 pmol/L) to ovulation (1694.0 +/- 564.4; P = 0.027) and reached a maximum in the luteal phase (2335.0 +/- 728.2; P = 0.0034). This rise correlated positively with serum E2. In conclusion, plasma 5HT and NE vary with the different phases of the menstrual cycle. Plasma NE rises during ovulation and seems to to correlate positively with serum E2 levels. Plasma 5HT reaches a nadir during ovulation and correlates inversely with serum LH.