Modern management of insulin-dependent diabetes mellitus

Research navigating the course of clinical practice in diabetes

Three of the four largest and, arguably, most important long-term clinical trials focusing on diabetes in the past 2 decades have had medical nutrition therapy (MNT) as a major element of their experimental therapies: the Diabetes Control and Complications Trial and its follow-up study the Epidemiology of Diabetes Interventions and Complications Study, the Diabetes Prevention Program, and the Look AHEAD (Action for Health in Diabetes) study. The important features of these studies, their major results, and implications for current and future practice of MNT in the prevention and treatment of diabetes are delineated. The evidence suggests that dietetics professionals have an increasingly important role in the early initiation of MNT in the treatment and prevention of diabetes and in establishing the long-term relationships required to shape behavior and sustain the lifestyle habits that translate into significant reductions in the incidence of diabetes-related health outcomes and improved cost-effectiveness over time.

US public health and the 21st century: diabetes mellitus

No one can question the remarkable contribution of US public health to understanding the causes and consequences of illness, disability, and death. However, some commentators question the agenda: the endless pursuit of individual risk factors and the cursory attention to social determinants of disease. We attempt to illustrate some limitations of US public health by focusing on type-2 diabetes (adult-onset non-insulin-dependent diabetes)--an increasingly prevalent but still poorly understood medical condition with devastating complications and implications for quality of life. A more theoretically based multilevel approach to diabetes, outlined for the 21st century, has an almost exclusive downstream curative focus, that ranges from midstream preventive programmes to upstream healthy public policy.

Postprandial insulin profiles with implantable pump therapy may explain decreased frequency of severe hypoglycemia, compared with intensive subcutaneous regimens, in insulin-dependent diabetes mellitus patients

PURPOSE

To examine the mechanism of the decreased frequency of severe hypoglycemia with implantable pump therapy compared with subcutaneous intensive therapy.

PATIENTS AND METHODS

Eight subjects with insulin-dependent diabetes mellitus (IDDM), enrolled in an implantable insulin pump study, were admitted to the General Clinical Research Center and on 2 separate days were given either a dose of preprandial insulin chosen to maintain normoglycemia for a standard (450 kcal, 50% carbohydrate) breakfast or 1.75 times the dose. The two doses were administered subcutaneously (by syringe or with an external pump) during one inpatient admission and by implantable pump (intraperitoneally, n=6; or intravenously, n=2) during a separate admission. Blood glucose, plasma-free insulin, and neurocognitive function were measured for 4 hours after the meal.

RESULTS

Subcutaneous administration resulted in 7 episodes of hypoglycemia (2 with the usual dose and 5 with the 1.75-fold dose), defined as blood glucose less than 50 mg/dL; implantable pump treatment resulted in only 2 episodes, both with the 1.75-fold dose (P <0.05, Fisher's two-tailed test for implantable versus subcutaneous). Compared with subcutaneous delivery, implantable pump therapy provided significantly lower insulin levels during the final 2 hours after administration of the usual dose and the 1.75-fold dose (P <0.005). In addition to the decreased frequency of hypoglycemia, implantable pump therapy resulted in significantly lower area under the glycemia curve during the first 120 minutes with the 1.75-fold dose compared with subcutaneous administration.

CONCLUSIONS

The lower frequency of severe hypoglycemia with intensive therapy administered by implantable pump therapy is explained by the more rapid clearance of insulin delivered intraperitoneally or intravenously compared with intensive subcutaneous injection regimens. The lower frequency of severe hypoglycemia with implantable pump therapy compared with subcutaneous therapy demonstrated in clinical trials is confirmed by this study, in which we attempted to induce hypoglycemia.

Relationship between prorenin, IGF-I, IGF-binding proteins and retinopathy in diabetic patients

Plasma prorenin and renin, serum insulin-like growth factor I (IGF-I) and IGF-binding protein (IGFBP-2 and IGFBP-3) concentrations were measured in 22 randomly selected male and female patients with insulin-dependent diabetes mellitus (IDDM) or non-IDDM (NIDDM). Plasma prorenin concentration was significantly elevated in patients with proliferative retinopathy (1869.5 +/- 785.0 mUL-1, mean +/- SEM) compared to patients with nonproliferative retinopathy (325.5 +/- 73.2 mUL-1, P < 0.003) and those without retinopathy (318.6 +/- 47.3 mUL-1, P < 0.007). Similarly, serum insulin-like growth factor-I (IGF-I) concentration in patients with proliferative retinopathy (126.3 +/- 21.5 micrograms L-1) was significantly higher than in patients with nonproliferative retinopathy (126.3 +/- 14.85 micrograms L-1, P < 0.004) and without retinopathy (135.2 +/- 37.26, P < 0.05). There was moderately strong positive correlation between plasma prorenin and serum IGF-I concentrations (r = 0.56, P < 0.01). Plasma prorenin concentration was uninfluenced by change in renal function (creatinine clearance, serum creatinine or BUN), but IGF-I levels were inversely related to creatinine clearance (r = 0.67, P < 0.002). There was no demonstrable relationship between IGF-binding proteins and prorenin or renin concentrations. In view of some overlap between plasma prorenin and serum IGF-I concentrations in diabetic patients with proliferative and nonproliferative retinopathy, measurement of both markers may be more useful in predicting the development of proliferative retinopathy in patients with diabetes mellitus than either measurement alone.

Glycemic control in diabetes mellitus: have changes in therapy made a difference?

PURPOSE

New methods of measuring and controlling glycemia in diabetes mellitus have been developed and implemented in the past 10 years. We examined whether glycemia, as measured by glycosylated hemoglobin, changed in outpatient insulin-dependent diabetes mellitus (IDDM) and noninsulin-dependent diabetes mellitus (NIDDM) populations between 1985 and 1993 and whether contemporaneous changes in therapy could account for observed changes in glycemia.

PATIENTS AND METHODS

Outpatients were selected based on having glycated hemoglobin (HbA1c) measured in the Massachusetts General Hospital laboratory during March 1985 (IDDM n = 94 and NIDDM n = 137) or during March 1993 (IDDM n = 89 and NIDDM n = 118). Chart reviews established demographic and clinical characteristics, including frequency of blood glucose self-monitoring, insulin injections, office visits, and HbA1c measurements during the year prior to the HbA1c result.

RESULTS

Mean HbA1c level was significantly lower in the 1993 IDDM cohort compared with the 1985 cohort (8.77% +/- 1.7% versus 9.47% +/- 2.1%, P = 0.014). In the NIDDM cohorts, the difference in mean HbA1c did not achieve statistical significance (8.35% +/- 1.6% in 1993 versus 8.75% +/- 2.1% in 1985, P = 0.09); however, when adjusted for differences in NIDDM duration, HbA1c in the 1993 cohort was significantly lower than that in the 1985 cohort. The largest decrease in HbA1c in NIDDM was in patients treated with insulin (9.53% +/- 2.0% versus 8.54% +/- 1.5% in 1985 and 1993, respectively, P = 0.004). Multiple linear regression analyses demonstrated that increased frequency of self-monitoring and of insulin injections were associated with lower HbA1c in IDDM.

CONCLUSIONS

The level of average glycemia has decreased in IDDM patients over the past 8 years, attributable, at least in part, to an increased frequency of monitoring and of insulin injections. Glycemia decreased in NIDDM, especially in the subset of patients treated with insulin. This temporal shift in glycemic control should have a salutary effect on the development of long-term microvascular and neurologic complications.

Nutrition interventions for intensive therapy in the Diabetes Control and Complications Trial. The DCCT Research Group

As part of an intensive treatment regimen that had as its goal achieving and maintaining blood glucose levels in the normal range in individuals with insulin-dependent diabetes mellitus, dietitians in the Diabetes Control and Complications Trial implemented varying nutrition intervention strategies to counsel patients to attain normoglycemia. Dietary management encompassed recommendations on altering insulin dosages for varying food intake. Nutrition intervention was tailored to best meet a participant's life-style, motivation, ability to grasp information, diet history, and specific intensive insulin therapy. Dietitians were integral participants in the team management of individuals in the intensive treatment group. Selected nutrition interventions--Healthy Food Choices, exchange systems, carbohydrate counting, and total available glucose--and behavior management approaches were coupled with intensive insulin therapy. Case presentations illustrate each nutrition intervention in the attainment of normoglycemia.

Inappropriate use of high-dose glyburide to treat uncontrolled type 2 diabetes mellitus

OBJECTIVE

To report a case of chronic glyburide overdose.

CASE SUMMARY

A patient with noninsulin-dependent diabetes mellitus (NIDDM) who had previously developed secondary failure while taking a maximal dosage of glipizide was switched to glyburide 5 mg/d. The patient initially experienced adequate glycemic control while taking glyburide, but subsequently experienced deterioration in glycemic control. This necessitated gradual increases in the dosage of glyburide until the maximum dosage of 20 mg/d was reached. Because the patient's diabetic control did not improve with this dosage of glyburide, she decided independently to increase the dosage further. She ingested an average daily dose of 37.7 mg of glyburide over the 18 days that preceded her clinic visit without experiencing any glyburide-related adverse effects.

DISCUSSION

Progression of NIDDM may be responsible for the development of secondary sulfonylurea failure in NIDDM patients treated with oral sulfonylurea drugs. Consequently, these patients should be treated as patients dependent on insulin.

CONCLUSIONS

NIDDM patients treated with oral sulfonylurea drugs require long-term blood glucose monitoring to detect the development of secondary sulfonylurea failure. Patients who experience secondary failure to a particular sulfonylurea drug do not appear to develop long-term blood glucose control when switched to a different oral sulfonylurea drug. These patients should be treated with insulin therapy.

The use of multiple insulin injection therapy using 'NovoPen' in a routine out-patient setting

Multiple injection therapy using self-contained cartridge devices such as NovoPen has become a standard option for the treatment of insulin-requiring diabetes in recent years. Such treatment was previously viewed as impractical by the majority of patients and their physicians. Many small pilot studies have suggested that the use of such therapy leads to improvements in glycaemic control. We have many (greater than 200) patients in our clinic who use this form of treatment in the context of a routine out-patient department, where intensive supervision, which characterises all studies involving small numbers, is not practical. We have carried out a questionnaire survey of these patients to ascertain their attitudes to this form of therapy, and made some assessment of its impact on glycaemic control. Multiple injection therapy is a very popular form of therapy, leading to improvements in lifestyle and reduction in frequency of hypoglycaemic symptoms. However, its lack of impact on glycaemic control as estimated by measurement of haemoglobin A1 is disappointing.