Comparison of morning or bedtime insulin with and without glyburide in secondary sulfonylurea failure

Insulin monotherapy versus combinations of insulin with oral hypoglycaemic agents in patients with type 2 diabetes mellitus

BACKGROUND

It is unclear whether patients with type 2 diabetes who have poor glycaemic control despite maximal oral hypoglycaemic agents (OHAs) should be commenced on insulin as monotherapy, or insulin combined with oral hypoglycaemic agents (insulin-OHA combination therapy).

OBJECTIVES

To assess the effects of insulin monotherapy versus insulin-OHA combinations therapy.

SEARCH STRATEGY

Eligible studies were identified by searching MEDLINE, EMBASE, and The Cochrane Library. Date of last search: May 2004.

SELECTION CRITERIA

Randomised controlled trials (RCTs) with 2 months minimum follow-up duration comparing insulin monotherapy (all schemes) with insulin-OHA combination therapy.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of study quality were undertaken by three reviewers in pairs.

MAIN RESULTS

Twenty RCTs (mean trial duration 10 months) including 1,811 participants, with mean age 59.8 years and mean known duration of diabetes 9.6 years. Overall, study methodological quality was low. Twenty-eight comparisons in 20 RCTs were ordered according to clinical considerations. No studies assessed diabetes-related morbidity, mortality or total mortality. From 13 studies (21 comparisons), sufficient data were extracted to calculate pooled effects on glycaemic control. Insulin-OHA combination therapy had statistically significant benefits on glycaemic control over insulin monotherapy only when the latter was applied as a once-daily injection of NPH insulin. Conversely, twice-daily insulin monotherapy (NPH or mixed insulin) provided superior glycaemic control to insulin-OHA combination therapy regimens where insulin was administered as a single morning injection. In more conventional comparisons, regimens utilising OHAs with bedtime NPH insulin provided comparable glycaemic control to insulin monotherapy (administered as twice daily, or multiple daily injections). Overall, insulin-OHA combination therapy was associated with a 43% relative reduction in total daily insulin requirement compared to insulin monotherapy. Of the 14 studies (22 comparisons) reporting hypoglycaemia, 13 demonstrated no significant difference in the frequency of symptomatic or biochemical hypoglycaemia between insulin and combination therapy regimens. No significant differences in quality of life related issues were detected. Combination therapy with bedtime NPH insulin resulted in statistically significantly less weight gain compared to insulin monotherapy, provided metformin was used +/-sulphonylurea. In all other comparisons no significant differences with respect to weight gain were detected.

REVIEWERS' CONCLUSIONS

Bedtime NPH insulin combined with oral hypoglycaemic agents provides comparable glycaemic control to insulin monotherapy and is associated with less weight gain if metformin is used.

The contribution of metformin to glycaemic control in patients with Type 2 diabetes mellitus receiving combination therapy with insulin

Combination therapy of oral hypoglycaemic agents and insulin is a therapeutic option for those who have deterioration in glycaemic control. We examined the contribution of metformin by withdrawing it from Type 2 diabetic patients who had been stabilised on combination therapy. Fifty-one subjects with Type 2 diabetes and secondary oral hypoglycaemic agent failure were studied in a randomised, open and parallel study. In the first phase of 36 weeks, subjects were stabilised on combined therapy of sulphonylureas and nocturnal insulin, with or without metformin. During the second phase, metformin was withdrawn. The primary variables for efficacy were HbA(1c), fasting plasma glucose and 3-point capillary blood glucose profiles. After stabilisation with combination therapy, those subjects on metformin used less insulin to maintain glycaemic control (13.7+/-6.8 vs. 23.0+/-9.4 U/day, P=0.001) and had lower HbA(1c) values (8.13+/-0.89 vs. 9.05+/-1.30%, P=0.003) compared with those not given metformin. Withdrawal of metformin therapy caused deterioration in HbA(1c) (P=0.001). This study confirms that metformin plays an important role in the success of the combination therapy. The rational use of metformin and sulphonylurea together with insulin will help to improve metabolic control in Type 2 diabetes patients who have secondary drug failure.

[Role and modalities of insulin treatment in type 2 diabetics]

INTRODUCTION

The natural history of type 2 diabetes mellitus is characterized by an inescapable and gradual worsening of a decrease in insulin secretion. Thus after several years of progress, less than half of type 2 diabetic patients have good glycemic control. This explains the increase in insulin prescription to type 2 diabetic patients in France in recent years. This work's objective is to take into account recent publication data to clarify the status of and adjustments in insulin therapy.

CURRENT KNOWLEDGE AND KEY POINTS

The benefit of insulin treatment-mediated glycemic control optimization on microvascular complications is now proven. However, there is still controversy concerning macrovascular complications. Hypoglycemic risk in type 2 diabetic patients is limited and the main problem with insulin treatment is weight gain. Following failure with treatment by tablets, the most suitable treatment in terms of metabolic improvement, weight gain limitation and treatment adhesion is to add an intermediate insulin injection at bedtime. The next step remains several injections a day, with metformine addition if possible.

FUTURE PROSPECTS AND PROJECTS

Therapeutic treatment in type 2 diabetes mellitus may become an earlier start of insulin therapy to preserve the remaining pancreatic insulin reserve. The role of brief and long-lasting insulin analogues, as well as inhaled insulin, which will soon be available, should be specified.

Gliclazide and bedtime insulin are more efficient than insulin alone for type 2 diabetic patients with sulfonylurea secondary failure

To determine the effects of combined therapy of gliclazide and bedtime insulin on glycemic control and C-peptide secretion, we studied 25 patients with type 2 diabetes and sulfonylurea secondary failure, aged 56.8 +/- 8.3 years, with a duration of diabetes of 10.6 +/- 6.6 years, fasting plasma glucose of 277.3 +/- 64.6 mg/dl and a body mass index of 27.4 +/- 4.8 kg/m2. Patients were submitted to three therapeutic regimens lasting 2 months each: 320 mg gliclazide (phase 1), 320 mg gliclazide and bedtime NPH insulin (phase 2), and insulin (phase 3). At the end of each period, glycemic and C-peptide curves in response to a mixed meal were determined. During combined therapy, there was a decrease in all glycemic curve values (P<0.01). Twelve patients (48%) reached fasting plasma glucose <140 mg/dl with a significant weight gain of 64.8 kg (43.1-98.8) vs 66.7 kg (42.8-101.4) (P<0.05), with no increase in C-peptide secretion or decrease in HbA1. C-Peptide glucose score (C-peptide/glucose x 100) increased from 0.9 (0.2-2.1) to 1.3 (0.2-4.7) during combined therapy (P<0.01). Despite a 50% increase in insulin doses in phase 3 (12 U (9-30) vs 18 U (11-60); P<0.01) only 3 patients who responded to combined therapy maintained fasting plasma glucose <140 mg/dl (P<0.02). A tendency to a higher absolute increase in C-peptide (0.99 (0.15-2.5) vs 0.6 (0-2.15); P = 0.08) and C-peptide incremental area (2.47 (0.22-6.2) vs 1.2 (0-3.35); P = 0.07) was observed among responders. We conclude that combined therapy resulted in a better glucose response to a mixed meal than insulin alone and should be tried in type 2 diabetic patients before starting insulin monotherapy, despite difficulties in predicting the response.

Pharmacotherapy of type 2 diabetes mellitus

OBJECTIVE

To review the drug treatments and some of the popular, nontraditional remedies now available for type 2 diabetes mellitus, as well as selected investigational agents; to describe each medication's place in the overall approach to treatment.

DATA SOURCES

English-language journals, abstracts, review articles, and newspaper accounts.

DATA SYNTHESIS

In the past five years, there has been tremendous progress in the pharmacotherapy of diabetes, particularly type 2 diabetes. Several new agents have entered the clinical arena, and many more are in the late stages of investigation leading to approval. Sulfonylureas stimulate the production and release of insulin; these drugs must be used in patients with an intact pancreas. The meglitinides are nonsulfonylurea agents that are also insulin secretagogues. Unlike the sulfonylureas, repaglinide appears to require the presence of glucose to close the adenosine triphosphate-sensitive potassium channels and induce calcium influx. Metformin reduces hepatic glucose production in some patients and increases peripheral glucose utilization, but its use is hampered by a high percentage of adverse reactions. Disaccharidase inhibitors effectively compensate for the defective early-phase insulin release by slowing the production of sugars from carbohydrates. Thiazolidinediones appear to activate peroxisome proliferator-activated receptor gamma, which is involved in the metabolism of lipids. Short-acting insulin and the role of weight-loss agents are also discussed.

CONCLUSIONS

The availability of new options for diabetes therapy provides a chance for successful therapy in a larger number of patients. However, it is important to consider how much true benefit these new forms of treatment will have on the diabetic community. The best choice for a patient remains controversial.

Insulin lispro in the treatment of patients with type 2 diabetes mellitus after oral agent failure

This study assessed the safety profile and efficacy of a new combination therapy (insulin lispro plus sulfonylurea) in patients with type 2 diabetes mellitus experiencing secondary oral agent failure. A total of 423 patients were randomly assigned to 3 treatment groups: preprandial insulin lispro plus sulfonylurea (L + S), bedtime neutral protamine Hagedorn (NPH) insulin plus sulfonylurea (N + S), and preprandial insulin lispro plus bedtime NPH insulin (L + N). Mean decreases in glycosylated hemoglobin from baseline were 1.60%+/-1.27% for patients receiving L + S, 1.21%+/-1.21% for those receiving N + S, and 1.40%+/-1.46% for those receiving L + N (within treatment, P<0.001; for L + S vs. N + S, P = 0.003). Fasting blood glucose level was higher in patients receiving L + S (171+/-46.5 mg/dL) or L + N (166+/-52.5 mg/dL) than in those receiving N + S (144+/-48.2 mg/dL) (P<0.001, for both comparisons). Conversely, postprandial blood glucose level was lower in patients receiving L + S (165+/-41.6 mg/dL) or L + N (165+/-46.3 mg/dL) than in those receiving N + S (213+/-58.3 mg/dL) (P<0.001, for both comparisons). The overall rate of hypoglycemia (episodes per 30 days) was not statistically significant when the L + S, N + S, and L + N therapies were compared (0.99+/-1.74 vs. 0.87+/-2.31 vs. 1.16+/-2.38, respectively). The rate of nocturnal hypoglycemia was lowest in the L + S group (0.00+/-0.00 vs. 0.10+/-0.37 for the N + S group vs. 0.15+/-0.54 for the L + N group; P = 0.004). L + S, which has a safety profile equal to those of N + S and L + N, is an effective treatment for patients with type 2 diabetes who experience oral sulfonylurea agent failure. L + S offers an alternative to these established combination therapies in patients whose type 2 diabetes cannot be controlled with a sulfonylurea alone.

Efficacy of combination therapy in non-insulin dependent diabetes mellitus

Secondary failure of oral hypoglycaemic agents raises the dilemma of whether to institute therapy with insulin alone, or in combination. We reviewed our experience of combination therapy following secondary failure of oral hypoglycaemic therapy. Seventeen subjects were receiving combination therapy for 6 months or more. Such treatment was associated with a significant fall in HbA1C--from 10.7 +/- 0.38 per cent to 8.3 +/- 0.35 per cent (p < 0.01) after 6 months and remained significantly reduced at 12 months (8.7 +/- 0.34 per cent (p < 0.01)). Mean body weight, systolic and diastolic blood pressure were unchanged during treatment with adjuvant insulin therapy. Insulin therapy is a useful adjunct in the daily management of subjects with NIDDM who experience secondary failure of oral hypoglycaemic agents.

Screening, prevention, counseling, and treatment for the complications of type II diabetes mellitus. Putting evidence into practice

PURPOSE

To summarise current knowledge of interventions that should improve the care of patients with type II diabetes mellitus. Interventions lie within the realms of preventions, screening, and treatment, all of which are focused on office practice.

METHODS

Review of the literature by a multidisciplinary team involved in the care of patients with diabetes, followed by synthesis of the literature into a clinical care guideline. Literature was identified through consultation with experts and a focused MEDLINE search.

MAIN RESULTS

An algorithm-based guideline for screening and treatment of the complications of diabetes was developed. The emphasis is on prevention of atherosclerotic disease, and prevention, screening, and early treatment of microvascular disease. Implementation of these practices has the potential to significantly improve quality of life and increase life expectancy in patients with type II diabetes mellitus.

New concepts for treatment of non-insulin-dependent diabetes mellitus

Non-insulin-dependent diabetes mellitus remains a major cause of morbidity and premature mortality in our community. Although potentially amenable to control by lifestyle modification, this is difficult to achieve in practice. Additional approaches using drugs that enhance insulin secretion, suppress hepatic glucose production, and increase insulin sensitivity are available, and new agents are being developed. The thiazolidinedione drugs hold particular promise as insulin-sensitizing agents; however, at present, insulin administration is often also required. The importance of detection and treatment of risk factors for cardiovascular disease and the earlier detection and management of microvascular and infective complications remain of crucial importance. (Trends Endocrinol Metab 1997;8:187-191). (c) 1997, Elsevier Science Inc.

Problems and pitfalls of sulphonylurea therapy in older patients

The prevalence of non-insulin-dependent diabetes mellitus (type II) increases with age, so that approximately half of all known patients in English-speaking countries are over 65 years of age. There is no reason to believe that the criteria for blood glucose control should be any less stringent for elderly patients unless they have a limited life expectancy. Sulphonylurea drugs remain an effective means of achieving blood glucose control after failure of dietary therapy alone in older patients. However, changes in normal metabolism of drugs with age and the development of other pathologies in elderly patients make it important that these drugs are prescribed with care. Severe symptomatic hypoglycaemia is the most serious adverse effect of sulphonylurea drugs and this becomes progressively more likely with increasing age, depending primarily on the substantial reduction of renal function with normal aging. Other adverse effects are much less commonly of clinical importance. To minimise the risk of hypoglycaemia, it is important that patients receive closely supervised dietary management with education about their disease for at least 3 months before sulphonylurea drugs are prescribed. In elderly patients a short-acting agent with no active metabolites should be used. As patients become older, those receiving long-acting agents can be changed to short-acting agents before problems arise. If blood glucose control appears satisfactory on treatment, then symptoms of hypoglycaemia should be sought. If control is poor, then the criteria for introduction of insulin, with appropriate education, do not differ from those in younger patients.