Appropriate insulin regimes for type 2 diabetes: a multicenter randomized crossover study

Review: Diabetes and insulin therapy in older people

Concerns about hypoglycaemia, plus lack of evidence of benefit, contributed to underutilisation of insulin for older people with type 2 diabetes in the past. Following the UKPDS it is clear that many elderly patients treated with diet and oral antidiabetic agents will develop beta-cell failure and will be at risk of worsening glycaemic control with reduced well-being unless insulin is considered. Following diabetes diagnosis, the mainstay of treatment will be dietary control and exercise together with management of cardiovascular risk factors. When glycaemic control deteriorates oral agents will be needed. However, whereas in the past insulin was seen as a last resort for older type 2 patients there is support for considering its early use in selected older people with preserved cognitive function and poor glycaemic control, as well as for frail older people with weight loss and poor quality of life. The regimens of choice may include a combination of basal insulin with oral agents or twice-daily combinations of premixed short and intermediate acting insulin. The development of insulin analogues with their associated reduced risk of hypoglycaemia may also herald a new era of insulin treatment for older people.

Review of Insulin Therapy

The objective of this article is to review the different types of insulin and to explain some of the different dosing regimens that are used. Articles were obtained via a MEDLINE search and product package inserts. There is no one insulin therapy that is best for all patients. Type 1 diabetes patients require insulin therapy tomaintain life. Studies support intensive insulin dosing in these patients to obtain an A1C of less than 7.0%. Insulin therapy for type 2 diabetes patients may be a little less clear. Long-acting insulin in combination with an oral agentmay be just as effective as insulin alone, and in patients who fail oral therapy, a simple insulin regimen is preferred over a complex one.

Differences between long-acting insulins for the treatment of type 2 diabetes

IMPORTANCE OF THE FIELD

Most guidelines suggest that failure of oral antidiabetic drugs should be followed by the addition of a basal insulin with aggressive titration of the dose. In most countries, neutral protamine Hagedorn (NPH)-insulin, glargine and detemir are the only choices. Clinical trials show that the metabolism and metabolic outcomes after treatment with intermediate- or long-acting insulins differ little. Despite this, the hypoglycaemic potential, effect on body weight and adherence to insulin treatment may affect the choice of basal insulin. Adherence seems to be negatively correlated to the prescribed dose and the number of injections. Furthermore, the choice of basal insulin might be influenced by the number of units necessary to achieve the goal for HbA1c.

AREAS COVERED IN THIS REVIEW

By searching the literature systematically, we identified all randomised clinical trials comparing long-acting insulins (human NPH-insulin and the analogues glargine and detemir) for the treatment of type 2 diabetes conducted over the last 10 years. We continued by reviewing only studies in which similar antihyperglycaemic potential of the treatments was achieved.

WHAT THE READER WILL GAIN

According to the inclusion criteria for this review, all drugs were efficacious regarding the main purpose of decreasing glycaemia. For an equal efficacy, we were able to detect other differences between the treatments and, furthermore, an estimate on the number of units of insulin needed to achieve comparable glycaemic control.

TAKE HOME MESSAGE

The analysis confirmed a favourable profile of both analogues regarding hypoglycaemia. For detemir, we additionally identified a favourable profile regarding weight gain and need for an increased number of units of insulin to achieve comparable glycosylated haemoglobin (HbA1c) responses. We conclude that the efficacy of insulin treatment seems to vary little between the available products, however doses needed to achieve similar effects vary; units used per HbA1c reduction could be a relevant parameter for the choice of insulin.

Insulin therapy in type 2 diabetes: what is the evidence?

AIM

To systematically review the literature regarding insulin use in patients with type 2 diabetes mellitus

METHODS

A Medline and Embase search was performed to identify randomized controlled trials (RCT) published in English between 1 January 2000 and 1 April 2008, involving insulin therapy in adults with type 2 diabetes mellitus. The RCTs must comprise at least glycaemic control (glycosylated haemoglobin (HbA1c), postprandial plasma glucose and /or fasting blood glucose (FBG)) and hypoglycaemic events as outcome measurements.

RESULTS

The Pubmed search resulted in 943 hits; the Embase search gave 692 hits. A total of 116 RCTs were selected by title or abstract. Eventually 78 trials met the inclusion criteria. The studies were very diverse and of different quality. They comprised all possible insulin regimens with and without combination with oral medication. Continuing metformin and/or sulphonylurea after start of therapy with basal long-acting insulin results in better glycaemic control with less insulin requirements, less weight gain and less hypoglycaemic events. Long-acting insulin analogues in combination with oral medication are associated with similar glycaemic control but fewer hypoglycaemic episodes compared with NPH insulin. Most of the trials demonstrated better glycaemic control with premix insulin therapy than with a long-acting insulin once daily, but premix insulin causes more hypoglycaemic episodes. Analogue premix provides similar HbA1c, but lower postprandial glucose levels compared with human premix, without increase in hypoglycaemic events or weight gain. Drawing conclusions from the limited number of studies concerning basal-bolus regimen seems not possible. Some studies showed that rapid-acting insulin analogues frequently result in a better HbA1c or postprandial glucose without increase of hypoglycaemia than regular human insulin.

CONCLUSION

A once-daily basal insulin regimen added to oral medication is an ideal starting point. All next steps, from one to two or even more injections per day should be taken very carefully and in thorough deliberation with the patient, who has to comply with such a regimen for many years.

Treatment satisfaction and quality of life using an early insulinization strategy with insulin glargine compared to an adjusted oral therapy in the management of Type 2 diabetes: the Canadian INSIGHT Study

The objective was to compare the impact on treatment satisfaction (TS) and quality of life (QoL) of early insulinization with glargine versus adjusting oral antidiabetic drug (OAD) therapy in people with Type 2 diabetes with uncontrolled glycemia. TS and QoL were assessed at baseline, weeks 12 and 24 within the Canadian INSIGHT, a randomized 24-week trial of Type 2 patients. A total of 366 patients randomized to either the insulin glargine arm (n=182) or the adjusted OAD therapy arm (n=184) completed both questionnaires. At baseline, TS and QoL were similar in both groups. A1c reduction was greater in the insulin glargine arm. TS improved from baseline in both treatment arms; however, there was greater increase with insulin glargine+OAD. Perceived frequency of hypoglycemia and hypoglycemia were lower at week 24, with no differences between the two groups. Perceived frequency of hyperglycemia improved with glargine at week 12, and no difference was found at 24 weeks. Finally, QoL improved in both groups, but significantly more with glargine at both weeks 12 and 24. Improving glucose control by adding insulin glargine to OAD therapy had a positive impact on TS and general QoL without complaints related to hypoglycemia.

Why and how to use insulin therapy earlier in the management of type 2 diabetes

Most patients with type 2 diabetes are inadequately controlled on their current therapy. Suboptimal glycemic control can have devastating consequences, such as retinopathy, nephropathy, neuropathy, and cardiovascular disease that may ultimately lead to mortality. Most patients eventually need insulin therapy, and initiating insulin earlier in the course of type 2 diabetes may lead to optimal glycemic control and prevent or delay diabetes-related complications. Although insulin therapy is the most effective method of managing hyperglycemia, it is often delayed owing to concerns about the complexity and inconvenience of treatment regimens; fear of injections, hypoglycemia or weight gain; and the time required to learn how to effectively manage insulin therapy. The development of insulin analogs, biphasic insulin analogs, and more convenient insulin delivery systems may make insulin therapy more manageable and help more patients achieve their treatment goals.

An open, randomized, parallel-group study to compare the efficacy and safety profile of inhaled human insulin (Exubera) with glibenclamide as adjunctive therapy in patients with type 2 diabetes poorly controlled on metformin

OBJECTIVE

To compare the efficacy and safety profile of adding inhaled human insulin (INH) (Exubera) or glibenclamide to metformin monotherapy in patients with poorly controlled type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted an open-label, parallel, 24-week multicenter trial. Patients uncontrolled on metformin were randomized to adjunctive INH (n = 243) or glibenclamide (n = 233). Before randomization, patients were divided into two HbA(1c) (A1C) arms: > or =8 to < or =9.5% (moderately high) and >9.5 to < or =12% (very high). The primary efficacy end point was A1C change from baseline.

RESULTS

Mean adjusted A1C changes from baseline were -2.03 and -1.88% in the INH and glibenclamide groups, respectively; between-treatment difference -0.17% (95% CI -0.34 to 0.01; P = 0.058), consistent with the noninferiority criterion. In the A1C >9.5% arm, inhaled insulin demonstrated a significantly greater reduction in A1C than glibenclamide, between-treatment difference -0.37% (-0.62 to -0.12; P = 0.004). In the A1C < or =9.5% arm, between-treatment difference was 0.04% (-0.19 to 0.27; P = 0.733). Hypoglycemia (events per subject-month) was greater with INH (0.18) than glibenclamide (0.08), risk ratio 2.24 (1.58-3.16), but there were no associated discontinuations. Other adverse events, except increased cough in the INH group, were similar. At week 24, changes from baseline in pulmonary function parameters were small. Insulin antibody binding increased more with INH but did not have any associated clinical manifestations.

CONCLUSIONS

In patients with type 2 diabetes poorly controlled on metformin, adding INH or glibenclamide was similarly effective in improving glycemic control, and both were well tolerated. A predefined subgroup with very high A1C (>9.5%) was more effectively treated with the addition of INH.

A Comparison of Bedtime Insulin Glargine with Bedtime Neutral Protamine Hagedorn Insulin in Patients with Type 2 Diabetes: Subgroup Analysis of Patients Taking Once-Daily Insulin in a Multicenter, Randomized, Parallel Group Study

BACKGROUND

Basal insulin is frequently administered once daily. This subgroup analysis of a multicenter, randomized, parallel study compared insulin glargine (Lantus Aventis Pharmaceuticals, Bridgewater, NJ) with neutral protamine Hagedorn (NPH) insulin in patients with type 2 diabetes, evaluating only patients treated previously with once-daily NPH insulin.

METHODS

Patients received bedtime insulin glargine or NPH insulin, with preprandial regular insulin. One hundred patients (mean age, 57.9 years; mean glycohemoglobin, 8.4%; mean fasting blood glucose, 167 mg/dL) were treated for up to 28 weeks.

RESULTS

Patients treated with insulin glargine (n = 52) and NPH insulin (n = 48) achieved similar reductions from baseline in glycohemoglobin (-0.41% versus -0.46%) and fasting blood glucose (-22 mg/dL versus -22 mg/dL) at week 28. The proportion of patients reaching target fasting blood glucose (<120 mg/dL) at 28 weeks was 34.2% with insulin glargine and 24.4% with NPH insulin. Similar proportions of patients achieved glycohemoglobin less than 7% and less than 8% in both groups. Baseline and week-28 mean daily doses of insulin glargine (27.3 IU versus 36.4 IU) were similar to NPH insulin doses (25.5 IU versus 30.2 IU). However, significantly fewer patients reported one or more episodes of hypoglycemia with insulin glargine (46.2%) versus NPH insulin (60.4%; P < 0.05). Significantly fewer patients also reported one or more symptomatic episodes confirmed by blood glucose less than 50 mg/dL with insulin glargine (17.3%) versus NPH insulin (31.3%; P < 0.005).

CONCLUSION

Bedtime insulin glargine is as effective as bedtime NPH insulin in improving glycemic control, with significantly less hypoglycemia.

A direct efficacy and safety comparison of insulin aspart, human soluble insulin, and human premix insulin (70/30) in patients with type 2 diabetes

OBJECTIVE

Because there are limited data on the comparison of insulin aspart and mixed insulin in type 2 diabetes, this trial was performed to compare the efficacy and safety of preprandial insulin aspart with human soluble insulin (HI) and human premix (70% NPH/30% regular) insulin (MIX).

RESEARCH DESIGN AND METHODS

A total of 231 type 2 diabetic patients were randomized to insulin aspart (n = 75), HI (n = 80), or MIX (n = 76) for 3 months. Insulin aspart and HI were administered with or without bedtime NPH insulin. A total of 204 patients completed the trial according to protocol. HbA1c, 7-point blood glucose, insulin dosage, and hypoglycemic episodes were recorded. The primary end point was "change of HbA1c" from baseline to last visit. Analysis for equivalence was performed by t tests with three subtests.

RESULTS

HbA1c decreased 0.91 +/- 1.00 for insulin aspart, 0.73 +/- 0.87 for HI, and 0.65 +/- 1.10 for MIX with the following confidence intervals: insulin aspart HI (-0.21 to 0.57, P = 0.025), insulin aspart MIX (-0.17 to 0.69, P = 0.092), and HI-MIX (-0.33 to 0.48, P = 0.006). Postprandial blood glucose decreased in the insulin aspart group: 0.44 mmol/l to >1.67 mmol/l compared with HI and 1.1 mmol/l to >1.67 mmol/l compared with MIX. Preprandial insulin doses were similar in the insulin aspart and HI groups (10-14.5 U). Hypoglycemic events per month were 0.56 HI, 0.40 insulin aspart, and 0.19 MIX.

CONCLUSIONS

Statistically, insulin aspart was not equivalent to another treatment in terms of HbA1c reduction. Insulin aspart treatment resulted in improved HbA1c and postprandial blood glucose. The application of insulin aspart was safe and well tolerated.

A review of basal insulins

Tight glycaemic control (ideally, HbA1c<7%) is central to reducing the risk of long-term complications of diabetes. This approach, for both Type 1 and Type 2 diabetes, commonly involves the use of basal insulin, and must be achieved with minimal risk of hypoglycaemia (particularly nocturnal episodes). Indeed, concern around hypoglycaemia is a major barrier to achieving tight glycaemic control, and is a common problem with those protracted-acting insulins most frequently used in clinical practice for basal insulin supply. Other drawbacks include inter- and intra-patient variability that compromises dosing reproducibility and unsuitability for single daily dosing. New long-acting human insulin analogues with action profiles designed to overcome these problems are now available in clinical practice or are under evaluation in clinical trials. Clinical evidence suggests efficacy and safety advantages for these analogues over NPH insulin (the most commonly used basal insulin), and may bring closer the goal of tight glycaemic control in patients with diabetes.

Common problems in outpatient management of patients with diabetes in the age of insulin analogues

Most patients with diabetes are managed in an outpatient primary care setting. This article reviews common dilemmas in outpatient insulin therapy and presents the evidence regarding the rational use of insulin therapy and combination oral agent-insulin therapy.

Combined bedtime insulin--daytime sulphonylurea regimen compared with two different daily insulin regimens in type 2 diabetes: effects on HbA1c and hypoglycaemia rate--a randomised trial

BACKGROUND

Several efficacy studies of insulin-therapy regimens in patients with type 2 diabetes mellitus have shown varying results. Moreover, most studies did not address hypoglycaemia frequency and severity.

METHODS

In this multicentre study, we compared the glycaemic efficacy and incidence rate of hypoglycaemic episodes between 3 treatment regimens in obese type 2 diabetic patients with secondary failure to sulphonylurea and metformin. During the run-in phase, patients were treated with glimepiride and metformin. After 3 months, 261 patients with HbA(1c) values >6.5% were randomised to (A) glimepiride + Neutral Protein Hagedorn (NPH) insulin at bedtime, (B) NPH insulin twice daily and (C) 30/70 mixture of short-acting and NPH insulin twice daily. The therapeutic aim was an HbA(1c) level < or =6.5%.

RESULTS

Mean HbA(1c) achieved at 9 months was significantly higher in group A: 8.9% versus 8.3% and 8.4% in groups B and C, respectively (P < 0.001). There was no difference in the mild hypoglycaemic event rate, 0.36 versus 0.48 versus 0.53 events per patient month, in groups A, B and C, respectively. Severe hypoglycaemic events, requiring help from others, did not occur throughout the study. The mean weight gain and insulin dose were comparable in all three groups.

CONCLUSIONS

The glimepiride + NPH insulin treatment resulted in a higher HbA(1c) level, as compared to the other regimens. In the clinical setting of this multicentre study, good glycaemic control was only achieved in a minority of the patients, irrespective of the applied regimen.

Insulin improves well-being for selected elderly type 2 diabetic subjects

The effects of insulin therapy on patient well-being, treatment satisfaction and mood, and on carer strain were studied in 30 elderly Type 2 diabetic patients (age 73 +/- 7 (SD) yr) in poor glycaemic control on tablet therapy. A comparison group of ten poorly controlled patients who remained on oral agents was also studied. After 4 weeks of insulin treatment, there were significant improvements in mental health, role-emotional, role-physical (all P<0.05) and vitality (P<0.01) domains of the short form health survey (SF-36), and also in the diabetes treatment and satisfaction questionnaire (DTSQ) and geriatric depression scale (both P<0.01) compared to baseline. After 12 weeks, the improvements in mental health, social functioning and vitality (P<0.01 for all domains), and in the DTSQ were sustained. Carer strain was lower at 4 weeks. No changes in outcomes were seen in the comparison group. In selected elderly Type 2 diabetic patients, insulin treatment is associated with significant improvements in well-being, treatment satisfaction and mood, even without significant improvements in glycaemic control and without increase in carer strain. The SF-36 and DTSQ are sensitive to the benefits of the changes in the treatment for these patients.