Does insulin lispro preserve the physiological defences to hypoglycaemia during intensive insulin therapy with a conventional basal bolus regimen?

Interventions That Restore Awareness of Hypoglycemia in Adults With Type 1 Diabetes: A Systematic Review and Meta-analysis

OBJECTIVE

Impaired awareness of hypoglycemia (IAH) increases the risk of severe hypoglycemia (SH) sixfold and affects 30% of adults with type 1 diabetes (T1D). This systematic review and meta-analysis looks at the educational, technological, and pharmacological interventions aimed at restoring hypoglycemia awareness (HA) in adults with T1D.

RESEARCH DESIGN AND METHODS

We searched The Cochrane Library, MEDLINE, Embase, Science Citation Index Expanded, Social Sciences Citation Index, PsycINFO, and CINAHL from inception until 1 October 2014. Included studies described HA status at baseline. Outcome measures were SH rates, change in HA, counterregulatory hormone responses, and glycemic control.

RESULTS

Forty-three studies (18 randomized controlled trials, 25 before-and-after studies) met the inclusion criteria, comprising 27 educational, 11 technological, and 5 pharmacological interventions. Educational interventions included structured diabetes education on flexible insulin therapy, including psychotherapeutic and behavioral techniques. These were able to reduce SH and improve glycemic control, with greater benefit from the latter two techniques in improving IAH. Technological interventions (insulin pump therapy, continuous glucose monitoring, and sensor-augmented pump) reduced SH, improved glycemic control, and restored awareness when used in combination with structured education and frequent contact. Pharmacological studies included four insulin studies and one noninsulin study, but with low background SH prevalence rates.

CONCLUSIONS

This review provides evidence for the effectiveness of a stepped-care approach in the management of patients with IAH, initially with structured diabetes education in flexible insulin therapy, which may incorporate psychotherapeutic and behavioral therapies, progressing to diabetes technology, incorporating sensors and insulin pumps, in those with persisting need.

Severe hypoglycaemia in type 1 diabetes mellitus: underlying drivers and potential strategies for successful prevention

Hypoglycaemia remains an over-riding factor limiting optimal glycaemic control in type 1 diabetes. Severe hypoglycaemia is prevalent in almost half of those with long-duration diabetes and is one of the most feared diabetes-related complications. In this review, we present an overview of the increasing body of literature seeking to elucidate the underlying pathophysiology of severe hypoglycaemia and the limited evidence behind the strategies employed to prevent episodes. Drivers of severe hypoglycaemia including impaired counter-regulation, hypoglycaemia-associated autonomic failure, psychosocial and behavioural factors and neuroimaging correlates are discussed. Treatment strategies encompassing structured education, insulin analogue regimens, continuous subcutaneous insulin infusion pumps, continuous glucose sensing and beta-cell replacement therapies have been employed, yet there is little randomized controlled trial evidence demonstrating effectiveness of new technologies in reducing severe hypoglycaemia. Optimally designed interventional trials evaluating these existing technologies and using modern methods of teaching patients flexible insulin use within structured education programmes with the specific goal of preventing severe hypoglycaemia are required. Individuals at high risk need to be monitored with meticulous collection of data on awareness, as well as frequency and severity of all hypoglycaemic episodes.

Counter-regulatory hormone responses to spontaneous hypoglycaemia during treatment with insulin Aspart or human soluble insulin: a double-blinded randomized cross-over study

AIMS

To compare insulin Aspart and human insulin with respect to glycaemic control, hypoglycaemic frequency and counter-regulatory responses to spontaneous hypoglycaemia.

METHODS

Glycaemic control, hypoglycaemic frequency, p-insulin concentrations, insulin dosages and patients' satisfaction were examined in a randomized, double-blinded cross-over study for two periods of 8 weeks. Sixteen patients with type 1 diabetes were subjected to three daily injections of human soluble insulin or Aspart in addition to Neutral Protamine Hagedorn (NPH) insulin twice daily. Each intervention period was followed by hospitalization where episodes of spontaneous hypoglycaemia and counter-regulatory hormone responses were evaluated from frequently obtained blood samples.

RESULTS

No difference between soluble insulin and insulin Aspart was found regarding HbA1c (7.0 ± 0.2 vs. 7.0 ± 0.2%, ns), hypoglycaemic frequency (1.1 ± 0.2 vs. 0.9 ± 0.1 events per patient per week, ns), nocturnal hypoglycaemia, severe hypoglycaemic events, dosages of bolus insulin (31.8 ± 0.4 vs. 30.0 ± 0.6 IU day(-1), ns), or NPH insulin (26.7 ± 1.8 vs. 26.0 ± 1.7 IU day(-1) , ns) or in patients satisfaction (ns). Modest differences existed in the counter-regulatory responses regarding growth hormone, glucagon and ghrelin whereas no differences were found in relation to free fatty acid, cortisol, insulin-like growth factor (IGF)-I, IGF-II and IGF-binding proteins 1 and 2. Treatment with insulin Aspart resulted in well-defined peaks in serum insulin concentrations as compared with more blunted insulin peaks using human soluble insulin.

CONCLUSION

Although insulin Aspart treatment was associated with clear postprandial insulin peaks, no improvement in glycaemic control was obtained and no difference in the hypoglycaemic frequency was observed. However, insulin Aspart elicited a slightly different physiological response to spontaneous hypoglycaemia compared with human insulin.

Insulin detemir causes increased symptom awareness during hypoglycaemia compared to human insulin

AIM

The long-acting insulin analogue detemir (Levemir) has structural and physicochemical properties which differ from human insulin. The aim of the present study was to test whether this leads to altered hormone and symptom response during hypoglycaemia.

METHODS

12 healthy subjects [6f/6m, age 32 +/- 6 years (mean +/- s.d.), body mass index (BMI) 24.2 +/- 2.5 kg/m(2)] underwent a 200-min stepwise hypoglycaemic clamp (45 min steps of 4.4, 3.7, 3.0 and 2.3 mmol/l) with either detemir or human insulin in random order. A bolus of detemir (660 mU/kg) or human insulin (60 mU/kg) was given before insulin was infused at a rate of 5 (detemir) or 2 (human insulin) mU/kg/min. Blood was drawn and a semi-quantitative symptom questionnaire was administered before and after each plateau of the hypoglycaemic clamp. Cognitive function was assessed during each step.

RESULTS

Blood glucose levels and glucose infusion rates were comparable with detemir and human insulin. The total symptom score was higher with detemir during the 3 and 2.3 mmol glucose step compared to human insulin (p = 0.048). Especially sweating was increased with detemir (p = 0.02) with an earlier and faster increase during the clamp (interaction insulin x time: p = 0.04). No significant differences between detemir and human insulin in cortisol, norepinephrine, epinephrine, glucagon, growth hormone, lactate or free fatty acid (FFA) levels during hypoglycaemia were observed, and there were no significant differences in cognitive function tests.

CONCLUSIONS

Insulin detemir increased symptom awareness during hypoglycaemia compared to human insulin in healthy individuals, whereas counter-regulatory hormone response and cognitive function were unaltered.

Angiotensin-converting enzyme activity and cognitive impairment during hypoglycaemia in healthy humans

Introduction: In type 1 diabetes increased risk of severe hypoglycaemia is associated with high angiotensin-converting enzyme (ACE) activity. We tested in healthy humans the hypothesis that this association is explained by the reduced ability of subjects with high ACE activity to maintain normal cognitive function during hypoglycaemia.

Methods: Sixteen healthy volunteers selected by either particularly high or low serum ACE activity were subjected to hypoglycaemia (plasma glucose 2.7 mmol/L). Cognitive function was assessed by choice reaction tests.

Results: Despite a similar hypoglycaemic stimulus in the two groups, only the group with high ACE activity showed significant deterioration in cognitive performance during hypoglycaemia. In the high ACE group mean reaction time (MRT) in the most complex choice reaction task was prolonged and error rate (ER) was increased in contrast to the low ACE group. The total hypoglycaemic symptom response was greater in the high ACE group than in the low ACE group (p=0.031).There were no differences in responses of counterregulatory hormones or in concentrations of substrates between the groups.

Conclusion: Healthy humans with high ACE activity are more susceptible to cognitive dysfunction and report higher symptom scores during mild hypoglycaemia than subjects with low ACE activity.

Short acting insulin analogues versus regular human insulin in patients with diabetes mellitus

BACKGROUND

Short acting insulin analogue use for diabetic patients is still controversial, as reflected in many scientific debates.

OBJECTIVES

To assess the effects of short acting insulin analogues versus regular human insulin.

SEARCH STRATEGY

The Cochrane Library (Issue 3, 2005), MEDLINE, EMBASE until September 2005.

SELECTION CRITERIA

Randomised controlled trials with an intervention duration of at least 4 weeks.

DATA COLLECTION AND ANALYSIS

Trial selection and evaluation of study quality was done independently by two reviewers.

MAIN RESULTS

Altogether 8274 participants took part in 49 randomised controlled studies. Most studies were of poor methodological quality. In patients with type 1 diabetes, the weighted mean difference (WMD) of HbA1c was -0.1% (95% CI: -0.2 to -0.1) in favour of insulin analogue, whereas in patients with type 2 diabetes the WMD was 0.0% (95% CI: -0.1 to 0.0). In subgroup analyses of different types of interventions in type 1 diabetic patients, the WMD in HbA1c was -0.2% (95% CI: -0.3 to -0.1) in favour of insulin analogue in studies using continuous subcutaneous insulin injections (CSII), whereas for conventional intensified insulin therapy (IIT) studies the WMD in HbA1c was -0.1% (95% CI: -0.1 to 0.0). The WMD of the overall mean hypoglycaemic episodes per patient per month was -0.2 (95% CI: -1.1 to 0.7) and -0.2 (95% CI: -0.5 to 0.1) for analogues in comparison to regular insulin in patients with type 1 diabetes and type 2 diabetes, respectively. For studies in type 1 diabetes patients the incidence of severe hypoglycaemia ranged from 0 to 247.3 (median 21.8) episodes per 100 person-years for insulin analogues and from 0 to 544 (median 46.1) for regular insulin, in type 2 the incidence ranged from 0 to 30.3 (median 0.3) episodes per 100 person-years for insulin analogues and from 0 to 50.4 (median 1.4) for regular insulin. No study was designed to investigate possible long term effects (e.g. mortality, diabetic complications), in particular in patients with diabetes related complications.

AUTHORS' CONCLUSIONS

Our analysis suggests only a minor benefit of short acting insulin analogues in the majority of diabetic patients treated with insulin. Until long term efficacy and safety data are available we suggest a cautious response to the vigorous promotion of insulin analogues. For safety purposes, we need a long-term follow-up of large numbers of patients and well designed studies in pregnant women to determine the safety profile for both the mother and the unborn child.

Short acting insulin analogues versus regular human insulin in patients with diabetes mellitus

BACKGROUND

In short acting insulin analogues the dissociation of hexamers is facilitated, achieving peak plasma concentrations about twice as high and within approximately half the time compared to regular human insulin. According to these properties this profile resembles the shape of non-diabetic patients more than that of regular human insulins. Despite this theoretical superiority of short acting insulin analogues over regular human insulin, the risk-benefit ratio of short acting insulin analogues in the treatment of diabetic patients is still unclear.

OBJECTIVES

To assess the effect of treatment with short acting insulin analogues versus regular human insulin.

SEARCH STRATEGY

A highly sensitive search for randomised controlled trials combined with key terms for identifying studies on short acting insulin analogues versus regular human insulin was performed using the Cochrane Library (issue 4, 2003), MEDLINE and EMBASE. Date of last search was December 2003.

SELECTION CRITERIA

We included randomised controlled trials with diabetic patients of all ages that compared short acting insulin analogues to regular human insulin. Intervention duration had to be at least 4 weeks.

DATA COLLECTION AND ANALYSIS

Trial selection as well as evaluation of study quality was done by two independent reviewers. The quality of reporting of each trial was assessed according to a modification of the quality criteria as specified by Schulz and Jadad.

MAIN RESULTS

Altogether 7933 participants took part in 42 randomised controlled studies. Most studies were of poor methodological quality. In patients with type 1 diabetes, the weighted mean difference (WMD) of HbA1c was estimated to be -0.1% (95% CI: -0.2% to -0.1%) in favour of insulin analogue, whereas in patients with type 2 diabetes the WMD was estimated to be 0.0% (95% CI: -0.1% to 0.1%). In subgroup analyses of different types of interventions in type 1 diabetic patients, the WMD in HbA1c was -0.2% (95% CI: -0.3% to -0.1%) in favour of insulin analogue in studies using continuous subcutaneous insulin injections (CSII) whereas for conventional intensified insulin therapy (IIT) studies the WMD in HbA1c was -0.1% (95% CI: -0.2% to -0.0%). The WMD of the overall mean hypoglycaemic episodes per patient per month was -0.2 (95% CI: -1.2 to 0.9) and -0.2 (95%CI: -0.5 to 0.1) for analogues in comparison to regular insulin in patients with type 1 diabetes and type 2 diabetes, respectively. For studies in type 1 diabetic patients the incidence of severe hypoglycaemia ranged from 0 to 247.3 (median 20.3) episodes per 100 person-years for insulin analogues and from 0 to 544 (median 37.2) for regular insulin, in type 2 the incidence ranged from 0 to 30.3 (median 0.6) episodes per 100 person-years for insulin analogues and from 0 to 50.4 (median 2.8) for regular insulin. No study was designed to investigate possible long term effects (e.g. mortality, diabetic complications), in particular in patients with diabetes related complications.

REVIEWERS' CONCLUSIONS

Our analysis suggests only a minor benefit of short acting insulin analogues in the majority of diabetic patients treated with insulin. Until long term efficacy and safety data are available we suggest a cautious response to the vigorous promotion of insulin analogues. Due to fears of potentially carcinogenic and proliferative effects, most studies to date have excluded patients with advanced diabetic complications. For safety purposes, we need a long-term follow-up of large numbers of patients who use short acting insulin analogues. Furthermore, we need well designed studies in pregnant women to determine the safety profile for both the mother and the unborn child.

Comparison of additional metformin or NPH insulin to mealtime insulin lispro therapy with mealtime human insulin therapy in secondary OAD failure

AIM

It has been found that non-fasting plasma glucose is a better marker of diabetic control than fasting plasma glucose in type 2 diabetes. The main aim of treatment of type 2 diabetic patients is to control plasma glucose and HbA1c levels. In this study, we aimed to assess the effects of three different insulin regimens (group I: lispro insulin + NPH insulin, group II: lispro insulin + metformin and group III: regular insulin + NPH insulin) on overall glycaemic control and metabolic parameters in type 2 diabetic patients with secondary oral anti-diabetic drug failure.

METHODS

Sixty type 2 diabetic patients with secondary OAD failure were randomly allocated into three different treatment groups equally. There were no significant differences between groups concerning age, body mass index, diabetes duration, HbA1c and serum lipid levels at the beginning of the study. During the 6-month treatment period, blood glucose levels were determined 10 times during 24 h at pre-meal, post-prandial 1 and 2 h and at bedtime.

RESULTS

Group I was found to be the most effective treatment regimen in controlling HbA1c levels (group I vs. group II, p = 0.013; group I vs. group III, p = 0.001; group II vs. group III, p > 0.05). When the comparison was made in each group, change in HbA1c was statistically significant for all groups (-3.18%, p = 0.001; -2.02%, p = 0.043 and -2.66%, p = 0.008 respectively). Group I was found to be more effective in controlling fasting and post-prandial plasma glucose levels measured at all times during the day when compared with group II and group III. In group II triglyceride levels were found to be significantly reduced, whereas other groups had no effect on lipids. No serious hypoglycaemic episodes were observed in any of the cases, whereas in group I hypoglycaemic episode rates were increased (chi2 = 8.843, p = 0.012).

CONCLUSIONS

Lispro insulin plus NPH insulin regimen is more effective in controlling both pre- and post-prandial glucose levels and HbA1c when compared to regular insulin plus NPH insulin combination. Mealtime lispro insulin plus metformin combination therapy should also be seriously considered as an effective and alternative treatment regimen. It is worthy of attention that insulin lispro plus metformin lowered triglyceride levels.

Comparison of lunch and bedtime NPH insulin plus mealtime insulin Lispro therapy with premeal regular insulin plus bedtime NPH insulin therapy in type 2 diabetes

AIM

Nonfasting plasma glucose is claimed to be a better marker of diabetic control than fasting plasma glucose in type 2 diabetes. In this study we compared the efficacy and safety profile of two different intensive insulin treatment strategies in patients with uncontrolled type 2 diabetes despite using a twice-daily insulin regimen.

METHODS

We studied 60 insulin-treated patients who had uncontrolled type 2 diabetes. The study was a 6-month, open-label, randomised, parallel clinical trial conducted in two diabetes centres. The main end-points for analysis were weekly self-monitored blood glucose readings, HbA1c levels, total daily insulin dose, weight gain and the number of hypoglycaemic episodes.

RESULTS

The breakfast 2-h, lunch 2-h and dinner 2-h postprandial glucose values and pre-dinner glucose values were significantly lower in the Lispro group than the regular insulin group. The HbA1c value at the end of the study was significantly lower in the Lispro group (7.3 +/- 0.7%) compared with the regular insulin group (7.7 +/- 0.7%; P<0.05). Mean insulin doses were similar in the treatment groups initially and at the end. There was a statistically significant increase in insulin dose in both groups from baseline to the end of the study (P<0.05). Overall hypoglycaemia rates were comparably low and similar in both groups during the study.

CONCLUSIONS

We have shown that mealtime insulin Lispro plus additional lunch and bedtime NPH insulin is superior to premeal regular insulin plus bedtime NPH insulin for overall glycaemic regulation with similar weight gain and comparable rates of hypoglycaemia.