Counterregulatory hormone responses to hypoglycemia in the elderly patient with diabetes

Association between different hemoglobin A1c levels and clinical outcomes among elderly nursing home residents with type 2 diabetes mellitus

OBJECTIVE

New guidelines recommend a target glycated hemoglobin (HbA1c) of 7.5% to 8.0% in elderly persons with type 2 diabetes mellitus (T2DM), but real-world data regarding outcomes associated with different HbA1c levels in the elderly are limited. This study assessed outcomes and their association with defined HbA1c thresholds and age ranges in insulin-treated, elderly, patients with T2DM in long-term care (LTC).

DESIGN

Retrospective analysis of medical charts and the Minimum Data Set (MDS) for the period September 2010 through September 2011.

SETTING

A total of 117 nursing homes in the United States.

PARTICIPANTS

Eligible patients had resided in LTC for 3 months or more, had at least 1 full MDS assessment, 2 or more records of insulin dispensing with no pump use, and 1 or more HbA1c measurements.

MEASUREMENTS

Outcomes that were measured included hypoglycemia, ketoacidosis, infections, falls, hospitalization, and emergency room (ER) visits.

RESULTS

A total of 583 patients were included (mean age 78.9 years, mean chart observation length 55 days). In all groups, hypoglycemia was lowest in patients with an HbA1c level higher than 9.0%. In patients 75 years or older, infection rates were highest when HbA1c levels were higher than 9.0%. Falls increased by HbA1c level in patients aged 65 to 74 years, but decreased by HbA1c levels in patients 85 years or older. Ketoacidosis, hospitalization, and ER visits were low in all groups.

CONCLUSION

These data suggest that better glycemic levels may not necessarily be associated with better clinical outcomes, and different age groups may exhibit different patterns, thereby supporting the call for individualized glycemic control among elderly patients.

Drug treatment for diabetes in nursing home residents

AIMS

The aim of this study was to describe drug treatment for diabetes in a large sample of nursing home residents and to compare subjects' health outcomes according to the anti-diabetic agents used.

METHODS

The cross-sectional data of 6275 residents [average age 86 years (± 8.2); 73.7% women] from 175 nursing homes in France were analysed. Participants were divided into one of the following four groups: diabetes non-drug treatment, diabetes hypoglycaemic (e.g. insulins, sulphonylurea) treatment, diabetes non-hypoglycaemic (e.g. metformin) treatment and no diabetes. Group comparisons were made on functional ability (activities of daily living score) and on the prevalence of the following variables (yes vs. no): emergency department visits, falls and fractures.

RESULTS

Of the participants, 1076 (17.1%) had diabetes: 222 participants in the non-drug treatment group, 722 in the hypoglycaemic group and 132 in the non-hypoglycaemic group. The remaining 5199 participants made up the group without diabetes. Insulin and metformin were used by 549 and 185 participants, respectively. Activities of daily living scores differed across the four groups, with those in the non-drug treatment group being the most disabled. Adjusted multivariate analyses showed that, compared with the group without diabetes, those in the hypoglycaemic group had a higher probability of emergency department visits (odds ratio 1.26, 95% CI 1.03-1.54) and increased the incidence rate ratios (1.02, 95% CI 1.00-1.04) of disability (activities of daily living score), whereas the non-hypoglycaemic group was not significantly associated with these outcomes.

CONCLUSIONS

The use of hypoglycaemic drugs was associated with poor health outcomes in nursing home residents. Therefore, more attention must be paid to adapting anti-diabetic treatment in this complex population.

Perioperative Glucose Control and Infection Risk in Older Surgical Patients

The aging of the U.S. population is leading to an increasing number of surgical procedures performed on older adults. At the same time, the quality of medical care is being more closely scrutinized. Surgical site infection is a widely-assessed outcome. Evidence suggests that strict perioperative serum glucose control among patients with or without diabetes can lower the risk of these infections, but it is unclear whether this control should be applied to older surgical patients. In this clinical review, we discuss current research on perioperative serum glucose management for cardiothoracic, orthopedic, and general/colorectal surgery. In addition, we summarize clinical recommendations and quality-of-care process indicators provided by surgical, diabetes, and geriatric medical organizations.

Penny wise and pound foolish: will shortsighted cost reduction measures compromise patient access to promising self-monitoring of blood glucose technology?

In this issue of Journal of Diabetes Science and Technology, Grady and coauthors enrolled 101 patients with type 1 and type 2 diabetes to evaluate new technology incorporated into the LifeScan VerioPro and VerioIQ blood glucose meters. The "pattern detection" software provides real-time, onscreen messages that alert users to patterns of high glucose (fasting and premeal) and low glucose as they are detected. The study showed that most participants possess a good understanding of the factors that can cause hyperglycemia; however, their understanding of the causes of hypoglycemia events was not as strong. Nevertheless, more than 70% of participants indicated they preferred to use a blood glucose meter that provides pattern detection capability. Although not designed to assess the impact of the pattern detection tool on clinical outcomes, the study highlights the value of continuous innovation in self-monitoring of blood glucose (SMBG) technology among manufacturers. Unfortunately, many patients may never have access to these systems due to reductions in Medicare reimbursement. Instead, they may be forced to use SMBG systems that are inaccurate and provide inadequate patient support. Stronger regulatory requirements are needed to ensure that all SMBG systems marketed to patients are accurate, reliable, and supported by adequate patient training, and current health care reimbursement policies should be restructured to encourage manufacturers to continue their efforts to develop innovative technology to further improve the utility and usability of their SMBG systems.

Hypoglycemia and diabetes: a report of a workgroup of the American Diabetes Association and the Endocrine Society

OBJECTIVE

To review the evidence about the impact of hypoglycemia on patients with diabetes that has become available since the past reviews of this subject by the American Diabetes Association and The Endocrine Society and to provide guidance about how this new information should be incorporated into clinical practice.

PARTICIPANTS

Five members of the American Diabetes Association and five members of The Endocrine Society with expertise in different aspects of hypoglycemia were invited by the Chair, who is a member of both, to participate in a planning conference call and a 2-day meeting that was also attended by staff from both organizations. Subsequent communications took place via e-mail and phone calls. The writing group consisted of those invitees who participated in the writing of the manuscript. The workgroup meeting was supported by educational grants to the American Diabetes Association from Lilly USA, LLC and Novo Nordisk and sponsorship to the American Diabetes Association from Sanofi. The sponsors had no input into the development of or content of the report.

EVIDENCE

The writing group considered data from recent clinical trials and other studies to update the prior workgroup report. Unpublished data were not used. Expert opinion was used to develop some conclusions.

CONSENSUS PROCESS

Consensus was achieved by group discussion during conference calls and face-to-face meetings, as well as by iterative revisions of the written document. The document was reviewed and approved by the American Diabetes Association's Professional Practice Committee in October 2012 and approved by the Executive Committee of the Board of Directors in November 2012 and was reviewed and approved by The Endocrine Society's Clinical Affairs Core Committee in October 2012 and by Council in November 2012.

CONCLUSIONS

The workgroup reconfirmed the previous definitions of hypoglycemia in diabetes, reviewed the implications of hypoglycemia on both short- and long-term outcomes, considered the implications of hypoglycemia on treatment outcomes, presented strategies to prevent hypoglycemia, and identified knowledge gaps that should be addressed by future research. In addition, tools for patients to report hypoglycemia at each visit and for clinicians to document counseling are provided.

Hypoglycemia and diabetes: a report of a workgroup of the American Diabetes Association and the Endocrine Society

OBJECTIVE

To review the evidence about the impact of hypoglycemia on patients with diabetes that has become available since the past reviews of this subject by the American Diabetes Association and The Endocrine Society and to provide guidance about how this new information should be incorporated into clinical practice.

PARTICIPANTS

Five members of the American Diabetes Association and five members of The Endocrine Society with expertise in different aspects of hypoglycemia were invited by the Chair, who is a member of both, to participate in a planning conference call and a 2-day meeting that was also attended by staff from both organizations. Subsequent communications took place via e-mail and phone calls. The writing group consisted of those invitees who participated in the writing of the manuscript. The workgroup meeting was supported by educational grants to the American Diabetes Association from Lilly USA, LLC and Novo Nordisk and sponsorship to the American Diabetes Association from Sanofi. The sponsors had no input into the development of or content of the report.

EVIDENCE

The writing group considered data from recent clinical trials and other studies to update the prior workgroup report. Unpublished data were not used. Expert opinion was used to develop some conclusions.

CONSENSUS PROCESS

Consensus was achieved by group discussion during conference calls and face-to-face meetings, as well as by iterative revisions of the written document. The document was reviewed and approved by the American Diabetes Association's Professional Practice Committee in October 2012 and approved by the Executive Committee of the Board of Directors in November 2012 and was reviewed and approved by The Endocrine Society's Clinical Affairs Core Committee in October 2012 and by Council in November 2012.

CONCLUSIONS

The workgroup reconfirmed the previous definitions of hypoglycemia in diabetes, reviewed the implications of hypoglycemia on both short- and long-term outcomes, considered the implications of hypoglycemia on treatment outcomes, presented strategies to prevent hypoglycemia, and identified knowledge gaps that should be addressed by future research. In addition, tools for patients to report hypoglycemia at each visit and for clinicians to document counseling are provided.

Performance variability of seven commonly used self-monitoring of blood glucose systems: clinical considerations for patients and providers

BACKGROUND

Blood glucose data are frequently used in clinical decision making, thus it is critical that self-monitoring of blood glucose (SMBG) systems consistently provide accurate results. Concerns about SMBG accuracy have prompted the development of newly proposed International Organization for Standardization (ISO) standards: ≥ 95% of individual glucose results shall fall within ± 15 mg/dl of the results of the manufacturer's reference procedure at glucose concentrations <100 mg/dl and within ± 15% for values ≥ 100 mg/dl. We evaluated seven marketed systems against the current and proposed ISO criteria (criterion A).

METHOD

Capillary blood samples were collected from 100 subjects and tested on seven systems: Accu-Chek Aviva Plus, Advocate Redi-Code, Element, Embrace, Prodigy Voice, TRUEbalance, and WaveSense Presto. Results were compared with manufacturer's documented reference system, YSI or perchloric acid hexokinase; three different strip lots from each system were tested on each subject, in duplicate.

RESULTS

Compared against current ISO criteria (≥ 95% within ± 15 mg/dl for values <75 mg/dl and ± 20% for values ≥ 75 mg/dl) the Accu-Chek Aviva Plus, Element, and WaveSense Presto systems met accuracy criteria. However, only the Accu-Chek Aviva Plus met the proposed ISO criteria (criterion A) in all three lots. The other six systems failed to meet the criteria in at least two of the three lots, showing lot-to-lot variability, high/low bias, and variations due to hematocrit.

CONCLUSIONS

Inaccurate SMBG readings can potentially adversely impact clinical decision making and outcomes. Clinicians can reduce controllable variables by prescribing accurate SMBG systems. Adherence to the proposed ISO criteria should enhance patient safety by improving the accuracy of SMBG systems.

Incidence and predictors of hypoglycaemia in type 2 diabetes - an analysis of the prospective DiaRegis registry

BACKGROUND

Hypoglycaemia is a serious adverse effect of antidiabetic drug therapy. We aimed to determine incidence rates of hypoglycaemia in type-2 diabetic patients and identify predictors of hypoglycaemia when treatment is intensified.

METHODS

DiaRegis is a prospective German registry that follows 3810 patients with type-2 diabetes referred for treatment intensification because of insufficient glycaemic control on one or two oral antidiabetic drugs.

RESULTS

Out of a total of 3347 patients with data available for the present analysis 473 (14.1%) presented any severity hypoglycaemia over a follow-up of 12 months. 0.4% were hospitalized (mean of 1.3±0.6 episodes), 0.1% needed medical assistance (1.0±0.0), 0.8% needed any help (1.1±0.5) and 10.1% no help (3.4±3.7), and 8.0% had no specific symptoms (3.6±3.5). Patients with incident hypoglycaemia had longer diabetes duration, higher HbA1c and a more frequent smoking history; more had co-morbid disease conditions such as coronary artery disease, peripheral arterial disease, amputation, heart failure, peripheral neuropathy, diabetic retinopathy and clinically relevant depression at baseline. Multivariable adjusted positive predictors of incident hypoglycaemia over the follow-up were prior anamnestic hypoglycaemia, retinopathy, depression, insulin use and blood glucose self-measurement, but not sulfonylurea use as previously reported for anamnestic or recalled hypogylcaemia. On the contrary, glitazones, DPP-4 inhibitors and GLP-1 analogues were associated with a reduced risk of hypoglycaemia.

CONCLUSIONS

Hypoglycaemia is a frequent adverse effect in ambulatory patients when antidiabetic treatment is intensified. Particular attention is warranted in patients with prior episodes of hypoglycaemia, microvascular disease such as retinopathy and in patients receiving insulin. On the other hand glitazones, DPP-4 inhibitors and GLP-1 analogues are associated with a reduced risk.

Oral antidiabetic treatment in type-2 diabetes in the elderly: balancing the need for glucose control and the risk of hypoglycemia

BACKGROUND

We aimed at identifying variables predicting hypoglycemia in elderly type 2 diabetic patients and the relation to HbA1c values achieved.

DESIGN

Prospective, observational registry in 3810 patients in primary care. Comparison of patients in different age tertiles: with an age < 60 (young, n=1,253), age 60 to < 70 (middle aged, n=1,184) to those ≥ 70 years (elderly, n=1,373). Odds Ratios (OR) with 95% confidence intervals (CI) were determined from univariable and multivariable regression analyses.

RESULTS

Elderly patients had a later diabetes diagnosis, a longer diabetes duration, better glucose control and more frequent co-morbid disease conditions. Overall 10.7% of patients experienced any severity hypoglycemia within the last 12 months prior to inclusion. Higher rates of hypoglycemia were observed in the elderly than in the young after adjusting for differences in HbA1c, fasting and post-prandial blood glucose (OR 1.68; 95%CI 1.16-2.45). This was particularly true for hypoglycemic episodes without specific symptoms (OR 1.74; 95%CI 1.05-2.89). In a multivariate model stroke / transitory ischemic attack, the presence of heart failure, clinically relevant depression, sulfonylurea use and blood glucose self-measurement were associated with hypoglycemic events.

CONCLUSION

Elderly patients are at an increased risk of hypoglycemia even at comparable glycemic control. Therefore identified variables associated with hypoglycemia in the elderly such as heart failure, clinically relevant depression, the use of sulfonylurea help to optimize the balance between glucose control and low levels of hypoglycemia. Asymptomatic hypoglycemia should not be disregarded as irrelevant but considered as a sign of possible hypoglycemia associated autonomic failure.

Insulin initiation in elderly patients with type 2 diabetes in France: a subpopulation of the LIGHT study

OBJECTIVE

To examine the management of basal insulin analogue initiation in combination with oral antidiabetic drug (OAD) therapy in elderly patients with type 2 diabetes (aged ≥70 years) by physicians via comparison to the same treatment strategy in younger individuals (<70 years).

METHODS

This subanalysis of a longitudinal observational study took place in a clinical setting across 761 health centres in France. A total of 1802 patients with type 2 diabetes (519 aged ≥70 years and 1283 aged <70 years) participated. The primary endpoint of this study was to assess the management of basal insulin analogue initiation along with OADs in elderly patients (aged ≥70 years) by physicians. Secondary endpoints included HbA(1c), percentage of patients achieving HbA(1c) target (<7.0%), fasting plasma glucose, weight change (kg) and hypoglycaemia.

RESULTS

The initial mean (standard deviation [SD]) basal insulin analogue dose was similar in the elderly and younger patient subgroups (0.18 [0.09] IU/kg vs. 0.18 [0.11] IU/kg, respectively; not significant [NS]). The mean (SD) number of injections per day was also comparable between age groups (1 [0.2] per day vs. 1 [0.3] per day, respectively for elderly and younger patients; NS). Three months after initiation of long-acting insulin analogue therapy, 3.5% (n = 18) of elderly patients ceased insulin treatment. At study end, the mean (SD) HbA(1c) for elderly patients was 7.6% (0.9%), and for younger patients it was 7.5% (0.9%). Also, the rate of overall hypoglycaemia was comparable in the elderly and younger patients (0.38 [1.2] events/patient/month vs. 0.35 [1.0] events/patient/month, respectively; NS). Limitations of this study include the possibility of inaccurate patient recall of hypoglycaemic events and deficiencies in the adverse events reporting system.

CONCLUSION

Basal insulin analogues were successfully initiated in elderly patients in combination with OAD therapies and were shown to provide effective glycaemic control. Levels of hypoglycaemia were also similar to those seen in younger patients.

Comparative effects of variations in duodenal glucose load on glycemic, insulinemic, and incretin responses in healthy young and older subjects

CONTEXT

Aging is associated with deteriorating glucose tolerance. Studies assessing glucose tolerance and subsequent insulin and incretin hormone release often fail to take into account the rate of gastric emptying when evaluating these responses.

OBJECTIVE

Our objective was to determine the comparative effects of variations in the small intestinal glucose load on the glycemic, insulinemic, and incretin responses in healthy young and older subjects.

MATERIALS AND METHODS

Twelve healthy young (six males, six females; age 22.2±2.3 yr) and 12 older (six males, six females; age 68.7±1.0 yr) subjects had measurements of blood glucose, serum insulin and plasma incretin hormones [glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP)] and calculations of insulin resistance (homeostatic model assessment) and β-cell function corrected for insulin sensitivity, before and during intraduodenal infusions of glucose at 1, 2, or 3 kcal/min or saline for 60 minutes. The study was double-blinded and randomized, and performed in the Discipline of Medicine at the Royal Adelaide Hospital.

RESULTS

At baseline, blood glucose and serum insulin were slightly higher in the older subjects (P<0.001), whereas GLP-1 and GIP were comparable between groups. In both groups, the glycemic, insulinemic, and GLP-1 responses were dependent on the duodenal glucose load in a nonlinear fashion (P<0.001). The glycemic response was greater (P<0.001) in the older subjects, whereas GLP-1 and GIP responses were comparable between groups. The older subjects were more insulin resistant (P<0.001) and had impaired β-cell function, particularly at higher glucose loads (P<0.05).

CONCLUSION

When glucose is infused into the small intestine at equal rates in healthy young and older subjects, GLP-1 and GIP responses are comparable, indicating that impaired incretin secretion does not account for age-related glucose intolerance.

Medically minimising the impact of hypoglycaemia in type 2 diabetes: a review

INTRODUCTION

Some therapies for type 2 diabetes (T2DM) are limited by hypoglycaemia, and this underestimated side effect carries an associated morbidity and financial burden. Large trials that have examined strict glycaemic control and cardiovascular outcomes in T2DM have highlighted the potential harm of exposure to hypoglycaemia in people with coronary heart disease.

AREAS COVERED

The responses to, and the morbidity associated with, hypoglycaemia in T2DM are discussed with identification of people most at risk of severe hypoglycaemia. The evidence base for non-pharmacological strategies and the risks of hypoglycaemia associated with various treatment modalities are examined. This review provides the clinician with a rational approach to the selection of different anti-diabetes drugs to minimize the risk of hypoglycaemia.

EXPERT OPINION

When managing T2DM, insulin and insulin secretagogues should be used judiciously and glycaemic targets individualized to avoid hypoglycaemia. Incretin mimetics present a lower risk of hypoglycaemia with similar efficacy as traditional agents in treating hyperglycaemia. The potential relationship between hypoglycaemia and precipitation of acute cardiovascular events is a highly topical area of research and may help determine what glycaemic targets are appropriate in people with T2DM.

Optimal glycemic control in the elderly: where is the evidence and who should be targeted?

In the near future, with the continuous increase in life expectancy observed in the population and with the aging of the baby boomers, an increase is expected in the absolute and relative number of the elderly population. With the aging phenomenon, the prevalence of a number of chronic diseases is increasing and requires interventions from different health professionals. Type 2 diabetes mellitus is a very frequent condition in the elderly and is characterized by variable degrees of hyperglycemia while ketosis is exceptional in this condition. The question of who should be offered optimal glycemic control becomes more and more pertinent as the older diabetic population grows but it has to be considered that the consequences of hypoglycemia related to the medications used to lower glycemia are not benign in the older population. Hence, the advantages and disadvantages of tight glycemic control will be reviewed in the light of recent data.

Clinical experience with vildagliptin in the management of type 2 diabetes in a patient population ≥75 years: a pooled analysis from a database of clinical trials

AIM

To report the experience with vildagliptin in a patient population with type 2 diabetes mellitus (T2DM) ≥75 years.

METHODS

Efficacy data from seven monotherapy and three add-on therapy to metformin studies, respectively, of ≥24 weeks duration were pooled; effects of 24 weeks of treatment with vildagliptin (50 mg bid) in patients ≥75 years were assessed in these two pooled datasets. Safety data were pooled from 38 studies of ≥12 to ≥104 weeks duration; adverse events (AEs) profiles of vildagliptin (50 mg bid) were evaluated relative to a pool of comparators; 301 patients ≥75 years were analysed. Data in patients <75 years are provided as a reference.

RESULTS

Mean age of the elderly population was 77 years. Changes in haemoglobin A1c (HbA1c) with vildagliptin in the patient group ≥75 years were -0.9% from a baseline of 8.3% in monotherapy (p < 0.0001) and -1.1% from a baseline of 8.5% in add-on therapy to metformin (p = 0.0004), and these reductions were similar to those seen in the younger patients. The corresponding weight changes in the elderly patients were -0.9 kg (p = 0.0277) and -0.2 kg [not significant (NS)], respectively, and no confirmed hypoglycaemic events, including no severe events, were reported. AEs, drug-related AEs, serious adverse events (SAEs) and deaths were reported with a lower frequency in older patients receiving vildagliptin than comparators [133.9 vs. 200.6, 14.5 vs. 21.8, 8.8 vs. 16.5 and 0.0 vs. 1.7 events per 100 subject year exposure (SYE), respectively], and the incidence of discontinuations due to AEs was similar in the two groups (7.2 vs. 7.5 events per 100 SYE, respectively). The safety profile of vildagliptin was overall similar in younger and older patients.

CONCLUSIONS

Vildagliptin was effective and well-tolerated in type 2 diabetic patients ≥75 years (mean age 77 years).

Exercise-related hypoglycemia in diabetes mellitus

Current recommendations are that people with Type 1 and Type 2 diabetes mellitus exercise regularly. However, in cases in which insulin or insulin secretagogues are used to manage diabetes, patients have an increased risk of developing hypoglycemia, which is amplified during and after exercise. Repeated episodes of hypoglycemia blunt autonomic nervous system, neuroendocrine and metabolic defenses (counter-regulatory responses) against subsequent episodes of falling blood glucose levels during exercise. Likewise, antecedent exercise blunts counter-regulatory responses to subsequent hypoglycemia. This can lead to a vicious cycle, by which each episode of either exercise or hypoglycemia further blunts counter-regulatory responses. Although contemporary insulin therapies cannot fully mimic physiologic changes in insulin secretion, people with diabetes have several management options to avoid hypoglycemia during and after exercise, including regularly monitoring blood glucose, reducing basal and/or bolus insulin, and consuming supplemental carbohydrates.

Neuroendocrine responses to hypoglycemia

The counterregulatory response to hypoglycemia is a complex and well-coordinated process. As blood glucose concentration declines, peripheral and central glucose sensors relay this information to central integrative centers to coordinate neuroendocrine, autonomic, and behavioral responses and avert the progression of hypoglycemia. Diabetes, both type 1 and type 2, can perturb these counterregulatory responses. Moreover, defective counterregulation in the setting of diabetes can progress to hypoglycemia unawareness. While the mechanisms that underlie the development of hypoglycemia unawareness are not completely known, possible causes include altered sensing of hypoglycemia by the brain and/or impaired coordination of responses to hypoglycemia. Further study is needed to better understand the intricacies of the counterregulatory response and the mechanisms contributing to the development of hypoglycemia unawareness.

Approach to managing hypoglycemia in elderly patients with diabetes

Hypoglycemia is a common clinical problem in elderly patients with diabetes. Aging modifies the counterregulatory and symptomatic responses to hypoglycemia. Hypoglycemia in the elderly is not only due to tight blood sugar control, but also due to a multitude of other factors. Hypoglycemia often occurs with insulin, sulfonylureas, or meglitinide therapy. However, other causes may also contribute to hypoglycemia, such as decreased cognition, renal impairment, or polypharmacy. The presenting features of hypoglycemia may be atypical and misinterpreted, resulting in delayed treatment. Morbidity is greater in elderly patients, and the risk of progression to severe hypoglycemia is high because of their altered symptom profile, diminished symptom intensity, and altered glycemic thresholds. Hypoglycemia seems to be the main limiting factor in their glycemic control. In this article we discuss strategies to prevent hypoglycemic episodes.

Hypoglycemia unawareness in older compared with middle-aged patients with type 2 diabetes

OBJECTIVE Older patients with type 2 diabetes are at a particularly high risk for severe hypoglycemic episodes, and experimental studies in healthy subjects hint at a reduced awareness of hypoglycemia in aged humans. However, subjective responses to hypoglycemia have rarely been assessed in older type 2 diabetic patients. RESEARCH DESIGN AND METHODS We tested hormonal, subjective, and cognitive responses (reaction time) to 30-min steady-state hypoglycemia at a level of 2.8 mmol/l in 13 older (> or =65 years) and 13 middle-aged (39-64 years) type 2 diabetic patients. RESULTS Hormonal counterregulatory responses to hypoglycemia did not differ between older and middle-aged patients. In contrast, middle-aged patients showed a pronounced increase in autonomic and neuroglycopenic symptom scores at the end of the hypoglycemic plateau that was not observed in older patients (both P < 0.01). Also, seven middle-aged patients, but only one older participant, correctly estimated their blood glucose concentration to be <3.3 mmol/l during hypoglycemia (P = 0.011). A profound prolongation of reaction times induced by hypoglycemia in both groups persisted even after 30 min of subsequent euglycemia. CONCLUSIONS Our data indicate marked subjective unawareness of hypoglycemia in older type 2 diabetic patients that does not depend on altered neuroendocrine counterregulation and may contribute to the increased probability of severe hypoglycemia frequently reported in these patients. The joint occurrence of hypoglycemia unawareness and deteriorated cognitive function is a critical factor to be carefully considered in the treatment of older patients.

Nateglinide, alone or in combination with metformin, is effective and well tolerated in treatment-naïve elderly patients with type 2 diabetes

AIM

The aim of this work was to assess the efficacy and tolerability of nateglinide alone or in combination with metformin in elderly patients with type 2 diabetes (T2DM).

METHODS

Study 1 was a 12-week, multicentre, randomized, double blind and placebo-controlled study of nateglinide monotherapy (120 mg, before meals) in 66 drug-naïve patients with T2DM aged >or=65 years. Study 2 was a 104-week, multicentre, randomized, double blind and active-controlled study of nateglinide (120 mg, before meals) or glyburide (up to 5 mg bid) in combination with metformin (up to 1000 mg bid) in 69 treatment-naïve patients with T2DM aged >or=65 years. HbA(1c), fasting and postprandial glucose levels, and safety assessments were made.

RESULTS

In Study 1, nateglinide significantly reduced HbA(1c) from baseline (7.6 +/- 0.1% to 6.9 +/- 0.1%; Delta = -0.7 +/- 0.1%, p < 0.001) and compared with placebo (between-group difference = -0.5%, p = 0.004 vs. nateglinide). No hypoglycaemia was reported. In Study 2, combination therapy with nateglinide/metformin significantly reduced HbA(1c) from baseline (7.8 +/- 0.2% to 6.6 +/- 0.1%; Delta = -1.2 +/- 0.2%, p < 0.001), as did glyburide/metformin (7.7 +/- 0.1% to 6.5 +/- 0.1%; Delta = -1.2 +/- 0.1%, p < 0.001). There was no difference between treatments (p = 0.310). One nateglinide/metformin-treated patient experienced a mild hypoglycaemic episode compared with eight episodes in eight patients on glyburide/metformin; one severe episode led to discontinuation. Target HbA(1c) (<7.0%) was achieved by 60% of patients receiving nateglinide (Study 1) and 70% of nateglinide/metformin-treated patients (Study 2).

CONCLUSION

Initial drug treatment with nateglinide, alone or in combination with metformin, is well tolerated and produces clinically meaningful improvements in glycaemic control in elderly patients with T2DM.

Antihyperglycaemic therapy in elderly patients with type 2 diabetes: potential role of incretin mimetics and DPP-4 inhibitors

Management of elderly patients with type II diabetes is complicated by age-related changes in physiology, comorbidities, polypharmacy and heterogeneity of functional status. A minimum goal in antidiabetic treatment in this population is to achieve a level of glycaemic control that avoids acute complications of diabetes, adverse effects and reduction in quality of life. Hypoglycaemia is a particular problem in elderly patients, and many antidiabetic agents pose increased risk for hypoglycaemia. In addition, many standard agents pose risks for older patients because of reduced renal function and common comorbidities. Newer agents based on enhancing incretin activity, including the glucagon-like peptide-1 mimetics exenatide and liraglutide and the oral dipeptidyl peptidase-4 inhibitors sitagliptin and vildagliptin, may offer particular advantages in elderly patients with diabetes.

The role of alpha-cell dysregulation in fasting and postprandial hyperglycemia in type 2 diabetes and therapeutic implications

The hyperglycemic activity of pancreatic extracts was encountered some 80 yr ago during efforts to optimize methods for the purification of insulin. The hyperglycemic substance was named "glucagon," and it was subsequently determined that glucagon is a 29-amino acid peptide synthesized and released from pancreatic alpha-cells. This article begins with a brief overview of the discovery of glucagon and the contributions that somatostatin and a sensitive and selective assay for pancreatic (vs. gut) glucagon made to understanding the physiological and pathophysiological roles of glucagon. Studies utilizing these tools to establish the function of glucagon in normal nutrient homeostasis and to document a relative glucagon excess in type 2 diabetes mellitus (T2DM) and precursors thereof are then discussed. The evidence that glucagon excess contributes to the development and maintenance of fasting hyperglycemia and that failure to suppress glucagon secretion contributes to postprandial hyperglycemia is then reviewed. Although key human studies are emphasized, salient animal studies highlighting the importance of glucagon in normal and defective glucoregulation are also described. The past eight decades of research in this area have led to development of new therapeutic approaches to treating T2DM that have been shown to, or are expected to, improve glycemic control in patients with T2DM in part by improving alpha-cell function or by blocking glucagon action. Accordingly, this review ends with a discussion of the status and therapeutic potential of glucagon receptor antagonists, alpha-cell selective somatostatin agonists, glucagon-like peptide-1 agonists, and dipeptidyl peptidase-IV inhibitors. Our overall conclusions are that there is considerable evidence that relative hyperglucagonemia contributes to fasting and postprandial hyperglycemia in patients with T2DM, and there are several new and emerging pharmacotherapies that may improve glycemic control in part by ameliorating the hyperglycemic effects of this relative glucagon excess.

Hypoglycemia in Type 2 diabetic patients randomized to and maintained on monotherapy with diet, sulfonylurea, metformin, or insulin for 6 years from diagnosis: UKPDS73

The UK Prospective Diabetes Study (UKPDS) showed that a more intensive glucose control policy reduced risk of diabetic complications. As hypoglycemia is a barrier to achieving glycemic targets, we examined its occurrence and contributing factors in UKPDS patients randomized to and remaining for 6 years on diet, sulfonylurea, metformin (overweight subjects only), or insulin monotherapy from diagnosis of Type 2 diabetes. Self-reported hypoglycemic episodes were categorized as (1) transient, (2) temporarily incapacitated, (3) requiring third-party assistance, and (4) requiring medical attention, recording the most severe episode each quarter. Proportions of patients reporting at least one episode per year were calculated in relation to therapy, HbA(1c), and clinical characteristics. In 5063 patients aged 25-65 years, only 2.5% per year reported substantive hypoglycemia (Grades 2-4) and 0.55% major hypoglycemia (Grade 3 or 4). Hypoglycemia was more frequent in younger (4.0% <45 years vs. 2.2% >or=45 years), female (3.0% vs. 2.2% male), normal weight (3.6% body mass index <25 kg/m(2) vs. 1.9% >or=25 kg/m(2)), less hyperglycemic (5.2% HbA(1c) <7% vs. 2.3% >or=7%), or islet autoantibody-positive patients (4.3% vs. 2.1% negative) (all P<.0001). More on basal insulin reported hypoglycemia (3.8% per year) than diet (0.1%), sulfonylurea (1.2%), or metformin (0.3%) therapy, but less than on basal and prandial insulin (5.3%) (all P<.0001). Low hypoglycemia rates seen during the first 6 years of intensive glucose lowering therapy in Type 2 diabetes are unlikely to have a major impact on attempts to achieve guideline glycemic targets when sulfonylurea, metformin, or insulin are used as monotherapy.

Diabetes in the elderly

We are approaching an epidemic of diabetes in the elderly. This epidemic and its associated complications will have a significant impact on quality of life in this age group. Recent studies suggest that diabetes can be prevented in a large number of patients with appropriate interventions. It seems that diabetes in this age group is metabolically distinct. As a result, the approach to therapy in the elderly differs from that in younger patients. Unfortunately, we still have huge gaps in our understanding of the pathogenesis and treatment of diabetes in the aged, and further studies are needed urgently.

Nutrition and Aging: Changes in the Regulation of Energy Metabolism With Aging

Changes in energy regulation occur during normal aging and contribute to the common phenomenon of weight and fat losses late in life. This review synthesizes data on aging-related changes in energy intake and energy expenditure and on the regulation of energy intake and expenditure. The ability of older adults to accurately regulate energy intake is impaired, with a number of possible explanations including delayed rate of absorption of macronutrients secondary to reductions in taste and smell acuity and numerous hormonal and metabolic mediators of energy regulation that change with aging. There are also changes in patterns of dietary intake and a reduction in the variety of foods consumed in old age that are thought to further reduce energy intake. Additionally, all components of energy expenditure decrease with aging, in particular energy expenditure for physical activity and basal metabolic rate, and the ability of energy expenditure to increase or decrease to attenuate energy imbalance during overeating or undereating also decreases. Combined, these changes result in an increased susceptibility to energy imbalance (both positive and negative) in old age that is associated with deteriorations in health. Practical interventions for prevention of weight and fat fluctuations in old age are anticipated here based on emerging knowledge of the role of such factors as dietary variety, taste, and palatability in late-life energy regulation.

Hypoglycaemia in Elderly Patients with Diabetes Mellitus

Achieving target glycaemic goals while avoiding hypoglycaemia is a major challenge in the management of elderly patients with diabetes mellitus. Repeated episodes of hypoglycaemia may cause extreme emotional distress in such patients, even when the episodes are relatively mild. Moreover, evidence is mounting that hypoglycaemia among elderly patients is a very real and costly health concern. The strongest predictors of severe hypoglycaemia in the elderly are advanced age, recent hospitalisation and polypharmacy. Education is the key to preventing recurrent or severe hypoglycaemia. As such, there should be close coordination of care between the patient, physician and all other healthcare providers in identifying the cause of hypoglycaemia in elderly patients, and appropriate steps should be taken to prevent further episodes. Prevention of hypoglycaemia has the potential to improve psychosocial aspects of elderly health, including enhanced quality of life, boosted confidence, improved compliance with antidiabetic regimens and avoidance of long-term complications. Since the elderly population represents a unique group, it is imperative to focus on the aetiologies that are exclusive to this group. Advanced age itself is a risk factor for hypoglycaemia, and elderly patients with comorbidities are at increased risk when they are hospitalised. Elderly patients with diabetes often have compromised renal function, which intereferes with drug elimination and thus predisposes them to prolonged life-threatening hypoglycaemia. In addition, patients on five or more prescription medications are prone to drug-associated hypoglycaemia. Although sulfonylurea-associated hypoglycaemia is common, drugs such as ACE inhibitors and nonselective beta-adrenoceptor antagonists can also predispose patients to hypoglycaemia. Greater attention should be paid to the avoidance of hypgolycaemia in nursing home residents. Recurrent hypoglycaemia in elderly patients is not only detrimental to achieving good glycaemic control, it is also a substantial economic burden. Once the causes of hypoglycaemia have been identified, it is crucial to formulate and institute a prevention plan. Firstly, global evaluation of the patient should be carried out to identify possible predisposing risk factors. Secondly, target glycaemic goals should be tailored to each patient. Thirdly, selection of antidiabetic agents should be judicious, then patients and family should be educated to recognise and treat hypoglycaemia. Finally, coordinated care should be provided to identify, treat and prevent hypoglycaemia.

Identifying older diabetic patients at risk of poor glycemic control

BACKGROUND

Optimal glycemic control prevents the onset of diabetes complications. Identifying diabetic patients at risk of poor glycemic control could help promoting dedicated interventions. The purpose of this study was to identify predictors of poor short-term and long-term glycemic control in older diabetic in-patients.

METHODS

A total of 1354 older diabetic in-patients consecutively enrolled in a multicenter study formed the training population (retrospective arm); 264 patients consecutively admitted to a ward of general medicine formed the testing population (prospective arm). Glycated hemoglobin (HbA1c) was measured on admission and one year after the discharge in the testing population. Independent correlates of a discharge glycemia > or = 140 mg/dl in the training population were assessed by logistic regression analysis and a clinical prediction rule was developed. The ability of the prediction rule and that of admission HbA1c to predict discharge glycemia > or = 140 mg/dl and HbA1c > 7% one year after discharge was assessed in the testing population.

RESULTS

Selected admission variables (diastolic arterial pressure < 80 mmHg, glycemia = 143-218 mg/dl, glycemia > 218 mg/dl, history of insulinic or combined hypoglycemic therapy, Charlson's index > 2) were combined to obtain a score predicting a discharge fasting glycemia > or = 140 mg/dl in the training population. A modified score was obtained by adding 1 if admission HbA1c exceeded 7.8%. The modified score was the best predictor of both discharge glycemia > or = 140 mg/dl (sensitivity = 79%, specificity = 63%) and 1 year HbA1c > 7% (sensitivity = 72%, specificity = 71%) in the testing population.

CONCLUSION

A simple clinical prediction rule might help identify older diabetic in-patients at risk of both short and long term poor glycemic control.

Glucose counterregulation in Type 2 diabetes mellitus

Glucose counterregulatory failure and hypoglycaemia unawareness frequently complicate treatment of Type 1 diabetes mellitus, especially when aiming for intensive metabolic control. Since tight metabolic control reduces microvascular long-term complications in Type 2 diabetes mellitus, the integrity of glucose counterregulation in Type 2 diabetic patients is important. Using a Medline search, we identified 12 studies in which counterregulatory responses to insulin-induced hypoglycaemia were compared between Type 2 diabetic patients and appropriate controls. A review of these studies showed that some patients with Type 2 diabetes mellitus develop mild counterregulatory dysfunction and reduced awareness of insulin-induced hypoglycaemia. Some studies suggested an association between counterregulatory impairment and intensity of metabolic control. We speculate that the relatively low frequency of (severe) hypoglycaemic events in Type 2 diabetes may explain why glucose counterregulation remains unaffected in most patients. We hypothesize that residual beta-cell reserve and insulin resistance provide protection against severe hypoglycaemia and limit impaired counterregulation. Diabet. Med. 18, 519-527 (2001)

Antihypertensive drug therapy and hypoglycemia in elderly diabetic patients treated with insulin and/or sulfonylureas. Gruppo Italiano di Farmacovigilanza nell'Anziano (GIFA)

We performed this case control study to evaluate the risk of hypoglycemia associated with the use of antihypertensive drugs in older hospitalized diabetic patients treated with sulfonylureas and/or insulin. All diabetic patients admitted during 4 months in 1988, month in 1991, 4 months in 1993 and 4 months in 1995 (n = 3477, mean age 71.4 +/- 0.2 years, 1542 males and 1935 females) were enrolled in the study. During the four annual surveys 86 patients (mean age 71.1 +/- 1.4 years, 33 males and 53 females) presented hypoglycemia during hospital stay. The patients who presented hypoglycemia were less frequently users of sulfonylureas and more frequently users of a combination of insulin and sulfonylureas. Use of antihypertensive drugs was similar in the two groups studied, and among potentially interacting drugs considered in the analysis, sulfonamides were more frequently used in patients who experienced hypoglycemia. Moreover, patients with hypoglycemia used a higher number of drugs, had a longer length of stay and had a greater prevalence of hypoglycemia as admission problem. Finally, although not significant, liver and renal diseases were more frequent among patients with hypoglycemia. In the multivariate analysis, contemporary use of insulin and sulfonylureas, liver disease and length of stay were significantly associated with hypoglycemia, while none of the antihypertensive drugs showed a significant association with the occurrence of hypoglycemia during hospital stay. Our results indicate that antihypertensive drugs do not increase the risk of hypoglycemia in elderly diabetic patients.

Oral glibenclamide suppresses glucagon secretion during insulin-induced hypoglycemia in patients with type 2 diabetes

Intensifying pharmacological therapy in patients with type 2 diabetes increases the risk of hypoglycemia and often requires the simultaneous use of more than one agent. Combining insulin and sulfonylurea is an effective and frequently used therapy in such patients. However, sulfonylurea derivatives have been shown to affect the release of glucagon, indicating a possible effect of such therapy on hormonal counterregulation to hypoglycemia. Thirteen patients receiving combined therapy were studied on two occasions: 1) after a wash-out period of glibenclamide (-GLIB), and 2) after resuming combined treatment for 6 months (+GLIB). We performed nonstep-wise, hyperinsulinemic hypoglycemic clamps using a constant i.v. insulin infusion and clamping blood glucose at 2.7 mmol/L (48 mg/dL) for 60 min. C Peptide levels were significantly higher during + GLIB, but no significant differences were seen in peripheral plasma insulin levels (+GLIB mean +/- SD, 70 +/- 17 mU/L vs. -GLIB, 75 +/- 14; P = 0.26). Epinephrine responses were similar in the two tests, but when glibenclamide was present the glucagon response was smaller, both the peak value (P = 0.016) and the incremental area under the curve (P = 0.011) as well as the total area under the curve (P = 0.016). These results suggest that intraislet insulin secretion is of importance for the alpha-cell responsiveness to hypoglycemia in these patients.

Individual sulfonylureas and serious hypoglycemia in older people

OBJECTIVE

To compare the risk of serious hypoglycemia associated with the use of individual sulfonylureas in older people.

DESIGN

A retrospective cohort study.

SETTING

The Tennessee Medicaid Program.

PATIENTS

A total of 13,963 Medicaid enrollees, aged 65 years or older, who were prescribed one of six sulfonylureas from 1985 to 1989.

MAIN OUTCOME MEASURE

Hospitalization, emergency room admission, or death associated with neuroglycopenic or autonomic symptoms, myocardial infarction, stroke, or injury, with a concomitant blood glucose determination of less than 2.8 mmol/L (50 mg/dL).

RESULTS

We identified 255 persons with a first episode of serious hypoglycemia during 20,715 person-years of sulfonylurea use. The crude rate (per 1000 person-years) of serious hypoglycemia was highest in glyburide users, 16.6 (95% confidence interval [CI], 13.2 to 19.9 and lowest among users of tolbutamide, 3.5 (95% CI, 1.2 to 5.9). Users of tolbutamide, tolazamide, and glipizide had lower risks of serious hypoglycemia than users of chlorpropamide, whereas the risk of serious hypoglycemia among glyburide users did not differ from that of chlorpropamide users. Among second generation sulfonylureas, the adjusted relative risk of severe hypoglycemia among glyburide users, compared with glipizide users, was 1.9 (95% CI, 1.2 to 2.9). An increased risk of serious hypoglycemia associated with use of glyburide compared with glipizide occurred in all strata, including those defined by gender, race, nursing home residence, dose, and duration of use.

CONCLUSIONS

Significant differences in risk of serious hypoglycemia were observed among users of individual agents. This may be explained by duration, timing, or potency of hypoglycemic action. These data confirm previous findings that chlorpropamide use is associated with high risk of hypoglycemia and indicate that among second generation sulfonylureas, glipizide is less associated with hypoglycemia than is glyburide. More information comparing the effectiveness of glycemic control among individual sulfonylureas is needed to assist prescribers in selecting a specific agent for use in clinical practice.

Diabetes mellitus in older patients. Is tight blood glucose control warranted?

Diabetes mellitus is a major health problem in the older population, where it is mainly of the non-insulin-dependent type [i.e. non-insulin-dependent diabetes mellitus (NIDDM)]. Epidemiological evidence and extrapolation of trial data from patients with insulin-dependent diabetes mellitus (IDDM) suggests that improving glycaemic control reduces the risk of developing microvascular complications (i.e. retinopathy, nephropathy and neuropathy) and also slows the rate of progression of these complications in patients with early disease. Macrovascular morbidity and mortality is, however, more common than microvascular disease in the older population and the evidence that improved glycaemic control significantly reduces the impact of macrovascular disease is weak. Thus, the overall benefits of tight glycaemic control are less well defined in older patients, who tend to have NIDDM, than in younger patients with IDDM. There are small but significant risks associated with tight glycaemic control in the older patient, including potentially fatal hypoglycaemia with sulphonyl-ureas and/or insulin, and fatal metformin-induced lactic acidosis. Patients at especially high risk of these complications can, however, be identified and inappropriate pharmacological intervention can be avoided.

Diabetes in the elderly

Diabetes affects at least 20% of the population over the age of 65. Half of these patients are unaware that they have the disease. Diabetes in middle-aged subjects is characterized by an impairment in glucose induced insulin release, increased fasting hepatic glucose output and resistance to insulin mediated glucose disposal. In contrast, diabetes in the elderly is primarily associated with insulin deficiency. The presentation of diabetes in the aged is often non-specific. The elderly have an increased frequency of complications from diabetes. They are particularly susceptible to hypoglycaemia, because of reduced awareness of hypoglycaemic warning symptoms and altered release of counterregulatory hormones. Although no data are yet available from randomized controlled trials, there is abundant epidemiological evidence to suggest that adequate control of blood glucose can be expected to reduce the risk of long-term complications. A team approach is ideal for the management of the elderly patient with diabetes. Little data is available on which to base a diet and exercise prescription for elderly patients. Gliclazide appears to be the sulphonylurea of choice in the aged because it is associated with a lower frequency of hypoglycaemic reactions. Urine glucose testing is unreliable, and capillary glucose monitoring is preferred. Fructosamine may prove to be superior to haemoglobin A1C for monitoring long-term control.

Glucagon secretory response to hypoglycaemia, adrenaline and carbachol in streptozotocin-diabetic rats

Glucagon response to insulin-induced hypoglycaemia is impared in diabetes, but the mechanism is not established. Pancreatic A cell hyporesponsiveness to adrenergic or cholinergic stimulation could contribute to the impairment. We therefore compared the plasma glucagon responses to intravenous infusion of adrenaline (1200 ng kg(-1) min(-1) for 20 min) or to intravenous injection of the cholinergic agonist carbachol (50 micrograms kg(-1)) in chloral hydrate-anaesthetized rats made diabetic with the use of streptozotocin (80 mg kg(-1) subcutaneously) 6 weeks before and in anaesthetized control rats. Insulin was infused intravenously to reduce plasma glucose levels to below 1.8 mmol L(-1). As expected, the plasma glucagon response was reduced by approximately 45% in streptozotocin-diabetic rats compared with controls (P = 0.045). During adrenaline infusion, plasma glucagon levels increased by 277 +/- 92 pg mL(-1) in controls (P = 0.009) and by 570 +/- 137 pg mL(-1) in the diabetic rats (P = 0.002). Thus, the plasma glucagon response to adrenaline was approximately doubled in the diabetic rats (P = 0.045). Following carbachol injection, plasma glucagon levels were raised by 1211 +/- 208 pg mL(-1) (P < 0.001) in controls but only by 555 +/- 242 pg mL(-1) in the diabetic rats (P = 0.049). Thus, the plasma glucagon response to carbachol was impared by approximately 58% in the diabetic rats (P = 0.028). We conclude that carbachol-stimulated glucagon secretion is impared concomitantly with the impared glucagon response to hypoglycaemia in streptozotocin-diabetic rats, whereas adrenaline-induced glucagon secretion is exaggerated. We suggest that a reduced pancreatic A cell responsiveness to cholinergic stimulation could contribute to the impairment of the glucagon response to insulin-induced hypoglycaemia in diabetes.