Non-insulin-dependent diabetes mellitus in the elderly

Efficacy / safety balance of DPP-4 inhibitors versus SGLT2 inhibitors in elderly patients with type 2 diabetes

Dipeptidyl peptidase-4 inhibitors (DPP-4is) and sodium-glucose cotransporter type 2 inhibitors (SGLT2is) offer new options for the oral management of type 2 diabetes mellitus (T2DM), with the advantage in the elderly population to be devoid of a high risk of hypoglycaemia. SGLT2is have also shown benefits regarding cardiovascular (heart failure) and renal protection, including in patients with T2DM aged ≥ 65 years while DPP-4is have only proved cardiovascular and renal safety without superiority compared with placebo. The glucose-lowering efficacy of the two pharmacological classes is almost similar including in older patients with T2DM. However, the tolerance and safety profile may be highly different and overall more favourable with DPP-4is than with SGLT2is. Some adverse events have been reported with SGLT2is which may be more prevalent or severe in older patients than in younger patients. The present comprehensive review focuses on the benefit/risk balance in the elderly population with T2DM by comparing the profile of DPP-4is and SGLT2is regarding the following potential issues: metabolic disorders (hypoglycaemia and diabetic ketoacidosis); cardiac and vascular issues (atheromatous cardiovascular disease, heart failure, volume reduction hypotension, and lower limb amputations); renal endpoints including acute renal injury; risk of infections; digestive disorders; bone and skin adverse events; and cancer risk. Both DPP-4is and SGLT2is have their own advantages and disadvantages. Personalised treatment is recommended based upon the efficacy/safety profile of each drug class and individual patient characteristics that may be markedly different among the heterogeneous population of older individuals with T2DM.

Careful use to minimize adverse events of oral antidiabetic medications in the elderly

INTRODUCTION

An increasing number of older patients has type 2 diabetes treated with different oral antidiabetic agents whose safety may raise concern considering some particularities of a heterogeneous elderly population.

AREAS COVERED

This article discusses some characteristics of older patients that could increase the risk of adverse events, with a focus on hypoglycemia. It describes the most frequent and/or severe complications reported in the elderly in both randomized controlled trials and observational studies with metformin, sulfonylureas, meglitinides, alpha-glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase-4 inhibitors (gliptins) and sodium-glucose cotransporter type 2 inhibitors (gliflozins).

EXPERT OPINION

Old patients may present comorbidities (renal impairment, vascular disease, heart failure, risk of dehydration, osteoporosis, cognitive dysfunction) that could increase the risk of severe adverse events. Sulfonylureas (and meglitinides) induce hypoglycemia, which may be associated with falls/fractures and cardiovascular events. Medications lacking hypoglycemia should be preferred. Gliptins appear to have the best tolerance/safety profile whereas gliflozins exert a cardiorenal protection. However, data are lacking in very old or frailty old patients so that caution and appropriate supervision of such patients are required. Taking advantage of a large choice of pharmacotherapies, personalized treatment is recommended based upon both drug safety profiles and old patient individual characteristics.

Carbohydrate oxidation and glucose utilisation under hyperglycaemia in aged and young males during exercise at the same relative exercise intensity

PURPOSE

The purpose of the present study was to investigate the age-related carbohydrate oxidation and glucose utilisation rate response during exercise at the same relative intensity under hyperglycaemia in aged and young males.

METHODS

16 endurance-trained aged (n = 8; 69.1 ± 5.2 year) and young (n = 8; 22.4 ± 2.9 year) males were studied during 40 min of cycling exercise (60% [Formula: see text]) under both hyperglycaemic and euglycaemic (control) conditions. Venous blood samples were collected at baseline, post-infusion, mid- and post-exercise. Carbohydrate and fat oxidation rates were determined at both 15 and 35 min during exercise, and glucose utilisation rates were calculated.

RESULTS

The aged group displayed significantly lower rates of carbohydrate oxidation during exercise during maintained hyperglycemia (15 min = 2.3 ± 0.4 vs. 1.6 ± 0.5 g min^-1; 35 min = 2.3 ± 0.5 vs. 1.5 ± 0.5 g min^-1) and control (15 min = 2.2 ± 0.4 vs. 1.6 ± 0.7 g min^-1; 35 min = 1.9 ± 0.7 vs. 1.3 ± 0.7 g min^-1) conditions (P = 0.01). The rate of glucose utilisation during exercise was also significantly reduced (85.76 ± 23.95 vs. 56.67 ± 15.09 μM kg^-1 min^-1). There were no differences between age groups for anthropometric measures, fat oxidation, insulin, glucose, NEFA, glycerol and lactate (P > 0.05) although hyperglycemia resulted in elevated glucose and insulin, and attenuated fat metabolite levels.

CONCLUSION

Our findings highlight that ageing results in a reduction in carbohydrate oxidation and utilisation rates during exercise at the same relative exercise intensity.

Biphasic insulin aspart 30 in the treatment of elderly patients with type 2 diabetes: a subgroup analysis of the PRESENT Korea NovoMixstudy

AIMS

To evaluate the efficacy, safety and treatment satisfaction with biphasic insulin aspart 30 (BIAsp30) in elderly patients with type 2 diabetes.

METHODS

The Physicians' Routine Evaluation of Safety and Efficacy of NovoMix 0 Therapy Korea study was a 6-month, prospective, observational study. No study-specific interventions were involved except the collection of data. All patients with type 2 diabetes not adequately controlled on their previous therapy, and who were prescribed BIAsp30 as monotherapy, or in combination with oral hypoglycaemic agents, were eligible for the study. This subgroup analysis was based on the outcomes in patients > or years (n = 1720).

RESULTS

BIAsp30 treatment was associated with significant mean reductions in haemoglobin A1c, fasting plasma glucose and post-prandial plasma glucose levels of 1.2 +/- 1.6%, 2.3 +/- 3.5 mmol/l and 4.8 +/- 5.3 mmol/l at 6 months (p < 0.0001 for all), from baseline levels of 9.1 +/- 1.7%, 10.7 +/- 3.4 mmol/l and 16.7 +/- 5.0 mmol/l, respectively. The rate of hypoglycaemia declined from 3.02 to 1.31 episodes per patient year, between baseline and study end. The proportion of patients reporting adverse drug reactions was low (0.3 and 0.1% at 3 and 6 months, respectively). Body weight gain was mild at <0.1 kg at 3 months, and 0.3 kg at 6 months. As compared to the previous treatment, >80% of patients were rated as being either 'very satisfied' or 'satisfied' with BIAsp30 treatment.

CONCLUSIONS

In this subanalysis of Korean elderly patients with type 2 diabetes inadequately controlled on their previous therapies, treatment with BIAsp30 offered improvements in glycaemic control and was well tolerated. Body weight gain was minimal with BIAsp30, and treatment satisfaction among these patients appeared to be high.

Diabetes mellitus in the elderly: insulin resistance and/or impaired insulin secretion?

Elderly people are more glucose intolerant and insulin resistant than young individuals, and many of them will develop type 2 diabetes. It remains, however, controversial whether this decrease in function is due to an inevitable consequence of "biological aging" or due to environmental or lifestyle variables. Indeed, increased adiposity/altered fat distribution, decreased fat free mass/abnormal muscle composition, poor dietary habits and physical inactivity all contribute to reduce insulin sensitivity. Insulin resistance in elderly people appears to predominate in skeletal muscle, whereas hepatic glucose output seems to be almost unaffected. Several abnormalities in islet beta-cell and insulin secretion were also pointed out in elderly people such as increased amyloid deposition and decreased amylin secretion, impaired insulin secretion pulsatility, decreased insulin sensitivity of pancreatic beta-cells to insulinotropic gut hormones and diminished insulin response to non-glucose stimuli such as arginine. Controversial results were reported concerning the effects of aging on absolute insulin secretion in response to oral or intravenous glucose. However, insulin secretion appears to decrease with age, with significantly diminished beta-cell sensitivity and acute insulin response to glucose, provided it is analyzed relative to concomitant decreased insulin sensitivity. Thus, there is an interplay between decreased insulin secretion and increased insulin resistance that largely explains the abnormal glucose metabolism seen in elderly. Weight loss, especially reduction of abdominal adiposity, and increased physical activity may contribute to improve insulin sensitivity and glucose tolerance, and prevent the development of type 2 diabetes in elderly people.

Treatment of type 2 diabetes

Type 2 diabetes is a heterogeneous disease resulting from a dynamic interaction between defects in insulin secretion and insulin action. As most subjects are overweighted or obese, the initial treatment is optimization of the meal plan and enhancement of physical activity in order to obtain sustained weight reduction. In case of failure of life-style changes, various oral antihyperglycaemic agents may be used. Some are targeting defective insulin secretion (sulphonylureas, glinides) while others are targeting insulin resistance (metformin, thiazolidinediones). Criteria of drug selection should include both patient's characteristics (body weight, age, degree of hyperglycaemia, comorbidities) and pharmacological properties of the compound (mode of action, safety profile, cost). Monotherapy is usually recommended first, but combined therapy using drugs with additive or synergistic effects may be required to obtain appropriate blood glucose control. As the natural history of the disease is characterized by a progressive exhaustion of beta cells, exogenous insulin may be required in the long term, usually in combination with oral agents. Finally, as patients with type 2 diabetes are insulin-resistant and often have a metabolic syndrome, a multifactorial intervention including aggressive treatment of arterial hypertension and dyslipidaemia is recommended in order to reduce the incidence of cardiovascular complications.

Prevalence of hypothyroidism and diabetes mellitus in elderly kibbutz members

The aim of this study was to determine the prevalence of hypothyroidism and diabetes mellitus (DM) in elderly (aged 65-92 years) kibbutz members in Northern Israel.

METHOD

The medical records of 1096 elderly (642 females and 454 males) residing in 11 kibbutzim were reviewed for data regarding thyroid function tests (TSH and FT4) and fasting blood glucose. Fasting blood glucose levels above 7.8 mmol/l was considered diagnostic for diabetes mellitus.

RESULTS

The prevalence of hypothyroidism was 14% (9.7% in males and 18.2% in females) and that of DM was 11.5% (12.1% in males and 11.1% in females). In 74% of the diabetics the diagnosis was made after the age of 60 years. Distribution of treatment modalities in diabetics was as follows: diet only 42%. oral hypoglycemic agents 52% and Insulin 6%. Subclinical hypothyroidism (serum TSH levels above 4.5 mU/L with normal FT4 levels) was detected in 38% of all the hypothyroid subjects.

CONCLUSION

The data suggest that diabetes mellitus and primary hypothyroidism are common disorders in elderly subjects. DM in the elderly can usually be handled with diet and oral hypoglycemic drugs. Since the clinical features of hypothyroidism in the elderly are often atypical, we suggest that elderly subjects should be screened for hypothyroidism.

Oral antidiabetic agents. A guide to selection

Type 2 diabetes mellitus (formerly named non-insulin-dependent diabetes mellitus or NIDDM) is a heterogeneous disease resulting from a dynamic interaction between defects in insulin secretion and insulin action. Various pharmacological approaches can be used to improve glucose homeostasis via different modes of action: sulphonylureas essentially stimulate insulin secretion, biguanides (metformin) act by promoting glucose utilisation and reducing hepatic-glucose production, alpha-glucosidase inhibitors (acarbose) slow down carbohydrate absorption from the gut and thiazolidinediones (troglitazone) enhance cellular insulin action on glucose and lipid metabolism. These pharmacological treatments may be used individually for certain types of patients, or may be combined in a stepwise fashion to provide more ideal glycaemic control for most patients. Selection of oral antihyperglycaemic agents as first-line drug or combined therapy should be based on both the pharmacological properties of the compounds (efficacy and safety, profile) and the clinical characteristics of the patient (stage of disease, bodyweight, etc.). Mildly hyperglycaemic patients should preferably be treated with metformin, acarbose or thiazolidinediones (which are not associated with any hypoglycaemic risk), while more severely hyperglycaemic individuals should receive a sulphonylurea. In moderately hyperglycaemic patients, sulphonylureas should be preferred in nonobese patients while metformin, and probably also thiazolidinediones, should have priority in obese insulin-resistant type 2 diabetic patients. Acarbose is mainly indicated to reduce post-prandial glucose fluctuations and improve glycaemic stability. Each antihyperglycaemic agent may also be combined with insulin therapy to improve glycaemic control and/or reduce the insulin requirement of diabetic patients after secondary failure to oral treatment. Finally, safety should be taken into account in elderly patients and/or those with renal impairment, especially as far as the use of sulphonylureas (higher risk of hypoglycaemia) and metformin (higher risk of lactic acidosis) is concerned.