Effect of pioglitazone on insulin sensitivity, vascular function and cardiovascular inflammatory markers in insulin-resistant non-diabetic Asian Indians

In praise of pioglitazone: An economically efficacious therapy for type 2 diabetes and other manifestations of the metabolic syndrome

Pioglitazone improves glycaemic control, not only by lowering insulin resistance, but also by improving beta cell function. Because of the improved beta cell function the glycaemic control that occurs with pioglitazone is prolonged. Pioglitazone has positive effects not only on cardiac risk factors and surrogate measures of cardiovascular disease, it also lowers the incidence of cardiac events in patients with diabetes. The recurrence of transient ischaemic attack and ischaemic stroke is also reduced in non-diabetic, insulin-resistant subjects. Utilized at preclinical stages (but not later) of heart failure, pioglitazone improves diastolic function and avoids progression to heart failure. Pioglitazone, through suppression of atrial remodelling, also decreases the incidence of atrial fibrillation. The manifestations of diseases associated with insulin resistance (non-alcoholic steatohepatitis and polycystic ovary disease) are also improved with pioglitazone. Pioglitazone may possibly improve psoriasis and other dermopathies. Pioglitazone is therefore an inexpensive and efficacious drug for the insulin-resistant subject with diabetes that is underutilized because of biases that have evolved from the toxicities of other thiazolidinediones.

Differences in type 2 diabetes risk between East, South, and Southeast Asians living in Singapore: the multi-ethnic cohort

INTRODUCTION

Prospective data on differences in type two diabetes (T2D) risk between Asian ethnic groups are sparse. We, therefore, compared T2D risk for East (Chinese), South (Indian), and Southeast (Malay) Asians and examined biological factors that may contribute to ethnic differences.

RESEARCH DESIGN AND METHODS

We included 7427 adults of Chinese, Malay, and Indian origin participating in the Singapore multi-ethnic cohort. Information on sociodemographic, lifestyle, and biological risk factors (body mass index (BMI), waist circumference, blood lipids, blood pressure, C reactive protein, adiponectin, and homeostasis model assessment for insulin resistance and beta-cell function) were collected using standardized interviews and physical examinations. T2D cases were based on physician diagnoses, a national medical registry, fasting plasma glucose, or glycated hemoglobin A1c. We used multivariable logistic association and mediation analyses.

RESULTS

During an average follow-up of 7.2 years (SD 2.2 years), we documented 595 cases of incident diabetes. Ethnic Malays (OR 2.08, 95% CI 1.69 to 2.56) and Indians (OR 2.22, 95% CI 1.80 to 2.74) had an approximately twofold higher risk of T2D compared with ethnic Chinese. Higher BMI explained the higher risk for Malay compared with Chinese ethnicity. Higher BMI, waist circumference, inflammation, and insulin resistance, and lower beta-cell function and high-density lipoprotein-cholesterol significantly contributed to the higher T2D risk for Indian compared with Chinese ethnicity. However, part of the higher T2D risk associated with Indian ethnicity remained unexplained. Despite their lower diabetes risk, Chinese participants had the lowest adiponectin levels.

CONCLUSIONS

Different Asian ethnic groups have unique biological risk factor profiles related to T2D development that may warrant targeted approaches for prevention and treatment.

Risk Amplifiers for Vascular Disease and CKD in South Asians: When Intrinsic β-Cell Dysfunction Meets a High-Carbohydrate Diet

South Asians, comprising almost one fourth of the world population, are at higher risk of type 2 diabetes mellitus, hypertension, cardiovascular disease, and CKD compared with other ethnic groups. This has major public health implications in South Asia and in other parts of the world to where South Asians have immigrated. The interplay of various modifiable and nonmodifiable risk factors confers this risk. Traditional models of cardiometabolic disease progression and CKD evaluation may not be applicable in this population with a unique genetic predisposition and phenotype. A wider understanding of dietary and lifestyle influences, genetic and metabolic risk factors, and the pitfalls of conventional equations estimating kidney function in this population are required in providing care for kidney diseases. Targeted screening of this population for metabolic and vascular risk factors and individualized management plan for disease management may be necessary. Addressing unhealthy dietary patterns, promoting physical activity, and medication management that adheres to cultural factors are crucial steps to mitigate the risk of cardiovascular disease and CKD in this population. In South Asian countries, a large rural and urban community-based multipronged approach using polypills and community health workers to decrease the incidence of these diseases may be cost-effective.

Bladder cancer with pioglitazone: A case-control study

BACKGROUND

Varied reports suggest a contentious relationship of bladder malignancy with pioglitazone in patients with type 2 diabetes.

AIM

To study an association (prevalence and predictors) of bladder malignancy with pioglitazone therapy in Asian-Indian type 2 diabetes patients.

METHOD

In this observational multicenter study, type 2 diabetic patients attending out-patient diabetes-clinic were evaluated. A detailed history of anti-diabetic medication, dose, duration, pioglitazone usage, time since initiation of pioglitazone, physical examination, biochemical tests and details pertaining to prevalent neuropathy, retinopathy and nephropathy were recorded. Details of bladder cancer or any malignancy (if present), time since diagnosis, risk factors for bladder cancer and histopathology records were noted. The study cohort was divided into two groups-pioglitazone ever users (Group A) and never users (Group B).

RESULTS

A total of 8000 patients were screened out of which 1560 were excluded. Among 6440 included patients, 1056 (16.3%) patients were in group A and 5384 (83.6%) group B. Patients on pioglitazone were older (59.1 vs 57.7 years, p < 0.001), had longer duration of diabetes (12.7 vs 10.6 years, p < 0.001) with poor glycemic control (HbA1c 8.5 vs 8.3%, p < 0.01). A total of 74 patients had prevalent bladder cancer [16 (1.5%) in Group A and 58 in Group B (1.0%)]. Prevalent bladder cancer was not significantly greater in ever-users (odds ratio OR = 1.29, 95% confidence interval CI, 0.83-2.00) compared to never-users (odds ratio OR = 0.94, 95% confidence interval CI, 0.834-1.061) of pioglitazone (p = 0.207). However, history of hematuria in pioglitazone-users; while older age (>58 year), history of smoking and hematuria in the whole cohort were significant associated with bladder cancer. In the entire study cohort, 254 patients; 3.5% of males (128 out of 3575) and 4.6% of females (126 out of 2713) developed any malignancy. Age was significantly associated with prevalent malignancy in people with diabetes (odds ratio OR 1.036, 95% confidence interval CI: 1.022-1.051, p = 0.00) on multivariate forward regression.

CONCLUSION

Pioglitazone use in Asian-Indians is not associated with an increased bladder cancer risk. However, pioglitazone should be restricted in individuals with history of hematuria. Age more than 58 years is a significant risk factor for development of any malignancy, particularly bladder cancer.

Clinical management of type 2 diabetes in south Asia

Compared with other ethnic groups, south Asian people with type 2 diabetes tend to develop the disease at a younger age and manifest with higher glycaemia, dyslipidaemia, nephropathy, and cardiovascular diseases. Additionally, specific issues that can affect treatment of type 2 diabetes in south Asia include poor awareness of the disease, delay in diagnosis, inadequate treatment, the use of ineffective and often harmful alternative medicines, and frequent non-compliance with lifestyle recommendations and drug treatment. Disease development at younger ages, delayed diagnosis, and inadequate management result in early development of severe complications and premature mortality. In this Series paper, we describe the challenges associated with the increasing burden of type 2 diabetes in south Asia and discuss ways to improve clinical care of people with the disorder in the region (defined to include Bangladesh, Bhutan, India, Nepal, Pakistan, and Sri Lanka). Treatment of diabetes in south Asia needs to be individualised on the basis of diverse and heterogeneous lifestyle, phenotype, environmental, social, cultural, and economic factors. Aggressive management of risk factors from diagnosis is necessary to reduce the risk of microvascular and macrovascular complications, focusing on provision of basic treatments (eg, metformin, low-cost statins, and blood pressure-lowering drugs) and other interventions such as smoking cessation. Strengthening of the primary care model of care, better referral linkages, and implementation of rehabilitation services to care for patients with chronic complications will be important. Finally, improvement of physicians' skills, provision of relevant training to non-physician health-care workers, and the development and regular updating of national clinical management guidelines will also be crucial to improve diabetes care in the region.

A Proposed India-Specific Algorithm for Management of Type 2 Diabetes

Several algorithms and guidelines have been proposed by countries and international professional bodies; however, no recent updated management algorithm is available for Asian Indians. Specifically, algorithms developed and validated in developed nations may not be relevant or applicable to patients in India because of several factors: early age of onset of diabetes, occurrence of diabetes in nonobese and sometimes lean people, differences in the relative contributions of insulin resistance and β-cell dysfunction, marked postprandial glycemia, frequent infections including tuberculosis, low access to healthcare and medications in people of low socioeconomic stratum, ethnic dietary practices (e.g., ingestion of high-carbohydrate diets), and inadequate education regarding hypoglycemia. All these factors should be considered to choose appropriate therapeutic option in this population. The proposed algorithm is simple, suggests less expensive drugs, and tries to provide an effective and comprehensive framework for delivery of diabetes therapy in primary care in India. The proposed guidelines agree with international recommendations in favoring individualization of therapeutic targets as well as modalities of treatment in a flexible manner suitable to the Indian population.

Need for ethnic-specific guidelines for prevention, diagnosis, and management of type 2 diabetes in South asians

Noncommunicable diseases, including type 2 diabetes mellitus and cardiovascular diseases (CVDs), cause 7.9 million deaths every year in South Asia. India has nearly 65.1 million cases of diabetes, and Pakistan and Bangladesh are at the 12(th) and 13(th) positions in the global list of high prevalence countries, respectively. The prevalence in India is continuously increasing and is recently reported to be nearly 14% and 8% in urban areas and rural areas, respectively. Diabetes in South Asians is, in some manner, different from that in other races; it occurs nearly a decade earlier, at lower body mass index and waist circumference levels, and with more postprandial hyperglycemia, dyslipidemia, nephropathy, and CVD than in whites. Decision regarding prevention and management of diabetes should be taken in the background of heterogeneity of diet, attitudes, and cultural milieu in South Asia. A need for a low-cost, integrated, yet individualized approach specific for South Asian countries has been increasingly felt since escalating research has uncovered characteristic phenotype, dietary and socioeconomic patterns. Although most such guidelines formulated in developed countries such as the United States or the United Kingdom could be generally applied to developing South Asian countries, there are fundamental differences in applicability of lifestyle and diets (heterogeneous, different from western diets), availability and cost of drugs and insulins, monitoring methods and devices, and insulin pump. Moreover, the monitoring, education, care, and rehabilitation will differ according to different socioeconomic strata and levels of health care (primary, secondary, or tertiary). Some of the potential ethnic-specific modifications have been suggested in this review.

Diabetes in South Asians

Economic, dietary and other lifestyle transitions have been occurring rapidly in most South Asian countries, making their populations more vulnerable to developing Type 2 diabetes and cardiovascular diseases. Recent data show an increasing prevalence of Type 2 diabetes in urban areas as well as in semi-urban and rural areas, inclusive of people belonging to middle and low socio-economic strata. Prime determinants for Type 2 diabetes in South Asians include physical inactivity, imbalanced diets, abdominal obesity, excess hepatic fat and, possibly, adverse perinatal and early life nutrition and intra-country migration. It is reported that Type 2 diabetes affects South Asians a decade earlier and some complications, for example nephropathy, are more prevalent and progressive than in other races. Further, prevalence of pre-diabetes is high, and so is conversion to diabetes, while more than 50% of those who are affected remain undiagnosed. Attitudes, cultural differences and religious and social beliefs pose barriers in effective prevention and management of Type 2 diabetes in South Asians. Inadequate resources, insufficient healthcare budgets, lack of medical reimbursement and socio-economic factors contribute to the cost of diabetes management. The challenge is to develop new translational strategies, which are pragmatic, cost-effective and scalable and can be adopted by the South Asian countries with limited resources. The key areas that need focus are: generation of awareness, prioritizing health care for vulnerable subgroups (children, women, pregnant women and the underprivileged), screening of high-risk groups, maximum coverage of the population with essential medicines, and strengthening primary care. An effective national diabetes control programme in each South Asian country should be formulated, with these issues in mind.

Pathogenesis of type 2 diabetes in South Asians

The risk of developing type 2 diabetes mellitus (T2DM) is exceptionally high among both native and migrant South Asians. T2DM occurs more often and at a younger age and lower BMI, and the risk of coronary artery and cerebrovascular disease, and renal complications is higher for South Asians compared with people of White Caucasian descent. The high prevalence of T2DM and its related complications in South Asians, which comprise one-fifth of the total world's population, poses a major health and socioeconomic burden. The underlying cause of this excess risk, however, is still not completely understood. Therefore, gaining insight into the pathogenesis of T2DM in South Asians is of great importance. The predominant mechanism, in this ethnicity seems to be insulin resistance (IR) rather than an impaired β-cell function. In this systematic review, we describe several possible mechanisms that may underlie or contribute to the increased IR observed in South Asians.

The future liver of the Asia pacific: fatter and firmer from more fructose and fortune?

The Asia Pacific region is the most diverse and the most populous region in the world. Recent socioeconomic changes have resulted in an emerging epidemic of non-communicable diseases such as type 2 diabetes and nonalcoholic fatty liver disease. The prevalence of nonalcoholic fatty liver disease in Asian Pacific countries now approximates that seen in Western countries. This increase is fueled by rising obesity, partly due to adoption of Western style diets and exposure to compounds such as high fructose corn syrup that are not included in traditional diets. Furthermore, South Asian populations may be more genetically susceptible via the inheritance of polymorphisms in apolipoprotein 3 that increase insulin resistance and nonalcoholic fatty liver disease. Importantly, there remains a substantial lack of data on the incidence and natural history of nonalcoholic steatohepatitis and subsequent complications such as hepatocellular carcinoma in Asian Pacific populations. This information gap prevents estimation of current and future disease burden and impedes efforts to lobby health policymakers to improve public health measures, as given the size of Asian Pacific populations, prevention rather than treatment of non-communicable diseases remains key. This review article addresses these issues and highlights research priorities for nonalcoholic fatty liver disease within the Asia Pacific region.

Salt sensitivity, insulin resistance, and public health in India

OBJECTIVE

To provide a current overview of the worldwide prevalence and pattern of cardiovascular disease and discuss the role of sodium intake and salt sensitivity, with a focus on the Asian Indian population.

METHODS

An extensive search of the literature from PubMed and the Cochrane Library was undertaken. Moreover, the pathophysiologic basis of the relationship between sodium intake and insulin sensitivity in various populations was reviewed.

RESULTS

High blood pressure is the most common cause of cardiovascular disease and mortality globally. Although salt sensitivity is a frequent determinant of hypertension, a strong link between salt sensitivity and cardiovascular disease associated with insulin resistance has not received adequate attention. This may be particularly relevant to the public health challenges of increasing prevalences of obesity, diabetes, and cardiometabolic syndrome in India where, according to recent estimates, approximately 60% of the world's cases of cardiovascular disease occur and the salt consumption is among the highest in any large population.

CONCLUSION

There is evidence for a strong link between increased salt sensitivity and insulin resistance leading to metabolic syndrome and cardiovascular disease. This relationship may be particularly relevant to the escalating epidemic of cardiovascular disease in the southern Asian Indian population. A broad-based community action to achieve at least a modest restriction of salt intake can yield important health benefits and is urgently needed.

The impacts of thiazolidinediones on circulating C-reactive protein levels in different diseases: a meta-analysis

OBJECTIVES

Thiazolidinediones (TZDs), including rosiglitazone and pioglitazone, are widely used as antidiabetic agents. Here we present an updated meta-analysis of the respective effects of rosiglitazone and pioglitazone on the levels of C-reactive protein (CRP), a biomarker and predictor of CAD risks.

METHODS AND RESULTS

PubMed and EMBASE were systematically searched using the terms "C-reactive protein" and "rosiglitazone" or "pioglitazone" or "thiazolidinedione". A total of 59 rosiglitazone studies and 36 pioglitazone studies were included for evaluation. These were classified as 2-group studies and 1-group studies according to their study design. Standard mean difference (SMD) of CRP and 95% CI were calculated to evaluate the effect of TZDs on CRP. The overall SMD for rosiglitazone treatment is -0.392 (95% CI, [-0.446, -0.338]) in 2-group studies and -0.424 (95% CI, [-0.501, -0.346]) in 1-group studies. The overall SMD for pioglitazone treatment is -0.577 (95% CI, [-0.732, -0.421]) in 2-group studies and -0.327 (95% CI, [-0.439, -0.216]) in 1-group studies. Moreover, TZDs were found to significantly reduce CRP levels in both diabetes mellitus (DM) and non-DM patients.

CONCLUSIONS

Our meta-analysis suggested that both rosiglitazone and pioglitazone significantly decrease serum CRP levels. TZDs presented their CRP-lowering effect in both DM and non-DM patients.

Obesity-related non-communicable diseases: South Asians vs White Caucasians

South Asians are at higher risk than White Caucasians for the development of obesity and obesity-related non-communicable diseases (OR-NCDs), including insulin resistance, the metabolic syndrome, type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). Rapid nutrition and lifestyle transitions have contributed to acceleration of OR-NCDs in South Asians. Differences in determinants and associated factors for OR-NCDs between South Asians and White Caucasians include body phenotype (high body fat, high truncal, subcutaneous and intra-abdominal fat, and low muscle mass), biochemical parameters (hyperinsulinemia, hyperglycemia, dyslipidemia, hyperleptinemia, low levels of adiponectin and high levels of C-reactive protein), procoagulant state and endothelial dysfunction. Higher prevalence, earlier onset and increased complications of T2DM and CHD are often seen at lower levels of body mass index (BMI) and waist circumference (WC) in South Asians than White Caucasians. In view of these data, lower cut-offs for obesity and abdominal obesity have been advocated for Asian Indians (BMI; overweight >23 to 24.9 kg m(-2) and obesity ≥ 25 kg m(-2); and WC; men ≥ 90 cm and women ≥ 80 cm, respectively). Imbalanced nutrition, physical inactivity, perinatal adverse events and genetic differences are also important contributory factors. Other differences between South Asians and White Caucasians include lower disease awareness and health-seeking behavior, delayed diagnosis due to atypical presentation and language barriers, and religious and sociocultural factors. All these factors result in poorer prevention, less aggressive therapy, poorer response to medical and surgical interventions, and higher morbidity and mortality in the former. Finally, differences in response to pharmacological agents may exist between South Asians and White Caucasians, although these have been inadequately studied. In view of these data, prevention and management strategies should be more aggressive for South Asians for more positive health outcomes. Finally, lower cut-offs of obesity and abdominal obesity for South Asians are expected to help physicians in better and more effective prevention of OR-NCDs.

Thiazolidinedione insulin sensitizers and the heart: a tale of two organs?

Thiazolidinediones (TZDs) are relatively new agents for the treatment of type 2 diabetes. They act as agonists at the PPAR-gamma nuclear receptor and their therapeutic effects include decreased insulin resistance and hyperglycaemia, an improved plasma lipid, inflammation and pro-coagulant profile, and amelioration of hypertension, microalbuminuria and hepatic steatosis. The most common side effects of TZDs include weight gain and oedema, with occasional reports of congestive heart failure (CHF). This review discusses the benefit-risk profile of TZDs in treating patients with type 2 diabetes, with particular reference to the heart. To provide context, we explore briefly the epidemiology and pathophysiology of heart failure in patients with type 2 diabetes, touch on the association of heart disease and cardiovascular mortality with antihyperglycaemic treatment modalities other than TZDs, and then focus on the effects of TZDs on the heart, cardiovascular risk factors and outcomes. We describe the cluster of host factors, which seems to predispose patients with type 2 diabetes to TZD-induced or TZD-exacerbated oedema and CHF and then provide an overview of the putative mechanisms of these TZD-related side effects. We also propose that certain diuretics (amiloride and spironolactone), by targeting the distal nephron that expresses PPARgamma in collecting duct cells, might be of benefit in ameliorating the fluid retention and oedema associated with TZDs.

Thiazolidinediones and their Fluid-Related Adverse Effects

Thiazolidinediones (TZDs) or glitazones are agents that are widely used for the treatment of type 2 diabetes mellitus. These drugs have a multitude of therapeutic effects including reduction in insulin resistance and hyperglycaemia, anti-inflammatory effects and amelioration of hypertension, microalbuminuria and hepatic steatosis. The TZD molecular target, peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear transcription factor, is expressed diffusely in humans, including many tissues comprising the cardiovascular and renal systems. This suggests a potential for TZDs to elicit perturbing effects on these systems, which are independent of their effects on glucose and lipid metabolism. One of the most common adverse effects of TZDs is fluid retention, which can result in, or exacerbate, oedema and congestive heart failure (CHF). The frequency of peripheral oedema is approximately 5% when TZDs are used in mono- or combination oral therapy, and about 15% when used with insulin. Patients with type 2 diabetes are at high risk of myriad morbid complications, including CHF. The development of CHF, particularly in the elderly, is a harbinger of premature mortality. TZD-induced oedema is largely peripheral, may have its origins in changes in haemodynamics, with some contribution from molecules, which regulate cell and tissue permeability (e.g. vascular endothelial growth factor and protein kinase Cbeta), and remains the preponderant manifestation of TZD-induced fluid retention even in those with existing heart failure. Preclinical and pilot clinical data attest to the fact that at least part of the fluid retention derives from a direct effect of TZDs on sodium reabsorption via the renal medullary collecting duct, a mechanism that is sensitive to diuretic agents that have this nephron segment as their site of action, in whole or in part (spironolactone, amiloride and hydrochlorothiazide). Our review suggests various potential clinical strategies by which TZD-induced fluid retention might be effectively monitored and addressed.