Heart rate elevation and diabetic retinopathy in patients with type 2 diabetes mellitus and normoalbuminuria

The Relationship between Carotid Intima-Media Thickness and Ocular Circulation in Type-2 Diabetes

Purpose

To compare clinical findings, including ocular blood flow and intima-media thickness (IMT) of the carotid artery, in mild nonproliferative diabetic retinopathy (NPDR) and no diabetic retinopathy (NDR) patients, and to determine risk factors contributing to mild NPDR.

Methods

In 129 subjects (129 eyes) with type-2 diabetes patients and mild NPDR or NDR, standard statistical techniques were used to determine associations between clinical findings, including diabetes duration, blood levels of creatinine and hemoglobin A1c (HbA1c), central macular thickness (CMT; measured with optical coherence tomography), mean blur rate (MBR; measured with laser speckle flowgraphy), and ultrasound-measured carotid IMT.

Results

Diabetes duration, IMT, and CMT were significantly higher in the mild NPDR patients than the NDR patients (P=0.004, P=0.004, and P=0.003, respectively), while conversely, MBR in the overall optic nerve head (MBR-A) was lower in the mild NPDR patients. Furthermore, a logistic regression analysis showed that diabetes duration (OR, 1.11; P=0.006), diastolic blood pressure (OR, 0.93; P=0.025), heart rate (OR, 1.07; P=0.004), IMT (OR, 8.65; P=0.005), and CMT (OR, 1.03; P=0.007) were independent contributing factors to mild NPDR. Spearman's rank correlation test also showed that IMT was negatively correlated with MBR-A (P=0.011).

Conclusions

Increased IMT showed a close association with ocular ischemia in patients with type-2 diabetes and contributed to the presence of mild NPDR. These findings suggest that IMT may be an early biomarker of mild NPDR.

Prevalence and risk factors for diabetic retinopathy in China: a multi-hospital-based cross-sectional study

Purpose

To determine the prevalence and risk factors for diabetic retinopathy (DR) and sight-threatening diabetic retinopathy (STDR) in a multi-hospital-based DR screening programme among patients with diabetes in China, the Lifeline Express Diabetic Retinopathy Screening Program.

Methods

Patients with diabetes in eight hospitals across mainland China (both southern and northern) from January 2014 to July 2016 were recruited in this programme. All participants underwent a standardised interview and examinations and received digital fundus photography. DR severity was graded from retinal fundus photographs by retina specialists in the reading centre of Joint Shantou International Eye Center, according to the grading standards of the English National Screening Programme. STDR was defined as the presence of preproliferative DR (R2), proliferative DR (R3) and/or maculopathy (M1).

Results

16 305 patients with diabetes were screened for DR in total. Fundus photographs were gradable for 15 078 patients (92.5%). The age–gender-standardised prevalence of any DR and STDR was 27.9% (95% CI, 27.2% to 28.6%) and 12.6% (95% CI, 12.1% to 13.1%), respectively. In the multiple logistic regression analysis, younger age (OR, 0.967), longer duration of diabetes (OR, 1.093), higher haemoglobin A1c (OR, 1.115), higher fasting plasma glucose (OR, 1.074), higher systolic blood pressure (OR, 1.014), faster heart rate (OR, 1.010), higher low-density lipoprotein (OR, 1.149), lower triglycerides (OR, 0.975), higher blood urea nitrogen (BUN) (OR, 1.012) and elevated serum creatinine level (OR, 1.003) were associated with the presence of DR. Similar risk factors, except for BUN and triglycerides, were found for STDR.

Conclusions

The prevalence of DR and STDR in diabetes was 27.9% and 12.6%, respectively in this multi-hospital-based population across China. Compared with Western population with diabetes, similar risk factors for DR and STDR were found in Chinese patients with diabetes.

Early changes in cardiovascular structure and function in adolescents with type 1 diabetes

Background

Children with type 1 diabetes (T1D) are at higher risk of early adult-onset cardiovascular disease. We assessed cardiovascular structure and function in adolescents with T1D compared with healthy controls and the relationships between peripheral vascular function and myocardial parameters.

Methods and results

199 T1D [14.4 ± 1.6 years, diabetes duration 6.2 (2.0–12.8) years] and 178 controls (14.4 ± 2.1 years) completed endothelial function by flow mediated vasodilatation (FMD), arterial stiffness using pulse wave velocity (PWV) along with M-mode, pulse wave and tissue Doppler, and myocardial deformation echocardiographic imaging. Systolic (113 ± 10 vs. 110 ± 9 mmHg; p = 0.0005) and diastolic (62 ± 7 vs. 58 ± 7 mmHg; p < 0.0001) blood pressures, carotid femoral PWV and endothelial dysfunction measurements were increased in T1D compared with controls. Systolic and diastolic left ventricular dimensions and function by M-mode and pulse wave Doppler assessment were not significantly different. Mitral valve lateral e’ (17.6 ± 2.6 vs. 18.6 ± 2.6 cm/s; p < 0.001) and a’ (5.4 ± 1.1 vs. 5.9 ± 1.1 cm/s; p < 0.001) myocardial velocities were decreased and E/e’ (7.3 ± 1.2 vs. 6.7 ± 1.3; p = 0.0003) increased in T1D. Left ventricular mid circumferential strain (−20.4 ± 2.3 vs. −19.5 ± 1.7 %; p < 0.001) was higher, whereas global longitudinal strain was lower (−19.0 ± 1.9 vs. −19.8 ± 1.5 % p < 0.001) in T1D.

Conclusions

Adolescents with T1D exhibit early changes in blood pressure, peripheral vascular function and left ventricular myocardial deformation indices with a shift from longitudinal to circumferential shortening. Longitudinal follow-up of these changes in ongoing prospective trials may allow detection of those most at risk for cardiovascular abnormalities including hypertension that could preferentially benefit from early therapeutic interventions.

An ecological approach to cognitive enhancement: complex motor training

Cognitive training has received a lot of attention recently, yielding findings that can be conflicting and controversial. In this paper, we present a novel approach to cognitive training based on complex motor activities. In a randomized controlled design, participants were assigned to one of three conditions: aerobic exercise, working memory training or designed sport--an intervention specifically tailored to include both physical and cognitive demands. After training for eight weeks, the designed sport group showed the largest gains in all cognitive measures, illustrating the efficacy of complex motor activities to enhance cognition. Designed sport training also revealed impressive health benefits, namely decreased heart rate and blood pressure. In this period of skepticism over the efficacy of computerized cognitive training, we discuss the potential of ecological interventions targeting both cognition and physical fitness, and propose some possible applications.

Risk factors for development and progression of nonproliferative retinopathy in normoalbuminuric patients with type 1 diabetes

BACKGROUND

The aim of this study was to evaluate risk factors for development and progression of nonproliferative retinopathy (NPR) in normoalbuminuric patients with type 1 diabetes mellitus (T1DM).

METHODS

A total of 223 T1DM with normal renal function and normoalbuminuria were included in this study and followed for 48 months. Photodocumented retinopathy status was made according to the EURODIAB protocol. Urinary albumin excretion rate (UAE) was measured from at least two 24-h urine samples. Possible risk factors for development or progression of NPR were examined in backward stepwise Cox's multiple regression analysis.

RESULTS

The majority of patients (70%) had no retinopathy while 67 (30%) had NPR at baseline. Patients with NPR were older, had longer duration of diabetes, higher systolic blood pressure, BMI, resting heart rate, UAE and lower estimated glomerular filtration rate (p ≤ 0.04 for all). After 48 months 24 patients (10.7%) developed NPR or progressed to proliferative retinopathy. Systolic blood pressure (HR 1.03, CI 1.01-1.05, p=0.02), UAE (HR 1.14, CI 1.07-1.21, p<0.001), and resting heart rate (HR 1.05, CI 1.01-1.09, p=0.006) were significantly associated with development or progression of NPR.

CONCLUSIONS

Our results suggest that retinopathy is present and may progress in T1DM even when coexisting renal disease is excluded. Normoalbuminuric T1DM requires close monitoring for the early detection of retinopathy, especially if they have a higher UAE, systolic blood pressure and resting heart rate.

Renal hyperfiltration is associated with glucose-dependent changes in fractional excretion of sodium in patients with uncomplicated type 1 diabetes

OBJECTIVE

Renal hyperfiltration is a common abnormality associated with diabetic nephropathy in patients with type 1 diabetes (T1D). In animal models, increased proximal tubular sodium reabsorption results in decreased distal sodium delivery, tubuloglomerular feedback activation, afferent vasodilatation, and hyperfiltration. The role of tubular factors is less well understood in humans. The aim of the current study was therefore to compare the fractional sodium excretion (FENa) in hyperfiltering (T1D-H) versus normofiltering (T1D-N) patients and healthy control (HC) subjects, as well as the role of ambient hyperglycemia on FENa.

RESEARCH DESIGN AND METHODS

Blood pressure, renal function (inulin for glomerular filtration rate [GFR], and paraaminohippurate for effective renal plasma flow), FENa, and circulating neurohormones were measured in T1D-H (n = 28, GFR ≥135 mL/min/1.73 m(2)), T1D-N (n = 30), and HC (n = 35) subjects during clamped euglycemia. Studies were repeated in a subset of patients during clamped hyperglycemia.

RESULTS

During clamped euglycemia, T1D-H exhibited lower FENa than T1D-N and HC subjects (0.64 ± 0.06% vs. 0.91 ± 0.12% and 0.90 ± 0.10%, P < 0.05). During clamped hyperglycemia, FENa increased (Δ + 0.88 ± 0.22% vs. Δ + 0.02 ± 0.21%; between-group effect, P = 0.01) significantly in T1D-H, whereas FENa did not change in T1D-N. When treated as continuous variables, elevated GFR values were associated with hyperglycemia-induced increases in FENa (R(2) = 0.20, P = 0.007).

CONCLUSIONS

Patients with uncomplicated T1D-H exhibit lower FENa under euglycemic conditions, which may help to identify patients with hyperfiltration outside of a controlled laboratory setting. Increased FENa in T1D-H but not T1D-N under clamped hyperglycemic conditions suggests that the mechanisms responsible for increased sodium reabsorption leading to hyperfiltration can be saturated.

Resting heart rate is associated with nonproliferative retinopathy in normoalbuminuric type 1 diabetic patients

Previous studies have reported that retinopathy might be already present in the normoalbuminuric state in type 1 diabetic patients. The aim of this study was to evaluate the prevalence and predictors of nonproliferative retinopathy in normoalbuminuric type 1 diabetic patients. The study included 312 normoalbuminuric type 1 diabetic patients with normal renal function before any interventions with statins, angiotensin-converting enzyme inhibitors, or angiotensin II receptor blockers. Diagnosis of nonproliferative retinopathy was made by fundoscopy after pupillary dilatation. Urinary albumin excretion (UAE) rate was measured from at least two 24-hour urine samples. Nonproliferative retinopathy was present in 36% of normoalbuminuric patients. Patients with nonproliferative retinopathy were older and had longer duration of diabetes, higher hemoglobin A1c , daily insulin dose, and higher resting heart rate (RHR) (P≤.01 for all). Patients in the 4th quartile of RHR were older and had longer duration of diabetes, higher hemoglobin A1c , daily insulin dose, serum creatinine, UAE, and a significantly higher prevalence of nonproliferative retinopathy compared with subjects in the 2nd, 3rd, and 4th quartiles (P<.05). In logistic regression analysis, after adjustment for risk factors, higher RHR was significantly associated with risk of nonproliferative retinopathy in patients (P<.001), with odds ratios of 1.02 to 1.08. These data suggest that RHR is independently associated with nonproliferative retinopathy in normoalbuminuric type 1 diabetic patients.

Renal hyperfiltration and systemic blood pressure in patients with uncomplicated type 1 diabetes mellitus

BACKGROUND

Patients with type 1 diabetes mellitus (DM) and renal hyperfiltration also exhibit systemic microvascular abnormalities, including endothelial dysfunction. The effect of renal hyperfiltration on systemic blood pressure (BP) is less clear. We therefore measured BP, renal hemodynamic function and circulating renin angiotensin aldosterone system (RAAS) mediators in type 1 DM patients with hyperfiltration (n = 36, DM-H, GFR≥135 ml/min/1.73 m(2)) or normofiltration (n = 40, DM-N), and 56 healthy controls (HC). Since renal hyperfiltration represents a state of intrarenal RAAS activation, we hypothesized that hyperfiltration would be associated with higher BP and elevated levels of circulating RAAS mediators.

METHODS

BP, glomerular filtration rate (GFR - inulin), effective renal plasma flow (paraaminohippurate) and circulating RAAS components were measured in DM-H, DM-N and HC during clamped euglycemia (4-6 mmol/L). Studies were repeated in DM-H and DM-N during clamped hyperglycemia (9-11 mmol/L).

RESULTS

Baseline GFR was elevated in DM-H vs. DM-N and HC (167±6 vs. 115±2 and 115±2 ml/min/1.73 m(2), p<0.0001). Baseline systolic BP (SBP, 117±2 vs. 111±2 vs. 109±1, p = 0.004) and heart rate (76±1 vs. 67±1 vs. 61±1, p<0.0001) were higher in DM-H vs. DM-N and HC. Despite higher SBP in DM-H, plasma aldosterone was lower in DM-H vs. DM-N and HC (42±5 vs. 86±14 vs. 276±41 ng/dl, p = 0.01). GFR (p<0.0001) and SBP (p<0.0001) increased during hyperglycemia in DM-N but not in DM-H.

CONCLUSIONS

DM-H was associated with higher heart rate and SBP values and an exaggerated suppression of systemic aldosterone. Future work should focus on the mechanisms that explain this paradox in diabetes of renal hyperfiltration coupled with systemic RAAS suppression.

Resting heart rate and the risk of microvascular complications in patients with type 2 diabetes mellitus

Background

A higher resting heart rate is associated with an increased probability of cardiovascular complications and premature death in patients with type 2 diabetes mellitus. The impact of heart rate on the risk of developing microvascular complications, such as diabetic retinopathy and nephropathy, is, however, unknown. The present study tests the hypothesis that a higher resting heart rate is associated with an increased incidence and a greater progression of microvascular complications in patients with type 2 diabetes mellitus.

Methods and Results

The relation between baseline resting heart rate and the development of a major microvascular event was examined in 11 140 patients who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) study. Major microvascular events were defined as a composite of new or worsening nephropathy or new or worsening retinopathy. Patients with a higher baseline heart rate were at increased risk of a new major microvascular complication during follow-up (adjusted hazard ratio: 1.13 per 10 beats per minute; 95% confidence interval: 1.07–1.20; P<0.001). The excess hazard was evident for both nephropathy (adjusted hazard ratio: 1.16 per 10 beats per minute; 95% confidence interval: 1.08–1.25) and retinopathy (adjusted hazard ratio: 1.11 per 10 beats per minute; 95% confidence interval: 1.02–1.21).

Conclusion

Patients with type 2 diabetes mellitus who have a higher resting heart rate experience a greater incidence of new-onset or progressive nephropathy and retinopathy.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00145925. http://www.advance-trial.com/static/html/prehome/prehome.asp

Diabetic retinopathy is associated with early autonomic dysfunction assessed by exercise-related heart rate changes

Diabetic retinopathy has been associated with cardiac autonomic dysfunction in both type 1 and type 2 diabetes mellitus (DM) patients. Heart rate (HR) changes during exercise testing indicate early alterations in autonomous tonus. The aim of the present study was to investigate the association of diabetic retinopathy with exercise-related HR changes. A cross-sectional study was performed on 72 type 2 and 40 type 1 DM patients. Autonomic dysfunction was assessed by exercise-related HR changes (Bruce protocol). The maximum HR increase, defined as the difference between the peak exercise rate and the resting rate at baseline, and HR recovery, defined as the reduction in HR from the peak exercise to the HR at 1, 2, and 4 min after the cessation of the exercise, were determined. In type 2 DM patients, lower maximum HR increase (OR = 1.62, 95%CI = 1.03-2.54; P = 0.036), lower HR recovery at 2 (OR = 2.04, 95%CI = 1.16-3.57; P = 0.012) and 4 min (OR = 2.67, 95%CI = 1.37-5.20; P = 0.004) were associated with diabetic retinopathy, adjusted for confounding factors. In type 1 DM, the absence of an increase in HR at intervals of 10 bpm each during exercise added 100% to the odds for diabetic retinopathy (OR = 2.01, 95%CI = 1.1-3.69; P = 0.02) when adjusted for DM duration, A1c test and diastolic blood pressure. In conclusion, early autonomic dysfunction was associated with diabetic retinopathy. The recognition of HR changes during exercise can be used to identify a high-risk group for diabetic retinopathy.

Biological mechanisms of disease and death in Moscow: rationale and design of the survey on Stress Aging and Health in Russia (SAHR)

BACKGROUND

Prior research has revealed large differences in health and mortality across countries, socioeconomic groups, and individuals. Russia experiences one of the world's highest levels of all-cause and cardiovascular mortality, great mortality differences within the population, and a heavy burden of ill health. Psychological stress has been suggested as a likely explanation of health loss and premature death in Russia and Eastern Europe. However, physiological mechanisms connecting stress with health in Russia remain unclear since existing epidemiological data are scarce and limited to conventional risk factors.

METHOD AND DESIGN

The survey on Stress Aging and Health in Russia (SAHR) is addressing this knowledge gap by collecting an unusually rich database that includes a wide range of reported information, physical and cognitive health outcomes, and biomarkers in a sample of Muscovite men and women aged 55 and older. The total planned sample size is 2,000 individuals. The sample was randomly selected from epidemiological cohorts formed in Moscow between the mid-1970s and the 1990s and from medical population registers. The baseline data collection was carried out from December 2006 to June 2009. Interviews and medical tests were administered at hospital or at home according to standardized protocol. Questionnaire information includes health, socio-demographic characteristics, economic well-being, cognitive functioning, and batteries on stress and depression. Biomarkers include anthropometry, grip strength, resting ECG, conventional cardiovascular factors of risk such as lipid profile and blood pressure, and other biochemical parameters such as those related to inflammation, glucose and insulin resistance, coagulation, fibrinolysis, and stress hormones. In addition to these measurements, SAHR includes dynamic biomarkers provided by 24-hour ECG (Holter) monitoring. This method continuously registers the beat-to-beat heart rate in naturalistic conditions without restrictions on normal daily activities. It provides information about heart functioning, including heart rate variability and ischemic and arrhythmic events.Re-examination of the study subjects will be conducted in 2009-2011 and will focus on health, functional status, economic conditions, behaviors, and attitudes towards aging. The subjects are also followed up for mortality and non-fatal health events.

DISCUSSION

The SAHR will produce a valuable set of established and novel biomarkers combined with self-reported data for the international research community and will provide important insights into factors and biological mechanisms of mortality and health losses in Russia.

Factors affecting heart rate as measured at home among treated hypertensive patients: the Japan home versus office blood pressure measurement evaluation (J-HOME) study

We previously reported that a resting heart rate measured at home (home HR) of >or=70 beats per minute was a powerful predictor of the risk of cardiovascular disease mortality, and identified factors affecting home HR in the general Japanese population. The present study examines factors affecting home HR in hypertensive patients treated with antihypertensive medications. Home HR was measured using a home blood pressure (BP) device. Information about the characteristics of the patients was collected using questionnaires administered by a physician. Among 3,400 patients, 3,086 measured home HR both in the morning and evening. The mean values of home HR in the morning and evening were 67.2+/-9.1 and 69.6+/-9.2 beats per minute, respectively. Multivariate linear regression analysis showed that lower age, diabetes mellitus, habitual smoking, higher diastolic BP, and the lack of beta-blocker or angiotensin-converting enzyme inhibitor use were determinants of elevated morning or evening home HR. These results suggest that adequate control of risk factors for cardiovascular disease such as smoking and diabetes mellitus or use of heart rate-lowering agents might help to decrease home HR in treated hypertensive patients.

Current literature in diabetes

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of diabetes/metabolism. Each bibliography is divided into 17 sections: 1 Books, Reviews & Symposia; 2 General; 3 Genetics; 4 Epidemiology; 5 Immunology; 6 Prediction; 7 Prevention; 8 INTERVENTION: a&rpar General; b&rpar Pharmacology; 9 Pathology: a&rpar General; b&rpar Cardiovascular; c&rpar Neurological; d&rpar Renal; 10 Endocrinology & Metabolism; 11 Nutrition; 12 Animal Studies; 13 Techniques. Within each section, articles are listed in alphabetical order with respect to author (9 Weeks journals - Search completed at 1st Aug 2001)