Elevated heart rate predicts β cell function in non-diabetic individuals: the RISC cohort

Development and validation of machine learning-augmented algorithm for insulin sensitivity assessment in the community and primary care settings: a population-based study in China

Objective

Insulin plays a central role in the regulation of energy and glucose homeostasis, and insulin resistance (IR) is widely considered as the "common soil" of a cluster of cardiometabolic disorders. Assessment of insulin sensitivity is very important in preventing and treating IR-related disease. This study aims to develop and validate machine learning (ML)-augmented algorithms for insulin sensitivity assessment in the community and primary care settings.

Methods

We analyzed the data of 9358 participants over 40 years old who participated in the population-based cohort of the Hubei center of the REACTION study (Risk Evaluation of Cancers in Chinese Diabetic Individuals). Three non-ensemble algorithms and four ensemble algorithms were used to develop the models with 70 non-laboratory variables for the community and 87 (70 non-laboratory and 17 laboratory) variables for the primary care settings to screen the classifier of the state-of-the-art. The models with the best performance were further streamlined using top-ranked 5, 8, 10, 13, 15, and 20 features. Performances of these ML models were evaluated using the area under the receiver operating characteristic curve (AUROC), the area under the precision-recall curve (AUPR), and the Brier score. The Shapley additive explanation (SHAP) analysis was employed to evaluate the importance of features and interpret the models.

Results

The LightGBM models developed for the community (AUROC 0.794, AUPR 0.575, Brier score 0.145) and primary care settings (AUROC 0.867, AUPR 0.705, Brier score 0.119) achieved higher performance than the models constructed by the other six algorithms. The streamlined LightGBM models for the community (AUROC 0.791, AUPR 0.563, Brier score 0.146) and primary care settings (AUROC 0.863, AUPR 0.692, Brier score 0.124) using the 20 top-ranked variables also showed excellent performance. SHAP analysis indicated that the top-ranked features included fasting plasma glucose (FPG), waist circumference (WC), body mass index (BMI), triglycerides (TG), gender, waist-to-height ratio (WHtR), the number of daughters born, resting pulse rate (RPR), etc.

Conclusion

The ML models using the LightGBM algorithm are efficient to predict insulin sensitivity in the community and primary care settings accurately and might potentially become an efficient and practical tool for insulin sensitivity assessment in these settings.

Brain Dopamine-Clock Interactions Regulate Cardiometabolic Physiology: Mechanisms of the Observed Cardioprotective Effects of Circadian-Timed Bromocriptine-QR Therapy in Type 2 Diabetes Subjects

Despite enormous global efforts within clinical research and medical practice to reduce cardiovascular disease(s) (CVD), it still remains the leading cause of death worldwide. While genetic factors clearly contribute to CVD etiology, the preponderance of epidemiological data indicate that a major common denominator among diverse ethnic populations from around the world contributing to CVD is the composite of Western lifestyle cofactors, particularly Western diets (high saturated fat/simple sugar [particularly high fructose and sucrose and to a lesser extent glucose] diets), psychosocial stress, depression, and altered sleep/wake architecture. Such Western lifestyle cofactors are potent drivers for the increased risk of metabolic syndrome and its attendant downstream CVD. The central nervous system (CNS) evolved to respond to and anticipate changes in the external (and internal) environment to adapt survival mechanisms to perceived stresses (challenges to normal biological function), including the aforementioned Western lifestyle cofactors. Within the CNS of vertebrates in the wild, the biological clock circuitry surveils the environment and has evolved mechanisms for the induction of the obese, insulin-resistant state as a survival mechanism against an anticipated ensuing season of low/no food availability. The peripheral tissues utilize fat as an energy source under muscle insulin resistance, while increased hepatic insulin resistance more readily supplies glucose to the brain. This neural clock function also orchestrates the reversal of the obese, insulin-resistant condition when the low food availability season ends. The circadian neural network that produces these seasonal shifts in metabolism is also responsive to Western lifestyle stressors that drive the CNS clock into survival mode. A major component of this natural or Western lifestyle stressor-induced CNS clock neurophysiological shift potentiating the obese, insulin-resistant state is a diminution of the circadian peak of dopaminergic input activity to the pacemaker clock center, suprachiasmatic nucleus. Pharmacologically preventing this loss of circadian peak dopaminergic activity both prevents and reverses existing metabolic syndrome in a wide variety of animal models of the disorder, including high fat-fed animals. Clinically, across a variety of different study designs, circadian-timed bromocriptine-QR (quick release) (a unique formulation of micronized bromocriptine-a dopamine D2 receptor agonist) therapy of type 2 diabetes subjects improved hyperglycemia, hyperlipidemia, hypertension, immune sterile inflammation, and/or adverse cardiovascular event rate. The present review details the seminal circadian science investigations delineating important roles for CNS circadian peak dopaminergic activity in the regulation of peripheral fuel metabolism and cardiovascular biology and also summarizes the clinical study findings of bromocriptine-QR therapy on cardiometabolic outcomes in type 2 diabetes subjects.

Association between initial in-hospital heart rate and glycemic control in patients with acute ischemic stroke and diabetes mellitus

BACKGROUND

A high resting heart rate (HR) has been associated with an increased risk of diabetes mellitus. This study explored the association between initial in-hospital HR and glycemic control in patients with acute ischemic stroke (AIS) and diabetes mellitus.

METHODS

We analyzed data from 4,715 patients with AIS and type 2 diabetes mellitus enrolled in the Chang Gung Research Database between January 2010 and September 2018. The study outcome was unfavorable glycemic control, defined as glycated hemoglobin (HbA1c) ≥ 7%. In statistical analyses, the mean initial in-hospital HR was used as both a continuous and categorical variable. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression analysis. The associations between the HR subgroups and HbA1c levels were analyzed using a generalized linear model.

RESULTS

Compared with the reference group (HR < 60 bpm), the adjusted ORs for unfavorable glycemic control were 1.093 (95% CI 0.786-1.519) for an HR of 60-69 bpm, 1.370 (95% CI 0.991-1.892) for an HR of 70-79 bpm, and 1.608 (95% CI 1.145-2.257) for an HR of ≥ 80 bpm. Even after adjusting for possible confounders, the HbA1c levels after admission and discharge among diabetic stroke patients increased significantly in the subgroups with higher HRs (p < 0.001).

CONCLUSIONS

High initial in-hospital HR is associated with unfavorable glycemic control in patients with AIS and diabetes mellitus, particularly in those with an HR of ≥ 80 bpm, compared with those with an HR of < 60 bpm.

Role of insulin resistance in the association between resting heart rate and type 2 diabetes: A prospective study

BACKGROUND

Elevated resting heart rate (RHR) is a predictor of incident type 2 diabetes (T2D). Insulin resistance is thought to play a role in this association; however, the extent to which insulin resistance mediates this association is unclear.

METHODS

1309 Japanese individuals without diabetes were recruited during 2009-2012 and followed for 5 years, of whom 78 developed T2D, as diagnosed by the 75 g oral glucose tolerance test. Supine RHR was measured by electrocardiography. Using logistic regression analysis, we examined the association between RHR and incident T2D, and interaction with the homeostasis model assessment of insulin resistance (HOMA-IR) index. Causal mediation analysis was applied to decompose the effect of RHR on the outcome and estimate the proportion mediated by the HOMA-IR index.

RESULTS

The sex- and age-adjusted cumulative incidence rate of T2D increased with increasing RHR. After adjustment for sex, age, waist circumference, current smoking status, alcohol use, habitual exercise, and cardiovascular disease medications, individuals with a RHR ≥80 bpm, compared with <60 bpm, showed an increased risk of incident T2D [odds ratio (OR), 2.89; 95 % confidence interval (CI), 1.07 to 7.80]. Multivariate adjusted OR for the total effect per 1 SD increase in RHR on incident T2D was 1.37 (95 % CI, 1.01 to 1.74) in the mediation analysis, and the proportion of the total indirect effect mediated by the HOMA-IR index was 27.5 % (95 % CI, 1.5 to 53.5).

CONCLUSIONS

Approximately 30 % of the effect of RHR on incident T2D was explained by the indirect effect of insulin resistance.

Circadian-timed quick-release bromocriptine lowers elevated resting heart rate in patients with type 2 diabetes mellitus

OBJECTIVE

Sympathetic nervous system (SNS) overactivity is a risk factor for insulin resistance and cardiovascular disease (CVD). We evaluated the impact of bromocriptine-QR, a dopamine-agonist antidiabetes medication, on elevated resting heart rate (RHR) (a marker of SNS overactivity in metabolic syndrome), blood pressure (BP) and the relationship between bromocriptine-QR's effects on RHR and HbA1c in type 2 diabetes subjects.

DESIGN AND SUBJECTS

RHR and BP changes were evaluated in this post hoc analysis of data from a randomized controlled trial in 1014 type 2 diabetes subjects randomized to bromocriptine-QR vs placebo added to standard therapy (diet ± ≤2 oral antidiabetes medications) for 24 weeks without concomitant antihypertensive or antidiabetes medication changes, stratified by baseline RHR (bRHR).

RESULTS

In subjects with bRHR ≥70 beats/min, bromocriptine-QR vs placebo reduced RHR by -3.4 beats/min and reduced BP (baseline 130/79; systolic, diastolic, mean arterial BP reductions [mm Hg]: -3.6 [P = .02], -1.9 [P = .05], -2.5 [P = .02]). RHR reductions increased with higher baseline HbA1c (bHbA1c) (-2.7 [P = .03], -5 [P = .002], -6.1 [P = .002] with bHbA1c ≤7, >7, ≥7.5%, respectively] in the bRHR ≥70 group and more so with bRHR ≥80 (-4.5 [P = .07], -7.8 [P = .015], -9.9 [P = .005]). Subjects with bRHR <70 had no significant change in RHR or BP. With bHbA1c ≥7.5%, %HbA1c reductions with bromocriptine-QR vs placebo were -0.50 (P = .04), -0.73 (P = .005) and -1.22 (P = .008) with bRHR <70, ≥70 and ≥80, respectively. With bRHR ≥70, the magnitude of bromocriptine-QR-induced RHR reduction was an independent predictor of bromocriptine-QR's HbA1c lowering effect.

CONCLUSION

Bromocriptine-QR lowers elevated RHR with concurrent decrease in BP and hyperglycaemia. These findings suggest a potential sympatholytic mechanism contributing to bromocriptine-QR's antidiabetes effect and potentially its previously demonstrated effect to reduce CVD events.

Negative Affect-Related Autonomic Arousal Mediates the Association between Baroreflex Dysfunction and Insulin Resistance in Non-Diabetic Young Adults

Autonomic dysfunction, in particular under-regulation of heart rate (HR) by the baroreflex, is implicated in development of insulin resistance (IR). According to reactivity hypothesis, sympathetic response to stressors may be more sensitive at predicting IR than baroreceptor sensitivity (BRS), a baseline measure of baroreflex functioning. Using ecological momentary assessment (EMA) of negative affect coupled with minute-to-minute HR and heart-rate variability (HRV) monitoring, we examined whether negative affect (NA)-related autonomic arousal mediates the association of BRS with IR. At baseline, BRS was measured, and fasting serum glucose and insulin levels were collected from 178 young adults (18-39 years old), from which homeostasis model assessment of IR (HOMA-IR) and beta-cell functioning (HOMA %B) were derived. Participants subsequently underwent one day of Holter HR and HRV monitoring while reporting negative affect levels via EMA. Multilevel modeling was used to assess the associations of momentary negative affect with HR and low- (LF) and high-frequency (HF) HRV during the 5-minute intervals following each EMA reading. Structural equation modeling was then used to determine whether individual differences in these associations mediated the association of BRS with IR, measured by HOMA-IR, HOMA %B, and insulin levels. As predicted, BRS was negatively associated with the IR (β = -.17, p = .024). However, NA-related autonomic arousal mediated their association, accounting for 56% of the covariance between BRS and IR. Not only do these results provide support for reactivity hypothesis, they reveal a potential point of intervention in the treatment of affective dysregulation.

Risk factors for hyperglycemia in pregnancy in the DALI study differ by period of pregnancy and OGTT time point

OBJECTIVE

Risk factors are widely used to identify women at risk for gestational diabetes mellitus (GDM) without clear distinction by pregnancy period or oral glucose tolerance test (OGTT) time points. We aimed to assess the clinical risk factors for Hyperglycemia in pregnancy (HiP) differentiating by these two aspects.

DESIGN AND METHODS

Nine hundred seventy-one overweight/obese pregnant women, enrolled in the DALI study for preventing GDM. OGTTs were performed at ≤19 + 6, 24-28 and 35-37 weeks (IADPSG/WHO2013 criteria). Women with GDM or overt diabetes at one time point did not proceed to further OGTTs. Potential independent variables included baseline maternal and current pregnancy characteristics.

STATISTICAL ANALYSIS

Multivariate logistic regression.

RESULTS

Clinical characteristics independently associated with GDM/overt diabetes were at ≤19 + 6 weeks, previous abnormal glucose tolerance (odds ratio (OR): 3.11; 95% CI: 1.41-6.85), previous GDM (OR: 2.22; 95% CI: 1.20-4.11), neck circumference (NC) (OR: 1.58; 95% CI: 1.06-2.36 for the upper tertile), resting heart rate (RHR, OR: 1.99; 95% CI: 1.31-3.00 for the upper tertile) and recruitment site; at 24-28 weeks, previous stillbirth (OR: 2.92; 95% CI: 1.18-7.22), RHR (OR: 3.32; 95% CI: 1.70-6.49 for the upper tertile) and recruitment site; at 35-37 weeks, maternal height (OR: 0.41; 95% CI: 0.20-0.87 for upper tertile). Clinical characteristics independently associated with GDM/overt diabetes differed by OGTT time point (e.g. at ≤19 + 6 weeks, NC was associated with abnormal fasting but not postchallenge glucose).

CONCLUSION

In this population, most clinical characteristics associated with GDM/overt diabetes were non-modifiable and differed by pregnancy period and OGTT time point. The identified risk factors can help define the target population for future intervention trials.