Continuous glucose monitoring-derived time in range and CV are associated with altered tissue characteristics of the carotid artery wall in people with type 2 diabetes.

AIMS/HYPOTHESIS: Previous studies have suggested that glucose variability may accelerate atherosclerosis progression in people with type 2 diabetes. Current guidelines recommend assessing glycaemic control using continuous glucose monitoring (CGM), which provides a comprehensive glycaemic profile to supplement HbA1c measurement. However, the association between CGM-derived metrics and atherosclerosis progression is not entirely clear. METHODS: This exploratory study used baseline data and data obtained after 104 weeks from an ongoing prospective, multicentre, observational study. Six hundred study participants with type 2 diabetes and no apparent history of symptomatic cardiovascular disease underwent CGM and ultrasonographic atherosclerosis measurements of the carotid arteries, including the intima-media thickness (IMT) and grey-scale median (GSM), at baseline and 104 weeks. Non-invasive ultrasonic tissue characterisation of the carotid artery wall or plaque using the GSM reflects vascular composition. Multivariate regression models were used to analyse the association between CGM-derived indices, mainly time in range (TIR) and CV, and changes in carotid atherosclerosis index values. RESULTS: Over the 104-week study period, there were modest increases in mean IMT (from 0.759±0.153 to 0.773±0.152 mm, p<0.001) and thickened-lesion GSM (from 43.5±19.5 to 53.9±23.5 units, p<0.001), but no significant changes in common carotid artery maximum-IMT (from 1.109±0.442 to 1.116±0.469 mm, p=0.453) or mean GSM (from 48.7±19.3 to 49.8±20.8 units, p=0.092). In a linear regression model with adjustment for possible atherosclerotic risk factors, including HbA1c, TIR and CV at baseline were significantly associated with the annual change in mean GSM (regression coefficient per 10% increase in TIR 0.52; 95% CI 0.06, 0.98; Hochberg-adjusted p value 0.038; regression coefficient per 1% increase in CV -0.12; 95% CI -0.22, -0.02; Hochberg-adjusted p value 0.038). TIR and CV at baseline were also significantly associated with the annual change in thickened-lesion GSM (regression coefficient per 10% increase in TIR 0.95; 95% CI 0.12, 1.79; Hochberg-adjusted p value 0.038; regression coefficient per 1% increase in CV -0.19; 95% CI -0.36, -0.01; Hochberg-adjusted p value 0.038). Participants who achieved target CGM-derived metrics at baseline, as proposed by an international consensus, showed significant annual changes in mean GSM compared with those who did not (0.94±6.88 vs -0.21±6.19 units/year, p=0.007). CONCLUSIONS/INTERPRETATION: TIR and CV were significantly associated with changes in the tissue characteristics of the carotid artery wall. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry, number UMIN000032325.

The Importance of Continuous Glucose Monitoring-derived Metrics Beyond HbA1c for Optimal Individualized Glycemic Control.

CONTEXT: Current guidelines recommend assessing glycemic control using continuous glucose monitoring (CGM) and hemoglobin A1c (HbA1c) measurement. OBJECTIVE: This study aimed to clarify the characteristics of patients who might benefit from CGM metrics in addition to HbA1c monitoring. METHODS: CGM metrics, specifically time in range (TIR), time below range (TBR), and time above range (TAR), were determined in 999 outpatients with type 2 diabetes and compared between HbA1c categories (HbA1c < 53 mmol/mol [7.0%, HbA1c <  53], HbA1c 53-63 mmol/mol [7.0-7.9%, HbA1c 53-63], HbA1c 64-74 mmol/mol [8.0-8.9%, HbA1c 64-74], and HbA1c ≥ 75 mmol/mol [9.0%, HbA1c ≥  75]) and between patients with identical HbA1c categories who were stratified by age, types of antidiabetic agents, and renal function. RESULTS: For HbA1c <  53 category, patients aged ≥ 65 years had a significantly higher nocturnal TBR than those aged < 65 years. For HbA1c <  53 and HbA1c 53-63 categories, patients receiving insulin and/or sulfonylureas had a significantly higher TAR and TBR, and a lower TIR than those not receiving these drugs, and for HbA1c 64-74 category, they had a significantly higher TBR. For HbA1c <  53, HbA1c 53-63, and HbA1c 64-74 categories, patients with an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 had a significantly higher TBR during some periods than those with an eGFR ≥ 60. CONCLUSION: Higher HbA1c levels do not always protect against hypoglycemic episodes. Our data demonstrate that using CGM metrics to complement HbA1c monitoring is beneficial, especially in older people, users of insulin and/or sulfonylureas, and patients with chronic kidney disease.

Associations between continuous glucose monitoring-derived metrics and HbA1c in patients with type 2 diabetes mellitus.

AIMS: The aim of this study was to define the relationship between time in range (TIR) and hemoglobin A1c (HbA1c) levels in patients with type 2 diabetes mellitus (T2DM). METHODS: The glycemic profile of 999 Japanese patients was analyzed with FreeStyle Libre Pro Continuous Glucose Monitoring (FLP-CGM) while they continued their prescribed glucose-lowering medications. FLP-CGM data recorded over 8 consecutive days were analyzed. RESULTS: The regression model for HbA1c on TIR was HbA1c = 9.4966-0.0309 × TIR. The predicted HbA1c level for TIR of 70% was 7.33% and is higher than reports subjecting mostly T1DM. The TIR corresponding to HbA1c 7.0% was 80.64%. The patients with low TIR tended to have long duration of diabetes, used high dose of daily insulin, high body mass index, high HbA1c, liver dysfunction and high triglyceride. Relatively higher percentages of patients of this group used sulfonylureas, glucagon like peptide-1 receptor agonists and insulin. CONCLUSIONS: Our data showed predicted HbA1c corresponding to TIR is largely depends on study population, thus is not uniform. Our results provide new insights on the management of T2DM. However, caution should be exercised in extending the HbA1C-TIR relationship using FLP-CGM to any other sensors since there could be a risk of hypoglycemia in doing so.

Risk Factor Analysis for Type 2 Diabetes Patients About Hypoglycemia Using Continuous Glucose Monitoring: Results from a Prospective Observational Study.

Introduction: To determine the relationship between hypoglycemia and glucose variability in outpatients with type 2 diabetes mellitus (T2DM). Materials and Methods: The study participants were 999 outpatients with T2DM who used the FreeStyle Libre Pro for continuous glucose monitoring (FLP-CGM). Hypoglycemia was defined as glucose level of <3.0 mM, and the frequency of episodes and duration of hypoglycemia were evaluated by comparing patients who did or did not achieve time-below-range <3.0 mM (TBR<3.0) of <1% of the time. The association of TBR<3.0 and long% coefficient of variation (%CV) with medications used was examined using multivariate analysis with a proportional odds model. Results: The average TBR<3.0 was 0.33% (4.75 min). The TBR<3.0 >1% group comprised 71/999 patients. Patients of the TBR<3.0 >1% group had lower body mass index, longer disease duration, and poorer renal function. For the TBR<3.0 >1% group, the predicted cutoff values were 7.19 mM average glucose (AG), and 30.30% for %CV. When AG <7.19 mM and %CV >30.30% were considered as hypoglycemic risk factors, the frequency and duration of hypoglycemia increased as the risk factor values increased. In multivariate analysis, sulfonylurea (SU) use, insulin use, and low blood glucose index correlated significantly with increased length of TBR<3.0 and %CV, even after adjustment for concomitant diabetes medications. Conclusion: In T2DM, maintaining TBR<3.0 <1% requires to keep AG >7.2 mM and %CV <30%, in addition to comprehensive management of CGM metrics. Since SU and insulin use is associated with prolonged TBR<3.0 and increased %CV, their doses should be adjusted to avoid excessive fall in AG and raising %CV.

Relationship between blood glucose variability in ambulatory glucose profile and standardized continuous glucose monitoring metrics: Subanalysis of a prospective cohort study.

AIM: To clarify the relationship between ambulatory glucose profile (AGP) indexes and standardized continuous glucose monitoring (CGM) metrics in patients with type 2 diabetes (T2D). METHODS: This is an exploratory, cross-sectional analysis of baseline data collected from a prospective, multicentre, 5-year follow-up observational study conducted and published previously by our group. The study participants were 999 outpatients with T2D who used CGM at baseline, and had no apparent history of cardiovascular disease. We investigated the relationship between average interquartile range (IQR) and time in range (TIR). We also calculated, for the first time, the cutoff values to achieve the TIR target values. RESULTS: In both the TIR more than 70% and TIR more than 90% achievement groups, the average IQR was notably small compared with the non-achievement groups. Particularly in comparison of the TIR quartiles, the average IQR became significantly smaller as the TIR became larger. The average IQR correlated negatively with TIR, and the cutoff values for TIR of more than 70% achievement and TIR of more than 90% achievement were an average IQR (>70%/>90%) of 2.13/1.85 mmol/L. CONCLUSION: Our results showed a negative correlation between TIR and the range of blood glucose variations visually represented in AGP. The results also showed that the range of blood glucose variations in AGP is associated with indices of intraday and interday blood glucose variations and also with hypoglycaemia. Our results may provide new perspectives in the assessment and application of AGP in the clinical setting.

Associations of continuous glucose monitoring-assessed glucose variability with intima-media thickness and ultrasonic tissue characteristics of the carotid arteries: a cross-sectional analysis in patients with type 2 diabetes.

BACKGROUND: The association between glucose variability and the progression of atherosclerosis is not completely understood. We aimed to evaluate the associations of glucose variability with the progression of atherosclerosis in the early stages. METHODS: We conducted a cross-sectional analysis to investigate the associations of glucose variability, assessed by continuous glucose monitoring, with intima-media thickness (IMT) and gray-scale median (GSM) of the carotid arteries, which are different indicators for the progression of atherosclerosis. We used baseline data from a hospital-based multicenter prospective observational cohort study among Japanese patients with type 2 diabetes without a history of cardiovascular diseases aged between 30 and 80 years. Continuous glucose monitoring was performed by Freestyle Libre Pro, and glucose levels obtained every 15 min for a maximum of eight days were used to calculate the metrics of glucose variability. IMT and GSM were evaluated by ultrasonography, and the former indicates thickening of intima-media complex in the carotid artery wall, while the latter indicates tissue characteristics. RESULTS: Among 600 study participants (age: 64.9 ± 9.2 (mean ± SD) years; 63.2%: men; HbA1c: 7.0 ± 0.8%), participants with a larger intra- and inter-day glucose variability had a lower GSM and most of these associations were statistically significant. No trend based on glucose variability was shown regarding IMT. Standard deviation of glucose (regression coefficient, ß = - 5.822; 95% CI - 8.875 to - 2.768, P < 0.001), glucose coefficient of variation (ß = - 0.418; - 0.685 to - 0.151, P = 0.002), mean amplitude of glycemic excursion (ß = - 1.689; - 2.567 to - 0.811, P < 0.001), mean of daily differences (ß = - 6.500; - 9.758 to - 3.241, P < 0.001), and interquartile range (ß = - 4.289; - 6.964 to - 1.614, P = 0.002) had a statistically significant association with mean-GSM after adjustment for conventional cardiovascular risk factors, including HbA1c. No metrics of glucose variability had a statistically significant association with IMT. CONCLUSIONS: Continuous glucose monitoring-assessed glucose variability was associated with the tissue characteristics of the carotid artery wall in type 2 diabetes patients without cardiovascular diseases.

Associations between continuous glucose monitoring-derived metrics and diabetic retinopathy and albuminuria in patients with type 2 diabetes.

INTRODUCTION: Preventing the development and progression of diabetic microvascular complications through optimal blood glucose control remains an important challenge. Whether metrics based on continuous glucose monitoring are useful for the management of diabetic microvascular complications is not entirely clear. RESEARCH DESIGN AND METHODS: This is an exploratory analysis of an ongoing prospective, multicenter, 5-year follow-up observational study. Study participants included 999 outpatients with type 2 diabetes who underwent continuous glucose monitoring at baseline. Associations between continuous glucose monitoring-derived metrics and the severity of diabetic retinopathy or albuminuria were investigated using multivariable proportional odds models. RESULTS: The overall prevalence of diabetic retinopathy was 22.2%. Multivariate analysis with proportional odds models demonstrated that continuous glucose monitoring-derived metrics related to intraday and interday glucose variability are significantly associated with the severity of diabetic retinopathy, even after adjusting for various possible risk factors. However, significant relationships were not observed after adjusting for hemoglobin A1c (HbA1c) levels. The prevalence of microalbuminuria and macroalbuminuria was 20.3% and 6.7%, respectively. Similarly, multivariate analysis demonstrated that those metrics are significantly associated with the severity of albuminuria. These relationships remained significant even after further adjusting for HbA1c levels. CONCLUSIONS: Continuous glucose monitoring-derived metrics related to intraday and interday glucose variability are significantly associated with the severity of diabetic retinopathy or albuminuria in patients with type 2 diabetes. Thus, evaluating these metrics might possibly be useful for risk assessment of diabetic microvascular complications.Trial registration number UMIN000032325.

Associations between continuous glucose monitoring-derived metrics and arterial stiffness in Japanese patients with type 2 diabetes.

BACKGROUND: Previous studies have suggested that high mean glucose levels and glycemic abnormalities such as glucose fluctuation and hypoglycemia accelerate the progression of atherosclerosis in patients with type 2 diabetes. Although continuous glucose monitoring (CGM) that could evaluate such glycemic abnormalities has been rapidly adopted, the associations between CGM-derived metrics and arterial stiffness are not entirely clear. METHODS: This exploratory cross-sectional study used baseline data from an ongoing prospective, multicenter, observational study with 5 years of follow-up. Study participants included 445 outpatients with type 2 diabetes and no history of apparent cardiovascular disease who underwent CGM and brachial-ankle pulse wave velocity (baPWV) measurement at baseline. Associations between CGM-derived metrics and baPWV were analyzed using multivariate regression models. RESULTS: In a linear regression model, all CGM-derived metrics were significantly associated with baPWV, but HbA1c was not. Some CGM-derived metrics related to intra-day glucose variability, hyperglycemia, and hypoglycemia remained significantly associated with baPWV after adjusting for possible atherosclerotic risk factors, including HbA1c. Based on baPWV ≥ 1800 cm/s as indicative of high arterial stiffness, multivariate logistic regression found that some CGM-derived metrics related to intra-day glucose variability and hyperglycemia are significantly associated with high arterial stiffness even after adjusting for possible atherosclerotic risk factors, including HbA1c. CONCLUSIONS: Multiple CGM-derived metrics are significantly associated with baPWV and high arterial stiffness in patients with type 2 diabetes who have no history of apparent cardiovascular disease. These metrics might be useful for identifying patients at high risk of developing cardiovascular disease.

Protocol of a Prospective Observational Study on the Relationship Between Glucose Fluctuation and Cardiovascular Events in Patients with Type 2 Diabetes.

INTRODUCTION: A recent study demonstrated that large glucose fluctuations were associated with an increased incidence of cardiovascular disease (CVD) in patients with type 2 diabetes mellitus (T2DM) and acute myocardial infarction. However, it is unknown whether glucose fluctuations are related to the incidence of CVD or the progression of atherosclerosis in patients with T2DM with no apparent history of CVD. In this protocol, we will be investigating the relationships of glucose fluctuations evaluated by continuous glucose monitoring (CGM) to the incidence of composite cardiovascular events and the progression of atherosclerosis in patients with T2DM who had no apparent history of CVD. METHODS: This is a prospective, multicenter, 5-year follow-up observational study. Between April 2018 and October 2019, 1000 participants are expected to be recruited at 34 medical institutions. CGM using FreeStyle Libre Pro is useful for evaluating glucose fluctuations by continuously monitoring glucose levels in interstitial fluid for up to 14 days. The primary study outcome is the relationship between fluctuations in glucose levels evaluated by CGM and the incidence of composite cardiovascular events. Secondary outcomes include the relationships of fluctuations in glucose levels evaluated by CGM to changes in carotid intima media thickness evaluated by echography or grayscale median (an index of tissue characteristics of the carotid wall), brachial-ankle pulse wave velocity, development or progression of diabetic retinopathy or nephropathy, quality-of-life-related diabetes therapy, quality of sleep, development of dementia, and autonomic nerve function. PLANNED OUTCOME: This protocol is designed to investigate the relationship between glucose fluctuations and the incidence of composite cardiovascular events. We completed the registration of 1000 participants in March 2019. Thus, results will be available in 2024. We expect that evaluating glucose fluctuations will aid the identification of patients with a high probability of developing CVD. TRIAL REGISTRATION: ClinicalTrials.gov identifier, UMIN000032325.

Comparability of epidemiological information between self- and interviewer-administered questionnaires.

The aim of the present study was to determine the extent to which respondents provided the same answers to a health-related lifestyle questionnaire in self- and interviewer-administered forms. A total of 234 subjects completed a 110-item questionnaire in both interviewer and self-administered forms. Modes of administration were separated by a 2-week interval. The order was determined by random allocation. The presence and the extent of the tendency to give socially acceptable responses were evaluated using percentage of bias calculated as the ratio of the difference in proportion of positive responses or the mean between interviews and questionnaires and those in questionnaires. All percentages of bias were in the positive direction, ranging from 1.4% (physical exercise) to 26.1% (general life stress). The average percentage of bias was higher in women than in men and were stronger for younger respondents. The age differences between interviewer and respondent were inversely and most strongly related to percentage of bias. Self- and interviewer-administered questionnaires yield very similar results in discriminating between subjects, but the interviewer-administered questionnaire showed systematically more desirable responses to questions related to lifestyle factors. The differences in characteristics between interviewer and respondent may be important determinants of the socially desirability bias in the interview.