Visit-to-visit systolic blood pressure variability and microvascular complications among patients with diabetes

Minimum number of readings necessary for determining long-term visit-to-visit blood pressure variability to predict cardiovascular outcomes in people with diabetes

BACKGROUND

People with diabetes often have increased blood pressure (BP) variability because of autonomic dysfunction and arterial stiffness, making it a critical factor in predicting clinical outcomes. We investigated the reproducibility of long-term visit-to-visit BP variability (VVV) and the minimum number of BP readings to reliably determine VVV in people with diabetes.

METHODS

This multicenter retrospective study used data from electronic health records of the Korea University Medical Center database. Altogether, 10 475 people with diabetes who had more than nine BP readings during a maximum period of 2 years were identified. This study focused on the coefficient of variation of these readings and their correlation with major adverse cardiovascular events (MACE) over a 3-year follow-up period.

RESULTS

The mean age of the participants was 65.2 years. Of these, 53.2% were men, and 87.4% had hypertension. The mean coefficient of variation of multiple SBP readings that best predicted the 3-year MACE were 8.4, 9.5, 9.0, 9.0, and 9.7 for three, five, seven, nine, and all readings, respectively. Patients with high VVV (coefficient of variation of five SBP readings >9) exhibited a higher incidence of 3-year MACE (10.1%) than those with low VVV (5.4%, P  < 0.001). In the multivariable analysis, high VVV of both SBP and DBP were independently associated with 3-year MACE.

CONCLUSION

Long-term VVV in the BP is a reproducible and reliable predictor of cardiovascular outcomes in people with diabetes. A minimum of five BP measurements are recommended for effective intraindividual VVV estimation and cardiovascular risk assessment.

Visit-to-visit variability of blood pressure and risk of diabetic retinopathy: a systematic review and meta-analysis

BACKGROUND

Diabetes mellitus (DM), a worldwide disease affecting more than 400 million people, is associated with high blood pressure (BP). In addition to macrovascular complications, high BP in DM patients is potentially linked to microvascular complications. More than 70% of DM patients have retinopathy. To our knowledge, no systematic review and meta-analysis has been conducted on the relationship between visit-to-visit variability in blood pressure and diabetic retinopathy risk.

METHODS

This systematic review and meta-analysis study was performed on the related articles. The search strategy, screening, and data selection were all checklist-based. A comprehensive search was done in three databases, including PubMed, Google Scholar, and Scopus. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) were followed. English clinical studies published up to January 2023 contained diabetic patients as the population, retinopathy as the outcome, and visit-to-visit blood pressure as the intervention. Using the QUIPS technique, two authors independently quantify the risk of bias in included publications. The meta-analysis was conducted using R version 4.4.1. We calculated relative risk (RR) as the effect size, applying the random effect model. Standard deviation (SD) and coefficient of variation (CV), were used as measures of BP variability.

RESULTS

A total number of 8 studies with 743,315 participants were covered in this systematic review. After meta-analysis, we concluded that the group with higher SD of BP variability had 2 percent higher risk than the control group (RR = 1.02, 95% CI = 1.01-1.03, I-squared = 41%); however, results of our analysis for CV of BP variability showed no significant contrast with control group thus no increased risk was reported (RR = 1.04, 95% CI = 0.94-1.15, I-squared = 32%, P-value = 0.23).

CONCLUSION

In conclusion, an increased SD of BP variability significantly increased the relative risk for the development of retinopathy.

Association of blood pressure with incident diabetic microvascular complications among diabetic patients: Longitudinal findings from the UK Biobank

Background

Evidence suggests a correlation of blood pressure (BP) level with presence of diabetic microvascular complications (DMCs), but the effect of BP on DMCs incidence is not well-established. We aimed to explore the associations between BP and DMCs (diabetic retinopathy, diabetic kidney disease, and diabetic neuropathy) risk in participants with diabetes.

Methods

This study included 23 030 participants, free of any DMCs at baseline, from the UK Biobank. We applied multivariable-adjusted Cox regression models to estimate BP-DMCs association and constructed BP genetic risk scores (GRSs) to test their association with DMCs phenotypes. Differences in incidences of DMCs were also compared between the 2017 ACC/AHA and JNC 7 guidelines (traditional criteria) of hypertension.

Results

Compared to systolic blood pressure (SBP)<120 mm Hg, participants with SBP≥160 mm Hg had a hazard ratio (HR) of 1.50 (95% confidence interval (CI) = 1.09, 2.06) for DMCs. Similarly, DMCs risk increased by 9% for every 10 mm Hg of higher SBP at baseline (95% CI = 1.04, 1.13). The highest tercile SBP GRS was associated with 32% higher DMCs risk (95% CI = 1.11, 1.56) compared to the lowest tercile. We found no significant differences in DMCs incidence between JNC 7 and 2017 ACC/AHA guidelines.

Conclusions

Genetic and epidemiological evidence suggests participants with higher SBP had an increased risk of DMCs, but hypertension defined by 2017 ACC/AHA guidelines may not impact DMCs incidence compared with JNC 7 criteria, contributing to the care and prevention of DMCs.

American Association of Clinical Endocrinology Clinical Practice Guideline: Developing a Diabetes Mellitus Comprehensive Care Plan-2022 Update

OBJECTIVE

The objective of this clinical practice guideline is to provide updated and new evidence-based recommendations for the comprehensive care of persons with diabetes mellitus to clinicians, diabetes-care teams, other health care professionals and stakeholders, and individuals with diabetes and their caregivers.

METHODS

The American Association of Clinical Endocrinology selected a task force of medical experts and staff who updated and assessed clinical questions and recommendations from the prior 2015 version of this guideline and conducted literature searches for relevant scientific papers published from January 1, 2015, through May 15, 2022. Selected studies from results of literature searches composed the evidence base to update 2015 recommendations as well as to develop new recommendations based on review of clinical evidence, current practice, expertise, and consensus, according to established American Association of Clinical Endocrinology protocol for guideline development.

RESULTS

This guideline includes 170 updated and new evidence-based clinical practice recommendations for the comprehensive care of persons with diabetes. Recommendations are divided into four sections: (1) screening, diagnosis, glycemic targets, and glycemic monitoring; (2) comorbidities and complications, including obesity and management with lifestyle, nutrition, and bariatric surgery, hypertension, dyslipidemia, retinopathy, neuropathy, diabetic kidney disease, and cardiovascular disease; (3) management of prediabetes, type 2 diabetes with antihyperglycemic pharmacotherapy and glycemic targets, type 1 diabetes with insulin therapy, hypoglycemia, hospitalized persons, and women with diabetes in pregnancy; (4) education and new topics regarding diabetes and infertility, nutritional supplements, secondary diabetes, social determinants of health, and virtual care, as well as updated recommendations on cancer risk, nonpharmacologic components of pediatric care plans, depression, education and team approach, occupational risk, role of sleep medicine, and vaccinations in persons with diabetes.

CONCLUSIONS

This updated clinical practice guideline provides evidence-based recommendations to assist with person-centered, team-based clinical decision-making to improve the care of persons with diabetes mellitus.

The Impact of Systolic Blood Pressure, Pulse Pressure, and Their Variability on Diabetes Retinopathy among Patients with Type 2 Diabetes

OBJECTIVES

To evaluate the effects of variations in systolic blood pressure (SBP) and pulse pressure (PP) on diabetic retinopathy (DR) in patients with type 2 diabetes.

METHODS

A total of 3275 type 2 diabetes patients without DR at Taiwan Lee's United Clinic from 2002 to 2014 were enrolled in the study. The average age of the patients was 65.5 (±12.2) years, and the follow-up period ranged from 3 to 10 years. Blood pressure variability was defined as the standard deviation (SD) of the average blood pressure values over the entire study period and was calculated for each patient. The mean SD for SBP was 11.16, and a SBP ≥ 130 mmHg (1 mmHg = 0.133 kPa) was defined as high SBP. Based on these data, patients were divided into four groups as follows: group 1 (G1, mean SBP < 130 mmHg, SD of SBP < 11.16 mmHg), group 2 (G2, mean SBP < 130 mmHg, SD ≥ 11.16 mmHg), group 3 (G3, mean SBP ≥ 130 mmHg, SD of SBP < 11.16 mmHg), and group 4 (G4, mean SBP ≥ 130 mmHg, SD ≥ 11.16 mmHg). Based on a mean PP of 80 mmHg with a pulse pressure SD of 6.53 mmHg, the patients were regrouped into four groups designated G1'-G4'.

RESULTS

After adjusting for patient age, sex, and disease course, Cox regression showed that the mean and SD of SBP, pulse pressure, and their SDs were risk factors for DR. After stratifying the patients based on the mean and SD of the SBP, we found that the patients in the G4 group had the highest risk of DR (hazard ratio (HR) = 1.980, 95% CI: 1.716~2.285, P < 0.01) and patients in the G1 group had the lowest risk. Patients in the G3 group (HR = 1.409, 95% CI: 1.284~1.546, P < 0.01) had a higher risk of DR compared to those in the G2 group (HR = 1.353, 95% CI: 1.116~1.640, P < 0.01). After the restratification of patients based on the mean and SD of the pulse pressures, it was found that patients in the G2' group had the highest risk of DR (HR = 2.086, 95% CI: 1.641~2.652, P < 0.01), whilst patients in the G1' group had the lowest risk. Also, the risk of DR in the G4' group (HR = 1.507, 95% CI: 1.135~2.000, P < 0.01) was higher than that in the G3' group (HR = 1.289, 95% CI: 1.181~1.408, P < 0.01).

CONCLUSIONS

Variability in SBP and PP are risk factors for DR in patients with type 2 diabetes. The variability of PP was better able to predict the occurrence of DR than mean pulse pressure.

Long-term blood pressure variability, incidence of hypertension and changes in renal function in type 2 diabetes

OBJECTIVES

Long-term visit-to-visit SBP variability (VVV) predicts cerebro-cardiovascular and renal events in patients with hypertension. Whether VVV predicts hypertension and/or chronic kidney disease is currently unknown. We assessed the role of VVV on the development of hypertension and changes in renal function in patients with type 2 diabetes and normal blood pressure (NBP) in a real-life clinical setting.

METHODS

Clinical records from 8998 patients with type 2 diabetes, NBP, and normal estimated glomerular filtration rate (eGFR) were analyzed. VVV was measured by SD of the mean SBP recorded in at least four visits during 2 consecutive years before follow-up. Hypertension was defined as SBP at least 140 mmHg and DBP at least 90 mmHg or the presence of antihypertensive treatment. Renal function was defined as worsening of albuminuria status and/or a reduction in eGFR at least 30% from baseline.

RESULTS

After a mean follow-up time of 3.5 ± 2.8 years, 3795 patients developed hypertension (12.1 per 100 person-years). An increase of 5 mmHg VVV was associated with a 19% (P < 0.0001) and a 5% (P = 0.008) independent increased risk of developing hypertension and worsening of albuminuria, respectively. We found no association between VVV and eGFR decrease from baseline. Patients with VVV in the upper quartile (>12.8 mmHg) showed a 50% increased risk of developing hypertension (P < 0.0001) and an almost 20% increased risk of worsening albuminuria (P = 0.004) as compared with those in the lower one (<6.9 mmHg).

CONCLUSION

Increased VVV independently predicts incident hypertension and albuminuria worsening in type 2 diabetes and NBP.

Hypertension and diabetes mellitus: highlights of a complex relationship

PURPOSE OF REVIEW

Herein, we provide a review of the recent literature on the epidemiological and pathophysiological relationship between hypertension (HTN) and diabetes mellitus, along with prognostic implications and current treatment concepts.

RECENT FINDINGS

Diabetes mellitus affects ∼10% of US adults. The prevalence of HTN in adults with diabetes mellitus was 76.3% or 66.0% based on the definitions used by guidelines. There exist differences among major society guidelines regarding the definition of HTN and target blood pressure (BP) levels. Recent basic and clinical research studies have shed light on pathophysiologic and genetic links between HTN and diabetes mellitus. Randomized controlled trials over the past 5 years have confirmed the favorable BP and cardiovascular risk reduction by antidiabetic agents.

SUMMARY

HTN and diabetes mellitus are 'silent killers' with rising global prevalence. The development of HTN and diabetes mellitus tracks each other over time. The coexistence of both clinical entities synergistically contributes to micro- and macro-vasculopathy along with cardiovascular and all-cause mortality. Various shared mechanisms underlie the pathophysiological relationship between HTN and diabetes mellitus. Moreover, BP reduction with lifestyle interventions and antihypertensive agents is a primary target for reducing cardiovascular risk among patients with HTN and diabetes mellitus.

Relationship between arterial stiffness and variability of home blood pressure monitoring

Variability of blood pressure (BP) is known as a prognostic value for the subsequent target organ damage in hypertensive patients. Arterial stiffness is a risk factor for cardiovascular morbidity and mortality. The relationship between the arterial stiffness and the BP variability has been controversial. The objective of the present study was to investigate the relationship between arterial stiffness and home BP variability in patients with high normal BP and new onset hypertension (HTN).Four hundred sixty three patients (252 males, 49 ± 12 year-old) with high normal BP or HTN were enrolled. Using radial applanation tonometry, pulse wave analysis (PWA) was performed for evaluation of systemic arterial stiffness. All patients underwent both home BP monitoring (HBPM) and PWA. Home BP variability was calculated as the standard deviation (SD) of 7 measurements of HBPM. Multiple linear regression analysis was performed to estimate and test the independent effects of home BP variability on the arterial stiffness.Mutivariate analysis showed that both systolic and diastolic morning BP variabilities were correlated with arterial stiffness expressed as augmentation pressure (AP, β-coefficient = 1.622, P = .01 and β-coefficient = 1.07, P = .035). The SDs of systolic and diastolic BP of evening were also associated with AP (β-coefficient = 1.843, P = .001 and β-coefficient = 1.088, P = .036). The SDs of morning and evening systolic BP were associated with augmentation index (AI, β-coefficient = 1.583, P = .02 and β-coefficient = 1.792, P = .001) and heart rate (75 bpm) adjusted AI (β-coefficient = 1.592, P = .001 and β-coefficient = 1.792, P = .001).In present study, the variability of systolic BP was closely related with arterial stiffness. The home BP variability might be important indicator of arterial stiffness.

Visit-to-visit blood pressure variability and risk of chronic kidney disease: A systematic review and meta-analyses

Objective

Previous studies have shown that visit-to-visit blood pressure variability (BPV) is associated with chronic kidney disease (CKD). However, the results have not been consistent among studies. This systematic review and meta-analysis was conducted to comprehensively assess the association between visit-to-visit BPV and the risk of CKD.

Methods

Medline, Embase, and the Cochrane Library were searched from the date of inception through 1 August 2019 using the terms “blood pressure variability,” “chronic kidney disease,” “nephropathy,” and other comparable terms. The primary outcome was the development of CKD. Two reviewers extracted the data independently. Meta-analysis was performed using a random effects model.

Results

Fourteen studies were included in the systematic review and meta-analysis. The risk of CKD was significantly greater in patients with high baseline systolic blood pressure variability (SBPV) than in patients with low baseline SBPV: the standard deviation (SD) showed relative risk (RR) of 1.69 and 95% CI of 1.38–2.08, the coefficient of variation (CV) showed RR of 1.23 and 95% CI of 1.12–1.36, and variance independent of mean (VIM) showed RR of 1.40 and 95% CI of 1.15–1.71. RRs for each unit increase in visit-to-visit SBPV and risk of CKD were 1.05 (95% CI: 1.03–1.07) for SD, 1.06 (95% CI: 1.03–1.09) for CV, and 1.1 (95% CI: 0.96–1.25) for VIM. Diastolic BPV was similarly predictive of CKD based on SD and CV.

Conclusions

Increased visit-to-visit BPV might be an independent risk factor for CKD. However, significant heterogeneity was present; thus, future prospective studies are needed to confirm our findings. Our results indicate that treatment of hypertension should control blood pressure levels and prevent abnormal fluctuations in blood pressure to reduce the risk of CKD.

Prognostic importance of visit-to-visit blood pressure variability for micro- and macrovascular outcomes in patients with type 2 diabetes: The Rio de Janeiro Type 2 Diabetes Cohort Study

BACKGROUND

The prognostic importance of an increased visit-to-visit blood pressure variability (BP-VVV) for the future development of micro- and macrovascular complications in type 2 diabetes has been scarcely investigated and is largely unsettled. We aimed to evaluate it in a prospective long-term follow-up study with 632 individuals with type 2 diabetes.

METHODS

BP-VVV parameters (systolic and diastolic standard deviations [SD] and variation coefficients) were measured during the first 24-months. Multivariate Cox analysis, adjusted for risk factors and mean BP levels, examined the associations between BP-VVV and the occurrence of microvascular (retinopathy, microalbuminuria, renal function deterioration, peripheral neuropathy) and macrovascular complications (total cardiovascular events [CVEs], major adverse CVEs [MACE] and cardiovascular and all-cause mortality). Improvement in risk discrimination was assessed by the C-statistic and integrated discrimination improvement (IDI) index.

RESULTS

Over a median follow-up of 11.3 years, 162 patients had a CVE (132 MACE), and 212 patients died (95 from cardiovascular diseases); 153 newly-developed or worsened diabetic retinopathy, 193 achieved the renal composite outcome (121 newly-developed microalbuminuria and 95 deteriorated renal function), and 171 newly-developed or worsened peripheral neuropathy. Systolic BP-VVV was an independent predictor of MACE (hazard ratio: 1.25, 95% CI 1.03-1.51 for a 1-SD increase in 24-month SD), but not of total CVEs, cardiovascular and all-cause mortality, and of any microvascular outcome. However, no BP-VVV parameter significantly improved cardiovascular risk discrimination (increase in C-statistic 0.001, relative IDI 0.9%).

CONCLUSIONS

Systolic BP-VVV was an independent predictor of MACE, but it did not improve cardiovascular risk stratification. The goal of anti-hypertensive treatment in patients with type 2 diabetes shall remain in controlling mean BP levels, not on decreasing their visit-to-visit variability.

Retrospective cohort study of the relationship between systolic blood pressure variability and multiple sclerosis disability

OBJECTIVE

To examine the relationship between visit-to-visit systolic blood pressure (SBP) variability and patient-reported outcome measure of disability in multiple sclerosis (MS) patients.

DESIGN

A retrospective cohort study of individuals with MS who completed a patient-determined disease steps (PDDS) scale between 2011 and 2015 at an MS specialty clinic.

PARTICIPANTS

Individuals with MS for whom both a completed PDDS scale and ≥3 SBP measures within the prior 12 months of the survey were available.

MAIN OUTCOME MEASURE

Participants were grouped into three classes of disability (no or mild (PDDS 0-1), moderate (2-3), severe (4-7)). SBP variability was calculated as within-subject SD using all SBP measures taken during the past 12 months. SBP variability was analysed by Tertile groups.

RESULTS

Ninety-two subjects were included in this analysis. Mean PDDS score was 2.22±1.89. Compared with subjects in Tertile 1 (lowest variability), the odds of being in a higher disability group was 3.5 times higher (OR=3.48; 95% CI: 1.08 to 11.25; p=0.037) in Tertile 2 and 5.2 times higher (OR=5.19; 95% CI: 1.53 to 17.61; p=0.008) in Tertile 3 (highest variability), independent of mean SBP, age, sex, race/ethnicity, body mass index and comorbidities (p for trend=0.008). Mean PDDS scores were 1.52±1.18 in Tertile 1, 2.73±1.02 in Tertile 2 and 2.42±0.89 in Tertile 3 after adjusting for the same covariates.

CONCLUSIONS

Our results show a significant gradient relationship between SBP variability and MS-related disability. More research is needed to determine the underlying pathophysiological relationship between SBP variability and MS disability progression.

The link between elevated long-term resting heart rate and SBP variability for all-cause mortality

BACKGROUND

Resting heart rate (RHR) and SBP are important risk markers for all-cause mortality. However, the link between increased RHR and SBP for all causes of death remained unclear. We investigated the link between an increased visit-to-visit variation of RHR and SBP for risk of all-cause mortality in the general population.

METHODS

We examined long-term visit-to-visit variation of RHR and blood pressure among 46 751 residents of Tangshan city, China (mean age: 52.58 ± 11.64 years; 78% men). Cox proportional hazard model was used to estimate the hazard ratios and 95% confidence interval (CI) adjusting for clinical characteristics assessed at the last examination (2010-2011).

RESULTS

A total of 1667 deaths were recorded over 4.97 ± 0.69 years follow-up. A rise in 1 SD of heart rate (4 bpm) was associated with an increased risk of death among the participants in third and fourth quartile of SBP-SD in the subgroups of general population [hazard ratio (95% CI) = 1.10 (1.03-1.67) and 1.16 (1.03-1.30), respectively], men [hazard ratio (95% CI) = 1.10 (1.02-1.17) and 1.16 (1.03-1.30), respectively], and participants under 65 years of age [hazard ratio (95% CI) = 1.16 (1.02-1.33) and 1.20 (1.03-1.39), respectively]. Similarly, 1-SD increase of SBP (7 mmHg) was associated with an increased risk of death among the participants in the highest quartiles of RHR-SD in the subgroups of the general population, men, and under 65 years of age.

CONCLUSION

An elevated long-term SBP variability combined with an increased RHR variability or vice versa may amplify the risk of all-cause mortality in general population, as well as in men and middle-age group.

Association between blood pressure variability, cardiovascular disease and mortality in type 2 diabetes: A systematic review and meta-analysis

AIM

To investigate the associations of blood pressure variability (BPV), expressed as long-term (visit-to-visit) and short-term (ambulatory blood pressure monitoring [ABPM] and home blood pressure monitoring [HBPM]) and all-cause mortality, major adverse cardiovascular events (MACEs), extended MACEs, microvascular complications (MiCs) and hypertension-mediated organ damage (HMOD) in adult patients with type 2 diabetes.

MATERIALS AND METHODS

PubMed, Medline, Embase, Cinahl, Web of Science, ClinicalTrials.gov and grey literature databases were searched for studies including patients with type 2 diabetes, at least one variable of BPV (visit-to-visit, HBPM, ABPM) and evaluation of the incidence of at least one of the following outcomes: all-cause mortality, MACEs, extended MACEs and/or MiCs and/or HMOD. The extracted information was analyzed using random effects meta-analysis and meta-regression.

RESULTS

Data from a total of 377 305 patients were analyzed. Systolic blood pressure (SBP) variability was associated with a significantly increased risk of all-cause mortality (HR 1.12, 95% CI 1.04-1.21), MACEs (HR 1.01, 95% CI 1.04-1.17), extended MACEs (HR 1.07, 95% CI 1.03-1.11) and MiCs (HR 1. 12, 95% CI 1.01-1.24), while diastolic blood pressure was not. Associations were mainly driven from studies on long-term SBP variability. Qualitative analysis showed that BPV was associated with the presence of HMOD expressed as carotid intima-media thickness, pulse wave velocity and left ventricular hypertrophy. Results were independent of mean blood pressure, glycaemic control and serum creatinine levels.

CONCLUSIONS

Our results suggest that BPV might provide additional information rather than mean blood pressure on the risk of cardiovascular disease in patients with type 2 diabetes.

Effect of angiotensin II receptor blocker and salt supplementation on short-term blood pressure variability in type 2 diabetes

High blood pressure variability (BPV) has been associated with increased cardiovascular (CV) risk. The effect of dietary salt and renin-angiotensin-aldosterone system (RAAS) activity on short-term BPV in type 2 diabetes mellitus (T2DM) is not well characterised. We aimed to determine the effect of dietary salt (sodium chloride, NaCl) supplementation on 24-h mean arterial BPV (24hBPV) during angiotensin II receptor blocker (telmisartan) use and to evaluate the effects of age, sex, plasma renin activity (PRA) and serum aldosterone on 24hBPV. In a randomised, double-blind, crossover study, patients with T2DM (n = 28), treated with telmisartan received NaCl (100 mmol/24 h) or placebo capsules during 2 weeks of telmisartan. Following a 6-week washout, the protocol was repeated in reverse. 24hBPV was evaluated as a co-efficient of variation [CV (%) = mean/standard deviation] × 100). Twenty-four hour urinary sodium excretion, ambulatory BP and biochemical tests were performed at each phase. Results were analysed using a linear mixed model to generate predicted values for 24hBPV. Predicted 24hBPV was higher with telmisartan vs baseline (p = 0.01), with a trend towards reduced 24hBPV with salt (p = 0.052). Predicted 24hBPV was lower in females (p = 0.017), increasing age (p = 0.001) and increasing PRA (p = 0.011). In patients with T2DM, predicted 24hBPV increased from baseline with telmisartan, but there was no additional increase in predicted 24hBPV with salt supplementation. This suggests that in the short-term, salt supplementation has no apparent deleterious effects on 24hBPV. Long-term studies are required to evaluate the effect of 24hBPV on CV outcomes in patients with T2DM.

Increasing SBP variability is associated with an increased risk of developing incident diabetic foot ulcers

OBJECTIVE

SBP variability may be a target for mitigating end-organ damage associated with vascular disease. We evaluated the relationship between increased SBP variability and risk of incident diabetic foot ulceration.

METHODS

Using a nested case-control design, we followed patients diagnosed with diabetes and treated within the US Department of Veterans Affairs Healthcare system for development of a diabetic foot ulcer (event) between 2006 and 2010. Each case was randomly matched to up to five controls based on age, sex, race/ethnicity, and calendar time. SBP variability was computed using at least three blood pressure measurements from the year preceding the event. The association between SBP variability and foot ulceration was examined using conditional logistic regression. Potential protective effects of calcium channel blockers, which blunt SBP variability, were also explored.

RESULTS

The study sample included 51 111 cases and 129 247 controls. Compared with those in quartile 1 (lowest variability), patients in quartiles 2-4 had higher adjusted odds ratios for diabetic foot ulcer development: 1.11 (95% CI 1.07-1.16), 1.20 (95% CI 1.15-1.25), 1.29 (95% CI 1.24-1.34) (P for trend <0.001). Calcium channel blockers were associated with reduced risks of ulceration for those without peripheral vascular disease (OR = 0.87, 95% CI 0.84-0.90, P < 0.001) or neuropathy (OR = 0.85, 95% CI 0.82-0.89, P < 0.001) in adjusted subgroup analyses.

CONCLUSION

This study describes a graded relationship between SBP variability and risk of diabetic foot ulceration, providing a potential new and modifiable target to reduce this common complication.

Association of Visit-to-Visit Variability of Blood Pressure with Cardiovascular Disease among Type 2 Diabetes Mellitus Patients: A Cohort Study

BACKGROUND

Increasing evidence has shown that visit-to-visit variability (VVV) of blood pressure (BP) is associated with an increased risk of cardiovascular disease (CVD). The objective of this study was to evaluate the impact of VVV of systolic blood pressure (SBP) and diastolic blood pressure (DBP) on the risk of CVD among patients with type 2 diabetes mellitus (T2DM) in China.

METHODS

We conducted a retrospective cohort study of 10,163 T2DM patients who were not previously diagnosed with CVD from January 2008 to December 2012 in Ningbo, China. The VVV of BP was calculated using five metrics, including standard deviation (SD), coefficient of variation (CV), variation independent of mean, average real variability, and successive variability (SV) of measurements, obtained over a 24-month measurement period. Hazard ratios and 95% confidence intervals (CIs) were estimated by Cox proportional hazards regression models for the associations of variability in BP with risk of CVD.

RESULTS

A total of 894 CVD events were observed during a median follow-up of 49.5 months. The hazard ratio in the highest quintile of SD of SBP was 1.24 (95% CI, 1.01 to 1.52) compared with patients in the lowest quintile. The association between higher VVV of DBP and risk of CVD was not consistent across different metrics and sensitivity analyses.

CONCLUSION

Higher VVV of SBP was associated with an increased risk of CVD, irrespective of the mean SBP level. Future studies are needed to confirm these findings.

Blood Pressure Variability and Autonomic Dysfunction

PURPOSE OF REVIEW

This review considers the relationship between abnormal blood pressure (BP) variability and autonomic dysfunction through an attempt to answer questions about its clinical relevance and pertinence to diabetes and cardiovascular autonomic neuropathy (CAN) and which therapeutic measures can lessen its cardiovascular impact.

RECENT FINDINGS

Office, ambulatory, and home BP monitoring identify posture-related, circadian, short-term, and long-term BP variabilities. Abnormal BP variability is a risk marker for organ damage, mortality, and cardiovascular events. Moreover, BP variability changes are common in diabetes and associated with CAN and possibly exacerbated by comorbidities like nephropathy, obstructive sleep apnoea syndrome, and chronic pain. The prognostic role of nondipping and reverse dipping is well documented in diabetes. Some findings suggest the possibility of restoring dipping with the dosage time of antihypertensive agents. Diabetes is a favorable scenario for altered BP variability, which might mediate the harmful effects of CAN. Preliminary data suggest the protective effect of targeting BP variability. However, further longitudinal outcome studies are needed. In the meantime, BP variability measures and practical expedients in antihypertensive treatment should be implemented in diabetes.

Prognostic impact of systolic blood pressure variability in people with diabetes

Objective

Blood pressure variability (BPV) has been associated with risk of cardiovascular events in observational studies, independently of mean BP levels. In states with higher autonomic imbalance, such as in diabetes, the importance of BP variability may theoretically be even greater. We aimed to investigate the incremental value of BPV for prediction of cardiovascular and all-cause mortality in patients with type 2 diabetes.

Methods

We identified 9,855 patients without pre-existing cardiovascular disease who did not change BP-lowering treatment during the observation period from a Swedish primary health care cohort of patients with type 2 diabetes. BPV was summarized as the standard deviation (SD), coefficient of variation (CV), or variation independent of mean (VIM). Patients were followed for a median of 4 years and associations with cardiovascular and all-cause mortality were investigated using Cox proportional hazards models.

Results

BPV was not associated with cardiovascular specific or all-cause mortality in the total sample. In patients who were not on BP-lowering drugs during the observation period (n = 2,949), variability measures were associated with all-cause mortality: hazard ratios were 1.05, 1.04 and 1.05 for 50% increases in SD, CV and VIM, respectively, adjusted for Framingham risk score risk factors, including mean BP. However, the addition of the variability measures in this subgroup only led to very minimal improvement in discrimination, indicating they may have limited clinical usefulness (change in C-statistic ranged from 0.000–0.003 in all models).

Conclusions

Although BPV was independently associated with all-cause mortality in diabetes patients in primary care who did not have pre-existing cardiovascular disease or BP-lowering drugs, it may be of minimal clinical usefulness above and beyond that of other routinely measured predictors, including mean BP.

Visit-to-visit HbA1c variability and systolic blood pressure (SBP) variability are significantly and additively associated with mortality in individuals with type 1 diabetes: An observational study

AIM

To investigate the relationship between variability in both visit-to-visit HbA1c and SBP and mortality in individuals with type 1 diabetes.

METHODS

The Scottish Care Information (SCI) Diabetes dataset was used to identify 5952 individuals with type 1 diabetes for inclusion in this observational study. The SCI-Diabetes dataset allowed access to blood pressure values, HbA1c readings, demographic information and mortality rates for all study participants. Participants were dichotomized to above and below median values for both HbA1c coefficient of variation (CV) and SBP CV, thus dividing participants into 4 cohorts for survival analysis. Survival analysis was carried out over 1430 days. A Cox proportional hazard model was used to allow comparison of mortality between the 4 cohorts.

RESULTS

Of the 5952 patients, death occurred in 416. CV for both HbA1c and SBP were significantly associated with mortality. The median values for HbA1c CV and SBP CV were 8.0 and 8.1, respectively. The hazard ratio for high HbA1c CV only (P = .0015) was 1.78 ± 0.36. The hazard ratio for high SBP CV only (P = .0018) was 1.69 ± 0.33. The hazard ratio for both high HbA1c CV and high SBP CV (P < .00001) was 2.37 ± 0.32.

CONCLUSIONS

Our findings demonstrate that variability of both HbA1c and SBP is significantly and additively associated with mortality in individuals with type 1 diabetes. The variability of these parameters might be useful for risk stratification and is a potential target for future interventional studies.

Methodological factors affecting quantification of blood pressure variability: a scoping review

OBJECTIVES

Blood pressure (BP) variability (BPV) may offer independent prognostic information. However, data supporting this notion are inconsistent, and this may be due to the wide variety of methodologies used for measuring BPV. A systematic analysis on the effect of BPV methodologies on BPV itself has never been undertaken and was the aim of this study. We also sought to determine the effect of participant characteristics on BPV.

METHODS

A scoping review process was used to identify the effect of BPV methodologies on BPV magnitude. Key methodological factors assessed were the number of BP readings or visits used to quantify BPV and the duration of BP monitoring. In addition, the relationship between age and mean BP level on BPV was investigated. Analyses were performed across studies that measured BPV over the short-term (using 24-h BP), mid-term (using home BP in the morning, evening or day-to-day) and long-term (using visit-to-visit clinic BP).

RESULTS

Data were extracted from 96 studies. The number of BP readings and visits used to quantify BPV were positively associated with mid-term and long-term BPV. Duration was weakly associated with mid-term (morning) BPV. Age was positively associated with long-term and mid-term (day-to-day), but not short-term BPV. Mean BP level was positively associated with BPV, except mid-term BPV (morning and evening).

CONCLUSION

The methodology used to quantify BPV, as well as age and mean BP level, affects the magnitude of BPV itself. This highlights the need to standardize BPV protocols, particularly regarding the number of BP readings and visits.

Periodic microstructures of blood capillaries revealed by synchrotron X-ray multi-resolution microscopic analysis

Cardiovascular diseases are closely related to structural blood capillaries lesions. Herein, microscopic investigations of mouse blood capillaries were performed at multiple spatial resolution by using synchrotron X-ray in-line phase contrast tomography and scanning transmission X-ray microscopy (STXM). The chemically fixed blood capillaries without any contrast agents were selected. For the first time, a periodic bamboo-shaped structure was observed at nanoscale resolution by STXM, and the three-dimensional tomographic slices at sub-micrometer resolution further confirmed the periodic wave profile of the blood capillaries. Then, a periodic microstructural model was suggested based on the microscopic images. By using high-performance imaging techniques, this work provides a better understanding of the relationship between the structure and function of blood capillaries, will be helpful in elucidating the causes of cardiovascular system diseases.

Predictive ability of visit-to-visit variability in HbA1c and systolic blood pressure for the development of microalbuminuria and retinopathy in people with type 2 diabetes

AIMS

We explored whether visit-to-visit variability in both glycated hemoglobin (HbA1c) and systolic blood pressure (SBP) simultaneously predicted the development of microalbuminuria and retinopathy, and whether the predictive ability of these measurements changed according to mean HbA1c and SBP levels in people with type 2 diabetes.

METHODS

A retrospective observational cohort study was conducted on 243 type 2 diabetes patients with normoalbuminuria and 486 without retinopathy at the first visit and within 1year thereafter. The two cohorts were followed up from 1995 until 2012. Multivariate and stratified analyses were performed using Cox proportional hazard models.

RESULTS

Microalbuminuria developed in 84 patients and retinopathy in 108. Hazard ratios (HRs) for the development of microalbuminuria associated with the coefficient of variation (CV) and variation independent of mean (VIM) of both HbA1c and SBP significantly increased. In participants with a mean SBP <130mmHg, the HRs for the development of retinopathy associated with CV and VIM of HbA1c were abruptly elevated and significant compared with those with a mean SBP ≥130mmHg.

CONCLUSIONS

Visit-to-visit variability in both HbA1c and SBP simultaneously predict the development of microalbuminuria. HbA1c variability may predict the development of retinopathy when the mean SBP is normal (<130mmHg).