Diabetes mellitus and aortic aneurysm rupture: a favorable association?

Association between diabetes status and long-term outcomes following open and endovascular repair of infrarenal abdominal aortic aneurysms

OBJECTIVE

Current literature reports conflicting findings regarding the effect of diabetes mellitus (DM) on outcomes of abdominal aortic aneurysm (AAA) repair. In this study we examined the effect of DM and its management on outcomes after open AAA repair (OAR) and endovascular AAA repair (EVAR).

METHODS

We identified all patients undergoing OAR or EVAR for infrarenal AAA between 2003 and 2018 in the Vascular Quality Initiative registry data linked with Medicare claims. We excluded patients with missing DM status. Patients were stratified by their preoperative DM status, and then further stratified by DM management: dietary, noninsulin antidiabetic medications (NIMs), or insulin. Outcomes of interest included 1-year aneurysm sac dynamics, 8-year aneurysm rupture, reintervention, and all-cause mortality. These outcomes were analyzed with the χ2 test, Kaplan-Meier methods, and multivariable Cox regression analyses.

RESULTS

We identified 34,021 EVAR patients and 4127 OAR patients, of whom 20% and 16% had DM, respectively. Of all DM patients, 22% were managed by dietary management, 59% by NIM, and 19% by insulin. After EVAR, DM patients were more likely to have stable sacs, whereas non-DM patients were more likely to have sac regression at 1 year. Compared with non-DM, DM was associated with a significantly lower risk for 8-year rupture in EVAR (EVAR hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.51-0.92). Compared with non-DM, NIM was associated with lower risk of rupture within 8-years for both EVAR and OAR (EVAR HR, 0.64; 95% CI, 0.44-0.94; OAR HR, 0.29; 95% CI, 0.41-0.80), whereas dietary control and insulin had a similar rupture risk compared with non-DM. However, compared with non-DM, DM was associated with a higher risk of 8-year all-cause mortality after EVAR and OAR (DM vs non-DM: EVAR HR, 1.17; 95% CI, 1.11-1.23; OAR HR, 1.16; 95% CI, 1.00-1.36). After further DM management substratification, compared with non-DM, management with NIM and insulin were associated with a higher 8-year mortality in EVAR and OAR (EVAR: NIM HR, 1.12; 95% CI, 1.05-1.20; insulin: HR, 1.40; 95% CI, 1.26-1.55; OAR: NIM HR, 1.27; 95% CI, 1.06-1.54; and insulin: HR, 1.57; 95% CI, 1.15-2.13). Finally, there was a similar risk of reintervention across the DM and non-DM populations for EVAR and OAR.

CONCLUSIONS

DM was associated with a lower adjusted risk of rupture after EVAR as well as OAR in patients managed with NIM. Nevertheless, just as in patients without AAA, preoperative DM was associated with a higher adjusted risk of all-cause mortality. Further study is needed to evaluate for differences in aneurysm-related mortality between DM and non-DM patients, and studies are planned to evaluate the independent effect of NIM on aneurysm-related outcomes.

Five Year Post-Endovascular Aneurysm Repair Aneurysm Sac Evolution in the GREAT Registry: an Insight in Diabetics Using Propensity Matched Controls

OBJECTIVE

To assess differences in the five year abdominal aortic aneurysm (AAA) sac regression rate after endovascular aneurysm repair (EVAR) in patients with and without diabetes mellitus (DM).

METHODS

An international prospective registry (Europe, USA, Brazil, Australia, and New Zealand) of patients treated with the GORE EXCLUDER endograft. All scheduled EVARs for infrarenal AAA between 2014 and 2016 with complete five year imaging follow up were included. Emergency procedures, ancillary proximal procedures, and inflammatory and infectious aetiologies were excluded. Descriptive and inferential statistics, and Cox proportional hazards survival models were used. A control group of patients without DM with similar age and comorbidities was selected using propensity scores, matched in a 1:2 scheme.

RESULTS

A total of 2 888 patients (86.1% male; mean age 73.5 ± 8 years) was included, of whom 545 (18.9%) had DM. Patients with DM had higher rates of hypertension (89.2% vs. 78.4%), dyslipidaemia (76.0% vs. 60.7%), coronary artery disease (52.3% vs. 37.9%), and chronic renal impairment (20.9% vs. 14.0%) (all p < .001). The mean pre-procedural AAA diameter was 58.1 ± 10 mm. Five years post-EVAR, the type 1A endoleak rate was 1.1% (0.6% DM vs. 1.2% non-DM), the endograft related re-intervention rate was 7.3% (6.2% vs. 7.6%), the major adverse cardiovascular event (MACE) rate was 1.4% (1.1% vs. 1.5%), and aortic related mortality rate was 1.0% (0.6% vs. 1.2%), without statistically significant differences between groups. The overall five year mortality rate was higher in diabetics (36.3% vs. 30.5%; hazard ratio [HR] 1.30, 95% confidence interval [CI] 1.07 - 1.58; p = .001). No statistically significant differences were found in sac regression rate (≥ 5 mm) between diabetics and non-diabetics 70.0% vs. 73.1%; HR 0.88, 95% CI 0.75-1.04; p = .131. These differences remained statistically non-significant after excluding patients performed out of instructions for use (p = .61) and patients with types 1, 2 or 3 endoleaks (p = .39).

CONCLUSION

The paradoxical relationship between DM and AAA does not appear to result in differences in post-EVAR sac regression rates. However, even when controlling for other comorbidities, patients with DM undergoing EVAR may have a higher five year mortality rate.

Nonsize Criteria for Surgical Intervention on the Ascending Thoracic Aorta

For decades, aortic surgery has relied on size criteria for intervention on the ascending aorta. While diameter has served well, diameter alone falls short of an ideal criterion. Herein, we examine the potential application of other, nondiameter criteria in aortic decision-making. These findings are summarized in this review. We have conducted multiple investigations of specific alternate nonsize criteria by leveraging our extensive database, which includes complete, verified anatomic, clinical, and mortality data on 2,501 patients with thoracic aortic aneurysm (TAA) and dissections (198 Type A, 201 Type B, and 2102 TAAs). We examined 14 potential intervention criteria. Each substudy had its own specific methodology, reported individually in the literature. The overall findings of these studies are presented here, with a special emphasis on how the findings can be incorporated into enhanced aortic decision-making-above and beyond sheer diameter. The following nondiameter criteria have been found useful in decision-making regarding surgical intervention. (1) Pain: In the absence of other specific cause, substernal chest pain mandates surgery. Well-developed afferent neural pathways carry warning signals to the brain. (2) Aortic length/tortuosity: Length is emerging as a mildly better predictor of impending events than diameter. (3) Genes: Specific genetic aberrations provide a powerful predictor of aortic behavior; malignant genetic variants obligate earlier surgery. (4) Family history: Aortic events closely follow those in relatives with a threefold increase in likelihood of aortic dissection for other family members once an index family dissection has occurred. (5) Bicuspid aortic valve: Previously thought to increase aortic risk (as a "Marfan light" situation), current data show that bicuspid valve is not a predictor of higher risk. (6) Diabetes actually protects against aortic events, via mural thickening and fibrosis. (7) Biomarkers: A specialized "RNA signature test" identifies aneurysm-bearing patients in the general population and promises to predict impending dissection. (8) Aortic stress: Blood pressure (BP) elevation from anxiety/exertion precipitates dissection, especially with high-intensity weightlifting. (9) Root dilatation imposes higher dissection risk than supracoronary ascending aneurysm. (10) Inflammation on positron emission tomography (PET) imaging implies high rupture risk and merits surgical intervention. (11) A KIF6 p.Trp719Arg variant elevates aortic dissection risk nearly two-fold. (12) Female sex confers some increased risk, which can be largely accommodated by using body-size-based nomograms (especially height nomograms). (13) Fluoroquinolones predispose to catastrophic dissection events and should be avoided rigorously in aneurysm patients. (14) Advancing age makes the aorta more vulnerable, increasing likelihood of dissection. In conclusion, nondiameter criteria can beneficially be brought to bear on the decision to observe or operate on specific TAA.

The Association between Diabetes Mellitus and its Management with Outcomes following Endovascular Repair for Descending Thoracic Aortic Aneurysm

OBJECTIVE

Prior literature is conflicted regarding the effect of diabetes mellitus (DM) on outcomes following endovascular repair of aortic aneurysms. In this study, we aimed to examine the association between DM and outcomes following TEVAR for TAA.

METHODS

We identified patients who underwent TEVAR for TAA of the descending thoracic aorta in the VQI between 2014-2022. We created two cohorts, DM and non-DM, based on the patient's preoperative DM status, and secondarily sub-stratified DM patients by management strategy: dietary management, non-insulin medications, and insulin therapy cohorts. Outcomes included perioperative and 5-year mortality, in-hospital complications, indications for repair, and one-year sac dynamics, which were analyzed with multivariable cox regression, multivariable logistic regression, and chi-square tests, respectively.

RESULTS

We identified 2,637 patients, of which 473 (18%) had DM preoperatively. Among DM patients, 25% were diet controlled, 54% non-insulin medications, and 21% insulin therapy. Within patients who underwent TEVAR for TAA, the proportions of ruptured presentation were higher in the dietary (11.1%) and insulin (14.3%) managed cohorts relative to non-insulin therapy (6.6%) and non-DM (6.9%). Following multivariable regression analysis, we found that DM was associated with similar perioperative mortality (OR: 1.14 [95% CI: 0.70-1.81]) and 5-year mortality compared with non-DM patients (HR: 1.15 [95% CI: 0.91-1.48]). Furthermore, all in-hospital complications were comparable between DM patients and non-DM patients. Compared with non-DM patients, dietary management of DM was significantly associated with higher adjusted perioperative mortality (OR: 2.16 [95% CI: 1.03-4.19]) and higher 5-year mortality (HR: 1.50 [95% CI: 1.03-2.20]), though this was not the case for other DM subgroups. All cohorts displayed similar one-year sac dynamics, with sac regression occurring in 47% of non-DM patients vs 46% of DM patients (P= 0.27).

CONCLUSION

Preoperatively, DM patients that underwent TEVAR had a higher proportion of ruptured presentation when treated with diet or insulin medications than when treated with non-insulin medications. Following TEVAR for descending TAA, DM was associated with a similar risk of perioperative and 5-year mortality to non-DM. In contrast, dietary therapy for DM was associated with significantly higher perioperative mortality and 5-year mortality.

Protection of diabetes in aortic abdominal aneurysm: Are antidiabetics the real effectors?

Aortic aneurysms, including abdominal aortic aneurysms (AAAs), is the second most prevalent aortic disease and represents an important cause of death worldwide. AAA is a permanent dilation of the aorta on its infrarenal portion, pathologically associated with oxidative stress, proteolysis, vascular smooth muscle cell loss, immune-inflammation, and extracellular matrix remodeling and degradation. Most epidemiological studies have shown a potential protective role of diabetes mellitus (DM) on the prevalence and incidence of AAA. The effect of DM on AAA might be explained mainly by two factors: hyperglycemia [or other DM-related factors such as insulin resistance (IR)] and/or by the effect of prescribed DM drugs, which may have a direct or indirect effect on the formation and progression of AAAs. However, recent studies further support that the protective role of DM in AAA may be attributable to antidiabetic therapies (i.e.: metformin or SGLT-2 inhibitors). This review summarizes current literature on the relationship between DM and the incidence, progression, and rupture of AAAs, and discusses the potential cellular and molecular pathways that may be involved in its vascular effects. Besides, we provide a summary of current antidiabetic therapies which use could be beneficial for AAA.

Association Between Metformin and Abdominal Aortic Aneurysm: A Meta-Analysis

Objective

To systematically examine the association between metformin and abdominal aortic aneurysm (AAA) and provide a basis for the treatment of AAA.

Methods

Pubmed, Embase, Cochrane Library, and Ovid databases were searched by computer to identify the literature related to metformin and AAA published until February 2022. The literature was screened according to the inclusion and exclusion criteria, data were extracted, and a quality assessment was conducted. The meta-analysis was performed using Stata 16.0 and RevMan 5.3 software.

Results

Seven articles containing a total of 10 cohort studies (85,050 patients) met the inclusion criteria and were included in the review. Meta-analysis showed that metformin can limit the expansion of AAA (MD = – 0.72, 95% CI: – 1.08 ~ −0.37, P < 0.00001), as well as reduce AAA repair or AAA rupture-related mortality (OR = 0.80, 95% CI:0.66 ~ 0.96, P = 0.02). The difference was statistically significant (P < 0.05).

Conclusion

Metformin can limit the expansion of AAA and reduce the incidence of AAA and postoperative mortality. However, further biological experiments and clinical trials still need to be conducted to support this.

Double-edged sword of diabetes mellitus for abdominal aortic aneurysm

INTRODUCTION

Diabetes mellitus (DM) has been proved to contribute to multiple comorbidities that are risk factors for abdominal aortic aneurysm (AAA). Remarkably, evidences from epidemiologic studies have demonstrated a negative association between the two disease states. On the other hand, hyperglycemic state was linked to post-operative morbidities following AAA repair. This review aims to provide a thorough picture on the double-edged nature of DM and major hypoglycemic medications on prevalence, growth rate and rupture of AAA, as well as DM-associated prognosis post AAA repair.

METHODS

We performed a comprehensive search in electronic databases to look for literatures demonstrating the association between DM and AAA. The primary focus of the literature search was on the impact of DM on the morbidity, enlargement and rupture rate, as well as post-operative complications of AAA. The role of antidiabetic medications was also explored.

RESULTS

Retrospective epidemiological studies and large database researches associated the presence of DM with decreased prevalence, slower expansion and limited rupture rate of AAA. Major hypoglycemic drugs exert similar protective effect as DM against AAA by targeting pathological hallmarks involved in AAA formation and progression, which were demonstrated predominantly by animal studies. Nevertheless, presence of DM or postoperative hyperglycemia was linked to poorer short-term and long-term prognosis, primarily due to greater risk of infection, longer duration of hospital stays and death.

CONCLUSION

While DM is a positive factor in the formation and progression of AAA, it is also associated with higher risk of negative outcomes following AAA repair. Concomitant use of antidiabetic medications may contribute to the protective mechanism of DM in AAA, but further studies are still warranted to explore their role following AAA repair.

Age-dependent differences in the prognostic relevance of body composition-related variables in type A aortic dissection patients

Background

The current research is allocated to appraise the association between the parameters of body composition and findings in type A aortic dissection (TAAD) cases in diverse age groups.

Methods

Data from consecutive TAAD patients undergoing implantation of modified triple-branched stent-graft from January 2017 and December 2019 were prospectively collected and analyzed. A regression model of Cox proportional hazard was employed to assess correlations among body composition-related variables (body mass index [BMI], lean body mass [LBM], body surface area [BSA], and LBM index) as well as cumulative mortality.

Results

Overall, 258 patients (53.9 ± 11.1 years old; 72.9% male) were separated into young (n = 110) and elderly (n = 148) age groups based upon whether they were younger or older than 50 years of age. Of these patients, 247 survivors were included in subsequent analyses over an average 26.8 ± 11.6 month follow-up duration. Multivariate analyses in the elderly group instead of young group indicated that increased BMI (p = 0.042), BMI ≤ 18.5 kg/m² (p = 0.025), and lower LBM index values (p = 0.019) were significant predictors of increased total all-cause cumulative mortality. BMI was considerably positively correlated with estimated all-cause cumulative mortality in elderly but not young TAAD cases.

Conclusion

Briefly, these results suggest that BMI and LBM indices are only significant predictors of TAAD patient all-cause mortality in elderly patient cohorts, whereas they do not offer significant prognostic value for younger patients. As such, these age differences must be taken into consideration when conducting stratified risk assessments based upon TAAD patient body composition characteristics.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01742-1.

Exploring the Correlation and Protective Role of Diabetes Mellitus in Aortic Aneurysm Disease

Introduction: Diabetes mellitus is recognised as a significant risk factor for cardiovascular and peripheral vascular disease, as the abnormal metabolic state increases the risk for atherosclerosis, occlusive arterial disease and vascular dysfunction. There have been reports of potential association across the literature that illustrates a link between diabetes mellitus and aortic aneurysm, with the former having a protective role on the development of the latter.

Methods: A thorough literature search was performed through electronic databases, to provide a comprehensive review of the study's reporting on the association of diabetes mellitus and aortic aneurysm, discussing the mechanisms that have been reported; furthemore, we reviewed the reports of the impact of oral hypoglycameic agents on aortic aneurysms.

Results: Various proposed mechanisms are involved in this protective process including endothelial dysfunction, chronic hyperglycemia and insulin resistance. The evidence suggests a negative association between these disease process, with prevelance of diabetes mellitus resulting in lower rates of aortic aneurysm, via its protective mechanistic action. The increase in advanced glycation end products, increased arterial stiffness and vascular remodelling seen in diabetes, was found to have a profound impact on aneurysm development, its slow progression and lower rupture rate in these individuals. This review has also highlighted the role of oral hypoglycaemic agents having a protective effect against AA disease.

Conclusion: A decrease in development, progression and mortality from aortic aneurysms as well as reduced rates of dissection, have been observed in those with diabetes. This review has provided a comprehensive insight on the effect of diabetes and its physiological processes, and elements of its con-committant treatment, having a protective role against these aortic diseases.

Circulating Biomarkers for the Prediction of Abdominal Aortic Aneurysm Growth

BACKGROUND

Abdominal aortic aneurysm represents a distinct group of vascular lesions, in terms of surveillance and treatment. Screening and follow-up of patients via duplex ultrasound has been well established and proposed by current guidelines. However, serum circulating biomarkers could earn a position in individualized patient surveillance, especially in cases of aggressive AAA growth rates. A systematic review was conducted to assess the correlation of AAA expansion rates with serum circulating biomarkers.

METHODS

A data search of English medical literature was conducted, using PubMed, EMBASE, and CENTRAL, until 7 March 2021, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement (PRISMA) guidelines. Studies reporting on humans, on abdominal aortic aneurysm growth rates and on serum circulating biomarkers were included. No statistical analysis was conducted.

RESULTS

A total of 25 studies with 4753 patients were included. Studies were divided in two broad categories: Those reporting on clinically applicable (8 studies) and those reporting on experimental (17 studies) biomarkers. Twenty-three out of 25 studies used duplex ultrasound (DUS) for following patients. Amongst clinically applicable biomarkers, D-dimers, LDL-C, HDL-C, TC, ApoB, and HbA1c were found to bear the most significant association with AAA growth rates. In terms of the experimental biomarkers, PIIINP, osteopontin, tPA, osteopontin, haptoglobin polymorphisms, insulin-like growth factor I, thioredoxin, neutrophil extracellular traps (NETs), and genetic factors, as polymorphisms and microRNAs were positively correlated with increased AAA expansion rates.

CONCLUSION

In the presence of future robust data, specific serum biomarkers could potentially form the basis of an individualized surveillance strategy of patients presenting with increased AAA growth rates.

Diabetes Is Not Associated with the Risk of Rupture Among Patients with Abdominal Aortic Aneurysms - Results From a Large Danish Register Based Matched Case Control Study From 1996 to 2016

OBJECTIVE

Numerous studies have shown a paradoxical protective effect of diabetes on the development and progression of abdominal aortic aneurysm (AAA). The aim of this study was to investigate whether the protective role of diabetes on AAA extends to rupture, given the presence of an AAA.

METHODS

This was a register based case control study. Patients with ruptured AAA (RAAA) were matched 1:1 with patients undergoing elective surgery for AAA by sex, age, and year of diagnosis. Multiple conditional logistic regression was performed to estimate the odds ratio (OR) associating a diagnosis of diabetes with RAAA. No protocol was registered.

RESULTS

From 1996 to 2016, there were 6293 potential people with RAAA. A total of 898 people with a RAAA were excluded since no matching controls existed. This left 5 395 cases in the study. The cases had a median age of 75, and 85.4% were men. Diabetes was defined by hospital diagnosis or the redemption of antidiabetic prescriptions within one year. Comparing cases with controls and the presence of diabetes, a significant crude OR of 0.82 (95% confidence interval [CI] 0.71-0.95) was found. When adjusting for confounders OR increased to 0.97 (CI 0.83-1.14). Stratifying by age and year of diagnosis did not change the results markedly. OR associating RAAA with diabetes was significantly elevated in women (adjusted OR 1.82 [CI 1.17-2.81]). Of the 5395 cases, the overall 30 days mortality was 58% (n = 3145). Using Cox regression, a crude hazard ratio (HR) of 1.06 (CI 0.93-1.22) was found for the 30 day mortality and having diabetes compared with not having diabetes. Adjusting for index year, male sex, and age had little effect on this estimate (HR 1.11 [CI 0.97-1.28]).

CONCLUSION

Diabetes was not found to protect against RAAA, given the presence of an AAA. Furthermore, diabetes did not increase the risk of dying within 30 days of RAAA.

Diabetes Mellitus: Is It Protective against Aneurysm? A Narrative Review

Objectives: In the course of extensive clinical aortic surgery, we noticed that the aorta was quite thick and fibrotic in diabetic patients. We thought the diabetic aortic aorta might be inimitable to aortic dissection. On this basis, we set out to review information in the literature regarding aortic growth and dissection in diabetic patients. Methods: We used a 2-step search approach to the available literature on diabetes and aneurysm. Firstly, databases including PubMed, Cochrane, Embase and TRIP were searched. Secondly, relevant studies were identified through secondary sources including references of initially selected articles. We address the relationship between diabetes and the incidence, prevalence, growth, mortality and rupture of an aneurysm. Results: Diabetes is thought to exert a protective role in both thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA). Diabetics were shown to have a slower aneurysm growth rate, lower rupture rate, delayed (> 65 years) age of rupture, decreased rate of mortality from an aneurysm and a decreased length of hospital stay. There was also noted a decreased rate of incidence and prevalence of TAA and AAA in diabetics, smaller aneurysm diameter, reduction in matrix metalloproteinases and an increased aortic wall stress in diabetics. Antidiabetic agents like metformin, thiazolidinediones and dipeptidyl peptidase-4 inhibitors may protect against an aneurysm. Conclusion: Our literature review provides strong (but often circumstantial) evidence that diabetic patients exhibit slower growth of aortic aneurysms and a lower rate of aortic dissection. Furthermore, clinical and experimental studies indicate that common antidiabetic medications on their own inhibit growth of aortic aneurysms. These findings indicate a paradoxically beneficial effect of the otherwise highly detrimental diabetic state.

Association between metformin prescription and growth rates of abdominal aortic aneurysms

Background

It has been suggested that diabetes medications, such as metformin, may have effects that inhibit abdominal aortic aneurysm (AAA) growth. The aim of this study was to examine the association of diabetes treatments with AAA growth in three patient cohorts.

Methods

AAA growth was studied using ultrasound surveillance in cohort 1, repeated CT in cohort 2 and more detailed repeat CT in cohort 3. Growth was estimated by the mean annual increase in maximum AAA diameter.

Results

A total of 1697 patients with an AAA were studied, of whom 118, 39 and 16 patients were prescribed metformin for the treatment of diabetes in cohorts 1, 2 and 3 respectively. Prescription of metformin was associated with a reduced likelihood of median or greater AAA growth in all three cohorts (cohort 1: adjusted odds ratio (OR) 0·59, 95 per cent c.i. 0·39 to 0·87, P = 0·008; cohort 2: adjusted OR 0·38, 0·18 to 0·80, P = 0·011; cohort 3: adjusted OR 0·13, 0·03 to 0·61, P = 0·010). No other diabetes treatment was significantly associated with AAA growth in any cohort.

Conclusion

These findings suggest a potential role for metformin in limiting AAA growth.

Using nationwide ‘big data’ from linked electronic health records to help improve outcomes in cardiovascular diseases: 33 studies using methods from epidemiology, informatics, economics and social science in the ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER) programme

Background

Electronic health records (EHRs), when linked across primary and secondary care and curated for research use, have the potential to improve our understanding of care quality and outcomes.

Objective

To evaluate new opportunities arising from linked EHRs for improving quality of care and outcomes for patients at risk of or with coronary disease across the patient journey.

Design

Epidemiological cohort, health informatics, health economics and ethnographic approaches were used.

Setting

230 NHS hospitals and 226 general practices in England and Wales.

Participants

Up to 2 million initially healthy adults, 100,000 people with stable coronary artery disease (SCAD) and up to 300,000 patients with acute coronary syndrome.

Main outcome measures

Quality of care, fatal and non-fatal cardiovascular disease (CVD) events.

Data platform and methods

We created a novel research platform [ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER)] based on linkage of four major sources of EHR data in primary care and national registries. We carried out 33 complementary studies within the CALIBER framework. We developed a web-based clinical decision support system (CDSS) in hospital chest pain clinics. We established a novel consented prognostic clinical cohort of SCAD patients.

Results

CALIBER was successfully established as a valid research platform based on linked EHR data in nearly 2 million adults with > 600 EHR phenotypes implemented on the web portal (seehttps://caliberresearch.org/portal). Despite national guidance, key opportunities for investigation and treatment were missed across the patient journey, resulting in a worse prognosis for patients in the UK compared with patients in health systems in other countries. Our novel, contemporary, high-resolution studies showed heterogeneous associations for CVD risk factors across CVDs. The CDSS did not alter the decision-making behaviour of clinicians in chest pain clinics. Prognostic models using real-world data validly discriminated risk of death and events, and were used in cost-effectiveness decision models.

Conclusions

Emerging ‘big data’ opportunities arising from the linkage of records at different stages of a patient’s journey are vital to the generation of actionable insights into the diagnosis, risk stratification and cost-effective treatment of people at risk of, or with, CVD.

Future work

The vast majority of NHS data remain inaccessible to research and this hampers efforts to improve efficiency and quality of care and to drive innovation. We propose three priority directions for further research. First, there is an urgent need to ‘unlock’ more detailed data within hospitals for the scale of the UK’s 65 million population. Second, there is a need for scaled approaches to using EHRs to design and carry out trials, and interpret the implementation of trial results. Third, large-scale, disease agnostic genetic and biological collections linked to such EHRs are required in order to deliver precision medicine and to innovate discovery.

Study registration

CALIBER studies are registered as follows: study 2 – NCT01569139, study 4 – NCT02176174 and NCT01164371, study 5 – NCT01163513, studies 6 and 7 – NCT01804439, study 8 – NCT02285322, and studies 26–29 – NCT01162187. Optimising the Management of Angina is registered as Current Controlled Trials ISRCTN54381840.

Funding

The National Institute for Health Research (NIHR) Programme Grants for Applied Research programme (RP-PG-0407-10314) (all 33 studies) and additional funding from the Wellcome Trust (study 1), Medical Research Council Partnership grant (study 3), Servier (study 16), NIHR Research Methods Fellowship funding (study 19) and NIHR Research for Patient Benefit (study 33).

Autonomic remodeling may be responsible for decreased incidence of aortic dissection in STZ-induced diabetic rats via down-regulation of matrix metalloprotease 2

Background

Epidemiological studies reported that diabetic patients had a lower incidence of aortic dissection (AD), but the definite mechanism is unknown. We aim to investigate the possible protective effect of diabetes mellitus (DM) on AD formation with an emphasis on autonomic remodeling.

Methods

Streptozotocin (STZ) intraperitoneal injection was applied to induce diabetes, unilateral renal artery stenosis (URAS) together with β-amino propionitrile (BAPN) oral treatment was used to induce AD. Sixty SD rats were equally and randomly divided into four groups (normal group, DM group, URAS + BAPN oral treatment group, DM + URAS + BAPN oral treatment group). Rats were fed for 6 weeks, the number of AD was recorded and remained rats were sacrificed. Thoracic aorta were harvested, morphological changes were assessed. Expression of tyrosine hydroxylase (TH), choline acetylase (ChAT), matrix metalloprotease 2 (MMP2) and matrix metalloprotease 9 (MMP9) were evaluated.

Results

A total of 7 AD was noted in S + B group, DM rats did not develop AD. Diabetic rats had a lower incidence of AD (P < 0.01). In dissected aorta, collagen deposition increased while elastic fiber became fragmented. These pathological changes diminished in diabetic rats. Diabetic rats had a lower expression of ChAT (P < 0.01). URAS + BAPN treatment elevated expression of TH in normal rat and ChAT in diabetic rats (P < 0.001). Expression of MMP2 and MMP9 elevated in all the rats after URAS + BAPN, but the elevation range of MMP2 in diabetic rats was smaller (P < 0.001).

Conclusions

STZ-induced diabetic rats have a lower incidence of AD after URAS and BAPN treatment, this protective effect could be possibly attributed to autonomic innervation modification and possible related down-regulation of MMP2.

Negative association of diabetes with rupture of abdominal aortic aneurysm

PURPOSE

To summarize the association of diabetes with abdominal aortic aneurysm rupture, we reviewed currently available studies with a systematic literature search and meta-analytic evaluation.

METHODS

To identify all studies reporting the association of diabetes with abdominal aortic aneurysm rupture, MEDLINE and EMBASE were searched through July 2015. For each study, data regarding diabetes prevalence in both the ruptured and non-ruptured groups were used to generate an unadjusted odds ratio for abdominal aortic aneurysm rupture and 95% confidence intervals. Alternatively, an unadjusted or adjusted odds ratio, or hazard ratio for abdominal aortic aneurysm rupture with 95% confidence interval was directly abstracted (as available) from each individual study.

RESULTS

Our search identified 11 eligible studies. A primary meta-analysis of nine studies reporting data on ruptured (not including non-ruptured symptomatic) abdominal aortic aneurysm demonstrated that diabetes was associated with significantly lower prevalence/incidence of abdominal aortic aneurysm rupture (odds ratio/hazard ratio, 0.71; 95% confidence interval, 0.56 to 0.89; p = 0.003). A secondary meta-analysis of all 11 studies (adding two studies in which non-ruptured symptomatic abdominal aortic aneurysm was included in the rupture group) also demonstrated that diabetes was associated with significantly lower prevalence/incidence of abdominal aortic aneurysm rupture (odds ratio/hazard ratio, 0.77; 95% confidence interval, 0.63 to 0.95; p = 0.01).

CONCLUSION

Diabetes is negatively associated with abdominal aortic aneurysm rupture.

Negative Association of Diabetes With Thoracic Aortic Dissection and Aneurysm

We performed a meta-analysis to assess the association of diabetes mellitus (DM) with the presence of thoracic aortic dissection (TAD) and/or thoracic aortic aneurysm (TAA). MEDLINE and EMBASE were searched through December 2015 using PubMed and OVID. For each study, data regarding DM prevalence in both the TAD/TAA and control groups were used to generate unadjusted odds ratios (ORs) for DM and 95% confidence intervals (CIs). Alternatively, an unadjusted and/or adjusted OR was directly abstracted from each individual study. Eleven eligible studies enrolling a total of 47 827 participants were included. A primary pooled analysis of all the 11 studies demonstrated that TAD/TAA was associated with significantly lower DM prevalence than controls (OR, 0.43; 95% CI, 0.31-0.59; P < .00001). Separate pooled analyses of 6 TAD case studies and 4 TAA case studies demonstrated TAD (OR, 0.34; 95% CI, 0.19-0.61; P = .0003) and TAA (OR, 0.65; 95% CI, 0.45-0.94; P = .02) were associated with significantly lower DM prevalence than controls. In conclusion, DM may be negatively associated with the presence of TAD/TAA.

Association of diabetes mellitus with presence, expansion, and rupture of abdominal aortic aneurysm: "Curiouser and curiouser!" cried ALICE

Both coronary artery and peripheral artery disease are representative atherosclerotic diseases that are positively associated with presence of abdominal aortic aneurysm (AAA). Diabetes mellitus, which is one of major risk factors of coronary artery and peripheral artery diseases, however, has been curiously suggested to be negatively associated with AAA, despite the positive associations of coronary artery and peripheral artery diseases with presence of AAA. In the present article, we overviewed epidemiologic evidence (meta-analyses) regarding the associations of diabetes mellitus with presence, expansion, and rupture of AAA through a systematic literature search. Our exhaustive search identified seven meta-analyses. Main results of almost all meta-analyses (except for the two earliest ones) apparently found that diabetes mellitus is negatively associated with presence, expansion, and rupture of AAA.

Abdominal aortic aneurysms--glycaemic status and mortality

AIMS

The prevalence of diabetes mellitus (DM) and mortality with respect to glycaemic status in patients with abdominal aortic aneurysms (AAA) was evaluated. Glycaemic status was assessed by an oral glucose tolerance test (OGTT) and by HbA1c.

METHODS

Sixty-six patients with AAA admitted to the vascular surgery unit for elective surgery between October 2006 and September 2007 were included. Seven patients had previously known DM. OGTT and HbA1c results were available from 58 patients. The patients were categorized as having DM, prediabetes and normoglycaemia according to the WHO's and American Diabetes Association's criteria.

RESULTS

The prevalence of newly diagnosed DM according to the OGTT and HbA1c results were 12% and 14% respectively. Mean follow-up time was 68 months and all-cause mortality 43%. HbA1c was an independent predictor for mortality in the DM category. Hazard ratio of all-cause mortality in the DM category defined by the HbA1c values was 6.35, 95% [CI 1.49-27.1]; p = 0.01.

CONCLUSIONS

DM defined by HbA1c ≥ 6.5% is an important determinant of mortality following surgical treatment for AAA. Half the patients with AAA and DM were unaware of their DM diagnosis. All patients with AAA should be tested for DM using HbA1c. The results should be confirmed in a larger prospective study.

Hyperglycemia Suppresses Calcium Phosphate-Induced Aneurysm Formation Through Inhibition of Macrophage Activation

Background

The aim of this study was to elucidate aspects of diabetes mellitus–induced suppression of aneurysm. We hypothesized that high glucose suppresses aneurysm by inhibiting macrophage activation via activation of Nr1h2 (also known as liver X receptor β), recently characterized as a glucose‐sensing nuclear receptor.

Methods and Results

Calcium phosphate (CaPO₄)–induced aneurysm formation was significantly suppressed in the arterial wall in type 1 and 2 diabetic mice. A murine macrophage cell line, RAW264.7, was treated with tumor necrosis factor α (TNF‐α) plus CaPO₄ and showed a significant increase in matrix metalloproteinase 9 (Mmp9) mRNA and secreted protein expression compared with TNF‐α alone. Elevated Mmp9 expression was significantly suppressed by hyperglycemic conditions (15.5 mmol/L glucose) compared with normoglycemic conditions (5.5 mmol/L glucose) or normoglycemic conditions with high osmotic pressure (5.5 mmol/L glucose +10.0 mmol/L mannitol). Nr1h2 mRNA and protein expression were suppressed by treatment with TNF‐α plus CaPO₄ but were restored by hyperglycemic conditions. Activation of Nr1h2 by the antagonist GW3965 during stimulation with TNF‐α plus CaPO₄ mimicked hyperglycemic conditions and inhibited Mmp9 upregulation, whereas the deactivation of Nr1h2 by small interfering RNA (siRNA) under hyperglycemic conditions canceled the suppressive effect and restored Mmp9 expression induced by TNF‐α plus CaPO₄. Moreover, Nr1h2 activation with GW3965 significantly suppressed CaPO₄‐induced aneurysm in mice compared with vehicle‐injected control mice.

Conclusions

Our results show that hyperglycemia suppresses macrophage activation and aneurysmal degeneration through the activation of Nr1h2. Although further validation of the underlying pathway is necessary, targeting Nr1h2 is a potential therapeutic approach to treating aneurysm.