PIEZO1 and PECAM1 interact at cell-cell junctions and partner in endothelial force sensing

Two prominent concepts for the sensing of shear stress by endothelium are the PIEZO1 channel as a mediator of mechanically activated calcium ion entry and the PECAM1 cell adhesion molecule as the apex of a triad with CDH5 and VGFR2. Here, we investigated if there is a relationship. By inserting a non-disruptive tag in native PIEZO1 of mice, we reveal in situ overlap of PIEZO1 with PECAM1. Through reconstitution and high resolution microscopy studies we show that PECAM1 interacts with PIEZO1 and directs it to cell-cell junctions. PECAM1 extracellular N-terminus is critical in this, but a C-terminal intracellular domain linked to shear stress also contributes. CDH5 similarly drives PIEZO1 to junctions but unlike PECAM1 its interaction with PIEZO1 is dynamic, increasing with shear stress. PIEZO1 does not interact with VGFR2. PIEZO1 is required in Ca2+-dependent formation of adherens junctions and associated cytoskeleton, consistent with it conferring force-dependent Ca2+ entry for junctional remodelling. The data suggest a pool of PIEZO1 at cell junctions, the coming together of PIEZO1 and PECAM1 mechanisms and intimate cooperation of PIEZO1 and adhesion molecules in tailoring junctional structure to mechanical requirement.

Association between operator volume and mortality in primary percutaneous coronary intervention

Background

There is a paucity of real-world data assessing the association of operator volumes and mortality specific to primary percutaneous coronary intervention (PPCI).

Methods

Demographic, clinical and outcome data for all patients undergoing PPCI in Leeds General Infirmary, UK, between 1 January 2009 and 31 December 2011, and 1 January 2013 and 31 December 2013, were obtained prospectively. Operator volumes were analysed according to annual operator PPCI volume (low volume: 1–54 PPCI per year; intermediate volume: 55–109 PPCI per year; high volume: ≥110 PPCI per year). Cox proportional hazards regression analyses were undertaken to investigate 30-day and 12-month all-cause mortality, adjusting for confounding factors.

Results

During this period, 4056 patients underwent PPCI, 3703 (91.3%) of whom were followed up for a minimum of 12 months. PPCI by low-volume operators was associated with significantly higher adjusted 30-day mortality (HR 1.48 (95% CI 1.05 to 2.08); p=0.02) compared with PPCI performed by high-volume operators, with no significant difference in adjusted 12-month mortality (HR 1.26 (95% CI 0.96 to 1.65); p=0.09). Comparisons between low-volume and intermediate-volume operators, and between intermediate and high-volume operators, showed no significant differences in 30-day and 12-month mortality.

Conclusions

Low operator volume is independently associated with higher probability of 30-day mortality compared with high operator volume, suggesting a volume–outcome relationship in PPCI at a threshold higher than current recommendations.

The Effect of Endogenous Cushing Syndrome on All-cause and Cause-specific Mortality

OBJECTIVE

We aimed to perform a systematic review and meta-analysis of all-cause and cause-specific mortality of patients with benign endogenous Cushing syndrome (CS).

METHODS

The protocol was registered in PROSPERO (CRD42017067530). PubMed, EMBASE, CINHAL, Web of Science, and Cochrane Central searches were undertaken from inception to January 2021. Outcomes were the standardized mortality ratio (SMR), proportion, and cause of deaths. The I2 test, subgroup analysis, and meta-regression were used to assess heterogeneity across studies.

RESULTS

SMR was reported in 14 articles including 3691 patients (13 Cushing disease [CD] and 7 adrenal CS [ACS] cohorts). Overall SMR was 3.0 (95% CI, 2.3-3.9; I2 = 80.5%) for all CS, 2.8 (95% CI, 2.1-3.7; I2 = 81.2%) for CD and 3.3 (95% CI, 0.5-6.6; I2 = 77.9%) for ACS. Proportion of deaths, reported in 87 articles including 19 181 CS patients (53 CD, 24 ACS, and 20 combined CS cohorts), was 0.05 (95% CI, 0.03-0.06) for all CS subtypes with meta-regression analysis revealing no differences between CS subtypes (P = .052). The proportion of deaths was 0.1 (10%) in articles published before 2000 and 0.03 (3%) in 2000 until the last search for CS (P < .001), CD (P < .001), and ACS (P = .01). The causes of death were atherosclerotic diseases and thromboembolism (43.4%), infection (12.7%), malignancy (10.6%), active disease (3.5%), adrenal insufficiency (3.0%), and suicide (2.2%). Despite improved outcomes in recent years, increased mortality from CS persists. The causes of death highlight the need to prevent and manage comorbidities in addition to treating hypercortisolism.

Mortality and Specific Causes of Death in Endogenous Cushing’s Syndrome: A Systematic Review, Meta-Analysis and Meta-Regression

Background: Endogenous Cushing’s syndrome (CS) refers to an inappropriate hypercortisolism usually caused by either Cushing’s disease (CD) or adrenal CS (ACS). CS results in significant morbidity and excess mortality if untreated. Even in treated cases there is often a significant health burden. Due to the rarity of CS (incidence ~ 1/1M population), single cohort studies have insufficient power for reporting accurate mortality data. Only one previous systematic review and meta-analysis for CS has been reported that limited its scope to the inclusion of specific CD subgroup. Aims: To perform a meta-analysis and meta-regression analysis of all-cause and specific cause -mortality amongst patients with benign endogenous CS. Methods: The protocol was registered in PROSPERO (CRD42017067530). Searches were undertaken of PubMed, EMBASE, CINHAL, web of science and Cochrane Central from start until April 2019. The primary outcomes were proportion of mortality and SMR. The meta-analysis was done with STATA version 16.1 software. The I2 test, subgroup analysis and meta-regression statistics were used to assess heterogeneity among included studies. Results: A total of 11,527 articles, were retrieved. 87 articles with 100 study cohorts containing 17,276 CS patients reporting mortality were included. Fifty-three study cohorts reported Cushing’s disease (CD) patients, 27 study cohorts reported for adrenal CS patients and 20 studies cohorts reported on both types of CS. The overall SMR of all type CS was 2.91 (95% CI 2.41–3.68) with I2 =40.3%. The SMR for CD was 3.27 (95% CI 2.33–4.21) with I2 = 55.6%. The SMR in ACS was 1.62 (95% CI 0.08–3.16) with I2 =0.0%. The overall proportion of death in CS was 0.05 (95% CI 0.03–0.06) with I2 =51.86%; in CD was 0.04 (95% CI 0.03–0.06) with I2 = 62.7% and in ACS 0.06 (95% CI 0.04–0.11) with I2 = 40.3 %. The proportion of death during the 30-day operative period was highest before 1991 at 0.07 and decreased to 0.03 in 1991–2000 to 0.01 in 2001–2010 and zero after 2011. The causes of death reported across 64 studies were cardiac causes (24.7%), infection (14.4%), cerebrovascular diseases (9.4%), malignancy (9.0%), thromboembolism (4.2%), active disease (2.9%), and adrenal insufficiency (2.7%). Conclusion: CS is associated with increase in overall mortality. Advances in operative techniques and care have decreased peri-operative mortality over a 20 year period. The causes of death highlight the need for aggressive management of cardiovascular risk, prevention of thrombo-embolism, infection control and a normalised cortisol level.

Real World Mortality and Specific Causes of Death in Chronic Oral Glucocorticoid Use: A Systematic Review, Meta-Analysis and Meta-Regression

Background: Glucocorticoids (GCs) are widely used as therapeutic agents with prevalence 0.9–3.7%, but they are associated with significant side effects. Understanding of mortality ratios and causes of death from GC use is poorly appreciated and likely to help shape future stratification of clinical practice. Aims: To perform a meta-analysis of all-cause and specific cause -mortality amongst chronic GC users. Methods: The protocol was registered in PROSPERO (CRD42017067530). Searches were undertaken of PubMed, EMBASE, CINHAL, web of science and Cochrane Central from 1966 to April 2019. The primary outcomes were proportion of death and SMR in chronic GC use patients. The meta-analysis was performed with STATA version 16.1. The I2, subgroup analysis and meta-regression were used to assess heterogeneity among included studies. Results: A total of 109,511 articles, were screened. One hundred eighteen articles with 128 patient cohorts containing 51,374 patients reporting mortality fulfilled the eligibility criteria and were included in the meta-analysis. SMR from seven autoimmune/inflammatory disease studies was 1.84 (95%CI 1.27,2.41) with I2 70.2 6%. The proportion of overall death was 0.12 (95% CI 0.1, .014) with I2 89.3%. The proportion of death was 0.18 (95% CI 0.13,0.24) with I2 92.0% in vasculitis diseases (40 studies), 0.10 (95% CI 0.08, 0.13) with I2 86.2% in connective tissue diseases (67 studies), 0.07 (95% CI 0.03, 0.13) with I2 88.7% in inflammatory diseases (15 studies), 0.28 (95% CI 0.21–0.37) with I2 0.0% in haematologic diseases (2 studies), and 0.06 (95% CI 0.05, 0.09) with I2 0.0% in respiratory diseases (3 studies). GC prescription reports were different across studies and led to different prediction of mortality with high heterogeneity. Proportion of death amongst a GC cumulative dose of 0.3 to 3.9 gram, 4.0 to 7.3 gram and 7.4 to 36.7 gram were 0.11 (95% CI 0.06, 0.20), 0.04 (95% CI 0.02, 0.08) and 0.16 (95% CI 0.08, 0.28), respectively. The proportion of deaths predicted by average mean dose of ≥ 5mg/d, &gt;5–7.5 mg/d, &gt;7.5–10 mg/d and &gt;10–30 mg/d were 0.02 (95% CI 0.01, 0.10), 0.15 (95% CI 0.15, 0.16), 0.08 (95% CI 0.03, 0.19) and 0.14 (95% CI 0.11, 0.19), respectively. The proportion of death predicted by a maintenance dose of ≥5mg/d, &gt;5–7.5 mg/d, &gt;7.5–10 mg/d and &gt;10–30 mg/d were 0.08 (95% CI 0.05, 0.13), 0.12(95% CI 0.05, 0.23), 0.11(95% CI 0.06, 0.210) and 0.12(95% CI 0.05, 0.24) respectively. The causes of death (77 studies) were cardiac (25.3%), infection (13.2%), malignancy (15.6%), respiratory failure (10.6%), active underlying disease (4.4%), cerebrovascular disease (1.1%) and thromboembolism (0.9%). Conclusion: This is the first meta-analysis of oral GC use and mortality from real-world clinical practice publications. Multiple factors contribute to mortality, including GC dose, duration of exposure, route, preparation, together with patient and disease-specific factors.

Face and content validity analysis of the Speech, Spatial and Qualities of Hearing Scale for Parents (SSQ-P) when used in a clinical service without interviews or week-long observation periods

OBJECTIVES

To assess the face and content validity of the Speech, Spatial and Qualities of Hearing Scale for Parents (SSQ-P) when used in a clinical setting without the recommended interviews and observation periods.

METHODS

SSQ-P responses completed by 145 parents of children with bilateral cochlear implants (aged between 5 and 16 years old) were analysed. To assess face validity, the proportion of missing/ambiguous and alternative responses was recorded for each of the 23 items. Where additional written comments were included in responses, a thematic-based analysis was used to identify reasons for the missing/ambiguous or alternative responses. Content validity was assessed using item response theory (IRT), with items having information score less than 0.5 and discrimination score less than 2.0 identified as poorly performing items.

RESULTS

All items of the SSQ-P exhibited some proportion of missing/ambiguous or alternative responses, with six items having >10% missing/ambiguous or alternative responses. IRT identified thirteen items that performed poorly in terms of information and discrimination. These included four of the six items with the most missing/ambiguous or alternative responses.

CONCLUSIONS

SSQ-P items that performed worse tended to describe scenarios that parents perceived as too specific, too vague or hazardous. Without the recommended administration via interviews following three week-long observation periods, parents found these items difficult to complete. The SSQ-P is therefore not recommended for use without the recommended administration method. However, several items performed well in terms of face and content validity, despite independent parent completion without formal observation periods. Thematic analysis suggested that minor re-wording might improve the face validity of items with high content validity but a high proportion of missing/ambiguous or alternative responses. Therefore, the results of the analyses form the basis on which a shortened version of the SSQ-P, more suitable for use in a clinical setting, could be developed in future studies.

Dose dependency of iatrogenic glucocorticoid excess and adrenal insufficiency and mortality: a cohort study in England

CONTEXT

Adrenal insufficiency and Cushing's syndrome are known adverse events of glucocorticoids. However, no population estimates of dose-related risks are available.

OBJECTIVE

To investigate dose-related risks of adrenal dysfunction and death in adults with six chronic inflammatory diseases treated with oral glucocorticoids.

DESIGN AND SETTING

Retrospective record-linkage open-cohort study spanning primary and hospital care in England.

PATIENTS

70,638 people oral glucocorticoid-users and 41,166 non-users aged ≥18 years registered in 389 practices in 1998-2017.

MAIN OUTCOME MEASURES

Incidence rates and hazard ratios (HRs) of diagnosed adrenal dysfunction and death.

RESULTS

During a median follow-up of 5.5 years, 183 patients had glucocorticoid-induced adrenal insufficiency and 248 glucocorticoid-induced Cushing's syndrome. A total of 22,317 (31.6%) and 7,544 (18.3%) deaths occurred amongst glucocorticoid users and non-users, respectively. Incidence of all outcomes increased with higher current daily and cumulative doses. For adrenal insufficiency, the increases in HRs were of 1.07 (95% CI 1.04-1.09) for every increase of 5mg per day and of 2.25 (95% CI 2.15-2.35) per 1000mg of cumulative prednisolone-equivalent dose over the past year. The respective increases in HRs for Cushing's syndrome were of 1.09 (95% CI 1.08-1.11) and 2.31 (95% CI 2.23-2.40) and for mortality of 1.26 (95% CI 2.24-1.28) and 2.05 (95% CI 2.04-2.06).

CONCLUSION

We report a high glucocorticoid dose-dependent increased risk of adrenal adverse events and death. The low observed absolute risk of adrenal insufficiency highlights a potential lack of awareness, and a need for increased physician and patient education about the risks of adrenal dysfunction induced by glucocorticoids.

Relative survival and excess mortality following primary percutaneous coronary intervention for ST-elevation myocardial infarction

BACKGROUND:

High survival rates are commonly reported following primary percutaneous coronary intervention for ST-elevation myocardial infarction, with most contemporary studies reporting overall survival.

AIMS:

The aim of this study was to describe survival following primary percutaneous coronary intervention for ST-elevation myocardial infarction corrected for non-cardiovascular deaths by reporting relative survival and investigate clinically significant factors associated with poor long-term outcomes.

METHODS AND RESULTS:

Using the prospective UK Percutaneous Coronary Intervention registry, primary percutaneous coronary intervention cases ( n=88,188; 2005-2013) were matched to mortality data for the UK populace. Crude five-year relative survival was 87.1% for the patients undergoing primary percutaneous coronary intervention and 94.7% for patients <55 years. Increasing age was associated with excess mortality up to four years following primary percutaneous coronary intervention (56-65 years: excess mortality rate ratio 1.61, 95% confidence interval 1.46-1.79; 66-75 years: 2.49, 2.26-2.75; >75 years: 4.69, 4.27-5.16). After four years, there was no excess mortality for ages 56-65 years (excess mortality rate ratio 1.27, 0.95-1.70), but persisting excess mortality for older groups (66-75 years: excess mortality rate ratio 1.72, 1.30-2.27; >75 years: 1.66, 1.15-2.41). Excess mortality was associated with cardiogenic shock (excess mortality rate ratio 6.10, 5.72-6.50), renal failure (2.52, 2.27-2.81), left main stem stenosis (1.67, 1.54-1.81), diabetes (1.58, 1.47-1.69), previous myocardial infarction (1.52, 1.40-1.65) and female sex (1.33, 1.26-1.41); whereas stent deployment (0.46, 0.42-0.50) especially drug eluting stents (0.27, 0.45-0.55), radial access (0.70, 0.63-0.71) and previous percutaneous coronary intervention (0.67, 0.60-0.75) were protective.

CONCLUSIONS:

Following primary percutaneous coronary intervention for ST-elevation myocardial infarction, long-term cardiovascular survival is excellent. Failure to account for non-cardiovascular death may result in an underestimation of the efficacy of primary percutaneous coronary intervention.

BβArg448Lys polymorphism is associated with altered fibrin clot structure and fibrinolysis in type 2 diabetes

Both type 2 diabetes (T2DM) and Bß448Lys variant of fibrinogen are associated with dense fibrin clots, impaired fibrinolysis and increased cardiovascular risk. It was our objective to investigate whether BßArg448Lys adds to vascular risk by modulating fibrin network structure and/or fibrinolysis in diabetes. The primary aim was to study effects of BßArg448Lys on fibrin network characteristics in T2DM. Secondary aims investigated interactions between gender and BßArg448Lys substitution in relation to fibrin clot properties and vascular disease. Genotyping for BßArg448Lys and dynamic clot studies were carried out on 822 T2DM patients enrolled in the Edinburgh Type 2 Diabetes Study. Turbidimetric assays of individual plasma samples analysed fibrin clot characteristics with additional experiments conducted on clots made from purified fibrinogen, further examined by confocal and electron microscopy. Plasma clot lysis time in Bß448Lys was longer than Bß448Arg variant (mean ± SD; 763 ± 322 and 719 ± 351 seconds [s], respectively; p<0.05). Clots made from plasma-purified fibrinogen of individuals with Arg/Arg, Arg/Lys and Lys/Lys genotypes showed differences in fibre thickness (46.75 ± 8.07, 38.40 ± 6.04 and 25 ± 4.99 nm, respectively; p<0.001) and clot lysis time (419 ± 64, 442 ± 87 and 517 ± 65 s, respectively; p=0.02), directly implicating the polymorphism in the observed changes. Women with Bß448Lys genotype had increased risk of cerebrovascular events and were younger compared with Bß448Arg variant (67.2 ± 4.0 and 68.2 ± 4.4 years, respectively; p=0.035). In conclusion, fibrinogen Bβ448Lys variant is associated with thrombotic fibrin clots in diabetes independently of traditional risk factors. Prospective studies are warranted to fully understand the role of BβArg448Lys in predisposition to vascular ischaemia in T2DM with the potential to develop individualised antithrombotic management strategies.

Clinical outcomes following primary percutaneous coronary intervention for ST-elevation myocardial infarction according to sex and race

Background:

Female sex and South Asian race have been associated with poor clinical outcomes following primary percutaneous coronary intervention (PPCI) for ST-segment elevation myocardial infarction (STEMI) but remain understudied in large real-world series. We therefore investigated the association of sex and race with clinical outcomes following PPCI.

Methods:

We conducted a prospective study of all patients undergoing PPCI for STEMI between January 2009 and December 2011 at a large UK cardiac centre. Clinical characteristics and outcomes were compared according to sex and race using Chi-square test, independent samples Student’s t-test and Mann–Whitney U-test. Primary and secondary outcomes were 12-month major adverse cardiovascular events (MACEs) – defined as all-cause mortality, myocardial infarction and unplanned revascularization, analysed using Cox proportional hazard models adjusting for cardiovascular risk factors.

Results:

Three thousand and forty-nine patients were included. Women ( n=826) were older than men ( n=2223) (median age 69 vs. 60 years, p <0.01). Mortality (hazard ratio 1.48 (1.15–1.90)) and MACE (hazard ratio 1.40 (1.14–1.72)) were higher in women in univariable analysis. However, there were no significant sex-differences in mortality or MACE after age-stratification alone. Multivariable analysis also showed no significant differences in outcomes between sexes. South Asians ( n=297) were younger but had a higher prevalence of most risk factors than White patients ( n=2570). Mortality and MACE did not differ significantly between South Asian and White patients in univariable or multivariable analysis.

Conclusion:

MACE and mortality was not greater in women, or in South Asian patients following PPCI after adjustment for cardiovascular risk factors including age, which was most strongly associated with both outcomes.

Piezo1 channels sense whole body physical activity to reset cardiovascular homeostasis and enhance performance

Mammalian biology adapts to physical activity but the molecular mechanisms sensing the activity remain enigmatic. Recent studies have revealed how Piezo1 protein senses mechanical force to enable vascular development. Here, we address Piezo1 in adult endothelium, the major control site in physical activity. Mice without endothelial Piezo1 lack obvious phenotype but close inspection reveals a specific effect on endothelium-dependent relaxation in mesenteric resistance artery. Strikingly, the Piezo1 is required for elevated blood pressure during whole body physical activity but not blood pressure during inactivity. Piezo1 is responsible for flow-sensitive non-inactivating non-selective cationic channels which depolarize the membrane potential. As fluid flow increases, depolarization increases to activate voltage-gated Ca²⁺ channels in the adjacent vascular smooth muscle cells, causing vasoconstriction. Physical performance is compromised in mice which lack endothelial Piezo1 and there is weight loss after sustained activity. The data suggest that Piezo1 channels sense physical activity to advantageously reset vascular control.The mechanisms that regulate the body's response to exercise are poorly understood. Here, Rode et al. show that the mechanically activated cation channel Piezo1 is a molecular sensor of physical exercise in the endothelium that triggers endothelial communication to mesenteric vessel muscle cells, leading to vasoconstriction.

Assessing the reporting of categorised quantitative variables in observational epidemiological studies

Background

One aspect to consider when reporting results of observational studies in epidemiology is how quantitative risk factors are analysed. The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines recommend that researchers describe how they handle quantitative variables when analysing data. For categorised quantitative variables, the authors are required to provide reasons and justifications informing their practice. We investigated and assessed the practices and reporting of categorised quantitative variables in epidemiology.

Methods

The assessment was based on five medical journals that publish epidemiological research. Observational studies published between April and June 2015 and investigating the relationships between quantitative exposures (or risk factors) and the outcomes were considered for assessment. A standard form was used to collect the data, and the reporting patterns amongst eligible studies were quantified and described.

Results

Out of 61 articles assessed for eligibility, 23 observational studies were included in the assessment. Categorisation of quantitative exposures occurred in 61% of these studies and reasons informing the practice were rarely provided. Only one article explained the choice of categorisation in the analysis. Transformation of quantitative exposures into four or five groups was common and dominant amongst studies using equally spaced categories. Dichotomisation was not popular; the practice featured in one article. Overall, the majority (86%) of the studies preferred ordered or arbitrary group categories. Other criterions used to decide categorical boundaries were based on established guidelines such as consensus statements and WHO standards.

Conclusion

Categorisation of continuous variables remains a dominant practice in epidemiological studies. The reasons informing the practice of categorisation within published work are limited and remain unknown in most articles. The existing STROBE guidelines could provide stronger recommendations on reporting quantitative risk factors in epidemiology.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-017-2137-z) contains supplementary material, which is available to authorized users.

Impact of left ventricular function and transaortic gradient on outcomes from transcatheter aortic valve implantation: data from the UK TAVI Registry

AIMS

Aortic valve surgery in the presence of reduced ejection fraction (EF) or low transaortic gradient is associated with adverse outcome. Low gradient (LG) may be associated with reduced EF, known as low EF-low gradient (LEF-LG), or "paradoxically" low with normal EF (P-LG). Our aim was to investigate the impact of EF and transaortic gradient on outcome following transcatheter aortic valve implantation (TAVI).

METHODS AND RESULTS

We retrospectively analysed the UK TAVI Registry from 2007 to 2011 (n=2,535 consecutive patients, mean age 81.3±7.5, logistic EuroSCORE 21.8±14). Thirty-day mortality was 7.8%, low EF (<50%) was present in 39%, low gradient (<64 mmHg) was present in 27%, LEF-LG in 15% and P-LG in 12% of patients, respectively. LEF-LG patients had the highest risk profile vs. the other groups (EuroSCORE 30±16 vs. 20±12, p<0.001). Neither EF nor gradient impacted on procedural outcome or 30-day mortality. Mortality at two years was significantly higher in LEF-LG patients (34.7%), whereas, in patients with low EF/high gradient (27.8%) or normal EF/low gradient (23%), mortality was not significantly different from that of normal EF/high gradient (23%) patients. LEF-LG independently predicted reduced survival, HR 1.7 (1.4-2.1).

CONCLUSIONS

Neither low EF nor low gradient affected procedural success or 30-day mortality. Long-term survival was reduced in LEF-LG patients but not in those with low EF and high gradient or P-LG with normal EF.

Factors that affect simulated driving in patients with obstructive sleep apnoea

Patients with obstructive sleep apnoea syndrome (OSAS) are at increased risk of involvement in road traffic accidents (RTAs) [1]. Clinicians diagnosing OSAS need to advise patients about driving but there are no validated tools and no robust objective data about which factors are important [2]. There are position statements, based solely on expert opinion, from various professional bodies [3–6]. In general, they conclude that a patient with significant daytime sleepiness and a recent RTA or near miss attributable to sleepiness, fatigue or inattention, should be considered a high-risk driver [3–6]. In a recent survey using clinical vignettes, we have shown that there is considerable variability in the advice that patients are likely to receive [7]. This indicates that clinicians require more robust guidance.

Objective data for advising sleep apnoea sufferers whether they are at increased risk of an accident when drivinghttp://ow.ly/TWPgm

Shaping dental contract reform: a clinical and cost-effective analysis of incentive-driven commissioning for improved oral health in primary dental care

OBJECTIVE

To evaluate the clinical and cost-effectiveness of a new blended dental contract incentivising improved oral health compared with a traditional dental contract based on units of dental activity (UDAs).

DESIGN

Non-randomised controlled study.

SETTING

Six UK primary care dental practices, three working under a new blended dental contract; three matched practices under a traditional contract.

PARTICIPANTS

550 new adult patients.

INTERVENTIONS

A new blended/incentive-driven primary care dentistry contract and service delivery model versus the traditional contract based on UDAs.

MAIN OUTCOME MEASURES

Primary outcome was as follows: percentage of sites with gingival bleeding on probing. Secondary outcomes were as follows: extracted and filled teeth (%), caries (International Caries Detection and Assessment System (ICDAS)), oral health-related quality of life (Oral Health Impact Profile-14 (OHIP-14)). Incremental cost-effective ratios used OHIP-14 and quality adjusted life years (QALYs) derived from the EQ-5D-3L.

RESULTS

At 24 months, 291/550 (53%) patients returned for final assessment; those lost to follow-up attended 6.46 appointments on average (SD 4.80). The primary outcome favoured patients in the blended contract group. Extractions and fillings were more frequent in this group. Blended contracts were financially attractive for the dental provider but carried a higher cost for the service commissioner. Differences in generic health-related quality of life were negligible. Positive changes over time in oral health-related quality of life in both groups were statistically significant.

CONCLUSIONS

This is the first UK study to assess the clinical and cost-effectiveness of a blended contract in primary care dentistry. Although the primary outcome favoured the blended contract, the results are limited because 47% patients did not attend at 24 months. This is consistent with 39% of adults not being regular attenders and 27% only visiting their dentist when they have a problem. Promotion of appropriate attendance, especially among those with high need, necessitates being factored into recruitment strategies of future studies.

Methods for the analysis of ordinal response data in medical image quality assessment

The assessment of image quality in medical imaging often requires observers to rate images for some metric or detectability task. These subjective results are used in optimization, radiation dose reduction or system comparison studies and may be compared to objective measures from a computer vision algorithm performing the same task. One popular scoring approach is to use a Likert scale, then assign consecutive numbers to the categories. The mean of these response values is then taken and used for comparison with the objective or second subjective response. Agreement is often assessed using correlation coefficients. We highlight a number of weaknesses in this common approach, including inappropriate analyses of ordinal data and the inability to properly account for correlations caused by repeated images or observers. We suggest alternative data collection and analysis techniques such as amendments to the scale and multilevel proportional odds models. We detail the suitability of each approach depending upon the data structure and demonstrate each method using a medical imaging example. Whilst others have raised some of these issues, we evaluated the entire study from data collection to analysis, suggested sources for software and further reading, and provided a checklist plus flowchart for use with any ordinal data. We hope that raised awareness of the limitations of the current approaches will encourage greater method consideration and the utilization of a more appropriate analysis. More accurate comparisons between measures in medical imaging will lead to a more robust contribution to the imaging literature and ultimately improved patient care.

Comparative survival after transapical, direct aortic, and subclavian transcatheter aortic valve implantation (data from the UK TAVI registry)

Many patients have iliofemoral vessel anatomy unsuitable for conventional transfemoral (TF) transcatheter aortic valve implantation (TAVI). Safe and practical alternatives to the TF approach are, therefore, needed. This study compared outcomes of alternative nonfemoral routes, transapical (TA), direct aortic (DA), and subclavian (SC), with standard femoral access. In this retrospective study, data from 3,962 patients in the UK TAVI registry were analyzed. All patients who received TAVI through a femoral, subclavian, TA, or DA approach were eligible for inclusion. The primary outcome measure was survival up to 2 years. Median Logistic EuroSCORE was similar for SC, DA, and TA but significantly lower in the TF cohort (22.1% vs 20.3% vs 21.2% vs 17.0%, respectively, p <0.0001). Estimated 1-year survival rate was similar for TF (84.6 ± 0.7%) and SC (80.5 ± 3%, p = 0.27) but significantly worse for TA (74.7 ± 1.6%, p <0.001) and DA (75.2 ± 3.3%, p <0.001). A Cox proportional hazard model was used to analyze survival up to 2 years. Survival in the SC group was not significantly different from the TF group (hazard ratio [HR] 1.22, 95% confidence interval [CI] 0.88 to 1.70, p = 0.24). In contrast, survival in the TA (HR 1.74, 95% CI 1.43 to 2.11; p <0.001) and DA (HR 1.55, 95% CI 1.13 to 2.14; p <0.01) cohorts was significantly reduced compared with TF. In conclusion, TA and DA TAVI were associated with similar survival, both significantly worse than with the TF route. In contrast, subclavian access was not significantly different from TF and may represent the safest nonfemoral access route for TAVI.

Patient Acceptability of the Yorkshire Dialysis Decision Aid (YoDDA) Booklet: A Prospective Non-Randomized Comparison Study Across 6 Predialysis Services

♦ Background:

Patients are satisfied with their kidney care but want more support in making dialysis choices. Predialysis leaflets vary across services, with few being sufficient to enable patients' informed decision making. We describe the acceptability of a patient decision aid and feasibility of evaluating its effectiveness within usual predialysis practice.

♦ Methods:

Prospective non-randomized comparison design, Usual Care or Usual Care Plus Yorkshire Dialysis Decision Aid Booklet (+YoDDA), in 6 referral centers (Yorkshire-Humber, UK) for patients with sustained deterioration of kidney function. Consenting (C) patients completed questionnaires after predialysis consultation (T1), and 6 weeks later (T2). Measures assessed YoDDA's utility to support patients' decisions and integration within usual care.

♦ Results:

Usual Care (n = 105) and +YoDDA (n = 84) participant characteristics were similar: male (62%), white (94%), age (mean = 62.6; standard deviation [SD] 14.4), kidney disease severity (glomerular filtration rate [eGFR] mean = 14.7; SD 3.7); decisional conflict was < 25; choice-preference for home versus hospital dialysis approximately 50:50. Patients valued receiving YoDDA, reading it on their own (96%), and sharing it with family (72%). The +YoDDA participants had higher scores for understanding kidney disease, reasoning about options, feeling in control, sharing their decision with family. Study engagement varied by center (estimated range 14 – 49%; mean 45%); participants varied in completion of decision quality measures.

♦ Conclusions:

Receiving YoDDA as part of predialysis education was valued and useful to patients with worsening kidney disease. Integrating YoDDA actively within predialysis programs will meet clinical guidelines and patient need to support dialysis decision making in the context of patients' lifestyle.

Variability in clinicians' opinions regarding fitness to drive in patients with obstructive sleep apnoea syndrome (OSAS)

We evaluated clinicians' current practice for giving advice to patients with obstructive sleep apnoea syndrome. Clinicians were invited to complete a web-based survey and indicate the advice they would give to patients in a number of scenarios about driving; they were also asked what they considered to be residual drowsiness and adequate compliance following CPAP treatment. In the least contentious scenario, 94% of clinicians would allow driving; in the most contentious a patient had a 50% chance of being allowed to drive. Following treatment with CPAP, clinicians' interpretation of what constituted residual drowsiness was inconsistent. In each vignette the same clinician was more likely to say 'yes' to 'excessive' than to 'irresistible' (71%±12% vs 42%±10%, p=0.0045). There was also a lack of consensus regarding 'adequate CPAP compliance'; 'yes' responses ranged from 13% to 64%. There is a need for clearer guidance; a recent update to the Driver and Vehicle Licensing Agency guidance, and a statement from the British Thoracic Society, making it clear that sleepiness while driving is the key issue, may help.

The INCENTIVE protocol: an evaluation of the organisation and delivery of NHS dental healthcare to patients-innovation in the commissioning of primary dental care service delivery and organisation in the UK

INTRODUCTION

In England, in 2006, new dental contracts devolved commissioning of dental services locally to Primary Care Trusts to meet the needs of their local population. The new national General Dental Services contracts (nGDS) were based on payment for Units of Dental Activity (UDAs) awarded in three treatment bands based on complexity of care. Recently, contract currency in UK dentistry is evolving from UDAs based on volume and case complexity towards 'blended contracts' that include incentives linked with key performance indicators such as quality and improved health outcome. Overall, evidence of the effectiveness of incentive-driven contracting of health providers is still emerging. The INCENTIVE Study aims to evaluate a blended contract model (incentive-driven) compared to traditional nGDS contracts on dental service delivery in practices in West Yorkshire, England.

METHODS AND ANALYSIS

The INCENTIVE model uses a mixed methods approach to comprehensively evaluate a new incentive-driven model of NHS dental service delivery. The study includes 6 dental surgeries located across three newly commissioned dental practices (blended contract) and three existing traditional practices (nGDS contracts). The newly commissioned practices have been matched to traditional practices by deprivation index, age profile, ethnicity, size of practice and taking on new patients. The study consists of three interlinked work packages: a qualitative study to explore stakeholder perspectives of the new service delivery model; an effectiveness study to assess the INCENTIVE model in reducing the risk of and amount of dental disease and enhance oral health-related quality of life in patients; and an economic study to assess cost-effectiveness of the INCENTIVE model in relation to clinical status and oral health-related quality of life.

ETHICS AND DISSEMINATION

The study has been approved by NRES Committee London, Bromley. The results of this study will be disseminated at national and international conferences and in international journals.

Hypofibrinolysis in type 2 diabetes: the role of the inflammatory pathway and complement C3

AIMS/HYPOTHESIS

Plasminogen activator inhibitor-1 (PAI-1) has been regarded as the main antifibrinolytic protein in diabetes, but recent work indicates that complement C3 (C3), an inflammatory protein, directly compromises fibrinolysis in type 1 diabetes. The aim of the current project was to investigate associations between C3 and fibrinolysis in a large cohort of individuals with type 2 diabetes.

METHODS

Plasma levels of C3, C-reactive protein (CRP), PAI-1 and fibrinogen were analysed by ELISA in 837 patients enrolled in the Edinburgh Type 2 Diabetes Study. Fibrin clot lysis was analysed using a validated turbidimetric assay.

RESULTS

Clot lysis time correlated with C3 and PAI-1 plasma levels (r = 0.24, p < 0.001 and r = 0.22, p < 0.001, respectively). In a multivariable regression model involving age, sex, BMI, C3, PAI-1, CRP and fibrinogen, and using log-transformed data as appropriate, C3 was associated with clot lysis time (regression coefficient 0.227 [95% CI 0.161, 0.292], p < 0.001), as was PAI-1 (regression coefficient 0.033 [95% CI 0.020, 0.064], p < 0.05) but not fibrinogen (regression coefficient 0.003 [95% CI -0.046, 0.051], p = 0.92) or CRP (regression coefficient 0.024 [95% CI -0.008, 0.056], p = 0.14). No correlation was demonstrated between plasma levels of C3 and PAI-1 (r = -0.03, p = 0.44), consistent with previous observations that the two proteins affect different pathways in the fibrinolytic system.

CONCLUSIONS/INTERPRETATION

Similarly to PAI-1, C3 plasma levels are independently associated with fibrin clot lysis in individuals with type 2 diabetes. Therefore, future studies should analyse C3 plasma levels as a surrogate marker of fibrinolysis potential in this population.

Cardiovascular risk in patients with small and medium abdominal aortic aneurysms, and no history of cardiovascular disease

Background

Cardiovascular disease (CVD) is the main cause of death in people with abdominal aortic aneurysm (AAA). There is little evidence that screening for AAA reduces all-cause or cardiovascular mortality. The aim of the study was to assess whether subjects with a small or medium AAA (3·0–5·4 cm), without previous history of clinical CVD, had raised levels of CVD biomarkers or increased total mortality.

Methods

This prospective study included subjects with a small or medium AAA and controls, all without a history of clinical CVD. CVD biomarkers (high-sensitivity C-reactive protein, hs-CRP; heart-type fatty acid-binding protein, H-FABP) were measured, and survival was recorded.

Results

Of a total of 815 people, 476 with an AAA and 339 controls, a cohort of 86 with small or medium AAA (3–5·4 cm) and 158 controls, all with no clinical history of CVD, were identified. The groups were matched for age and sex. The AAA group had higher median (i.q.r.) levels of hs-CRP (2·8 (1·2–6·0) versus 1·3 (0·5–3·5) mg/l; P &lt; 0·001) and H-FABP (4·6 (3·5–6·0) versus 4·0 (3·3–5·1) µg/l; P = 0·011) than controls. Smoking was more common in the AAA group; however, hs-CRP and H-FABP levels were not related to smoking. Mean survival was lower in the AAA group: 6·3 (95 per cent confidence interval (c·i.) 5·6 to 6·9) years versus 8·0 (7·6 to 8·1) years in controls (P &lt; 0·001). Adjusted mortality was higher in the AAA group (hazard ratio 3·41, 95 per cent c·i. 2·11 to 9·19; P &lt; 0·001).

Conclusion

People with small or medium AAA and no clinical symptoms of CVD have higher levels of hs-CRP and H-FABP, and higher mortality compared with controls. They should continue to receive secondary prevention against CVD.

Prospective development and validation of a model to predict heart failure hospitalisation

Objective

Acute heart failure syndrome (AHFS) is a major cause of hospitalisation and imparts a substantial burden on patients and healthcare systems. Tools to define risk of AHFS hospitalisation are lacking.

Methods

A prospective cohort study (n=628) of patients with stable chronic heart failure (CHF) secondary to left ventricular systolic dysfunction was used to derive an AHFS prediction model which was then assessed in a prospectively recruited validation cohort (n=462).

Results

Within the derivation cohort, 44 (7%) patients were hospitalised as a result of AHFS during 1 year of follow-up. Predictors of AHFS hospitalisation included furosemide equivalent dose, the presence of type 2 diabetes mellitus, AHFS hospitalisation within the previous year and pulmonary congestion on chest radiograph, all assessed at baseline. A multivariable model containing these four variables exhibited good calibration (Hosmer–Lemeshow p=0.38) and discrimination (C-statistic 0.77; 95% CI 0.71 to 0.84). Using a 2.5% risk cut-off for predicted AHFS, the model defined 38.5% of patients as low risk, with negative predictive value of 99.1%; this low risk cohort exhibited <1% excess all-cause mortality per annum when compared with contemporaneous actuarial data. Within the validation cohort, an identically applied model derived comparable performance parameters (C-statistic 0.81 (95% CI 0.74 to 0.87), Hosmer–Lemeshow p=0.15, negative predictive value 100%).

Conclusions

A prospectively derived and validated model using simply obtained clinical data can identify patients with CHF at low risk of hospitalisation due to AHFS in the year following assessment. This may guide the design of future strategies allocating resources to the management of CHF.

Do outcomes from transcatheter aortic valve implantation vary according to access route and valve type? The UK TAVI Registry

OBJECTIVES

To determine whether outcomes from transcatheter aortic valve implantation (TAVI) vary according to access route and valve type in a real-world population.

BACKGROUND

Registry and uncontrolled trial data have found that patients undergoing nonfemoral TAVI have higher early and late mortality. It is not clear whether worse outcomes relate directly to access route. There have been no direct comparisons of outcomes according to valve type.

METHODS

Data were collected prospectively on 1,620 patients undergoing TAVI in the UK and compared in 4 groups: SAPIEN transfemoral (TF); SAPIEN transapical (TA); CoreValve TF, CoreValve subclavian. Univariable and multivariable regression analysis was performed to identify independent predictors of mortality.

RESULTS

Mortality in patients undergoing SAPIEN TAVI via a TA approach was higher than with TF at 30 days (11.2% vs. 4.4%, P < 0.01), 1 year (28.7% vs. 18.1%, P = 0.01), and 2 years (56.0% vs. 43.5%, P = 0.01). Logistic EuroSCORE was higher in TA patients (22.5 ± 12.9% vs. 17.7 ± 11.1%, P < 0.0001). After multivariable analysis TA access was associated with increased mortality at 30 days (OR 2.56, 95% CI 1.46-4.48, P < 0.01) and 2 years (OR 1.75, 1.08-2.74, P = 0.02). There was no significant difference in mortality at any time-point between patients treated with SAPIEN (n = 812) and CoreValve (n = 808) prostheses. CoreValve-treated patients had a higher rate of permanent pacemaker implantation (23.1% vs. 7.2%, P < 0.0001), and grade ≥2 aortic regurgitation on postprocedure echocardiography (13.0% vs. 7.3%, P < 0.01).

CONCLUSIONS

Patients undergoing TA TAVI experienced increased early and late mortality compared to a TF approach. Survival was not influenced by valve type.

Modeling the Growth of Infrarenal Abdominal Aortic Aneurysms

BACKGROUND

Abdominal aortic aneurysm (AAA) growth is a complex process that is incompletely understood. Significant heterogeneity in growth trajectories between patients has led to difficulties in accurately modeling aneurysm growth across cohorts of patients. We set out to compare four models of aneurysm growth commonly used in the literature and confirm which best fits the patient data of our AAA cohort.

METHODS

Patients with AAA were included in the study if they had two or more abdominal ultrasound scans greater than 3 months apart. Patients were censored from analysis once their AAA exceeded 5.5 cm. Four models were applied using the R environment for statistical computing. Growth estimates and goodness of fit (using the Akaike Information Criterion, AIC) were compared, with p-values based on likelihood ratio testing.

RESULTS

Of 510 enrolled patients, 264 met the inclusion criteria, yielding a total of 1861 imaging studies during 932 cumulative years of surveillance. Overall, growth rates were: (1) 0.35 (0.31,0.39) cm/yr in the growth/time calculation, (2) 0.056 (0.042,0.068) cm/yr in the linear regression model, (3) 0.19 (0.17,0.21) cm/yr in the linear multilevel model, and (4) 0.21 (0.18,0.24) cm/yr in the quadratic multilevel model at time 0, slowing to 0.15 (0.12,0.17) cm/yr at 10 years. AIC was lowest in the quadratic multilevel model (1508) compared to other models (P < 0.0001).

CONCLUSION

AAA growth was heterogeneous between patients; the nested nature of the data is most appropriately modeled by multilevel modeling techniques.

An assessment of composite measures of hospital performance and associated mortality for patients with acute myocardial infarction. Analysis of individual hospital performance and outcome for the National Institute for Cardiovascular Outcomes Research (NICOR)

AIM

To investigate whether a hospital-specific opportunity-based composite score (OBCS) was associated with mortality in 136,392 patients with acute myocardial infarction (AMI) using data from the Myocardial Ischaemia National Audit Project (MINAP) 2008-2009.

METHODS AND RESULTS

For 199 hospitals a multidimensional hospital OBCS was calculated on the number of times that aspirin, thienopyridine, angiotensin-converting enzyme inhibitor (ACEi), statin, β-blocker, and referral for cardiac rehabilitation was given to individual patients, divided by the overall number of opportunities that hospitals had to give that care. OBCS and its six components were compared using funnel plots. Associations between OBCS performance and 30-day and 6-month all-cause mortality were quantified using mixed-effects regression analysis. Median hospital OBCS was 95.3% (range 75.8-100%). By OBCS, 24.1% of hospitals were below funnel plot 99.8% CI, compared to aspirin (11.1%), thienopyridine (15.1%), β-blockers (14.7%), ACEi (19.1%), statins (12.1%), and cardiac rehabilitation (17.6%) on discharge. Mortality (95% CI) decreased with increasing hospital OBCS quartile at 30 days [Q1, 2.25% (2.07-2.43%) vs. Q4, 1.40% (1.25-1.56%)] and 6 months [Q1, 7.93% (7.61-8.25%) vs. Q4, 5.53% (5.22-5.83%)]. Hospital OBCS quartile was inversely associated with adjusted 30-day and 6-month mortality [OR (95% CI), 0.87 (0.80-0.94) and 0.92 (0.88-0.96), respectively] and persisted after adjustment for coronary artery catheterization [0.89 (0.82-0.96) and 0.95 (0.91-0.98), respectively].

CONCLUSIONS

Multidimensional hospital OBCS in AMI survivors are high, discriminate hospital performance more readily than single performance indicators, and significantly inversely predict early and longer-term mortality.

Cardiac resynchronization therapy in pacemaker-dependent patients with left ventricular dysfunction

AIMS

Heart failure and left ventricular (LV) systolic dysfunction (LVSD) are common in patients with permanent pacemakers. The aim was to determine if cardiac resynchronization therapy (CRT) at the time of pulse generator replacement (PGR) is of benefit in patients with unavoidable RV pacing and LVSD.

METHODS AND RESULTS

Fifty patients with unavoidable RV pacing, LVSD, and mild or no symptoms of heart failure, listed for PGR were randomized 1 : 1 to either standard RV-PGR (comparator) or CRT. The primary endpoint was the difference in change in LV ejection fraction (LVEF) between RV-PGR and CRT groups from baseline to 6 months. Secondary endpoints included peak oxygen consumption, quality of life, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. At 6 months there was a difference in change in median (interquartile range) LVEF [9 (6-12) vs. -1.5 (-4.5 to -0.8)%; P < 0.0001] between the CRT and RV-PGR arms. There were also improvements in exercise capacity (P = 0.007), quality of life (P = 0.03), and NT-proBNP (P = 0.007) in those randomized to CRT. After 809 (729-880) days, 17 patients had died or been hospitalized (6 in CRT group and 11 in the comparator RV-PGR group) and two patients in the RV-PGR arm had required CRT for deteriorating heart failure. Patients with standard RV-PGR had more days in hospital during follow-up than those in the CRT group [4 (2-7) vs. 11 (6-16) days; P = 0.047].

CONCLUSION

Performing CRT in pacemaker patients with unavoidable RV pacing and LVSD but without severe symptoms of heart failure, at the time of PGR, improves cardiac function, exercise capacity, quality of life, and NT-pro-BNP levels.

Target setting for elective infra-renal AAA surgery: A single mortality figure?

OBJECTIVES

One of the key standards set by the UK NAAASP is that centres performing elective abdominal aortic aneurysm (AAA) repair have a mortality rate of <6%. In light of this, and the current aim to reduce elective AAA repair mortality to 3.5% by 2013, we sought to investigate the statistical validity of such targets.

METHODS

The National Vascular Database (NVD) was interrogated and the degree of AAA missing data and its geographical variation is described. Utilising published data from 2006 to 2008 a funnel plot was used to illustrate NHS Trust level data for current estimates of mortality rate. A binomial distribution model was applied to calculate variation in observed mortality rates in relation to number of patients treated, based on a "true" mortality rate of 3.5%. Funnel plots were constructed using simulated data-sets for units performing 10, 30, 50, 100 or 150 procedures annually with control-limits calculated using a cumulative probability distribution. Finally the effect of case-mix on mortality was modelled and shown graphically.

RESULTS

The NVD AAA data set shows a range of data missingness across variables (median 22%, IQR 10-64%). High levels of missingness typically coincide with non-required, non-preferred variables however this is subject to geographical variation. Funnel plots of simulated data demonstrate that smaller units have greater variability in 3-year mortality (range 0.0-10.0%) than the largest units performing 150 procedures annually (1.3-5.6%). Around 20% of NVD variables are described as "preferred", these typically relate to clinical measurements and patient medications and would inform any risk model of mortality. Data missingness amongst these variables ranges from 5 to 50%.

CONCLUSIONS

There are many problems with the use of a single mortality figure to assess performance. These include the natural statistical variability and the means by which "case-mix" is taken into consideration. This article calls for further research into mortality target setting and suggests strategies which may help provide solutions nationally and facilitate international comparison.

Gender-specific alterations in fibrin structure function in type 2 diabetes: associations with cardiometabolic and vascular markers

CONTEXT

Diabetes is associated with increased incidence of atherothrombotic disease. The fibrin network forms the backbone of the arterial thrombus, and fibrin clot structure determines predisposition to cardiovascular events.

OBJECTIVES

The aim of the study was to investigate fibrin clot structure/fibrinolysis in the largest type 2 diabetes cohort and analyze associations with cardiometabolic risk factors and vascular pathology.

DESIGN

Clot structure/fibrinolysis was assessed in 875 participants of the Edinburgh Type 2 Diabetes Study [age, 68 (range, 60-75) yr; 450 males] by turbidimetric assays, and clots were visualized by confocal microscopy. Four parameters of clot structure/fibrinolysis were analyzed, and plasma levels of fibrinogen and plasminogen activator inhibitor-1 were studied by Clauss assay and ELISA, respectively.

RESULTS

Clot maximum absorbance was increased in females compared with males (0.37 ± 0.005 and 0.34 ± 0.005 arbitrary unit, respectively; P < 0.001), and took longer to lyse (803 ± 20 and 665 ± 12 sec, respectively; P < 0.001). These gender differences in clot structure and fibrinolysis were still evident after correcting for fibrinogen and plasminogen activator inhibitor-1 plasma levels. A prothrombotic fibrin structure profile was associated with increased body mass index and low levels of high-density lipoprotein in women and with inadequate diabetes control in men. Clot formation time was related to previous cardiac ischemic events in both men and women after adjusting for traditional risk factors [odds ratio, 1.22 (95% confidence interval, 1.07, 1.38); and 1.33 (1.15, 1.50), respectively], and prothrombotic clots were associated with low ankle brachial index, renal impairment, and smoking, regardless of gender.

CONCLUSIONS

Women with type 2 diabetes have compact clots with compromised fibrinolysis compared with men. There are gender-specific associations between clotting parameters and cardiometabolic risk factors in this population, whereas vascular abnormalities, impaired renal function, and smoking are associated with prothrombotic clot structure profile regardless of gender.

Evaluation of the NICE mini-GRACE risk scores for acute myocardial infarction using the Myocardial Ischaemia National Audit Project (MINAP) 2003-2009: National Institute for Cardiovascular Outcomes Research (NICOR)

OBJECTIVE

To evaluate the performance of the National Institute for Health and Clinical Excellence (NICE) mini-Global Registry of Acute Coronary Events (GRACE) (MG) and adjusted mini-GRACE (AMG) risk scores.

DESIGN

Retrospective observational study.

SETTING

215 acute hospitals in England and Wales.

PATIENTS

137 084 patients discharged from hospital with a diagnosis of acute myocardial infarction (AMI) between 2003 and 2009, as recorded in the Myocardial Ischaemia National Audit Project (MINAP).

MAIN OUTCOME MEASURES

Model performance indices of calibration accuracy, discriminative and explanatory performance, including net reclassification index (NRI) and integrated discrimination improvement.

RESULTS

Of 495 263 index patients hospitalised with AMI, there were 53 196 ST elevation myocardial infarction and 83 888 non-ST elevation myocardial infarction (NSTEMI) (27.7%) cases with complete data for all AMG variables. For AMI, AMG calibration was better than MG calibration (Hosmer-Lemeshow goodness of fit test: p=0.33 vs p<0.05). MG and AMG predictive accuracy and discriminative ability were good (Brier score: 0.10 vs 0.09; C statistic: 0.82 and 0.84, respectively). The NRI of AMG over MG was 8.1% (p<0.05). Model performance was reduced in patients with NSTEMI, chronic heart failure, chronic renal failure and in patients aged ≥85 years.

CONCLUSIONS

The AMG and MG risk scores, utilised by NICE, demonstrated good performance across a range of indices using MINAP data, but performed less well in higher risk subgroups. Although indices were better for AMG, its application may be constrained by missing predictors.

Continuous measures of driving performance on an advanced office-based driving simulator can be used to predict simulator task failure in patients with obstructive sleep apnoea syndrome

INTRODUCTION

Some patients with obstructive sleep apnoea syndrome are at higher risk of being involved in road traffic accidents. It has not been possible to identify this group from clinical and polysomnographic information or using simple simulators. We explore the possibility of identifying this group from variables generated in an advanced PC-based driving simulator.

METHODS

All patients performed a 90 km motorway driving simulation. Two events were programmed to trigger evasive actions, one subtle and an alert driver should not crash, while for the other, even a fully alert driver might crash. Simulator parameters including standard deviation of lane position (SDLP) and reaction times at the veer event (VeerRT) were recorded. There were three possible outcomes: 'fail', 'indeterminate' and 'pass'. An exploratory study identified the simulator parameters predicting a 'fail' by regression analysis and this was then validated prospectively.

RESULTS

72 patients were included in the exploratory phase and 133 patients in the validation phase. 65 (32%) patients completed the run without any incidents, 45 (22%) failed, 95 (46%) were indeterminate. Prediction models using SDLP and VeerRT could predict 'fails' with a sensitivity of 82% and specificity of 96%. The models were subsequently confirmed in the validation phase.

CONCLUSIONS

Using continuously measured variables it has been possible to identify, with a high degree of accuracy, a subset of patients with obstructive sleep apnoea syndrome who fail a simulated driving test. This has the potential to identify at-risk drivers and improve the reliability of a clinician's decision-making.

A comparison of different approaches to unravel the latent structure within metabolic syndrome

BACKGROUND

Exploratory factor analysis is a commonly used statistical technique in metabolic syndrome research to uncover latent structure amongst metabolic variables. The application of factor analysis requires methodological decisions that reflect the hypothesis of the metabolic syndrome construct. These decisions often raise the complexity of the interpretation from the output. We propose two alternative techniques developed from cluster analysis which can achieve a clinically relevant structure, whilst maintaining intuitive advantages of clustering methodology.

METHODS

Two advanced techniques of clustering in the VARCLUS and matroid methods are discussed and implemented on a metabolic syndrome data set to analyze the structure of ten metabolic risk factors. The subjects were selected from the normative aging study based in Boston, Massachusetts. The sample included a total of 847 men aged between 21 and 81 years who provided complete data on selected risk factors during the period 1987 to 1991.

RESULTS

Four core components were identified by the clustering methods. These are labelled obesity, lipids, insulin resistance and blood pressure. The exploratory factor analysis with oblique rotation suggested an overlap of the loadings identified on the insulin resistance and obesity factors. The VARCLUS and matroid analyses separated these components and were able to demonstrate associations between individual risk factors.

CONCLUSIONS

An oblique rotation can be selected to reflect the clinical concept of a single underlying syndrome, however the results are often difficult to interpret. Factor loadings must be considered along with correlations between the factors. The correlated components produced by the VARCLUS and matroid analyses are not overlapped, which allows for a simpler application of the methodologies and interpretation of the results. These techniques encourage consistency in the interpretation whilst remaining faithful to the construct under study.

CFH, VEGF and HTRA1 promoter genotype may influence the response to intravitreal ranibizumab therapy for neovascular age-related macular degeneration

AIMS

To investigate an association between genotype for three single nucleotide polymorphisms strongly associated with the development of age-related macular degeneration (AMD) and the early response to treatment with intravitreal ranibizumab for neovascular AMD.

METHODS

Best corrected visual acuity letter score was recorded at baseline and each subsequent visit. Age, sex, smoking history, lesion type and the number of injections were also recorded. Genotypes were obtained for rs11200638 in HTRA1, rs1061170 in CFH and rs1413711 in VEGF. Data were analysed with treatment response at month 6 as both a binary (>5 letter improvement vs ≤5 letter gain) and a linear trait.

RESULTS

This initial study cohort consisted of 104 Caucasian neovascular AMD patients treated with intravitreal ranibizumab. Trends towards a more favourable outcome were seen with the higher AMD risk genotypes in CFH and VEGF in both the linear and binary models and in HTRA1 in the linear model alone. For CFH, mean letter score change after 6 months was +1.6, +5.9 and +7.2 letters for the TT, TC and CC genotypes and a >5 letter gain was seen in 34.6%, 56.6% and 56%, respectively. For VEGF, mean letter score change after 6 months was +1.3, +5.8 and +7.4 letters for the TT, TC and CC genotypes and a >5 letter gain was seen in 40%, 55.8% and 51.9%, respectively. For HTRA1, mean letter score change was +2.2, +7.5 and +2.9 letters for the GG, GA and AA genotypes.

CONCLUSIONS

This study reports preliminary evidence suggesting that the higher AMD risk genotypes in CFH, VEGF and HTRA1 may influence the short-term response to treatment with ranibizumab for neovascular AMD.

Resolving inequalities in care? Reduced mortality in the elderly after acute coronary syndromes. The Myocardial Ischaemia National Audit Project 2003-2010

AIMS

To examine age-dependent in-hospital mortality for hospitalization with acute coronary syndromes (ACS) in England and Wales.

METHODS AND RESULTS

Mixed-effects regression analysis using data from 616 011 ACS events at 255 hospitals as recorded in the Myocardial Ischemia National Audit Project (MINAP) 2003-2010; 102 415 (16.7%) patients were aged <55 years and 72 721 (11.9%) ≥85 years. Patients ≥85 years with ST-elevation myocardial infarction (STEMI) were less likely to receive emergency reperfusion therapy than those <55 years (RR = 0.27, 95% CI: 0.25-0.28). Older patients had greater lengths of stay (P< 0.001) and higher in-hospital mortality (P< 0.001). For STEMI and non-ST-elevation myocardial infarction (NSTEMI), there were reductions in in-hospital mortality from 2003 to 2010 across all age groups including the very elderly. For STEMI ≥ 85 years, in-hospital mortality reduced from 30.1% in 2003 to 19.4% in 2010 (RR = 0.54, 95% CI: 0.38-0.75, P< 0.001), and for NSTEMI ≥ 85 years, from 31.5% in 2003 to 20.4% in 2010 (RR = 0.56, 95% CI: 0.42-0.73, P< 0.001). Findings were upheld after multi-level adjustment (base = 2003): male STEMI 2010 OR = 0.60, 95% CI: 0.48-0.75; female STEMI 2010 OR = 0.55, 95% CI: 0.42-0.71; male NSTEMI OR = 0.50, 95% CI: 0.42-0.60; female NSTEMI OR = 0.49, 95% CI: 0.40-0.59.

CONCLUSION

For patients hospitalized with ACS in England and Wales, there have been substantial reductions in in-hospital mortality rates from 2003 to 2010 across all age groups. The temporal improvements in mortality were similar for sex and type of acute myocardial infarction. Age-dependent inequalities in the management of ACS were apparent.

Multiple imputation for completion of a national clinical audit dataset

The Myocardial Ischaemia National Audit Project (MINAP) is a register of heart attacks covering 234 acute admitting hospitals in England and Wales. It is used to assess the extent to which hospitals are attaining the government targets for patients with heart attacks (myocardial infarction). MINAP is therefore of national importance in coronary care and of potential international importance for research. As with most observational databases, there is missing data in MINAP, which has the potential to bias statistical analyses. In this paper, we use multiple imputation to reduce the impact of missing data and we give details of how our imputation scheme was implemented. The key contribution of this paper is the provision of multiply completed datasets, suited to a range of analyses, that can be used to make efficient inferences without the distractions of missing data. Our work will assist MINAP in achieving its priority goal of providing useful data with which to analyse patient care.