Factors associated with pneumococcal vaccination in 2040 people with type 2 diabetes: A cross-sectional study.

AIMS: Pneumococcal vaccination is recommended in diabetes because of the high risk for invasive pneumococcal disease and mortality; however, vaccination rates are below recommended targets. This study was conducted to identify possible reasons behind the low rate of vaccine uptake. METHODS: We examined baseline information from the Alberta Caring for Diabetes study, a prospective cohort study of 2040 adults with type 2 diabetes. Patients were recruited between December 2011 and December 2013. The baseline survey collected information on a wide range of socio-demographic characteristics, disease and management information, as well as health status measurements and health service utilization. Multivariable logistic regression analyses were conducted to identify factors associated with self-reported pneumococcal vaccination status. RESULTS: Mean age was 64 (SD 11) years, 45% were women, mean duration of diabetes was 12 (SD 10) years, and 1090 (53%) were vaccinated. Age≥65 years (adjusted odds ratio [aOR] 2.52; 95% CI: 1.98-3.20), respiratory disease (aOR 1.50; 95% CI: 1.17-1.93), and cancer (aOR 1.45; 95% CI: 1.08-1.94) were independently associated with pneumococcal vaccination. In addition, women, retirees, people with diabetes≥10 years, people using antihypertensive medications or insulin, and those who had their HbA1c, kidney function, or their weight or waist circumference measured by a healthcare professional in the past year were more likely to have been vaccinated. CONCLUSION: Based on this information, future programs aimed at people aged<65 years old, men, those who are currently working, those recently diagnosed with diabetes, and those with few comorbidities could have the most potential for improving pneumococcal vaccine uptake in people with diabetes.

Costarting sitagliptin with metformin is associated with a lower likelihood of disease progression in newly treated people with type 2 diabetes: a cohort study.

AIM: To examine whether early addition of sitagliptin to metformin is associated with a delay in type 2 diabetes progression. METHODS: Administrative health records from Alberta, Canada, for the period April 2008 to March 2015, were used to conduct a retrospective cohort study in new metformin users. People who started sitagliptin on the same day they initiated metformin therapy were compared with those who added sitagliptin later. Insulin initiation served as a surrogate marker for diabetes progression, and multivariable logistic regression models were used to evaluate the association with sitagliptin addition (costart vs later use). A mixed-effects linear regression model was used to examine the effect of timing of sitagliptin addition on HbA1c change over 1 year. RESULTS: The mean (sd) age of the 8764 people who used sitagliptin was 52.1 (11.1) years, 5665 (64.6%) were men, and 1153 (13.2%) started sitagliptin on the same day as metformin. Insulin was added to the therapy of 173 (15.0%) costarters and 1453 (19.1%) later sitagliptin users. The adjusted odds ratio for adding insulin was 0.76 (95% CI 0.64 to 0.90) in favour of costarting sitagliptin. HbA1c levels decreased in both groups 1 year after starting sitagliptin, with costarters having a significantly greater reduction [absolute between-group difference of 0.5% (95% CI 0.3 to 0.7)] compared with later sitagliptin users. CONCLUSION: Costarting drug therapy with sitagliptin and metformin was associated with a lower likelihood of disease progression in people with type 2 diabetes compared with adding sitagliptin later.

Transverse spin forces and non-equilibrium particle dynamics in a circularly polarized vacuum optical trap.

We provide a vivid demonstration of the mechanical effect of transverse spin momentum in an optical beam in free space. This component of the Poynting momentum was previously thought to be virtual, and unmeasurable. Here, its effect is revealed in the inertial motion of a probe particle in a circularly polarized Gaussian trap, in vacuum. Transverse spin forces combine with thermal fluctuations to induce a striking range of non-equilibrium phenomena. With increasing beam power we observe (i) growing departures from energy equipartition, (ii) the formation of coherent, thermally excited orbits and, ultimately, (iii) the ejection of the particle from the trap. As well as corroborating existing measurements of spin momentum, our results reveal its dynamic effect. We show how the under-damped motion of probe particles in structured light fields can expose the nature and morphology of optical momentum flows, and provide a testbed for elementary non-equilibrium statistical mechanics.

Risk of new-onset heart failure in patients using sitagliptin: a population-based cohort study.

AIMS: To examine whether patients using sitagliptin at the time of an acute coronary syndrome event are at increased risk of incident heart failure compared with those not exposed. METHODS: Using US claims data, people with diabetes without a history of heart failure in the 3 years before hospitalization for acute coronary syndrome were identified for the period 2004 to 2010. We used a nested case-control design, whereby cases were patients who developed incident heart failure <30 days after admission to hospital for acute coronary syndrome and were matched by age and sex with up to 10 controls with no heart failure. Subjects exposed or not exposed to sitagliptin in the 90 days before acute coronary syndrome admission were compared using conditional logistic regression after adjustment for clinical and laboratory data, healthcare utilization and propensity scores. RESULTS: In total, 457 cases of heart failure developing de novo after diagnosis of acute coronary syndrome were matched to 4570 controls. The average age of the subjects was 55 years and 65% were male. Overall, 11 of 147 (7%) people exposed to sitagliptin developed heart failure compared with 446 of the 4880 people not exposed (9%, adjusted odds ratio 0.75, 95% CI 0.38-1.46; P=0.40). Sitagliptin exposure before acute coronary syndrome was not associated with an increased risk of death or heart failure combined (7% vs 9%, adjusted odds ratio 0.66, 95% CI 0.34-1.28). CONCLUSIONS: In our sample of patients who are at high risk of heart failure after acute coronary syndrome, sitagliptin exposure was not associated with an increased risk of de novo heart failure.

'Lissajous-like' trajectories in optical tweezers.

When a microscopic particle moves through a low Reynolds number fluid, it creates a flow-field which exerts hydrodynamic forces on surrounding particles. In this work we study the 'Lissajous-like' trajectories of an optically trapped 'probe' microsphere as it is subjected to time-varying oscillatory hydrodynamic flow-fields created by a nearby moving particle (the 'actuator'). We show a breaking of time-reversal symmetry in the motion of the probe when the driving motion of the actuator is itself time-reversal symmetric. This symmetry breaking results in a fluid-pumping effect, which arises due to the action of both a time-dependent hydrodynamic flow and a position-dependent optical restoring force, which together determine the trajectory of the probe particle. We study this situation experimentally, and show that the form of the trajectories observed is in good agreement with Stokesian dynamics simulations. Our results are related to the techniques of active micro-rheology and flow measurement, and also highlight how the mere presence of an optical trap can perturb the environment it is in place to measure.

Transitional behavior in hydrodynamically coupled oscillators.

In this article we consider the complete set of synchronized and phase-locked states available to pairs of hydrodynamically coupled colloidal rotors, consisting of spherical beads driven about circular paths in the same, and in opposing senses. Oscillators such as these have previously been used as coarse grained, minimal models of beating cilia. Two mechanisms are known to be important in establishing synchrony. The first involves perturbation of the driving force, and the second involves deformation of the rotor trajectory. We demonstrate that these mechanisms are of similar strength, in the regime of interest, and interact to determine observed behavior. Combining analysis and simulation with experiments performed using holographic optical tweezers, we show how varying the amplitude of the driving force perturbation leads to a transition from synchronized to phase-locked states. Analogies with biological systems are discussed, as are implications for the design of biomimetic devices.

Cardiovascular safety of sulphonylureas: over 40 years of continuous controversy without an answer.

More than 40 years after publication of the University Group Diabetes Program trial, the cardiovascular safety of sulphonylureas is still contentious. Although several hypotheses linking sulphonylureas to adverse cardiovascular effects exist, none provide conclusive evidence. Adding to the controversy, current clinical trials and observational studies provide inconsistent, and sometimes conflicting, evidence for the cardiovascular effects of sulphonylureas. Overall, observational evidence suggests that an increased risk of adverse cardiovascular outcomes is associated with sulphonylureas; however, these data may be subject to residual confounding and bias. Although evidence from randomized controlled trials has suggested a neutral effect, the majority of these studies were not specifically designed to assess the effect of sulphonylureas on adverse cardiovascular event risk. Current ongoing large clinical trials may provide some clarity on the cardiovascular safety of sulphonylureas, but the results are not expected for several years. With the continued uncertainties concerning the cardiovascular safety of all antidiabetic drugs, a clear answer with regard to sulphonylureas is warranted. The objectives of the present article were to provide an overview of the controversy surrounding sulphonylurea-related cardiovascular effects, to discuss the limitations of the current literature, and to provide recommendations for future studies aiming to elucidate the true relationship between sulphonylureas and adverse cardiovascular effects in people with type 2 diabetes.

Cost-effectiveness analysis of adding pharmacists to primary care teams to reduce cardiovascular risk in patients with Type 2 diabetes: results from a randomized controlled trial.

BACKGROUND: Adding pharmacists to primary care teams significantly improved blood pressure control and reduced predicted 10-year cardiovascular risk in patients with Type 2 diabetes. This pre-specified sub-study evaluated the economic implications of this cardiovascular risk reduction strategy. METHODS: One-year outcomes and healthcare utilization data from the trial were used to determine cost-effectiveness from the public payer perspective. Costs were expressed in 2014 Canadian dollars and effectiveness was based on annualized risk of cardiovascular events derived from the UKPDS Risk Engine. RESULTS: The 123 evaluable trial patients included in this analysis had a mean age of 62 ( ± 11) years, 38% were men, and mean diabetes duration was 6 ( ± 7) years. Pharmacists provided 3.0 ( ± 1.9) hours of additional service to each intervention patient, which cost $226 ( ± $1143) per patient. The overall one-year per-patient costs for healthcare utilization were $190 lower in the intervention group compared with usual care [95% confidence interval (CI): -$1040, $668). Intervention patients had a significant 0.3% greater reduction in the annualized risk of a cardiovascular event (95% CI: 0.08%, 0.6%) compared with usual care. In the cost-effectiveness analysis, the intervention dominated usual care in 66% of 10,000 bootstrap replications. At a societal willingness-to-pay of $4000 per 1% reduction in annual cardiovascular risk, the probability that the intervention was cost-effective compared with usual care reached 95%. A sensitivity analysis using multiple imputation to replace missing data produced similar results. CONCLUSIONS: Within a randomized trial, adding pharmacists to primary care teams was a cost-effective strategy for reducing cardiovascular risk in patients with Type 2 diabetes. In most circumstances, this intervention may also be cost saving.

Risk of acute coronary events associated with glyburide compared with gliclazide use in patients with type 2 diabetes: a nested case-control study.

AIM: Sulfonylureas might increase the risk of adverse cardiovascular events; however, emerging evidence suggests there may be important differences amongst these drugs. Some, like glyburide, inhibit KATP channels in the heart and pancreas, while others, like gliclazide, are more likely to selectively inhibit KATP channels in the pancreas. We hypothesized that the risk of acute coronary syndrome (ACS) events would be higher in patients using glyburide compared with gliclazide. METHODS: This nested case-control study used administrative health data from Alberta, Canada. New users of glyburide or gliclazide aged ≥66 years between 1998 and 2010 were included. Cases were individuals with an ACS-related hospitalization or death. Up to four controls were matched based on birth year, sex, cohort-entry year and follow-up time. Multivariable conditional logistic regression was used to estimate adjusted odds ratios (OR), controlling for baseline drug use and co-morbidities. RESULTS: Our cohort included 7441 gliclazide and 13 884 glyburide users; 51.4% men, mean (s.d.) age 75.5 (6.6) years and mean (s.d.) duration of follow-up 5.5 (4.0) years. A total of 4239 patients had an ACS-related hospitalization or death and were matched to 16 723 controls. Compared with gliclazide use, glyburide use was associated with a higher risk (adjusted OR 1.14; 95% CI 1.06-1.23) of ACS-related hospitalization or death over 5.5 years (number needed to harm: 50). CONCLUSION: In this observational study, glyburide use was associated with a 14% higher risk of ACS events compared with gliclazide use. Although the difference is small and probably to have implications at the population level rather than the individual patient or clinician, any causal inferences regarding sulfonylurea use and adverse cardiovascular risk should be tested in a large-scale randomized controlled trial.

Stability analysis and thermal motion of optically trapped nanowires.

We investigate the stability and thermal motion of optically trapped nanowires, with aspect ratios in the range 10-100. A simple analytical model is used to determine qualitative features of the system, assuming that the nanowire is weakly scattering and the incident beam is paraxial. As expected, the model predicts that the nanowire will align with the beam axis. In this configuration the translational stiffness coefficients of the trap approach their limiting values for long nanowires like O(L(-3)), where L is the nanowire length, the limit for the stiffness parallel to the beam axis being zero. The rotational stiffness coefficients vary more slowly, according to O(L(-1)). Also, it is predicted that defocusing decreases the translational stiffness perpendicular to the beam, while increasing rotational stiffness. These findings are reinforced by comparison with rigorous electromagnetic calculations which additionally reveal the effects of radiation pressure and finite scattering. A strong polarization effect is observed in the numerical simulations and coupled translational and rotational motions arise which influence the trap stability. The use of nanowire traps for force sensing is discusse.

Adding pharmacists to primary care teams reduces predicted long-term risk of cardiovascular events in type 2 diabetic patients without established cardiovascular disease: results from a randomized trial.

AIM: To determine the impact of adding pharmacists to primary care teams on predicted 10-year risk of cardiovascular events in patients with Type 2 diabetes without established cardiovascular disease. METHODS: This was a pre-specified secondary analysis of randomized trial data. The main study found that, compared with usual care, addition of a pharmacist resulted in improvements in blood pressure, dyslipidaemia, and hyperglycaemia for primary care patients with Type 2 diabetes. In this sub-study, predicted 10-year risk of cardiovascular events at baseline and 1 year were calculated for patients free of cardiovascular disease at enrolment. The primary outcome was change in UK Prospective Diabetes Study (UKPDS) risk score; change in Framingham risk score was a secondary outcome. RESULTS: Baseline characteristics were similar between the 102 intervention patients and 93 control subjects: 59% women, median (interquartile range) age 57 (50-64) years, diabetes duration 3 (1-6.5) years, systolic blood pressure 128 (120-140) mmHg, total cholesterol 4.34 (3.75-5.04) mmol/l and HbA(1c) 54 mmol/mol (48-64 mmol/mol) [7.1% (6.5-8.0%)]. Median baseline UKPDS risk score was 10.2% (6.0-16.7%) for intervention patients and 9.5% (5.8-15.1%) for control subjects (P = 0.80). One-year post-randomization, the median absolute reduction in UKPDS risk score was 1.0% greater for intervention patients compared with control subjects (P = 0.032). Similar changes were seen with the Framingham risk score (median reduction 1.2% greater for intervention patients compared with control subjects, P = 0.048). The two risk scores were highly correlated (rho = 0.83; P < 0.001). CONCLUSION: Adding pharmacists to primary care teams for 1 year significantly reduced the predicted 10-year risk of cardiovascular events for patients with Type 2 diabetes without established cardiovascular disease.

Variations in tissue selectivity amongst insulin secretagogues: a systematic review.

AIM: Insulin secretagogues promote insulin release by binding to sulfonylurea receptors on pancreatic ß-cells (SUR1). However, these drugs also bind to receptor isoforms on cardiac myocytes (SUR2A) and vascular smooth muscle (SUR2B). Binding to SUR2A/SUR2B may inhibit ischaemic preconditioning, an endogenous protective mechanism enabling cardiac tissue to survive periods of ischaemia. This study was designed to identify insulin secretagogues that selectively bind to SUR1 when given at therapeutic doses. METHODS: Using accepted systematic review methods, three electronic databases were searched from inception to 13 June 2011. Original studies measuring the half-maximal inhibitory concentration (IC(50)) for an insulin secretagogue on K(ATP) channels using standard electrophysiological techniques were included. Steady-state concentrations (C(SS)) were estimated from the usual oral dose and clearance values for each drug. RESULTS: Data were extracted from 27 studies meeting all inclusion criteria. IC(50) values for SUR1 were below those for SUR2A/SUR2B for all insulin secretagogues and addition of C(SS) values identified three distinct patterns. The C(SS) for gliclazide, glipizide, mitiglinide and nateglinide lie between IC(50) values for SUR1 and SUR2A/SUR2B, suggesting that these drugs bind selectively to pancreatic receptors. The C(SS) for glimepiride and glyburide (glibenclamide) was above IC(50) values for all three isoforms, suggesting these drugs are non-selective. Tolbutamide and repaglinide may have partial pancreatic receptor selectivity because IC(50) values for SUR1 and SUR2A/SUR2B overlapped somewhat, with the C(SS) in the midst of these values. CONCLUSIONS: Insulin secretagogues display different tissue selectivity characteristics at therapeutic doses. This may translate into different levels of cardiovascular risk.

An optically actuated surface scanning probe.

We demonstrate the use of an extended, optically trapped probe that is capable of imaging surface topography with nanometre precision, whilst applying ultra-low, femto-Newton sized forces. This degree of precision and sensitivity is acquired through three distinct strategies. First, the probe itself is shaped in such a way as to soften the trap along the sensing axis and stiffen it in transverse directions. Next, these characteristics are enhanced by selectively position clamping independent motions of the probe. Finally, force clamping is used to refine the surface contact response. Detailed analyses are presented for each of these mechanisms. To test our sensor, we scan it laterally over a calibration sample consisting of a series of graduated steps, and demonstrate a height resolution of ∼ 11 nm. Using equipartition theory, we estimate that an average force of only ∼ 140 fN is exerted on the sample during the scan, making this technique ideal for the investigation of delicate biological samples.

Position clamping of optically trapped microscopic non-spherical probes.

We investigate the degree of control that can be exercised over an optically trapped microscopic non-spherical force probe. By position clamping translational and rotational modes in different ways, we are able to dramatically improve the position resolution of our probe with no reduction in sensitivity. We also demonstrate control over rotational-translational coupling, and exhibit a mechanism whereby the average centre of rotation of the probe can be displaced away from its centre.

Calibration of optically trapped nanotools.

Holographically trapped nanotools can be used in a novel form of force microscopy. By measuring the displacement of the tool in the optical traps, the contact force experienced by the probe can be inferred. In the following paper we experimentally demonstrate the calibration of such a device and show that its behaviour is independent of small changes in the relative position of the optical traps. Furthermore, we explore more general aspects of the thermal motion of the tool.

Insulin use and increased risk of mortality in type 2 diabetes: a cohort study.

AIM: To compare population-based rates of all-cause and cardiovascular (CV) mortality in newly treated patients with type 2 diabetes according to levels of insulin exposure. METHODS: Using the administrative databases of Saskatchewan Health, 12272 new users of oral antidiabetic therapy were identified between 1991 and 1996 and grouped according to cumulative insulin exposure based on total insulin dispensations per year: no exposure (reference group); low exposure (0 to <3); moderate exposure (3 to <12) and high exposure (> or =12). Time-varying multivariable Cox proportional hazards models were used to examine the relationship between insulin exposure and all-cause, CV-related and non-vascular mortality after adjustment for demographics, medications and comorbidities. RESULTS: Average age was 65 (s.d. 13.9) years, 45% were female, and mean follow-up was 5.1 (s.d. 2.2) years. In total, 1443 (12%) subjects started insulin, and 2681 (22%) deaths occurred. The highest mortality rates were in the high exposure group; 95 deaths/1000 person-years compared with 40 deaths/1000 person-years in the no exposure group [unadjusted hazard ratio (HR): 2.32; 95% confidence interval (CI): 1.96-2.73]. After adjustment, we observed a graded risk of mortality associated with increasing exposure to insulin: low exposure [adjusted HR (aHR): 1.75; 95% CI: 1.24-2.47], moderate exposure (aHR: 2.18; 1.82-2.60) and high exposure (aHR: 2.79; 2.36-3.30); p = 0.005 for trend. Analyses restricted to CV-related (p = 0.042 for trend) and non-vascular (p = 0.004 for trend) mortality showed virtually identical results. CONCLUSIONS: We observed a significant and graded association between mortality risk and insulin exposure level in an inception cohort of patients with type 2 diabetes that persisted despite multivariable adjustment.

Evaluation of attitudes and perceptions of key clinical stakeholders regarding out-of-hospital diagnosis and treatment of ST elevation myocardial infarction patients using a region-wide survey.

INTRODUCTION: In ST elevation myocardial infarction (STEMI), prehospital management (PHM) may improve clinical outcomes through a reduction in reperfusion delay. The purpose of this study was to evaluate perceptions among healthcare stakeholder groups relating to the barriers and facilitators of implementing a PHM programme. METHODS: A 25-question cross-sectional survey, using a four-point Likert scale assessing barriers and facilitators of PHM, was distributed to paramedics, cardiologists, emergency physicians and emergency nurses within the Edmonton region, where prehospital STEMI treatment is established. The proportion of responses on each question was compared and differences between groups were determined using chi(2) and Fisher's exact tests. RESULTS: 57% (355/619) of subjects responded: 69% paramedics, 50% cardiologists, 54% emergency physicians and 45% emergency nurses. A majority believed PHM reduced treatment delays in both rural (96-100%) and urban (86-96%) areas, while decreasing patient mortality (paramedics 97%, cardiologists 74%, emergency physicians 85%, emergency nurses 88%). Regarding the capability of paramedics to deliver PHM, paramedics 25%, cardiologists 33%, emergency physicians 67%, and emergency nurses 47% stated that urban paramedics are better equipped and trained than rural paramedics. Although 81% of paramedics supported the possibility of PHM delivery without physician overview, 0% of cardiologists, 98% of emergency physicians and 95% emergency nurses agreed. A majority (71-88%) favoured mandatory signed informed consent. CONCLUSIONS: While stakeholders agreed on the benefits of PHM, perceptual differences existed on paramedics' ability to deliver PHM without physician overview. Addressing real and perceived barriers through communication and educational programmes may enhance PHM within this healthcare region and facilitate the implementation of PHM programmes.

Constructing 3D crystal templates for photonic band gap materials using holographic optical tweezers.

A simple and robust method is presented for the construction of 3-dimensional crystals from silica and polystyrene microspheres. The crystals are suitable for use as templates in the production of three-dimensional photonic band gap (PBG) materials. Manipulation of the microspheres was achieved using a dynamic holographic assembler (DHA) consisting of computer controlled holographic optical tweezers. Attachment of the microspheres was achieved by adjusting their colloidal interactions during assembly. The method is demonstrated by constructing a variety of 3-dimensional crystals using spheres ranging in size from 3 microm down to 800 nm. A major advantage of the technique is that it may be used to build structures that cannot be made using self-assembly. This is illustrated through the construction of crystals in which line defects have been deliberately included, and by building simple cubic structures.

A new detection system for extremely small vertically mounted cantilevers.

Detection techniques currently used in scanning force microscopy impose limitations on the geometrical dimensions of the probes and, as a consequence, on their force sensitivity and temporal response. A new technique, based on scattered evanescent electromagnetic waves (SEW), is presented here that can detect the displacement of the extreme end of a vertically mounted cantilever. The resolution of this method is tested using different cantilever sizes and a theoretical model is developed to maximize the detection sensitivity. The applications presented here clearly show that the SEW detection system enables the use of force sensors with sub-micron size, opening new possibilities in the investigation of biomolecular systems and high speed imaging. Two types of cantilevers were successfully tested: a high force sensitivity lever with a spring constant of 0.17 pN nm(-1) and a resonant frequency of 32 kHz; and a high speed lever with a spring constant of 50 pN nm(-1) and a resonant frequency of 1.8 MHz. Both these force sensors were fabricated by modifying commercial microcantilevers in a focused ion beam system. It is important to emphasize that these modified cantilevers could not be detected by the conventional optical detection system used in commercial atomic force microscopes.

Influence of dye molecules on the birefringence of liquid crystal mixtures at near infrared frequencies.

The optical properties of nematic liquid crystals have been extensively exploited in the production of devices working in the visible range of the spectrum. These same properties can be employed to make devices that function in the near infrared as required for telecommunications applications. However, it is generally observed that the birefringence of liquid crystal mixtures decreases with increasing wavelength, making it important to identify new materials, optimized for use in the near infrared region. One route to high birefringence is to operate close to an absorption band edge, which in the present context implies choosing highly conjugated materials which are potentially colored and, thus, not suited to traditional display applications. In this paper we explore the usefulness of dye molecules as birefringence enhancers in mixtures with conventional nematic liquid crystals. The optical properties, in particular, the absorption edge, polarizability, and birefringence, of families of known dyes are calculated at optical (589 nm) and infrared (1550 nm) wavelengths, using electronic density functional theory. We demonstrate the expected correlation between the proximity of the absorption edge and the magnitude of the birefringence, and estimate the birefringence enhancement occurring when each dye is incorporated in a guest-host system.