Glycemic Index Versus Wheat Fiber on Arterial Wall Damage in Diabetes: A Randomized Controlled Trial.

OBJECTIVE: High cereal fiber and low-glycemic index (GI) diets are associated with reduced cardiovascular disease (CVD) risk in cohort studies. Clinical trial evidence on event incidence is lacking. Therefore, to make trial outcomes more directly relevant to CVD, we compared the effect on carotid plaque development in diabetes of a low-GI diet versus a whole-grain wheat-fiber diet. RESEARCH DESIGN AND METHODS: The study randomized 169 men and women with well-controlled type 2 diabetes to counseling on a low GI-diet or whole-grain wheat-fiber diet for 3 years. Change in carotid vessel wall volume (VWV) (prespecified primary end point) was assessed by MRI as an indication of arterial damage. RESULTS: Of 169 randomized participants, 134 completed the study. No treatment differences were seen in VWV. However, on the whole-grain wheat-fiber diet, VWV increased significantly from baseline, 23 mm3 (95% CI 4, 41; P = 0.016), but not on the low-GI diet, 8 mm3 (95% CI -10, 26; P = 0.381). The low-GI diet resulted in preservation of renal function, as estimated glomerular filtration rate, compared with the reduction following the wheat-fiber diet. HbA1c was modestly reduced over the first 9 months in the intention-to-treat analysis and extended with greater compliance to 15 months in the per-protocol analysis. CONCLUSIONS: Since the low-GI diet was similar to the whole-grain wheat-fiber diet recommended for cardiovascular risk reduction, the low-GI diet may also be effective for CVD risk reduction.

What influences safety in paramedicine? Understanding the impact of stress and fatigue on safety outcomes.

OBJECTIVE: The purpose of this study was to build on extant research linking fatigue to safety outcomes in paramedicine by assessing the influence of a multiplicity of workplace stressors, including chronic and critical incident stresses on safety outcomes. METHODS: A cross-sectional survey was deployed to 10 paramedic services in Ontario. Validated survey instruments measured operational and organizational chronic stress, critical incident stress, post-traumatic stress symptomatology (PTSS), fatigue, safety outcomes, and demographics. Analysis of covariance assessed associations of workplace stresses with safety outcomes and corroborated findings using hierarchical linear model and generalized estimating equations (GEE) by taking into account paramedic service when assessing the proposed associations. A non-responder survey was conducted to asses for demographic differences in those who did and did not complete the survey. RESULTS: This survey had a response rate of 40.5% (n = 717/1767); 80% of paramedics reported an injury or exposure to pathogen, 95% reported safety compromising behaviors, and 76% reported medical errors. In the GEE analyses, paramedic injury was significantly related to fatigue (0.13, SE = 0.06, P = 0.020), critical incident stress (0.03, SE = 0.01, P < 0.01), and PTSS (0.03, SE = 0.01, P < 0.01). Safety compromising behaviors were significantly associated with fatigue (0.37, SE = 0.06, P < 0.01), organizational stress (0.06, SE = 0.01, P < 0.01), and critical incident stress (0.01. SE = 0.01, P = 0.017). Medication errors were significantly related to fatigue (0.12, SE = 0.05, P < 0.01). Finally, the bivariate analysis showed increased stress factors and fatigue was associated with increased safety outcomes. CONCLUSION: These findings illustrate that a host of different stressors may influence safety-related behaviors. For those interested in safety, these findings point to the need for a holistic focus on fatigue and stress in paramedicine.

A systematic survey of the methods literature on the reporting quality and optimal methods of handling participants with missing outcome data for continuous outcomes in randomized controlled trials.

OBJECTIVE: To conduct (1) a systematic survey of the reporting quality of simulation studies dealing with how to handle missing participant data (MPD) in randomized control trials and (2) summarize the findings of these studies. STUDY DESIGN AND SETTING: We included simulation studies comparing statistical methods dealing with continuous MPD in randomized controlled trials addressing bias, precision, coverage, accuracy, power, type-I error, and overall ranking. For the reporting of simulation studies, we adapted previously developed criteria for reporting quality and applied them to eligible studies. RESULTS: Of 16,446 identified citations, the 60 eligible generally had important limitations in reporting, particularly in reporting simulation procedures. Of the 60 studies, 47 addressed ignorable and 32 addressed nonignorable data. For ignorable missing data, mixed model was most frequently the best on overall ranking (9 times best, 34.6% of times tested) and bias (10, 55.6%). Multiple imputation was also performed well. For nonignorable data, mixed model was most frequently the best on overall ranking (7, 46.7%) and bias (8, 57.1%). Mixed model performance varied on other criteria. Last observation carried forward (LOCF) was very seldom the best performing, and for nonignorable MPD frequently the worst. CONCLUSION: Simulation studies addressing methods to deal with MPD suffered from serious limitations. The mixed model approach was superior to other methods in terms of overall performance and bias. LOCF performed worst.

Cross-sectional associations between dietary intake and carotid intima media thickness in type 2 diabetes: baseline data from a randomised trial.

OBJECTIVE: To assess associations between dietary intake and carotid intima media thickness (CIMT) by carotid ultrasound (CUS), a surrogate marker of cardiovascular disease (CVD) risk, in those with type 2 diabetes. DESIGN: Cross-sectional analysis of baseline data from 325 participants from three randomised controlled trials collected in the same way. SETTING: Risk Factor Modification Centre, St. Michael's Hospital, Toronto, Canada. PARTICIPANTS: 325 participants with type 2 diabetes, taking oral antidiabetic agents, with an HbA1c between 6.5% and 8.0% at screening, without a recent cardiovascular event. MAIN OUTCOME MEASURES: CIMT by CUS and associations with dietary intake from 7-day food records, as well as anthropometric measures and fasting serum samples. RESULTS: CIMT was significantly inversely associated with dietary pulse intake (ß=-0.019, p=0.009), available carbohydrate (ß=-0.004, p=0.008), glycaemic load (ß=-0.001, p=0.007) and starch (ß=-0.126, p=0.010), and directly associated with total (ß=0.004, p=0.028) and saturated (ß=0.012, p=0.006) fat intake in multivariate regression models adjusted for age, smoking, previous CVD event, blood pressure medication, antidiabetic medication and ultrasonographer. CONCLUSIONS: Lower CIMT was significantly associated with greater consumption of dietary pulses and carbohydrates and lower total and saturated fat intake, suggesting a potential role for diet in CVD risk management in type 2 diabetes. Randomised controlled trials are anticipated to explore these associations further. TRIAL REGISTRATION NUMBER: NCT01063374.