The effectiveness of national guidelines for preventing cardiovascular disease: integrating effectiveness concepts and evaluating guidelines' use in the real world

Predicting Stroke Risk Based on Health Behaviours: Development of the Stroke Population Risk Tool (SPoRT)

Background

Health behaviours, important factors in cardiovascular disease, are increasingly a focus of prevention. We appraised whether stroke risk can be accurately assessed using self-reported information focused on health behaviours.

Methods

Behavioural, sociodemographic and other risk factors were assessed in a population-based survey of 82 259 Ontarians who were followed for a median of 8.6 years (688 000 person-years follow-up) starting in 2001. Predictive algorithms for 5-year incident stroke resulting in hospitalization were created and then validated in a similar 2007 survey of 28 605 respondents (median 4.2 years follow-up).

Results

We observed 3 236 incident stroke events (1 551 resulting in hospitalization; 1 685 in the community setting without hospital admission). The final algorithms were discriminating (C-stat: 0.85, men; 0.87, women) and well-calibrated (in 65 of 67 subgroups for men; 61 of 65 for women). An index was developed to summarize cumulative relative risk of incident stroke from health behaviours and stress. For men, each point on the index corresponded to a 12% relative risk increase (180% risk difference, lowest (0) to highest (9) scores). For women, each point corresponded to a 14% relative risk increase (340% difference, lowest (0) to highest (11) scores). Algorithms for secondary stroke outcomes (stroke resulting in death; classified as ischemic; excluding transient ischemic attack; and in the community setting) had similar health behaviour risk hazards.

Conclusion

Incident stroke can be accurately predicted using self-reported information focused on health behaviours. Risk assessment can be performed with population health surveys to support population health planning or outside of clinical settings to support patient-focused prevention.

Cardiovascular Disease Population Risk Tool (CVDPoRT): predictive algorithm for assessing CVD risk in the community setting. A study protocol

INTRODUCTION

Recent publications have called for substantial improvements in the design, conduct, analysis and reporting of prediction models. Publication of study protocols, with prespecification of key aspects of the analysis plan, can help to improve transparency, increase quality and protect against increased type I error. Valid population-based risk algorithms are essential for population health planning and policy decision-making. The purpose of this study is to develop, evaluate and apply cardiovascular disease (CVD) risk algorithms for the population setting.

METHODS AND ANALYSIS

The Ontario sample of the Canadian Community Health Survey (2001, 2003, 2005; 77,251 respondents) will be used to assess risk factors focusing on health behaviours (physical activity, diet, smoking and alcohol use). Incident CVD outcomes will be assessed through linkage to administrative healthcare databases (619,886 person-years of follow-up until 31 December 2011). Sociodemographic factors (age, sex, immigrant status, education) and mediating factors such as presence of diabetes and hypertension will be included as predictors. Algorithms will be developed using competing risks survival analysis. The analysis plan adheres to published recommendations for the development of valid prediction models to limit the risk of overfitting and improve the quality of predictions. Key considerations are fully prespecifying the predictor variables; appropriate handling of missing data; use of flexible functions for continuous predictors; and avoiding data-driven variable selection procedures. The 2007 and 2009 surveys (approximately 50,000 respondents) will be used for validation. Calibration will be assessed overall and in predefined subgroups of importance to clinicians and policymakers.

ETHICS AND DISSEMINATION

This study has been approved by the Ottawa Health Science Network Research Ethics Board. The findings will be disseminated through professional and scientific conferences, and in peer-reviewed journals. The algorithm will be accessible electronically for population and individual uses.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT02267447.

Xiaoxuming decoction for acute ischemic stroke: a systematic review and meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoxuming decoction (XXMD) is a well-known traditional Chinese herbal prescription in treatment of patients with stroke. The objective of this study is to assess the efficacy and safety of XXMD for acute ischemic stroke.

MATERIALS AND METHODS

A systematic literature search was conducted in 6 databases until June 2012 to identify randomized controlled trials (RCTs) of XXMD for acute ischemic stroke compared with western conventional medicine (WCM). The primary outcome measures were National Institutes of Health Stroke Scale (NIHSS) scores and modified Rankin Scale (mRS) scores. The secondary outcome measures were the clinical effective rate and adverse events at the end of treatment course. The methodological quality of RCTs was assessed independently using 12-item criteria according to the Cochrane Back Review Group. All data were analyzed using Review Manager 5.0 software.

RESULTS

Eight RCTs with 601 individuals published from 1992 to 2012 were identified. The studies were deemed to have a high risk of bias. Compared with WCM, 1 RCT showed significant effects of XXMD for improving mRS after stroke (p<0.05); 3 RCTs for improving NIHSS scores [n=186, weighted mean difference (WMD): -1.86, 95% CI: -3.25 to -0.48, z=2.63, p<0.01]; 7 RCTs for improving the clinical effective rate [n=531, risk ratio (RR)=1.17, 95% CI, 1.09 to 1.26, z=4.38, p<0.01]. Five trials contained safety assessments and stated that no adverse event was found, whereas the other 3 trials did not provide the information about adverse events.

CONCLUSIONS

This systematic review showed positive but weak evidence of XXMD for acute ischemic stroke because of the poor methodological quality and the small quantity of the included trials. The difficulties of fitting Chinese herbal medicine (CHM) into the double blinded RCTs have raised as follows: (A) traditional Chinese medicine (TCM) as whole systems of healthcare offers unique methodological and theoretical challenges for RCTs; (B) suspicions against the placebo and unwillingness to stop taking other CHMs make recruitment more difficulty, time-consumption, and cost; (C) the shortcomings of the TCM diagnostic process includes the lack of standardization in terminology, disagreement of pattern differentiation (Bianzheng), and neglect of formula corresponding to syndrome (TCM Zheng); (D) It is difficult to design credible herbal placebos with similar appearance, smells and tastes to the experimental CHM and at the same time is absent of any pharmacological activity; (E) the achieving efficacy of CHM complex interventions is often nonspecific and the outcome measures is subjective using Chinese quantitative instrument.