Rod Jackson

Driver sleepiness and risk of serious injury to car occupants: population based case control study

Abstract Objectives: To estimate the contribution of driver sleepiness to the causes of car crash injuries. Design: Population based case control study. Setting: Auckland region of New Zealand, April 1998 to July 1999. Participants: 571 car drivers involved in crashes where at least one occupant was admitted to hospital or killed (“injury crash”); 588 car drivers recruited while driving on public roads (controls), representative of all time spent driving in the study region during the study period. Main outcome measures: Relative risk for injury crash associated with driver characteristics related to sleep, and the population attributable risk for driver sleepiness. Results: There was a strong association between measures of acute sleepiness and the risk of an injury crash. After adjustment for major confounders significantly increased risk was associated with drivers who identified themselves as sleepy (Stanford sleepiness score 4-7 v 1-3; odds ratio 8.2, 95% confidence interval 3.4 to 19.7); with drivers who reported five hours or less of sleep in the previous 24 hours compared with more than five hours (2.7, 1.4 to 5.4); and with driving between 2 am and 5 am compared with other times of day (5.6, 1.4 to 22.7). No increase in risk was associated with measures of chronic sleepiness. The population attributable risk for driving with one or more of the acute sleepiness risk factors was 19% (15% to 25%). Conclusions: Acute sleepiness in car drivers significantly increases the risk of a crash in which a car occupant is injured or killed. Reductions in road traffic injuries may be achieved if fewer people drive when they are sleepy or have been deprived of sleep or drive between 2 am and 5 am. What is already known on this topic Driver sleepiness is considered a potentially important risk factor for car crashes and related injuries but the association has not been reliably quantified Published estimates of the proportion of car crashes attributable to driver sleepiness vary from about 3% to 30% What this study adds Driving while feeling sleepy, driving after five hours or less of sleep, and driving between 2 am and 5 am were associated with a substantial increase in the risk of a car crash resulting in serious injury or death Reduction in the prevalence of these three behaviours may reduce the incidence of injury crashes by up to 19%

Treatment with drugs to lower blood pressure and blood cholesterol based on an individual's absolute cardiovascular risk

In this review, we outline the rationale for targeting blood pressure and blood cholesterol lowering drug treatments to patients at high absolute cardiovascular risk, irrespective of their blood pressure or blood cholesterol levels. Because the specific levels of blood pressure and cholesterol are of little clinical relevance when considered in isolation from other risk factors, terms such as hypertension or hypercholesterolaemia have limited value. Separate management guidelines for raised blood pressure and blood cholesterol need to be replaced by integrated cardiovascular risk management guidelines, and absolute cardiovascular risk prediction scores should be used routinely. Since cardiovascular risk factors interact with each other, moderate reductions in several risk factors can be more effective than major reductions in one. An affordable daily pill combining low doses of various drugs could be useful for the many individuals with slightly abnormal cardiovascular risk factors.

Blood pressure-lowering treatment based on cardiovascular risk: a meta-analysis of individual patient data

BACKGROUND We aimed to investigate whether the benefits of blood pressure-lowering drugs are proportional to baseline cardiovascular risk, to establish whether absolute risk could be used to inform treatment decisions for blood pressure-lowering therapy, as is recommended for lipid-lowering therapy. METHODS This meta-analysis included individual participant data from trials that randomly assigned patients to either blood pressure-lowering drugs or placebo, or to more intensive or less intensive blood pressure-lowering regimens. The primary outcome was total major cardiovascular events, consisting of stroke, heart attack, heart failure, or cardiovascular death. Participants were separated into four categories of baseline 5-year major cardiovascular risk using a risk prediction equation developed from the placebo groups of the included trials (<11%, 11-15%, 15-21%, >21%). FINDINGS 11 trials and 26 randomised groups met the inclusion criteria, and included 67,475 individuals, of whom 51,917 had available data for the calculation of the risk equations. 4167 (8%) had a cardiovascular event during a median of 4·0 years (IQR 3·4-4·4) of follow-up. The mean estimated baseline levels of 5-year cardiovascular risk for each of the four risk groups were 6·0% (SD 2·0), 12·1% (1·5), 17·7% (1·7), and 26·8% (5·4). In each consecutive higher risk group, blood pressure-lowering treatment reduced the risk of cardiovascular events relatively by 18% (95% CI 7-27), 15% (4-25), 13% (2-22), and 15% (5-24), respectively (p=0·30 for trend). However, in absolute terms, treating 1000 patients in each group with blood pressure-lowering treatment for 5 years would prevent 14 (95% CI 8-21), 20 (8-31), 24 (8-40), and 38 (16-61) cardiovascular events, respectively (p=0·04 for trend). INTERPRETATION Lowering blood pressure provides similar relative protection at all levels of baseline cardiovascular risk, but progressively greater absolute risk reductions as baseline risk increases. These results support the use of predicted baseline cardiovascular disease risk equations to inform blood pressure-lowering treatment decisions. FUNDING None.BackgroundWe aimed to investigate whether the benefits of blood pressure-lowering drugs are proportional to baseline cardiovascular risk, to establish whether absolute risk could be used to inform ...

The role of driver sleepiness in car crashes: a systematic review of epidemiological studies.

To assess the available evidence for a causal role of driver sleepiness in car crashes or car crash injury, and to quantify the effect, a systematic review of the international literature was conducted. The review included all studies with a fatigue-related exposure measure, a crash or crash injury outcome measure and a comparison group, regardless of publication status, language or date of the study. Eighteen cross-sectional studies and one case-control study fulfilled the inclusion criteria. The fatigue-related exposures investigated in these studies were sleep disorders (n = 14), shift work (n = 2), sleep deprivation/fragmentation (n = 1), and excessive daytime sleepiness (n = 2). Only one study used an injury outcome measure. Studies were limited in their ability to establish a causal relationship by their design, by biases, and in many cases, by small sample sizes. The better quality cross-sectional studies were suggestive of a positive relationship between fatigue and crash risk, but could not provide reliable estimates of the strength of the association. The case-control study provided moderately strong evidence for an association between sleep apnoea and risk of driver injury, with an adjusted odds ratio of 7.2 (95% confidence interval 2.4-21.8). We conclude that the direct epidemiological evidence for a causal role of fatigue in car crashes is weak, but suggestive of an effect. To estimate the burden of injury due to fatigue-related crashes in the population, information is required from well-designed observational epidemiological studies about the prevalence of fatigue in the car driving population and the size of the risk this confers.

An international randomised placebo-controlled trial of a four-component combination pill ("polypill") in people with raised cardiovascular risk

Background There has been widespread interest in the potential of combination cardiovascular medications containing aspirin and agents to lower blood pressure and cholesterol (‘polypills’) to reduce cardiovascular disease. However, no reliable placebo-controlled data are available on both efficacy and tolerability. Methods We conducted a randomised, double-blind placebo-controlled trial of a polypill (containing aspirin 75 mg, lisinopril 10 mg, hydrochlorothiazide 12.5 mg and simvastatin 20 mg) in 378 individuals without an indication for any component of the polypill, but who had an estimated 5-year cardiovascular disease risk over 7.5%. The primary outcomes were systolic blood pressure (SBP), LDL-cholesterol and tolerability (proportion discontinued randomised therapy) at 12 weeks follow-up. Findings At baseline, mean BP was 134/81 mmHg and mean LDL-cholesterol was 3.7 mmol/L. Over 12 weeks, polypill treatment reduced SBP by 9.9 (95% CI: 7.7 to 12.1) mmHg and LDL-cholesterol by 0.8 (95% CI 0.6 to 0.9) mmol/L. The discontinuation rates in the polypill group compared to placebo were 23% vs 18% (RR 1.33, 95% CI 0.89 to 2.00, p = 0.2). There was an excess of side effects known to the component medicines (58% vs 42%, p = 0.001), which was mostly apparent within a few weeks, and usually did not warrant cessation of trial treatment. Conclusions This polypill achieved sizeable reductions in SBP and LDL-cholesterol but caused side effects in about 1 in 6 people. The halving in predicted cardiovascular risk is moderately lower than previous estimates and the side effect rate is moderately higher. Nonetheless, substantial net benefits would be expected among patients at high risk. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12607000099426

The contribution of alcohol to serious car crash injuries

Background: Alcohol impairment of drivers is considered the most important contributing cause of car crash injuries. The burden of injury attributable to drinking drivers has been estimated only indirectly. Methods: We conducted a population-based case–control study in Auckland, New Zealand between April 1998 and July 1999. Cases were 571 car drivers involved in crashes in which at least 1 occupant was admitted to the hospital or killed. Control subjects were 588 car drivers recruited on public roads, representative of driving in the region during the study period. Participants completed a structured interview and had blood or breath alcohol measurements. Results: Drinking alcohol before driving was strongly associated with injury crashes after controlling for known confounders. This was true for several measures of alcohol consumption: for self-report of 2 or more 12-g alcoholic drinks in the preceding 6 hours compared with none, the odds ratio (OR) was 7.9 (95% confidence interval = 3.4–18); for blood alcohol concentration 3 to 50 mg/100 mL compared with <3 mg/100 mL, the OR was 3.2 (1.1–10); and for blood alcohol concentration greater than 50 mg/100 mL compared with <3 mg/100 mL, the OR was 23 (9–56). Approximately 30% of car crash injuries in this population were attributable to alcohol, with two-thirds involving drivers with blood alcohol concentration in excess of 150 mg/100 mL. Equal proportions of alcohol-related injury crashes were attributable to drivers with blood alcohol concentrations of 3 to 50 mg/100 mL as those with levels of 51 to 150 mg/100 mL. Conclusion: Evidence about the proportion of crashes attributable to drivers at different blood alcohol concentrations can inform the prioritization of interventions that target different groups of drivers. These data indicate where there is the most potential for reduction of the injury burden.

Integrated electronic decision support increases cardiovascular disease risk assessment four fold in routine primary care practice

Background A decade of cardiovascular disease (CVD) risk-based guidelines, education programmes and widespread availability of paper-based risk prediction charts have not significantly influenced targeting of CVD risk management in New Zealand primary care practice. A web-based decision support system (PREDICT-CVD), integrated with primary care electronic medical record software was developed as one strategy to address this problem. Methods A before-after audit of 3564 electronic patient records assessed the impact of electronic decision support on documentation of CVD risk and CVD risk factors. Participants were patients meeting national guideline criteria for CVD risk assessment, registered with 84/107 (78.5%) general practitioners (GPs) in one large primary care organization who used electronic patient medical records, and had PREDICT-CVD installed. The GPs received group education sessions, practice IT support and a small risk assessment payment. Four weeks of practice visit records were audited from 1 month after installation of PREDICT-CVD, and during the same 4-week period 12 months earlier. Results Less than 3% of eligible patients had a documented CVD risk before PREDICT-CVD installation. This increased four-fold (RR = 4.0; 95% confidence interval 2.4–6.5) after installation and documentation of all relevant CVD risk factors also increased significantly. Conclusion Documentation of CVD risk in primary care patient records in New Zealand is negligible, despite being recommended as a prerequisite for targeted treatment for over 10 years, suggesting that previous strategies were ineffective. We demonstrate that integrated electronic decision support can quadruple CVD risk assessment in just one cycle of patient visits.

The GATE frame: critical appraisal with pictures

Epidemiological evidence about the accuracy of diagnostic tests, the power of prognostic markers, and the efficacy and safety of interventions is the cornerstone of evidence-based health care.1 Practitioners of evidence-based health care require critical appraisal skills to judge the validity of this evidence. The Evidence-Based Medicine (EBM) Working Group members are international leaders in teaching critical appraisal skills, and their users’ guides for appraising the validity of the healthcare literature2 have long been the basis of teaching programmes worldwide. However, we found that many of our students took a reductionist “paint by numbers” approach when using the Working Group’s guides. Students could answer individual appraisal questions correctly but would have difficulty assessing overall study quality. We believe this is due to a poor understanding of epidemiological study design. So over the past 15 years of teaching critical appraisal we have modified the EBM Working Group approach and developed the Graphic Appraisal Tool for Epidemiological studies (GATE) frame to help our students conceptualise the whole study as well as its component parts. GATE is a visual framework that illustrates the generic design of all epidemiological studies (figure 1). We now teach critical appraisal by “hanging” studies and the EBM Working Group’s appraisal questions on the GATE frame. Figure 1  The GATE frame. This editorial outlines the GATE approach to critical appraisal, illustrated throughout using the Heart and Estrogen/progestin Replacement Study (HERS), a randomised, double blind, placebo controlled trial of the effect of daily oestrogen plus progestin on coronary heart disease (CHD) death in postmenopausal women.3 A detailed critical appraisal of HERS using a GATE-based checklist is available online.4 The GATE frame incorporates a triangle, circle, square, and arrow (figure 1), labelled with the acronym PECOT (or PICOT). The triangle (figure 2) represents the population studied: “P” for population or …

Patients Prefer Pictures to Numbers to Express Cardiovascular Benefit From Treatment

PURPOSE This study aimed to determine which methods of expressing a preventive medication’s benefit encourage patients with known cardiovascular disease to decide to take the medication and which methods patients prefer. METHODS We identified patients in Auckland, New Zealand, family practices located in areas of differing socioeconomic status who had preexisting heart disease (myocardial infarction, angina, or both) and were taking statins. The patients were interviewed about their preference for methods of expressing the benefit of a hypothetical medication. Benefits were expressed numerically (relative risk, absolute risk, number needed to treat, odds ratio, natural frequency) and graphically. Statistical testing was adjusted for practice. RESULTS We interviewed 100 eligible patients, representing a 53% response rate. No matter how the risk was expressed, the majority of patients indicated they would be encouraged to take the medication. Two-thirds (68) of the patients preferred 1 method of expressing benefit over others. Of this group, 57% preferred the information presented graphically. This value was significantly greater (P <.001) than the 19% who chose the next most preferred option, relative risk. Few patients preferred absolute risk (13%) or natural frequencies (9%). Only a single patient (1%) preferred the odds ratio. None preferred number needed to treat. Ninety percent of patients responding to a question about framing preferred positive framing (description of the benefit of treatment) over negative framing (description of the harm of not being treated). CONCLUSIONS Although number needed to treat is a useful tool for communicating risk and benefit to clinicians, this format was the least likely to encourage patients to take medication. As graphical representation of benefit was the method patients preferred most, consideration should be given to developing visual aids to support shared clinical decision making.

Student engagement in very large classes: the teachers’ perspective

The rapid growth in the student population observed in higher education over the past 10–15 years in some countries has coincided with an increased recognition of student engagement and its value in developing knowledge. Active learning approaches have the potential to promote student engagement with lectures, but this becomes more challenging as class sizes increase. This study investigates student engagement from the teachers’ perspective, to identify current practices in teaching, learning and assessment designed to promote student engagement in courses with more than 1000 students enrolled at the University of Auckland, New Zealand. The study is based on semi‐structured interviews with six course coordinators. The results demonstrate that teaching techniques commonly associated with small‐class teaching can be used to engage students in very large classes. The effectiveness of these approaches from the students’ perspectives warrants further investigation.