Aspirin in the primary prevention of cardiovascular disease in the Women’s Health Study: Effect of noncompliance

Randomized evidence for aspirin in the primary prevention of cardiovascular disease (CVD) among women is limited and suggests at most a modest effect for total CVD. Lack of compliance, however, can null-bias estimated effects. We used marginal structural models (MSMs) to estimate the etiologic effect of continuous aspirin use on CVD events among 39,876 apparently healthy female health professionals aged 45 years and older in the Women's Health Study, a randomized trial of 100 mg aspirin every other day versus placebo. As-treated analyses and MSMs controlled for time-varying determinants of aspirin use and CVD. Predictors of aspirin use differed by randomized group and prior use and included medical history, CVD risk factors, and intermediate CVD events. Previously reported intent-to-treat analyses found small non-significant effects of aspirin on total CVD (hazard ratio (HR) = 0.91, 95 % confidence interval (CI) = 0.81-1.03) and CVD mortality (HR = 0.95, 95 % CI = 0.74-1.22). As-treated analyses were similar for total CVD with a slight reduction in CVD mortality (HR = 0.88, 95 % CI = 0.67-1.16). MSMs, which adjusted for non-compliance, were similar for total CVD (HR = 0.93; 95 % CI: 0.81, 1.07) but suggested lower CVD mortality with aspirin use (HR = 0.76; 95 % CI: 0.54, 1.08). Adjusting for non-compliance had little impact on the estimated effect of aspirin on total CVD, but strengthened the effect on CVD mortality. These results support a limited effect of low-dose aspirin on total CVD in women, but potential benefit for CVD mortality.     

Aspirin for CV prevention -- for which patients?

Put your patient on aspirin? Take him off? Here's what you need to know to get it right.     

Parental practices for prevention of home poisoning in children 1-6 years of age

On the basis of calls to the US poison control centers, each year more than 1 million children less than 5 years of age experience potentially toxic ingestions. Several prevention efforts and interventions have been tried to protect young children from poisonings occurring in their homes. The purpose of this study was to determine practices of parents and caregivers of children 1–6 years of age about home poisoning prevention. Seventy-six participants answered an anonymous survey. Caregivers demonstrated poor knowledge about the home poisoning prevention strategies. Only 20% of the participants knew the telephone number of the poison control center and 49% had it near the telephone in case of an emergency. This lack of knowledge was not related to gender, educational level, or occupation. Primary care physicians need to reinforce the orientation about poisoning prevention techniques to all caregivers in order to prevent accidental poisonings in small children.     

Are we losing the battle against cardiometabolic disease? The case for a paradigm shift in primary prevention

Background  

Cardiovascular and diabetic disease are the leading and preventable causes of death worldwide. The currently prognosticated dramatic increase in disease burden over the next two decades, however, bespeaks a low confidence in our prevention ability. This conflicts with the almost enthusiastic reporting of study results, which demonstrate substantial risk reductions secondary to simple lifestyle changes.     

Does gamma-tocopherol play a role in the primary prevention of heart disease and cancer? A review

Vitamin E consists of a group of eight isomers, four tocopherols (alpha-, beta-, gamma-, delta-tocopherol) and four tocotrienols (alpha-, beta-, gamma-, delta-tocotrienol). While extensive literature has been published on the potential health benefits of alpha-tocopherol, little is known about gamma-tocopherol, the major form of vitamin E in food in the U.S. gamma-tocopherol has recently received more research attention based on findings from in vitro and animal studies indicating that it has potent anti-inflammatory and antioxidant properties. Based on these recent studies, it is important to investigate the possible health benefits of gamma-tocopherol in humans. In this article, we review publications on dietary gamma-tocopherol intake, plasma gamma-tocopherol levels, cardiovascular disease and cancer risk in humans.     

Vitamin D for the prevention of preeclampsia? A hypothesis

Preeclampsia has been suggested to result from a partial breakdown of tolerance to the developing fetus after maternal immune maladaptation. Several of the proposed immunomodulatory properties of the hormonal vitamin D system could potentially have beneficial effects for successful maintenance of pregnancy. Preeclampsia is characterized by marked changes in vitamin D metabolism. This paper reviews the evidence suggesting that the immunomodulatory properties of 1,25(OH)2D may play a key role in maintaining immunological tolerance in pregnancy, and proposes that ensuring adequate vitamin D status/intake may help in the prevention and management of preeclampsia.     

Cost-effectiveness analysis with defined budget: how to distribute resources for the prevention of cardiovascular disease?

The aim of the study was to undertake cost-effectiveness calculations subject to a defined budget. The setting chosen was the prevention of cardiovascular disease (CVD) by means of three intervention programmes in a Swedish county council. The population in the county was divided into subgroups according to risk level. For each subgroup the cost per years of life saved was calculated, as well as the annual budget claims. The budget available was defined as present direct cost in the programmes. The calculations resulted in a programming solution showing the optimal distribution of resources between the programmes. Also a league table was constructed and the cut-off value for a 'acceptable' cost-effectiveness was shown. The conclusion that can be drawn is that a combination of internationally published intervention results and local data regarding epidemiology and resource improves the accuracy and usefulness of cost-effectiveness ratios. However, the model presented is a first attempt containing only three interventions: the planned next phase is to integrate more interventions in the model.     

The economics of primary prevention of cardiovascular disease – a systematic review of economic evaluations

Background

Global resource needs estimation is a critical part of addressing the HIV/AIDS epidemic. To generate these estimates knowledge of costs and cost structures is required. The evidence base for costs of HIV prevention programmes is limited. Even less is known about the existence of economies scale and whether, as economic theory suggests, average costs form a 'u'-shaped curve as scale increases. Using an econometric analysis, this paper addresses this question by estimating marginal costs and economies of scale for HIV prevention programmes for vulnerable groups in Southern India with different levels of coverage.

Methods

Two hybrid translog-cost functions were estimated. First, expenditure data from 78 state-funded HIV prevention projects in Andhra Pradesh were used to explore the impact of scale, institutional history and price on costs; second, economic cost data from 16 commercial sex worker projects across Tamil Nadu and Andhra Pradesh were analysed to additionally assess the impact of the value of inputs not reported in expenditure data and location. Coefficient estimates were used to calculate marginal costs and economies of scale.

Results

The econometric model yielded a good fit (R² = 0.46, p < 0.001 and R² = 0.79, p < 0.001, for the expenditure and economic cost datasets, respectively). The economies of scale index was greater than 1 for both datasets and fell as coverage increased. Analysis of the expenditure data found economies of scale were not exhausted, with a 0.002% change in total cost for each extra person reached and an 11% difference in total cost between target group categories. Estimation using the economic cost data suggests a point of minimum efficient scale at around 1750–2000 people reached, a 0.03% change in total cost for each extra person reached, and 28% lower costs in Tamil Nadu than Andhra Pradesh.

Conclusion

Econometric analysis of these standardized datasets provides insights into how costs change with coverage, the impact of project location and nature of the project target group. The results demonstrate the importance of understanding the nature of the cost function when designing, budgeting and estimating resource requirements for scaling up coverage of HIV prevention projects.     

Surveillance of hospital water and primary prevention of nosocomial legionellosis: what is the evidence?

Hospital-acquired Legionnaires' disease may be sporadic or may occur as part of an outbreak. As Legionella spp. are ubiquitous in many water systems, it is not surprising that hospital water may be colonized with Legionella pneumophila and other species. However, there is some controversy about the relationship between the presence of legionella in hospital water systems and nosocomial legionellosis. Primary prevention, i.e. measures to prevent legionella in a hospital or healthcare facility with no previous documented cases of nosocomial legionellosis, includes heightened awareness of hospital-acquired Legionnaires' disease with appropriate laboratory diagnostic facilities, and ensuring that the water system is well designed and maintained in accordance with national standards, e.g. the circulating hot water is maintained above 55 degrees C. Secondary prevention, i.e. preventing further cases occurring when a case has been confirmed, should include an investigation to exclude the hospital water system as a source. However, the necessity to sample hospital water routinely to detect legionella outside of outbreaks, i.e. as a component of primary prevention, is unclear. Some studies demonstrate a clear link but others do not. Differences between the patient populations studied, the methods of laboratory diagnosis of clinical cases, the analysis of hospital water and differences in the design of hospital water systems may partly explain this. Whilst further research, probably in the form of multi-centred prospective trials, is needed to confirm the relationship between environmental legionella and hospital-acquired legionellosis, including establishing the relative importance of L. pneumophila group 1 vs. non-group 1 and other Legionella spp., each hospital should consider the spectrum of patients at particular risk locally. Centres with transplant units or other patients with significant immunosuppression should, in the interim, consider routine sampling for legionella in hospital water in addition to other control measures. Therefore, infection control teams must work closely with hospital engineering and technical services departments and hospital management, as well as ensuring that physicians and others have a heightened awareness of hospital-acquired legionellosis.     

Promotion of folate for the prevention of neural tube defects: who benefits?

Since the publication of randomised trials showing firm evidence of prevention of neural tube defects with periconceptional folic acid, there have been population health promotion programmes to encourage women to take folic acid supplements, and the introduction of voluntary fortification of some foods with folic acid in Australia. In order to evaluate these two strategies, we collected data by self-administered questionnaire from a random sample of recently pregnant women in Western Australia between September 1997 and March 2000. Response to health promotion was measured in three ways: (1) knowledge of the association between periconceptional folate and prevention of spina bifida (the 'correct message'); (2) use of periconceptional vitamin supplements of folic acid daily in the periconceptional period; and (3) daily folate intake from fortified foods in the 6 months before pregnancy. We examined the relationship of maternal demographic and behavioural characteristics with these three measures. Overall, 62.3% of women were aware of the correct message before pregnancy, 28.5% reported taking 200 microg or more of folic acid from supplements daily in the periconceptional period and 56.6% of women obtained 100 microg or more of folic acid from fortified foods. Women who first became aware of the correct message during pregnancy or who were unaware of the correct message before or during pregnancy were more likely than women aware before pregnancy to be younger, having their first pregnancy, be single or in a de facto relationship, have no tertiary education, and be a public patient. Similar associations were seen for women taking either no folic acid or < 200 microg of folic acid in supplements daily in the periconceptional period. There were no significant associations between these demographic variables and amount of folate obtained from fortified foods. Women who were unaware of the correct message and did not take folic acid supplements were more likely to have smoked, not to have engaged in exercise, and not to have planned their pregnancy, whereas there was no association with these behavioural characteristics and intake of folate from fortified foods. These results indicate that health promotion strategies have not reached all segments of the target population equally, but there is no such disparity with folate-fortified foods, and they suggest that mandatory fortification of a staple food is likely to reach all women regardless of demographic and behavioural characteristics, and hence provide improved opportunity for prevention of neural tube defects in Australia.