Julia Critchley

Modelling the decline in coronary heart disease deaths in England and Wales, 1981-2000: comparing contributions from primary prevention and secondary prevention

Abstract Objective To investigate whether population based primary prevention (risk factor reduction in apparently healthy people) might be more powerful than current government initiatives favouring risk factor reduction in patients with coronary heart disease (CHD) (secondary prevention). Design, setting, and participants The IMPACT model was used to synthesise data for England and Wales describing CHD patient numbers, uptake of specific treatments, trends in major cardiovascular risk factors, and the mortality benefits of these specific risk factor changes in healthy people and in CHD patients. Results Between 1981 and 2000, CHD mortality rates fell by 54%, resulting in 68 230 fewer deaths in 2000. Overall smoking prevalence declined by 35% between 1981 and 2000, resulting in approximately 29 715 (minimum estimate 20 035, maximum estimate 44 675) fewer deaths attributable to smoking cessation: approximately 5035 in known CHD patients and approximately 24 680 in healthy people. Population total cholesterol concentrations fell by 4.2%, resulting in approximately 5770 fewer deaths attributable to dietary changes (1205 in CHD patients and 4565 in healthy people) plus 2135 fewer deaths attributable to statin treatment (1990 in CHD patients, 145 in people without CHD). Mean population blood pressure fell by 7.7%, resulting in approximately 5870 fewer deaths attributable to secular falls in blood pressure (520 in CHD patients and 5345 in healthy people) plus approximately 1890 fewer deaths attributable to antihypertensive treatments in people without CHD. Approximately 45 370 fewer deaths were thus attributable to reductions in the three major risk factors in the population: some 36 625 (81%) in people without recognised CHD and 8745 (19%) in CHD patients. Conclusions Compared with secondary prevention, primary prevention achieved a fourfold larger reduction in deaths. Future CHD policies should prioritise population-wide tobacco control and healthier diets.

Explaining the Increase in Coronary Heart Disease Mortality in Beijing Between 1984 and 1999

Background—Coronary heart disease (CHD) mortality is rising in many developing countries. We examined how much of the increase in CHD mortality in Beijing, China, between 1984 and 1999 could be attributed to changes in major cardiovascular risk factors and assessed the impact of medical and surgical treatments. Methods and Results—A validated, cell-based mortality model synthesized data on (1) patient numbers, (2) uptake of specific medical and surgical treatments, (3) treatment effectiveness, and (4) population trends in major cardiovascular risk factors (smoking, total cholesterol, blood pressure, obesity, and diabetes). Main data sources were the WHO MONICA and Sino-MONICA studies, the Chinese Multi-provincial Cohort Study, routine hospital statistics, and published meta-analyses. Age-adjusted CHD mortality rates increased by ≈50% in men and 27% in women (1608 more deaths in 1999 than expected by application of 1984 rates). Most of this increase (≈77%, or 1397 additional deaths) was attributable to substantial rises in total cholesterol levels (more than 1 mmol/L), plus increases in diabetes and obesity. Blood pressure decreased slightly, whereas smoking prevalence increased in men but decreased substantially in women. In 1999, medical and surgical treatments in patients together prevented or postponed ≈642 deaths, mainly from initial treatments for acute myocardial infarction (≈41%), hypertension (24%), angina (15%), secondary prevention (11%), and heart failure (10%). Multiway sensitivity analyses did not greatly influence the results. Conclusions—Much of the dramatic CHD mortality increases in Beijing can be explained by rises in total cholesterol, reflecting an increasingly “Western” diet. Without cardiological treatments, increases would have been even greater.

Cardiovascular risk factor trends and potential for reducing coronary heart disease mortality in the United States of America

OBJECTIVE To examine the potential for reducing cardiovascular risk factors in the United States of America enough to cause age-adjusted coronary heart disease (CHD) mortality rates to drop by 20% (from 2000 baseline figures) by 2010, as targeted under the Healthy People 2010 initiative. METHODS Using a previously validated, comprehensive CHD mortality model known as IMPACT that integrates trends in all the major cardiovascular risk factors, stratified by age and sex, we calculated how much CHD mortality would drop between 2000 and 2010 in the projected population of the United States aged 25-84 years (198 million). We did this for three assumed scenarios: (i) if recent risk factor trends were to continue to 2010; (ii) success in reaching all the Healthy People 2010 risk factor targets, and (iii) further drops in risk factors, to the levels already seen in the low-risk stratum. FINDINGS If age-adjusted CHD mortality rates observed in 2000 remained unchanged, some 388,000 CHD deaths would occur in 2010. First scenario: if recent risk factor trends continued to 2010, there would be approximately 19,000 fewer deaths than in 2000. Although improved total cholesterol, lowered blood pressure in men, decreased smoking and increased physical activity would account for some 51,000 fewer deaths, these would be offset by approximately 32,000 additional deaths from adverse trends in obesity and diabetes and in blood pressure in women. Second scenario: If Healthy People 2010 cardiovascular risk factor targets were reached, approximately 188,000 CHD deaths would be prevented. Scenario three: If the cardiovascular risk levels of the low-risk stratum were reached, approximately 372,000 CHD deaths would be prevented. CONCLUSION Achievement of the Healthy People 2010 cardiovascular risk factor targets would almost halve the predicted CHD death rates. Additional reductions in major risk factors could prevent or postpone substantially more deaths from CHD.

A review of co-morbidity between infectious and chronic disease in Sub Saharan Africa: TB and Diabetes Mellitus, HIV and Metabolic Syndrome, and the impact of globalization

BackgroundAfrica is facing a rapidly growing chronic non-communicable disease burden whilst at the same time experiencing continual high rates of infectious disease. It is well known that some infections increase the risk of certain chronic diseases and the converse. With an increasing dual burden of disease in Sub Saharan Africa the associations between diseases and our understanding of them will become of increased public health importance.AimsIn this review we explore the relationships reported between tuberculosis and diabetes mellitus, human immunodeficiency virus, its treatment and metabolic risk. We aimed to address the important issues surrounding these associations within a Sub Saharan African setting and to describe the impact of globalization upon them.FindingsDiabetes has been associated with a 3-fold incident risk of tuberculosis and it is hypothesised that tuberculosis may also increase the risk of developing diabetes. During co-morbid presentation of tuberculosis and diabetes both tuberculosis and diabetes outcomes are reported to worsen. Antiretroviral therapy for HIV has been associated with an increased risk of developing metabolic syndrome and HIV has been linked with an increased risk of developing both diabetes and cardiovascular disease. Globalization is clearly related to an increased risk of diabetes and cardiovascular disease. It may be exerting other negative and positive impacts upon infectious and chronic non-communicable disease associations but at present reporting upon these is sparse.ConclusionThe impact of these co-morbidities in Sub Saharan Africa is likely to be large. An increasing prevalence of diabetes may hinder efforts at tuberculosis control, increasing the number of susceptible individuals in populations where tuberculosis is endemic, and making successful treatment harder. Roll out of anti-retroviral treatment coverage within Sub Saharan Africa is an essential response to the HIV epidemic however it is likely to lead to a growing number of individuals suffering adverse metabolic consequences. One of the impacts of globalization is to create environments that increase both diabetes and cardiovascular risk but further work is needed to elucidate other potential impacts. Research is also needed to develop effective approaches to reducing the frequency and health impact of the co-morbidities described here.

Diabetes and the risk of tuberculosis: a neglected threat to public health?

Objectives: Tuberculosis (TB) remains a major global public health problem. In the past, a relationship between TB and diabetes mellitus (DM) was recognized, and its importance was acknowledged through joint treatment clinics. However, this is rarely highlighted in current research or control priorities. This paper aims to evaluate the evidence for an association between these two diseases. Methods: A Medline literature search was undertaken, supplemented by checking references and contacting experts. We critically appraised studies that quantified the association between TB and DM, and were published after 1995. We assessed study quality according to criteria such as sample size, method of selection of cases and controls, losses to follow-up, quality and method of control of confounding, and summarized the results narratively and in tabular form. Results: All studies identified statistically significant and clinically important associations, with the increase in risk or odds of TB varying between 1.5- and 7.8-fold for those with DM. Risk was highest at younger ages. Most studies had not measured and controlled adequately for potential major confounders. Discussion: There is strong evidence for an association between TB and DM, which has potential public health implications. Further well-designed studies are needed to assess the magnitude precisely.

Changes in health in England, with analysis by English regions and areas of deprivation, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013

Summary Background In the Global Burden of Disease Study 2013 (GBD 2013), knowledge about health and its determinants has been integrated into a comparable framework to inform health policy. Outputs of this analysis are relevant to current policy questions in England and elsewhere, particularly on health inequalities. We use GBD 2013 data on mortality and causes of death, and disease and injury incidence and prevalence to analyse the burden of disease and injury in England as a whole, in English regions, and within each English region by deprivation quintile. We also assess disease and injury burden in England attributable to potentially preventable risk factors. England and the English regions are compared with the remaining constituent countries of the UK and with comparable countries in the European Union (EU) and beyond. Methods We extracted data from the GBD 2013 to compare mortality, causes of death, years of life lost (YLLs), years lived with a disability (YLDs), and disability-adjusted life-years (DALYs) in England, the UK, and 18 other countries (the first 15 EU members [apart from the UK] and Australia, Canada, Norway, and the USA [EU15+]). We extended elements of the analysis to English regions, and subregional areas defined by deprivation quintile (deprivation areas). We used data split by the nine English regions (corresponding to the European boundaries of the Nomenclature for Territorial Statistics level 1 [NUTS 1] regions), and by quintile groups within each English region according to deprivation, thereby making 45 regional deprivation areas. Deprivation quintiles were defined by area of residence ranked at national level by Index of Multiple Deprivation score, 2010. Burden due to various risk factors is described for England using new GBD methodology to estimate independent and overlapping attributable risk for five tiers of behavioural, metabolic, and environmental risk factors. We present results for 306 causes and 2337 sequelae, and 79 risks or risk clusters. Findings Between 1990 and 2013, life expectancy from birth in England increased by 5·4 years (95% uncertainty interval 5·0–5·8) from 75·9 years (75·9–76·0) to 81·3 years (80·9–81·7); gains were greater for men than for women. Rates of age-standardised YLLs reduced by 41·1% (38·3–43·6), whereas DALYs were reduced by 23·8% (20·9–27·1), and YLDs by 1·4% (0·1–2·8). For these measures, England ranked better than the UK and the EU15+ means. Between 1990 and 2013, the range in life expectancy among 45 regional deprivation areas remained 8·2 years for men and decreased from 7·2 years in 1990 to 6·9 years in 2013 for women. In 2013, the leading cause of YLLs was ischaemic heart disease, and the leading cause of DALYs was low back and neck pain. Known risk factors accounted for 39·6% (37·7–41·7) of DALYs; leading behavioural risk factors were suboptimal diet (10·8% [9·1–12·7]) and tobacco (10·7% [9·4–12·0]). Interpretation Health in England is improving although substantial opportunities exist for further reductions in the burden of preventable disease. The gap in mortality rates between men and women has reduced, but marked health inequalities between the least deprived and most deprived areas remain. Declines in mortality have not been matched by similar declines in morbidity, resulting in people living longer with diseases. Health policies must therefore address the causes of ill health as well as those of premature mortality. Systematic action locally and nationally is needed to reduce risk exposures, support healthy behaviours, alleviate the severity of chronic disabling disorders, and mitigate the effects of socioeconomic deprivation. Funding Bill & Melinda Gates Foundation and Public Health England.

Explaining the recent decrease in coronary heart disease mortality rates in Ireland, 1985–2000

Study objectives: To examine the proportion of the recent decline in coronary heart disease (CHD) deaths in Ireland attributable to (a) “evidence based” medical and surgical treatments, and (b) changes in major cardiovascular risk factors. Design setting: IMPACT, a previously validated model, was used to combine and analyse data on the use and effectiveness of specific cardiology treatments and risk factor trends, stratified by age and sex. The main data sources were published trials and meta-analyses, official statistics, clinical audits, and observational studies. Results: Between 1985 and 2000, CHD mortality rates in Ireland fell by 47% in those aged 25–84. Some 43.6% of the observed decrease in mortality was attributed to treatment effects and 48.1% to favourable population risk factor trends; specifically declining smoking prevalence (25.6%), mean cholesterol concentrations (30.2%), and blood pressure levels (6.0%), but offset by increases in adverse population trends related to obesity, diabetes, and inactivity (−13.8%). Conclusions: The results emphasise the importance of a comprehensive strategy that maximises population coverage of effective treatments, and that actively promotes primary prevention, particularly tobacco control and a cardioprotective diet.

Life-Years Gained From Modern Cardiological Treatments and Population Risk Factor Changes in England and Wales, 1981-2000

OBJECTIVES We estimated life-years gained from cardiological treatments and cardiovascular risk factor changes in England and Wales between 1981 and 2000. METHODS We used the IMPACT model to integrate data on the number of coronary heart disease patients, treatment uptake and effectiveness, risk factor trends, and median survival in coronary heart disease patients. RESULTS Compared with 1981, there were 68230 fewer coronary deaths in 2000. Approximately 925415 life-years were gained among people aged 25-84 years (range: 745 195-1 138 655). Cardiological treatments for patients accounted for approximately 194145 life-years gained (range: 142505-259225), and population risk factor changes accounted for approximately 731270 life-years gained (range; 602695-879430). CONCLUSIONS Modest reductions in major risk factors led to gains in life-years 4 times higher than did cardiological treatments. Effective policies to promote healthy diets and physical activity might achieve even greater gains.

Corticosteroids for prevention of mortality in people with tuberculosis: a systematic review and meta-analysis

BACKGROUND The effects of corticosteroids are systemic, but their benefits in tuberculosis are thought to be organ specific, with clinicians using them routinely to treat some forms of tuberculosis (such as meningitis), but not others. We aimed to assess the effects of steroids on mortality attributable to all forms of tuberculosis across organ systems. METHODS We did a systematic review and meta-analysis to estimate the efficacy of steroids for the prevention of mortality in all forms of tuberculosis, and to quantify heterogeneity in this outcome between affected organ systems. We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Central Register of Controlled Trials, Medline, Embase, and Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) for studies published up to Sept 6, 2012, and checked reference lists of included studies and relevant reviews. We included all trials in people with tuberculosis in any organ system, with tuberculosis defined clinically or microbiologically. There were no restrictions by age, comorbidity, publication language, or type, dose, or duration of steroid treatment. We used the Mantel-Haenszel method to summarise mortality across trials. FINDINGS We identified 41 eligible trials, 18 of which assessed pulmonary tuberculosis. 20 of the 41 trials (including 13 of those for pulmonary tuberculosis) were done before the introduction of modern rifampicin-containing antituberculosis chemotherapy. Meta-analysis stratified by affected organ systems identified no heterogeneity; steroids reduced mortality by 17% (risk ratio [RR] 0·83, 95% CI 0·74-0·92; I(2) 0%), consistent across all organ groups. In a sensitivity analysis that only included trials that used rifampicin-containing regimens, the results were similar (RR 0·85, 95% CI 0·74-0·98; I(2) 21%). A sensitivity analysis in pulmonary tuberculosis that excluded trials with high potential risks of bias suggested a slight benefit, but the point estimate was closer to no effect and the difference was not significant (RR 0·93, 95% CI 0·60-1·44). INTERPRETATION Steroids could be effective in reducing mortality for all forms of tuberculosis, including pulmonary tuberculosis. However, further evidence is needed since few recent trials have assessed the effectiveness of corticosteroids in patients with pulmonary tuberculosis. FUNDING UK Department for International Development.

Life-Years Gained Among US Adults From Modern Treatments and Changes in the Prevalence of 6 Coronary Heart Disease Risk Factors Between 1980 and 2000

Has the recent US decline in coronary heart disease (CHD) mortality increased life expectancy? The authors estimated the number of life-years gained from CHD treatments and changes in the prevalence of cardiovascular disease risk factors for the US population between 1980 and 2000. The previously validated IMPACT model was used to integrate data on numbers of CHD patients, treatment uptake, treatment effectiveness, population risk factor trends, and median survival among US adults. There were 308,900 fewer CHD deaths in 2000 among Americans aged 25-84 years than if 1980 mortality rates had applied. These 308,900 fewer deaths represented approximately 3,147,800 life-years gained (sensitivity analysis range, 2,448,900-3,744,900). Treatments for patients accounted for approximately 1,092,400 (751,700-1,387,000) life-years gained, whereas changes in the prevalence of population risk factors accounted for a gain of 2,055,500 (1,697,200-2,346,300) life-years. However, the 2,770,500 life-years gained through decreased levels of smoking, cholesterol, blood pressure, and physical inactivity were diminished by a loss of 715,000 life-years attributable to increased rates of obesity and diabetes. Therefore, modest reductions in the prevalence of several major cardiovascular disease risk factors accounted for more than twice as many life-years gained as did treatments. Unfortunately, these gains were partially offset by substantial increases in obesity and diabetes.