Estimating trends and seasonality in coronary heart disease

We present two methods of estimating the trend, seasonality and noise in time series of coronary heart disease events. In contrast to previous work we use a non-linear trend, allow multiple seasonal components, and carefully examine the residuals from the fitted model. We show the importance of estimating these three aspects of the observed data to aid insight of the underlying process, although our major focus is on the seasonal components. For one method we allow the seasonal effects to vary over time and show how this helps the understanding of the association between coronary heart disease and varying temperature patterns. Copyright (C) 2004 John Wiley Sons, Ltd.

White blood cell count predicts reduction in coronary heart disease mortality with pravastatin

Background-Elevated serum inflammatory marker levels are associated with a greater long-term risk of cardiovascular events. Because 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitors (statins) may have an antiinflammatory action, it has been suggested that patients with elevated inflammatory marker levels may have a greater reduction in cardiovascular risk with statin treatment. Methods and Results-We evaluated the association between the white blood cell count (WBC) and coronary heart disease mortality during a mean follow-up of 6.0 years in the Long-Term Intervention With Pravastatin in Ischemic Disease (LIPID) Study, a clinical trial comparing pravastatin (40 mg/d) with a placebo in 9014 stable patients with previous myocardial infarction or unstable angina. An increase in baseline WBC was associated with greater coronary heart disease mortality in patients randomized to placebo (hazard ratio for 1 X 10(9)/L increase in WBC, 1.18; 95% CI, 1.12 to 1.25; P<0.001) but not pravastatin (hazard ratio, 1.02; 95% CI, 0.96 to 1.09; P=0.56; P for interaction=0.004). The numbers of coronary heart disease deaths prevented per 1000 patients treated with pravastatin were 0, 9, 30, and 38 for baseline WBC quartiles of <5.9, 6.0 to 6.9, 7.0 to 8.1, and >8.2X10(9)/L, respectively. WBC was a stronger predictor of this treatment benefit than the ratio of total to high-density lipoprotein cholesterol and a global measure of cardiac risk. There was also a greater reduction (P=0.052) in the combined incidence of cardiovascular mortality, nonfatal myocardial infarction, and stroke with pravastatin as baseline WBC increased ( by quartile: 3, 41, 61, and 60 events prevented per 1000 patients treated, respectively). Conclusions-These data support the hypothesis that individuals with evidence of inflammation may obtain a greater benefit from statin therapy.

Contribution of changes in risk factors to the decline of coronary heart disease mortality in Australia over three decades

BACKGROUND: Coronary heart disease has been a major cause of mortality in Australian adults, but the rate has declined by 83% from the 1968 peak by the year 2000. The study objective is to determine the contribution of changes in population risk factors - mean serum cholesterol and diastolic blood pressure and tobacco smoking prevalence - to the decline in coronary heart disease mortality in Australia over three decades. METHODS: Coronary heart disease deaths (International Classification of Disease-9, 410-414) and population by year, age group and sex were obtained from the Australian Bureau of Statistics. Risk factor levels were obtained from population surveys and estimated average annual changes by period were used to calculate average annual 'attributable' proportional declines in CHD mortality by period (age 35-64 years). RESULTS: Over the period 1968-2000, 74% of male decline and 81% of the female decline in coronary heart disease mortality rate was accounted for by the combined effect of reductions in the three risk factors. In males 36% of the decline was contributed by reductions in diastolic blood pressure, 22% by cholesterol and 16% by smoking. For females 56% was from diastolic blood pressure reduction, 20% from cholesterol and 5% from smoking. Effects of reductions in serum cholesterol on coronary heart disease mortality occurred mainly in the 1970s. Declines in diastolic blood pressure had effects on coronary heart disease mortality over the three decades, and declines in tobacco smoking had a significant effect in males in the 1980s. CONCLUSION: Most of the spectacular decline in coronary heart disease mortality over the last three decades in Australia can be ascribed to reductions in population risk factors from primary and secondary prevention.

Structural ambiguity of the Chinese version of the Hospital Anxiety and Depression Scale in patients with coronary heart disease

Background The Hospital Anxiety and Depression Scale (HADS) is a widely used screening tool designed as a case detector for clinically relevant anxiety and depression. Recent studies of the HADS in coronary heart disease (CHD) patients in European countries suggest it comprises three, rather than two, underlying sub-scale dimensions. The factor structure of the Chinese version of the HADS was evaluated in patients with CHD in mainland China. Methods Confirmatory factor analysis (CFA) was conducted on self-report HADS forms from 154 Chinese CHD patients. Results Little difference was observed in model fit between best performing three-factor and two-factor models. Conclusion The current observations are inconsistent with recent studies highlighting a dominant underlying tri-dimensional structure to the HADS in CHD patients. The Chinese version of the HADS may perform differently to European language versions of the instrument in patients with CHD.

Association between glutathione S-transferase M1 and T1 and the risk for coronary heart disease (CHD)

Deficiency of Glutathione S-transferases (GST) M1 and T1 are associated with chronic diseases (e.g. lung cancer, MS) and could be one factor for the risk for CHD.We conducted a pros-pective case-control study in 93 pts. with angiographically proven CHD and 161 controls matched for age ±2y and gender (resulting in n=91 pairs, of which 18 were female). Genes coding for functional GST M1 and T1 were analysed acoording to previously published methods. The association between GST M1, T1 was tested using Fisher's exact test; logistic regression analysis was performed to control for HDL-cholesterol, diabetes smoking, diabetes, hypertension. 41% of cases were smokers, 25% had diabetes and 68% hypertension, corresponding figures for controls were 31%, 13% and 33%. Mean HDL-cholesterol levels were comparable (pts: 46±14 mg/dl, controls: 43± 19 mg/dl). There was no overall significant correlation between functional GST T1 and M1 genotypes and CHD, however, there seems to be an association between GST M1, HDL-cholesterol and CHD. Larger studies are needed to verify these data.

Use of complementary and alternative medicine and self-tests by coronary heart disease patients

Background: Coronary heart disease patients have to learn to manage their condition to maximise quality of life and prevent recurrence or deterioration. They may develop their own informal methods of self-management in addition to the advice they receive as part of formal cardiac rehabilitation programmes. This study aimed to explore the use of complementary and alternative medicines and therapies (CAM), self-test kits and attitudes towards health of UK patients one year after referral to cardiac rehabilitation. Method: Questionnaire given to 463 patients attending an assessment clinic for 12 month follow up in four West Midlands hospitals. Results: 91.1% completed a questionnaire. 29.1% of patients used CAM and/or self-test kits for self-management but few (8.9%) used both methods. CAM was more often used for treating other illnesses than for CHD management. Self-test kit use (77.2%,) was more common than CAM (31.7%,) with BP monitors being the most prevalent (80.0%). Patients obtained self-test kits from a wide range of sources, for the most part (89.5%) purchased entirely on their own initiative. Predictors of self-management were post revascularisation status and higher scores on 'holism', 'rejection of authority' and 'individual responsibility'. Predictors of self-test kit use were higher `holism' and 'individual responsibility' scores. Conclusion: Patients are independently using new technologies to monitor their cardiovascular health, a role formerly carried out only by healthcare practitioners. Post-rehabilitation patients reported using CAM for self-management less frequently than they reported using self-test kits. Reports of CAM use were less frequent than in previous surveys of similar patient groups. Automatic assumptions cannot be made by clinicians about which CHD patients are most likely to self-manage. In order to increase trust and compliance it is important for doctors to encourage all CHD patients to disclose their self-management practices and to continue to address this in follow up consultations.

Comparison of estimates and calculations of risk of coronary heart disease by doctors and nurses using different calculation tools in general practice: cross sectional study

OBJECTIVE: To assess the effect of using different risk calculation tools on how general practitioners and practice nurses evaluate the risk of coronary heart disease with clinical data routinely available in patients' records. DESIGN: Subjective estimates of the risk of coronary heart disease and results of four different methods of calculation of risk were compared with each other and a reference standard that had been calculated with the Framingham equation; calculations were based on a sample of patients' records, randomly selected from groups at risk of coronary heart disease. SETTING: General practices in central England. PARTICIPANTS: 18 general practitioners and 18 practice nurses. MAIN OUTCOME MEASURES: Agreement of results of risk estimation and risk calculation with reference calculation; agreement of general practitioners with practice nurses; sensitivity and specificity of the different methods of risk calculation to detect patients at high or low risk of coronary heart disease. RESULTS: Only a minority of patients' records contained all of the risk factors required for the formal calculation of the risk of coronary heart disease (concentrations of high density lipoprotein (HDL) cholesterol were present in only 21%). Agreement of risk calculations with the reference standard was moderate (kappa=0.33-0.65 for practice nurses and 0.33 to 0.65 for general practitioners, depending on calculation tool), showing a trend for underestimation of risk. Moderate agreement was seen between the risks calculated by general practitioners and practice nurses for the same patients (kappa=0.47 to 0.58). The British charts gave the most sensitive results for risk of coronary heart disease (practice nurses 79%, general practitioners 80%), and it also gave the most specific results for practice nurses (100%), whereas the Sheffield table was the most specific method for general practitioners (89%). CONCLUSIONS: Routine calculation of the risk of coronary heart disease in primary care is hampered by poor availability of data on risk factors. General practitioners and practice nurses are able to evaluate the risk of coronary heart disease with only moderate accuracy. Data about risk factors need to be collected systematically, to allow the use of the most appropriate calculation tools.

The influence of patient and doctor gender on diagnosing coronary heart disease

Using novel methods, this paper explores sources of uncertainty and gender bias in primary care doctors' diagnostic decision-making about coronary heart disease (CHD). Claims about gendered consultation styles and quality of care are re-examined, along with the adequacy of CHD models for women. Randomly selected doctors in the UK and the US (n=112, 56 per country, stratified by gender) were shown standardised videotaped vignettes of actors portraying patients with CHD. Patients' age, gender, ethnicity and social class were varied systematically. During interviews, doctors gave free-recall accounts of their decision-making, which were analysed to determine patient and doctor gender effects. We found differences in male and female doctors' responses to different types of patient information. Female doctors recall more patient cues overall, particularly about history presentation, and particularly amongst women. Male doctors appear less affected by patient gender but both male and especially female doctors take more account of male patients' age, and consider more age-related disease possibilities for men than women. Findings highlight the need for better integration of knowledge about female presentations within accepted CHD risk models, and do not support the contention that women receive better-quality care from female doctors.