Use and cost of assistive technology the first year after stroke. A randomized controlled trial

OBJECTIVE

The objective was to compare and evaluate assistive technology given to patients treated in a stroke unit and patients treated in a general medical ward.

METHOD

Use and cost of assistive technology was evaluated in a randomized study comprising 249 patients during a 12-month period.

RESULT

Acute stroke unit care was associated with a higher prescription of assistive devices during the first 3 months. There was no difference in use and total mean cost per patient of assistive technology during the first year after stroke.

CONCLUSION

There was no difference in use or cost of assistive technology during the first year, but a beneficial effect was found on supplementary prescription of assistive devices during the first 3 months. The cost during the first year after stroke was a small fraction of the total costs for care and rehabilitation. It is not expensive for the community to equip these patients and their caregivers with assistive technology, and economic resources should be available to this vulnerable group of elderly patients.

Smoking and use of smokeless tobacco in treated hypertensive men at high coronary risk: utility of urinary cotinine determination

Guidelines for the treatment of hypertension underline the central importance of strenuous efforts to reduce the prevalence of smoking, as epidemiological studies consistently have demonstrated that smoking increases the risk of cardiovascular disease and death by some two- or three-fold. Accuracy of a questionnaire is examined against the ability of urinary cotinine determination to distinguish between men exposed to tobacco (94 smokers [25%], 30 snuff users [8%]) and men not exposed (n = 257), all of whom where treated hypertensives and were associated with at least one of the following factors: smoking, diabetes mellitus, serum cholesterol > or = 6.5 mmol/L. Main outcome variables in this cross-sectional study of 381 men were cotinine concentration and cotinine:creatinine ratio in overnight urine samples (decision limits: 2 mumol/L and 1.0 mmol/mol, respectively); tobacco use according to questionnaire; and follow-up examination by questionnaire of alleged non-smokers with high urinary cotinine levels. Questionnaire sensitivity was 85%, whereas the urinary cotinine assay showed 98% sensitivity and 99% specificity. Fourteen (15%) out of 94 patients may have used tobacco without reporting it in the questionnaire. In conclusion, cotinine measurement substantially improved the discrimination between smokers and non-smokers in men with multiple risk factors for cardiovascular disease.

Circulating oxidized low-density lipoprotein (LDL) is associated with risk factors of the metabolic syndrome and LDL size in clinically healthy 58-year-old men (AIR study)

OBJECTIVES

Hypothetically the atherogenic effect of the metabolic syndrome may be mediated through the increased occurrence of small LDL-particles which are easily modified to atherogenic oxidized LDL (ox-LDL). The aim of this study was to test this concept by examining the association between circulating ox-LDL, LDL-particle size, and the metabolic syndrome.

DESIGN AND RESULTS

A population-based sample of clinically healthy 58-year-old men (n = 391) was recruited. Ox-LDL was measured by ELISA (specific monoclonal antibody, mAb-4E6) and LDL-particle size by gradient gel electrophoresis. The results showed that ox-LDL significantly correlated to factors constituting the metabolic syndrome; triglycerides (r = 0.43), plasma insulin (r = 0.20), body mass index (r = 0.20), waist-to-hip ratio (r = 0.21) and HDL (r = -0.24); (P < 0.001). Ox-LDL correlated also to LDL-particle size (r = -0.42), Apo-B (r = 0.70), LDL (r = 0.65); (P < 0.001) and, furthermore, with Apo A-1 (r = -0.13) and heart rate (r = 0.13); (P < 0.01).

CONCLUSION

The metabolic syndrome was accompanied by high plasma ox-LDL concentrations compared with those without the syndrome. Ox-LDL levels were associated with most of the risk factors constituting the metabolic syndrome and was, in addition related to small LDL-particle size. To our knowledge the present study is the first one to demonstrate that circulating ox-LDL levels are associated with small LDL-particle size in a population representative sample of clinically healthy middle-aged men. The high degree of intercorrelation amongst several factors makes it difficult to clarify the independent role of any specific factor.

Endothelium-dependent flow-mediated vasodilatation, insulin resistance and the metabolic syndrome in 60-year-old men

OBJECTIVES

To evaluate the endothelium-dependent flow-mediated vasodilatation (FMD) in the brachial artery and to study the relationship to insulin sensitivity and to the metabolic syndrome in 60-year-old clinically healthy men.

SUBJECTS

The men were randomly selected from the general population (n = 55). The subjects with the metabolic syndrome were defined according to a definition proposed by a working group associated with the World Health Organization (WHO).

METHODS

Ultrasound images for measurement of lumen diameter of the brachial artery were recorded before and after reactive hyperaemia induced by occlusion of the artery, both with and without ischaemic hand exercise during the occlusion. Insulin-mediated glucose uptake was determined by euglycaemic hyperinsulinaemic clamp as a measure of insulin sensitivity.

RESULTS

The FMD was in the total group 3.2% when hyperaemia was induced by occlusion only and 8.7% after occlusion plus ischaemic hand exercise (P < 0.001, n = 51). However, no relationship was observed between any measure of FMD and insulin-mediated glucose uptake (r = -0.05 and r = 0.06, n = 47, P > 0.30). Furthermore, subjects with the metabolic syndrome (n = 13) did not differ in any measure of FMD compared with those with no risk factors (n = 11).

CONCLUSION

In this study the ultrasound method to evaluate endothelial function did not show that low insulin sensitivity or the metabolic syndrome were associated with impaired FMD in otherwise clinically healthy 60-year-old men.

Dose of metoprolol CR/XL and clinical outcomes in patients with heart failure: analysis of the experience in metoprolol CR/XL randomized intervention trial in chronic heart failure (MERIT-HF)

OBJECTIVES

We performed a post-hoc subgroup analysis in the Metoprolol CR/XL Randomized Intervention Trial in Chronic Heart Failure (MERIT-HF) with the aim of reporting on the heart rate (HR) response during the titration phase and clinical outcomes from the three-month follow-up visit to end of study in two dosage subgroups: one that had reached more than 100 mg of metoprolol CR/XL once daily (high-dose group; n = 1,202; mean 192 mg) and one that had reached 100 mg or less (low-dose group; n = 412; mean 76 mg).

BACKGROUND

Clinicians have questioned whether patients need to reach the target beta-blocker dose to receive benefit. METHODS; Outcome (Cox-adjusted) was compared with all placebo patients with dose available at the three-month visit (n = 1,845).

RESULTS

Data indicated somewhat higher risk in the low-dose group compared with the high-dose group. Heart rate was reduced to a similar degree in the two dose groups, indicating higher sensitivity for beta-blockade in the low-dose group. The reduction in total mortality with metoprolol CR/XL compared with placebo was similar: 38% (95% confidence interval [CI], 16 to 55) in high-dose group (p = 0.0022) and also 38% (95% CI, 11 to 57) in the low-dose group (p = 0.010).

CONCLUSIONS

Risk reduction was similar in the high- and low-dose subgroups, which, at least partly, may be the result of similar beta-blockade as judged from the HR response. The results support the idea of an individualized dose-titration regimen, which is guided by patient tolerability and the HR response. Further research is needed to shed light on why some patients respond with a marked HR reduction and reduced mortality risk on a relatively small dose of a beta-blocker.

Circulating ICAM-1 (intercellular cell-adhesion molecule 1) is associated with early stages of atherosclerosis development and with inflammatory cytokines in healthy 58-year-old men: the Atherosclerosis and Insulin Resistance (AIR) study

There is a lack of data on circulating levels of cell-adhesion molecules in relation to subclinical atherosclerosis measured in both the carotid and femoral arteries in humans. The aim of the present study was to investigate the relationship between clinically silent atherosclerosis and cell-adhesion molecules, and to explore the relationship between these molecules, C-reactive protein and the inflammatory cytokines interleukin-6, tumour necrosis factor-alpha (TNF-alpha), soluble TNF-alpha receptor p55 and soluble TNF-alpha receptor p75. The study group (n=391) consisted of clinically healthy 58-year-old men recruited from the general population. The results showed a positive trend between levels of soluble intercellular cell-adhesion molecule 1 (sICAM-1) and plaque occurrence in the carotid and femoral arteries (P=0.008), and also a univariate correlation between sICAM-1 levels and the composite variable of carotid and femoral intima-media thickness (P<0.001). When adjusted for other risk factors, the relationship between sICAM-1 and intima-media thickness no longer reached statistical significance. The level of sICAM-1 was associated with those of the pro-inflammatory cytokine TNF-alpha, its two soluble receptors, and also interleukin-6 and C-reactive protein. Levels of soluble E-selectin and vascular cell-adhesion molecule 1 (VCAM-1) showed weak or no association with subclinical atherosclerosis and inflammatory variables. Thus, in clinically healthy middle-aged men, levels of sICAM-1, but not of soluble VCAM-1 or E-selectin, were associated with both subclinical atherosclerosis and inflammatory variables.

Circulating oxidized LDL is associated with subclinical atherosclerosis development and inflammatory cytokines (AIR Study)

OBJECTIVE

Circulating oxidized LDL (Ox-LDL) is associated with clinical manifestations of atherosclerosis. However, no previous study has examined the relationship between subclinical atherosclerosis and Ox-LDL. The aims of the present study were to investigate the relationship between clinically silent ultrasound-assessed atherosclerotic changes in the carotid and femoral arteries and Ox-LDL and to explore the relationship between Ox-LDL, C-reactive protein, and the inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha.

METHODS AND RESULTS

The study group (n=391) consisted of clinically healthy, 58-year-old men recruited from the general population. Ox-LDL was measured by using a specific monoclonal antibody, mAb-4E6. The results showed that Ox-LDL was related to intima-media thickness and plaque occurrence in the carotid and femoral arteries. In addition, Ox-LDL was associated with tumor necrosis factor-alpha and C-reactive protein. Circulating Ox-LDL was also associated with LDL cholesterol but not with blood pressure or smoking. When adjusting for other risk factors, both LDL cholesterol and Ox-LDL seemed to be independent predictors of plaque occurrence in the carotid and femoral arteries (odds ratios for quintile 5 versus quintile 1 were 2.17, P=0.049 and 2.25, P=0.050, for LDL cholesterol and Ox-LDL, respectively).

CONCLUSIONS

Ox-LDL was associated with both subclinical atherosclerosis and inflammatory variables, supporting the concept that oxidatively modified LDL may play a major role in atherosclerosis development, although no causality can be shown in this cross-sectional study.

Lipoprotein(a) was an independent predictor for major coronary events in treated hypertensive men

BACKGROUND AND HYPOTHESIS

Lipoprotein(a) may play a part in the development of coronary heart disease. The purpose of this prospective study was to evaluate lipoprotein(a) as a predictor of major coronary events (fatal and nonfatal myocardial infarction and sudden death).

METHODS

This was a prospective study of 118 men, aged 56 to 77 years, with treated hypertension and at least one additional cardiovascular risk factor (hypercholesterolemia, diabetes mellitus, or smoking) were included in the study. Lipoprotein(a) was measured at entry and major coronary events were followed during follow-up.

RESULTS

The mean observation time was 3.0 years. Fourteen patients had a major coronary event during the follow-up period. Subjects with coronary heart disease (previous myocardial infarction, angina pectoris, or major electrocardiographic changes) at entry (n = 27) had significantly higher lipoprotein(a) levels than subjects without (n = 91) known coronary heart disease (p < 0.05). Lipoprotein(a) was a significant predictor for major coronary events (p = 0.033). Furthermore, when coronary disease at entry was included into the Cox regression analysis, lipoprotein(a) was an independent predictor for major coronary events (p = 0.044).

CONCLUSIONS

Among treated hypertensive men, lipoprotein(a) was an independent predictor of major coronary events.

Circulating oxidized LDL is associated with increased levels of cell-adhesion molecules in clinically healthy 58-year old men (AIR study)

BACKGROUND

Inflammation has been postulated to play an important role in atherosclerosis development. Recently, research in this field has been focused on the role of modified lipoproteins, primarily oxidized low density lipoprotein. Adhesion and transendothelial migration of circulating leukocytes, by the action of cell-adhesion molecules, seem to be critical steps in early atherogenesis. Previous in vitro studies on the relationship between ox-LDL and the expression of cell-adhesion molecules on endothelial cells have shown diverging results. Furthermore, there are as yet no reports on the relationship between circulating ox-LDL and cell-adhesion molecules in vivo.

MATERIAL/METHODS

The relationship between circulating ox-LDL and adhesion molecules was measured by ELISA in clinically healthy, 58-year-old men recruited from the general population (n=391).

RESULTS

The results of the present study showed that circulating ox-LDL was associated with sICAM-1 and sE-selectin, but not with sVCAM-1. After adjustment for other risk factors, i.e. systolic blood pressure, LDL cholesterol, apoB, apoA1 and smoking, the observed relationships between ox-LDL and sICAM-1 and sE-selectin, respectively, remained statistically significant.

CONCLUSIONS

The observed results fit into the concept that oxidatively modified LDL may regulate the increased expression of cell-adhesion molecules on endothelial cells in vivo. These observations were made in a population-based sample of clinically healthy, middle-aged Caucasian men. Since this was a cross-sectional study no conclusions can be drawn on causality.

Alcohol consumption, the metabolic syndrome and insulin resistance in 58-year-old clinically healthy men (AIR study)

It has been shown that a light-to-moderate intake of alcohol may enhance insulin sensitivity; a decrease in insulin sensitivity is a component of the clustering of risk factors known as the metabolic syndrome. However, previous studies have been limited to relatively small or heterogeneous study groups, or have used suboptimal methods of measuring insulin action. Hence the aim of the present study was to examine whether the metabolic syndrome (as recently defined),components of this syndrome and smoking are associated with alcohol consumption. The study was performed in a population-based sample of clinically healthy men (n=391), all 58 years old and not undergoing any treatment with cardiovascular drugs. Insulin-mediated glucose uptake (euglycaemic hyperinsulinaemic clamp) was measured in a subgroup of these subjects (n=104). Trend analysis showed no difference in alcohol intake across the groups of men with none of the criteria in the definition of the metabolic syndrome (n=77),men with one or more of the criteria (n=252) and men fulfilling all criteria (n=62). However, in the whole group (n=391), alcohol consumption was significantly positively associated with serum triacylglycerols (triglycerides), high-density lipoprotein (HDL) cholesterol and cigarette-years. Furthermore, alcohol consumption was positively associated with insulin-mediated glucose uptake (r=0.20, P<0.05). In multiple regression analyses, body mass index, alcohol consumption and serum triacylglycerols were independent co-variates to insulin-mediated glucose uptake. Thus, in 58-year-old healthy men recruited from the general population, there was a significant association between alcohol consumption, serum triacylglycerols, HDL cholesterol and cigarette-years. In a subgroup of 104 subjects, alcohol consumption was independently and positively associated with insulin-mediated glucose uptake. To our knowledge, this is the first study to show an independent relationship between insulin sensitivity, as measured by the clamp technique, and alcohol intake.

Health-related quality of life and sense of coherence among elderly patients with severe chronic heart failure in comparison with healthy controls

OBJECTIVE

To describe health-related quality of life (QoL) and sense of coherence (SOC) in a group of elderly people with moderate to severe chronic heart failure and to make comparisons with a healthy sex- and age-matched control group.

METHODS

Patients (n = 94), with a mean age of 81 years, hospitalized for chronic heart failure with New York Heart Association functional classification III to IV were age- and sex-matched to a healthy control group. The instruments used were the 36-Item Short Form Health Survey (SF-36) and SOC.

RESULTS

The patients had lower levels of health-related QoL scores (SF-36) but high and similar scores of SOC compared with the controls. There were, however, significant positive correlations between the SOC scores and the emotional dimensions in the SF-36 instrument.

CONCLUSION

The findings from this study indicate that old age and severe chronic heart failure were associated with limited functional abilities and impaired health-related QoL but also with internal resources such as SOC.

Insulin, insulin propeptides and intima-media thickness in the carotid artery in 58-year-old clinically healthy men. The Atherosclerosis and Insulin Resistance study (AIR)

AIMS

To examine the relationship between specific (intact) insulin, insulin propeptides and subclinical atherosclerosis.

METHODS

A cross-sectional study based on a stratified sampling of randomly selected, clinically healthy 58-year-old men (n = 391). Ultrasound examinations of the carotid arteries were performed with measurement of intima-media thickness (IMT) in the common carotid artery and in the carotid artery bulb. Fasting, cross-reacting plasma insulin (RIA), specific (intact) insulin, proinsulin, 32,33 split proinsulin and C-peptide were measured.

RESULTS

Plasma concentrations of cross-reacting plasma insulin, specific insulin, proinsulin, 32,33 split proinsulin and C-peptide were univariately associated with common carotid artery IMT. Established risk factors such as blood pressure, smoking, apoB, triglycerides, body mass index (BMI), and waist--hip ratio were also related to IMT. After adjustment for smoking, apoB, blood pressure and triglycerides, cross-reacting plasma insulin, proinsulin and C-peptide but not specific insulin and split 32,33 proinsulin remained associated with carotid artery IMT. No associations remained after adjustment for BMI.

CONCLUSIONS

Fasting plasma proinsulin, C-peptide, and insulin by cross-reacting RIA was associated with common carotid artery IMT independent of several conventional risk factors for atherosclerosis. The multicollinearity between the insulin peptides and propeptides makes it difficult to clarify the exact role of each peptide.

Post-occlusion brachial artery vasodilatation after ischaemic handgrip exercise is nitric oxide mediated

Flow-mediated vasodilatation (FMD) of the brachial artery is used as a measure to quantify endothelial dysfunction. However, FMD after occlusion only is small in healthy people over middle age, but can be increased after handgrip exercise. The aim of this study was to evaluate whether postocclusion vasodilatation after handgrip exercise is mediated by nitric oxide (NO). High frequency ultrasound was used to measure brachial artery diameter at rest and after reactive hyperaemia with and without handgrip exercise during NaCl or NG-monomethyl-L-arginine (L-NMMA) infusion in healthy 60-year-old men. Postocclusion vasodilation was significantly larger after handgrip exercise compared with occlusion only (P=0.0078). Postocclusion vasodilatation was significantly lower after ischaemic handgrip exercise during intra-arterial infusion of L-NMMA compared with infusion of NaCl (P = 0.039). It may be concluded that the increased postocclusion brachial artery vasodilatation observed after ischaemic handgrip exercise is at least partly NO mediated. This modification of the investigation procedure may improve our ability to quantify FMD in subjects with and without vascular disease.

Carotid and femoral atherosclerosis, cardiovascular risk factors and C-reactive protein in relation to smokeless tobacco use or smoking in 58-year-old men

Objectives. To examine the associations between smokeless tobacco use, smoking, cardiovascular risk factors, inflammation and ultrasound-assessed measures of atherosclerosis in the carotid and femoral arteries. Subjects. The study was performed in a population-based sample of clinically healthy men (n = 391) all 58 years old. Exclusion criteria were cardiovascular or other clinically overt diseases or continuous medication with cardiovascular drugs. Methods. The habits of smoking and oral moist snuff use were assessed by questionnaires. C-reactive protein (CRP) was assessed by high sensitive enzyme-linked immunosorbent assay (ELISA). Intima-media thickness (IMT) in the carotid bulb, the common carotid artery and the common femoral artery and plaque occurrence were measured by ultrasound. Results. The use of oral moist snuff was associated with serum triglycerides and waist-hip ratio (WHR), but not with CRP or ultrasound-assessed measures of subclinical atherosclerosis. Smoking, on the other hand, was associated with CRP, the components in the metabolic syndrome and IMT as well as plaques in the carotid and femoral arteries. In comparison to never-smokers the current smokers had higher values of WHR, triglycerides, C-reactive protein and IMT in carotid bulb and femoral artery. Ex-smokers were in general more obese and had a femoral IMT that was in-between that of never-smokers and current smokers. Conclusions. Tobacco smoking, but not oral moist snuff use, was associated with carotid and femoral artery IMT, and increased levels of CRP. Current smoking was also associated with abdominal obesity. Ex-smokers though, are generally more obese. Smoking was also associated with hyperinsulinaemia, dyslipidaemia and high blood pressure, i.e. the metabolic syndrome. The inhaled smoke from the combustion of tobacco seems to be an important aetiological factor in the atherosclerotic process.

Metoprolol controlled release/extended release in patients with severe heart failure: analysis of the experience in the MERIT-HF study

OBJECTIVES

This study analyzed the effect of the beta(1)-selective beta-blocker metoprolol succinate controlled release/extended release (CR/XL) once daily on mortality, hospitalizations and tolerability in patients with severe heart failure.

BACKGROUND

There continues to be resistance to the incorporation of beta-blockers into clinical care, largely due to concerns about their benefit in patients with more severe heart failure.

METHOD

SA subgroup of patients from Metoprolol CR/XL Randomized Intervention Trial in chronic Heart Failure (MERIT-HF) in New York Heart Association (NYHA) functional class III/IV with left ventricular ejection fraction < 0.25 were identified (n = 795). The analysis was by intention-to-treat.

RESULTS

The mean ejection fraction at baseline was 0.19, and the yearly placebo mortality during follow-up was 19.1%. Treatment with metoprolol CR/XL compared to placebo resulted in significant reductions in all predefined mortality end points including: total mortality, 45 versus 72 deaths (risk reduction 39%; 95% confidence interval 11% to 58%; p = 0.0086); sudden death, 22 vs. 39 deaths (45% [7% to 67%]; p = 0.024); and death due to worsening heart failure, 13 vs. 28 deaths (55% [13% to 77%]; p = 0.015). Metoprolol CR/XL also reduced the number of hospitalizations for worsening heart failure by 45% compared with placebo (p < 0.0001). The NYHA functional class improved in the metoprolol CR/XL group compared with placebo (p = 0.0031). Metoprolol CR/XL was well tolerated, with 31% fewer patients withdrawn from study medicine (all causes) compared with placebo (p = 0.027).

CONCLUSIONS

This subgroup analysis of the MERIT-HF study shows that patients with severe heart failure receive a similar mortality benefit and a similar reduction in hospitalizations for worsening heart failure with metoprolol CR/XL treatment as those patients included in the total study.

The clinical implications of cognitive impairment in elderly patients with chronic heart failure

The purpose of this study was to examine whether cognitive dysfunction was associated with poor participation in an outpatient treatment program for patients with chronic heart failure and if it was related to specific patient characteristics. Cognitive function was measured with the Mini Mental State Examination (MMSE). Twenty-three of 78 (29%) patients randomized to structured care did not participate in this program and nonparticipation during 6-month follow-up was associated with an MMSE score below the median and a low calculated creatinine clearance (CrCl) (R2=0.15, p=0.0025) at entry. In the entire group long duration of heart failure and low blood hemoglobin concentration were independently associated with an MMSE score below the median at entry (R2=0.14, p < 0.0001). Among elderly patients hospitalized with moderate-severe chronic heart failure, judged to be eligible for a nurse-directed outpatient program after discharge, a low MMSE score predicted nonparticipation in such a program. Cognitive dysfunction, which was related to the duration of heart failure, should be evaluated in the treatment of patients with chronic heart failure.

A new method to quantify postexercise ST-deviation--the ST-deficit. A study in men at high and low-risk for coronary heart disease

BACKGROUND

Quantitative heart rate adjusted exercise ST criteria like microV/beats per minute (bpm) improve the diagnostic accuracy of the exercise ECG. However, there are few quantitative HR adjusted postexercise variables available. The aim of the present exercise study was to evaluate a new such variable from computerized averaging of the postexercise ECG.

METHODS

The presence of possible myocardial ischaemia in a population based sample of 74 elderly male hypertensives at high-risk of coronary heart disease, and in 42 age-matched clinically healthy males (reference group) at low-risk was assessed by exercise ECG. All men had a normal resting ECG without signs of ischaemia.

VARIABLES STUDIED

standard ST-criteria, ST/HR slope < or =-2.4 microV. bpm-1, shape of the rate-recovery loop, the latter also with a new quantitative variable, the ST-deficit.

RESULTS

In spite of a normal resting ECG many subjects showed an abnormal ST/HR slope during exercise, 43% in the hypertension group and 26% in the reference group. An abnormal rate-recovery loop (ST-deficit) also contributed substantially to identify patients with possible myocardial ischaemia, 30 vs. 10%, respectively (P<0.02); cumulatively for the two HR adjusted criteria 53% vs. 29%, respectively (P<0.02). Mean ST-deficit was significantly lower in the high-risk group.

CONCLUSIONS

Effort-related myocardial ischaemia is frequently silent in elderly high-risk hypertensives and necessitates testing, preferably with computerized exercise ECG and heart rate adjusted ST criteria. A new quantitative variable to assess the postexercise rate-recovery loop in the time domain, the ST-deficit is described. This variable seems to effectively discriminate between subjects with low and high-risk for coronary heart disease and thus provides new information. Further studies are warranted to validate this variable against myocardial perfusion scintigraphy and coronary angiography.

Challenges of subgroup analyses in multinational clinical trials: experiences from the MERIT-HF trial

BACKGROUND

International placebo-controlled survival trials (Metoprolol Controlled-Release Randomised Intervention Trial in Heart Failure [MERIT-HF], Cardiac Insufficiency Bisoprolol Study [CIBIS-II], and Carvedilol Prospective Randomized Cumulative Survival trial [COPERNICUS]) evaluating the effects of b-blockade in patients with heart failure have all demonstrated highly significant positive effects on total mortality as well as total mortality plus all-cause hospitalization. Also, the analysis of the US Carvedilol Program indicated an effect on these end points. Although none of these trials are large enough to provide definitive results in any particular subgroup, it is natural for physicians to examine the consistency of results across various subgroups or risk groups. Our purpose was to examine both predefined and post hoc subgroups in the MERIT-HF trial to provide guidance as to whether any subgroup is at increased risk, despite an overall strongly positive effect, and to discuss the difficulties and limitations in conducting such subgroup analyses.

METHODS

The study was conducted at 313 clinical sites in 16 randomization regions across 14 countries, with a total of 3991 patients. Total mortality (first primary end point) and total mortality plus all-cause hospitalization (second primary end point) were analyzed on a time to first event. The first secondary end point was total mortality plus hospitalization for heart failure.

RESULTS

Overall, MERIT-HF demonstrated a hazard ratio of 0.66 for total mortality and 0.81 for mortality plus all-cause hospitalization. The hazard ratio of the first secondary end point of mortality plus hospitalization for heart failure was 0.69. The results were remarkably consistent for both primary outcomes and the first secondary outcome across all predefined subgroups as well as for nearly all post hoc subgroups. The results of the post hoc US subgroup showed a mortality hazard ratio of 1.05. However, the US results regarding both the second primary combined outcome of total mortality plus all-cause hospitalization and of the first secondary combined outcome of total mortality plus heart failure hospitalization were in concordance with the overall results of MERIT-HF. Tests of country by treatment interaction (14 countries) revealed a nonsignificant P value of.22 for total mortality. The mortality hazard ratio for US patients in New York Heart Association (NYHA) class III/IV was 0.80, and it was 2.24 for patients in NYHA class II, which is not consistent with causality by biologic gradient. We have not been able to identify any confounding factor in baseline characteristics, baseline treatment, or treatment during follow-up that could account for any treatment by country interaction. Thus we attribute the US subgroup mortality hazard ratio to be due to chance.

CONCLUSIONS

Just as we must be extremely cautious in overinterpreting positive effects in subgroups, even those that are predefined, we must also be cautious in focusing on subgroups with an apparent neutral or negative trend. We should examine subgroups to obtain a general sense of consistency, which is clearly the case in MERIT-HF. We should expect some variation of the treatment effect around the overall estimate as we examine a large number of subgroups because of small sample size in subgroups and chance. Thus the best estimate of the treatment effect on total mortality for any subgroup is the estimate of the hazard ratio for the overall trial.

The metabolic syndrome, smoking, and antibodies to oxidized LDL in 58-year-old clinically healthy men

BACKGROUND AND AIM

The aim was to examine whether the metabolic syndrome (as recently defined), its various components, and smoking were associated with circulating antibodies to oxidized low-density lipoproteins (IgG- and IgM-Ox-LDLAb) and malondialdehyde-treated LDL (IgG- and IgM-MDA-LDLAb) (ELISA) in a population sample of clinically healthy 58-year-old men (n = 391).

METHODS AND RESULTS

LDL peak particle size (gradient gel electrophoresis) and antibody titers were measured in all patients. Trend analysis showed significantly higher IgG-Ox-LDLAb and IgG-MDA-LDLAb titers across the range of men with none of the criteria defining metabolic syndrome (n = 77), those with > or = 1 criterion (n = 252) and those fulfilling the criteria (n = 62), which remained after adjustment for smoking. IgG-Ox-LDLAb was associated with plasma insulin, body mass index (BMI), the waist/hip ratio (WHR) and smoking. IgG-MDA-LDLAb was, in addition, related to diastolic blood pressure, serum triglycerides and a small LDL peak particle size. The IgM antibody titers only inversely correlated with smoking.

CONCLUSIONS

High serum titers of IgG antibodies to oxidized LDL and MDA-treated LDL were associated with the metabolic syndrome and smoking. Several of the factors in the metabolic syndrome were related to the IgG antibody titers to modified LDL. The high degree of intercorrelation among these factors makes it difficult to clarify the independent role of any specific factor.

Independent relationship between microalbuminuria and plasminogen activator inhibitor-1 activity (PAI-1) activity in clinically healthy 58-year-old men

The aim of this cross-sectional study was to investigate the relationship between low-grade albuminuria (microalbuminuria) and factors of the coagulation- and fibrinolysis systems in 104 clinically healthy 58-year-old men recruited from the general population. Urinary albumin excretion was significantly associated with body mass index, systolic and diastolic blood pressure, plasminogen activator inhibitor (PAI)-1 activity, tissue plasminogen activator (tPA) antigen, tPA activity (negatively) and protein S (P<0.05). There were no associations between urinary albumin excretion and antithrombin III, fibrinogen, protein C, thrombin/antithrombin factor or von Willebrand factor. In multiple regression analysis urinary albumin excretion was independently and significantly associated with PAI-1 activity and systolic blood pressure (P<0.05). In conclusion we report that urinary albumin excretion was independently and significantly associated with PAI-1 activity in clinically healthy 58-year-old men. This relationship may contribute to the previously reported increased cardiovascular morbidity in subjects with microalbuminuria.

MERIT-HF mortality and morbidity data

This survival study was designed to address whether beta-1-blockade utilizing metoprolol CR/XL (controlled release/extended release) once daily added to standard therapy reduces mortality and morbidity in patients with decreased ejection fraction and symptoms of heart failure. Enrolled in a double-blind randomized study were 3991 patients with chronic heart failure in NYHA functional class II-IV and ejection fraction < or = 0.40 stabilized on optimal standard therapy. Randomization was preceded by a 2-week single blind placebo run-in period. The study medication was uptitrated during 8 weeks starting with 12.5 mg (NYHA functional class III-IV) or 25 mg once daily (NYHA functional class II). The target dose was 200 mg once daily. The primary endpoints were all-cause mortality and combined all-cause mortality and hospitalization (time to first event) and other objectives were cause-specific data on hospitalization, NYHA functional class and quality of life. Mean follow-up time was 1 year. All-cause mortality was reduced in the metoprolol CR/XL group compared with the placebo group, 145 versus 217 deaths, 7.2% per patient year of follow-up versus 11.0% with a relative risk of 0.66 (95% CI 0.53-0.81, nominal p = 0.00009, p adjusted for interim analysis = 0.0062). This effect was consistent across all predefined subgroups. Sudden deaths were fewer in the metoprolol group (79 versus 132 deaths), RR 0.59 (p = 0.0002). Also deaths from worsening heart failure were fewer in the metoprolol group (30 versus 58 deaths), RR 0.51 (p = 0.0023). The combined endpoint total mortality or all-cause hospitalizations was also reduced by metoprolol (641 versus 767 events), RR 0.81 (p = 0.00012). Total mortality or hospitalizations due to worsening heart failure was also reduced (311 versus 439 events), RR 0.69 (p < 0.00001). The number of hospitalizations due to worsening heart failure (317 versus 451, p < 0.00001) and days in hospital due to worsening heart failure (3401 versus 5303 days, p < 0.00001) were also reduced by metoprolol. There was also an improvement in NYHA functional class, assessed by the physicians as well as the McMaster Overall Treatment Evaluation questionnaire (OTE), assessed by the patients (p = 0.028 and p = 0.089, respectively). Permanent early discontinuation was 13.9% in the metoprolol group and 15.3% in the placebo group (RR = 0.90). In conclusion, in patients with symptomatic heart failure metoprolol CR/XL once daily improved survival by 34%, sudden death by 41%, and deaths from worsening of heart failure by 49%. In addition to improvement of survival there was also a reduced need of hospitalizations for worsening heart failure and an improved NYHA functional class and of quality of life assessed in a substudy. Metoprolol was well tolerated with no difference in early discontinuation rate from placebo treatment.

Relationship between C-reactive protein and intima-media thickness in the carotid and femoral arteries and to antibodies against oxidized low-density lipoprotein in healthy men: the Atherosclerosis and Insulin Resistance (AIR) study

Results from several recent reports have linked high serum C-reactive protein (CRP) levels to atherosclerotic disease and its complications. The aims of the present study were to investigate the relationship between CRP levels and subclinical atherosclerosis, as measured by ultrasound in the carotid and femoral arteries; and also to examine whether CRP levels are associated with antibodies to oxidized low-density lipoprotein (Ox-LDL). The study group (n = 391) consisted of clinically healthy 58-year-old men recruited from the general population. CRP and antibody titres to Ox-LDL were measured by ELISA. The results showed an association between CRP and ultrasound-assessed subclinical atherosclerosis in the femoral artery (r = 0.14, P = 0.010), and also between CRP and systolic blood pressure, diastolic blood pressure, heart rate, triglycerides, high-density lipoprotein, body mass index, waist-to-hip ratio (WHR), blood glucose, cigarette-years and antibody titres to ox-LDL (r = 0.19, P < 0.001). In this clinically healthy population of 58-year-old men, CRP levels were associated with both intima-media thickness and plaque occurrence in the femoral artery. The association between CRP and femoral atherosclerosis was not independent of smoking, serum LDL cholesterol, or systolic blood pressure. CRP levels were independently related to abdominal obesity measured as WHR, smoking and antibody titres to Ox-LDL.

Multiple risk intervention trial in high risk hypertensive men: comparison of ultrasound intima-media thickness and clinical outcome during 6 years of follow-up

OBJECTIVES

The objective was to analyse whether a favourable change in risk factors, caused by a comprehensive risk factor modification programme, affected intima-media thickness (IMT) in the common carotid artery, and whether any such change was associated with a change in cardiovascular events during a 6-year follow-up.

DESIGN

Patients were randomized 1 : 1 to special intervention or usual care.

SETTING

Hypertension Unit at university hospital.

SUBJECTS

A total of 164 patients were randomized. Inclusion criteria were male, aged 50-72 years (at randomization) and one or more of the following: Serum cholesterol level > 6.5 mmol L(-1), smoking or diabetes mellitus. All patients were prescribed antihypertensive treatment since many years. In 142 men good quality ultrasound recording of the common carotid IMT were achieved at baseline, 119 were re-examined after 3.3 years, and 97 patients were available for examination after mean follow-up time of 6.2 years. Cardiovascular events were available for all randomized patients.

INTERVENTIONS

The nonpharmacological special intervention programme was based on one information meeting followed by five weekly 2-h sessions with participation of patients and spouses. The diet recommendations were similar to established guidelines. Overweight patients were instructed to lose weight, and diabetic patients were systematically taught self-monitoring of blood glucose. Smokers were invited to a smoking cessation programme with five weekly meetings. Follow-up visits were thereafter scheduled every 6 months. Lipid lowering drugs were recommended in the intervention group if the treatment goals using nonpharmacological measures were not achieved. Patients in the usual care group were told to quit smoking and to lower their consumption of fat and glucose. Antihypertensive treatment (i.e., selection of drugs) was on purpose kept similar in the two groups.

MAIN OUTCOME MEASURES

The IMT of the common carotid artery as measured by ultrasound. Cardiovascular events during follow-up.

RESULTS

Significant net reductions were seen for serum cholesterol, triglycerides, fasting glucose and smoking. No difference in change in IMT was observed during follow-up between the two randomization groups. The explanation was that patients with positive plaque status at baseline had a much larger increase in IMT over time than patients with negative plaque status, and that patients with positive plaque status more often survived and were available for re-examination after 6 years in the intervention group than in the usual care group. Total mortality was lower in the intervention group, compared with the usual care group, 13 and 29%, respectively (P=0.028).

CONCLUSIONS

In high risk populations, long-term studies with surrogate endpoints may be misleading because of missing data in patients where a large increase in IMT would have been observed, had they been re-examined. Another important conclusion from our study was that the gloomy prognosis for this patient category may be improved by a dedicated risk factor intervention programme. The improved prognosis was observed mainly in those patients at highest risk judged from history of cardiovascular disease or positive ultrasound plaque status at baseline.

Intact insulin, insulin propeptides, and intima-media thickness in the femoral artery in 58-year-old clinical healthy men--the Atherosclerosis and Insulin Resistance Study

The aim of this study was to examine the association between intact insulin, insulin propeptides, and femoral artery intima-media thickness. The design was a cross-sectional study and the study group (n = 391) consisted of randomly recruited clinically healthy 58-year-old Swedish men. The intima-media thickness of the common femoral artery was measured with ultrasound. Fasting plasma insulin; intact insulin; proinsulin; 32,33 split-proinsulin; and C-peptide concentrations were assessed. The results showed that the common femoral artery intima-media thickness correlated significantly and univariately with waist-hip ratio, systolic blood pressure, serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, ApoB, low-density lipoprotein peak particle size, and cigarette years. Furthermore, of intact insulin and insulin propeptides, only intact insulin and C-peptide were univariately associated with common femoral artery intima-media thickness (r= 0.14, p < 0.01; r= 0.18, p < 0.01; respectively). In a multiple regression analysis, common femoral artery intima-media thickness was independently associated with systolic blood pressure (beta-coefficient = 0.004, p = 0.002), ApoB (beta-coefficient = 0.338, p < 0.001 ) and cigarette years (beta-coefficient = 0.0004, p < 0.001), (R2= 25%, p<O0.00). In conclusion, smoking, systolic blood pressure, and ApoB but not insulin or insulin propeptides were independently associated with femoral atherosclerosis.

Sodium/lithium countertransport, insulin resistance, insulin peptides and microalbuminuria in clinically healthy 58-year-old men

The activity of the erythrocyte transport system, sodium/lithium countertransport (SLC), has been linked to the metabolic syndrome characterized by insulin resistance and compensatory hyperinsulinaemia. We measured SLC and insulin sensitivity with the euglycaemic hyperinsulinaemic clamp method in a patient sample (n = 93) randomly selected from a large clinically healthy group of 58-year-old men (n = 818). The lipid profile, blood pressure, body mass index (BMI) and insulin were also analysed. There was a significant difference (P < 0.001) in SLC between subjects with the metabolic syndrome (n = 19) and subjects without any components of this syndrome (n = 20). There was a highly significant correlation between SLC and BMI, waist/hip ratio, total body fat mass, serum triglycerides, plasma insulin, proinsulin split products and C-peptide in a univariate analysis. There was also a significant correlation between SLC and insulin sensitivity measured as insulin-mediated glucose uptake (P < 0.01). In multiple regression analysis, only two of the variables showing univariate significance were independently correlated to SLC, i.e. serum triglycerides (P < 0.001) and BMI (P < 0.01). The subjects with a SLC value in the highest tertile had a 6-fold higher prevalence of insulin resistance (low-insulin-mediated glucose uptake) as compared with those with a SLC value in the lowest tertile. We conclude that, in clinically healthy 58-year-old men from the general population, erythrocyte SLC is closely linked to metabolic syndrome, in particular to obesity, triglycerides and insulin resistance.

Low-density lipoprotein particle size, insulin resistance, and proinsulin in a population sample of 58-year-old men

The relationship between insulin sensitivity and low-density lipoprotein (LDL) peak particle size was examined in 104 clinically healthy 58-year-old men recruited from the general population. Insulin sensitivity was measured by the euglycemic hyperinsulinemic clamp method with adjustment for lean body mass. LDL peak particle size was determined by gradient gel electrophoresis, and insulin, proinsulin, and 32,33 split proinsulin were determined by 2-site immunoradiometric assays. The results showed that 16 subjects (15%) had pattern B, with a predominance of small LDL particles. These cases and a small LDL peak particle size were characterized by the features of the insulin resistance syndrome, ie, general and central obesity, elevated diastolic blood pressure, low serum concentrations of high-density lipoprotein (HDL) and apolipoprotein A1 (apoA1), increases in serum triglycerides and circulating insulin peptides, and low insulin-mediated glucose uptake. The correlation between insulin sensitivity and LDL peak particle size was significant (r = .33, P = .001) and independent of obesity. In a traditional multiple regression analysis, LDL peak particle size was independently associated not with insulin-mediated glucose uptake but with circulating triglycerides and HDL cholesterol, which together explained 67% of the variability in LDL particle size (P = .000). Of all insulin peptides, only proinsulin showed an independent relation to LDL peak particle size, but it disappeared after adjustment for other variables. We conclude that a small LDL particle size was associated with insulin resistance among these clinically healthy men, but this was not independent of serum triglycerides and HDL cholesterol. Serum proinsulin was more directly related to LDL particle size than insulin.

Antibodies to oxidized LDL in relation to intima-media thickness in carotid and femoral arteries in 58-year-old subjectively clinically healthy men

Antibody (Ab) titers to oxidized low density lipoprotein (OxLDL) have been found to be independent predictors of the progression of carotid atherosclerosis. Ab titers against OxLDL may be related to the entire burden of atherosclerosis in the vascular tree or, more specifically, to the disease process in different arterial regions. Therefore, the aim of the present study was to investigate the relationship between IgG and IgM titers to modified LDL and intima-media thickness (IMT) in the carotid and femoral arteries in subjectively clinically healthy 58-year-old men. IMT was measured by ultrasound, and Ab titers to modified LDL were measured by ELISA. The results showed that the common carotid artery IMT was associated with elevated titers of IgG-OxLDL Ab and independently with systolic blood pressure, smoking, and body mass index. The femoral artery IMT showed a negative correlation to IgM-OxLDL Ab and independent associations with smoking, systolic blood pressure, and total cholesterol. To summarize, in 58-year-old subjectively clinically healthy men recruited from the general population, there was a positive association between IgG-OxLDL Ab and IMT in the common carotid artery and a negative association between IgM-OxLDL Ab and IMT in the common femoral artery. However, these associations were not independent of other risk factors.

Insulin resistance and intima-media thickness in the carotid and femoral arteries of clinically healthy 58-year-old men. The Atherosclerosis and Insulin Resistance Study (AIR)

OBJECTIVE

To examine whether insulin resistance was associated with ultrasound-assessed measures of atherosclerosis in men with varying degrees of obesity.

DESIGN

A random selection of subjects from the general population were divided into quintiles of a body mass index/blood glucose score that was shown to be a valid and reproducible index of the degree of insulin sensitivity as assessed by the clamp technique. Every fourth man in quintiles 1 and 5 and every 20th man in quintiles 2-4 (in total, 104 men) were selected for an ultrasound examination of the carotid and femoral arteries and a euglycaemic hyperinsulinaemic clamp examination, adjusted for fat-free mass.

SETTING

A university hospital.

SUBJECTS

A total of 104 clinically healthy 58-year-old men of Swedish ancestry.

RESULTS

The mean common carotid artery intima-media thickness (IMT), but not the common femoral IMT, correlated significantly with glucose infusion rate (GIR) (r = - 0.20, P < 0.05), systolic blood pressure (r = 0.20, P < 0.05), pulse pressure (r = 0.23 P < 0.01), heart rate (r = 0.20, P < 0.05), HDL cholesterol (r = - 0.18, P < 0.05), log triglycerides (r = 0.28, P < 0.01), apoA1 (r = - 0.20, P < 0.05), apoB (r = 0.21, P < 0.05), LDL particle size (r = - 0.22, P < 0.05) and plasma insulin (r = 0.20, P < 0.05). In a multiple regression, common carotid IMT was independently associated with log triglycerides (beta = 0.25, P = 0.012) and pulse pressure (beta = 0.21, P = 0.031) (R2 = 8.7%, P = 0.005)

CONCLUSIONS

Insulin sensitivity, measured with the gold standard euglycaemic hyperinsulinaemic clamp method, showed similar associations with ultrasound-assessed measures of atherosclerosis in the carotid arteries as established cardiovascular risk factors, but only triglycerides and pulse pressure contributed independently to the variability in the common carotid intima-media thickness.

Effect of acute stroke unit care integrated with care continuum versus conventional treatment: A randomized 1-year study of elderly patients: the Göteborg 70+ Stroke Study

BACKGROUND AND PURPOSE

The aim of the study was to compare the effect of conventional treatment with the effect of acute stroke unit care integrated with geriatric stroke unit care continuum.

METHODS

A 1-year study was undertaken with 2:1 randomization to stroke unit care or conventional care, with assessment by an independent team. The study was composed of 249 elderly patients (aged >/=70 years) hospitalized for acute stroke, without previous cerebral lesion and without recognized need of care. Main outcome measures were patients at home after 1 year, ability in daily living activities, health-related quality of life score according to questionnaire, death or institutional care, and death or dependence.

RESULTS

One hundred two patients (61%) in the stroke unit and 49 patients (59%) in the general ward group were alive and at home after 1 year (95% CI -10% to 16%). There were no significant differences in daily life activities or quality of life. In patients with concomitant cardiac disease, there was a reduction in death or institutional care after 3 months in the stroke unit group compared with the group receiving conventional care (28% versus 49%, respectively; 95% CI -40% to -3%). This effect did not remain after 1 year. Patients seeking care after 24 hours often had mild stroke and lived alone.

CONCLUSIONS

There was no effect on the number of patients living at home after 1 year, but after 3 months of stroke unit care, a beneficial effect was found on mortality and the need for institutional care among those with concomitant heart disease. This study involved patients who were considerably older than those investigated in previous randomized studies of acute stroke unit care; thus, these findings will contribute to the specialized register of controlled trials in stroke.

Resource utilization and costs of stroke unit care integrated in a care continuum: A 1-year controlled, prospective, randomized study in elderly patients: the Göteborg 70+ Stroke Study

BACKGROUND AND PURPOSE

The aim of the present study was to examine resource utilization during a 12-month period after acute stroke in elderly patients randomized to care in an acute stroke unit integrated with a care continuum compared with conventional care in general medical wards. A secondary aim was to describe costs related to the severity of stroke.

METHODS

Two hundred forty-nine consecutive patients aged >/=70 years with acute stroke within 7 days before admission, living in their own homes in Göteborg, Sweden, without recognized need of care were randomized to 2 groups: 166 patients were assigned to nonintensive stroke unit care with a care continuum, and 83 patients were assigned to conventional care. There was no difference in mortality or the proportion of patients living at home after 1 year. Main outcomes were costs from inpatient care, outpatient care, and informal care.

RESULTS

Mean annual cost per patient was 170, 000 Swedish crowns (SEK) (equivalent to $25,373) and 191,000 SEK ($28,507) in the stroke unit and the general medical ward groups, respectively (P:=NS). Seventy percent of the total cost was for inpatient care, and 30% was for outpatient and informal care. For patients with mild, moderate, and severe stroke, the mean annual costs per patient were 107,000 SEK ($15,970), 263,000 SEK ($39, 254), and 220,000 SEK ($32,836), respectively (P:<0.001). There was no statistical difference in age or nonstroke diagnosis.

CONCLUSIONS

The total costs the first year did not differ significantly between the treatment groups in this prospective study. The total annual cost per patient showed a very large variation, which was related to stroke severity at onset and not to age or nonstroke diagnoses. Costs other than those for hospital care constituted a substantial fraction of total costs and must be taken into account when organizing the management of stroke patients. The high variability in costs necessitates a larger study to assess long-term cost effectiveness.

Insulin sensitivity and hemostatic factors in clinically healthy 58-year-old men

The objective of this cross-sectional study was to investigate the relationship between factors of the coagulation- and fibrinolysis systems and insulin sensitivity in 104 clinically healthy, 58-years-old men. Insulin sensitivity (hyperinsulinemic euglycemic clamp) adjusted for lean body mass, the metabolic syndrome according to a suggested definition, and different factors in the coagulation- and fibrinolysis system were determined. Subjects with the metabolic syndrome were characterised by increases in PAI-1 activity, tPA antigen, protein C and protein S and low concentrations of tPA activity. Insulin sensitivity was independently and reversibly associated with PAI-1 (p = 0.014) and directly with tPA activity (p = 0.001). Insulin sensitivity was also significantly negatively associated with protein S and protein C and several components in the metabolic syndrome, however not remaining significant in multivariate analyses. Protein C and protein S were significantly associated with PAI-1 activity, tPA activity (negatively), tPA antigen and antithrombin III. In conclusion, the data indicated that insulin resistance and several of the clustering components in the metabolic syndrome are accompanied by increased plasma concentrations of the anticoagulatory proteins C and S which may represent a mechanism which counteracts the concomitantly occurring hypofibrinolysis.

The metabolic syndrome, LDL particle size, and atherosclerosis: the Atherosclerosis and Insulin Resistance (AIR) study

An operative definition of the metabolic syndrome has been suggested by a working group associated with the World Health Organization in 1998. The aim of this study was to examine whether small, low density lipoprotein (LDL) particle size was associated with the metabolic syndrome and with subclinical atherosclerosis as measured by ultrasound in the carotid and femoral arteries. The study was performed in a population-based sample of clinically healthy men (N=391), all 58 years old and not undergoing any treatment with cardiovascular drugs. Exclusion criteria were cardiovascular or other clinically overt diseases or continuous medication with cardiovascular drugs. The results showed that subjects characterized by the metabolic syndrome (n=62) had a thicker mean intima-media complex (IMT) in both the carotid and femoral arteries (0.86 versus 0.77 mm, P:<0.001, and 1.03 versus 1. 00 mm, P:=0.022, respectively) and also lower mean values for LDL particle size (25.78 versus 26.80 nm, respectively, P:<0.001) compared with subjects with no risk factors (n=77). The group with the metabolic syndrome (n=62) also had higher mean values for serum cholesterol and heart rate. In the whole study group (N=391), there were significant but weak negative relationships between small LDL particle size, increasing IMT, and increasing cross-sectional intima-media area of the carotid and femoral arteries and also negative relationships between LDL particle size and plaque occurrence and size in the carotid and femoral arteries. In summary, this is the first large-scale study to demonstrate a relationship between the clustering of risk factors that constitute the metabolic syndrome and a small LDL particle size pattern and the occurrence of preclinical atherosclerosis in the carotid and femoral arteries, as assessed by the ultrasound technique, in healthy 58-year-old men recruited from the general population.

Screening, endpoint classification, and safety monitoring in the Metoprolol CR/XL Randomised Intervention Trial in Congestive Heart Failure (MERIT-HF)

The MERIT-HF study was designed to investigate the effect of once-daily dosing of metoprolol succinate CR/XL added to standard therapy in patients with chronic heart failure. A screening programme, aiming at identifying eligible patients for the study was used by 231 out of 313 sites, resulting in 8912 screened patients. These patients were older, more often women, had marginally higher ejection fraction and were more often in NYHA class IV compared to the finally randomised patients. There was a positive correlation between the number of screened and randomised patients and due to the high inclusion rate the number of randomised patients was increased from 3200 to 3991 patients. The clinical events were defined by a manual and were based on identical classifications made independently by two members of an Independent Endpoint Committee. Data from the case report form and the classifications made by the Endpoint Committee were in accordance for hospitalisation due to worsening heart failure on 722 occasions. On 207 occasions the data from the case report forms and the classification made by the committee differed regarding this clinical event. The Independent Safety Committee monitored safety aspects of the study by using asymmetric group sequential procedures. The study was stopped early on recommendation from the Independent Safety Committee, when the second pre-specified interim analysis (50% of total number of expected deaths) showed that the criterion for stopping due to benefit had been met and exceeded. In conclusion, a screening programme facilitated patient recruitment and showed the characteristics of the background population, the event classification was improved by using an independent endpoint committee, and the safety monitoring allowed an early closure of the study due to mortality benefit, without jeopardising the final analyses of the results.

Chlamydia pneumoniae seropositivity is associated with carotid artery intima-media thickness

BACKGROUND AND PURPOSE

Infection may both augment the atherosclerotic process and contribute to later manifestations of overt clinical disease. Chlamydia pneumoniae elementary bodies have been detected in atherosclerotic lesions. The aim of the present study was to investigate whether elevated titers of antibodies and circulating immune complexes to C pneumoniae were associated with ultrasound findings indicating presence of atherosclerosis in the carotid artery.

METHODS

Serum titers of antibodies to C pneumoniae (IgM, IgA, IgG, and circulating immune complex) were related to intima-media thickness (IMT) and plaque status measured by B-mode ultrasound in the carotid artery in 113 men with treated hypertension and at least 1 of the following risk factors: hypercholesterolemia, smoking, or diabetes.

RESULTS

Any of the titers was elevated in 56 (50%) men, and common carotid artery IMT was thicker in this group compared with the 57 men without any elevated titers (1.00 versus 0.92 mm, P<0.05). There were no accompanying differences in blood pressure, lipid levels, blood glucose, or smoking. Elevation of separate antibody types and circulation immune complex were also associated with increased IMT. In the latter group, systolic blood pressure was higher among seropositive patients compared with those who had no circulating immune complex. Seropositivity was not related to plaque status.

CONCLUSIONS

Seropositivity for C pneumoniae was associated with an increased intima-media thickness in the common carotid artery but not plaque status in hypertensive men at high risk for cardiovascular disease.

Effects of controlled-release metoprolol on total mortality, hospitalizations, and well-being in patients with heart failure: the Metoprolol CR/XL Randomized Intervention Trial in congestive heart failure (MERIT-HF). MERIT-HF Study Group

CONTEXT

Results from recent studies on the effects of beta1-blockade in patients with heart failure demonstrated a 34% reduction in total mortality. However, the effect of beta1-blockade on the frequency of hospitalizations, symptoms, and quality of life in patients with heart failure has not been fully explored.

OBJECTIVE

To examine the effects of the beta1-blocker controlled-release/extended-release metoprolol succinate (metoprolol CR/XL) on mortality, hospitalization, symptoms, and quality of life in patients with heart failure.

DESIGN

Randomized, double-blind controlled trial, preceded by a 2-week single-blind placebo run-in period, conducted from February 14, 1997, to October 31, 1998, with a mean follow-up of 1 year.

SETTING

Three hundred thirteen sites in 14 countries.

PARTICIPANTS

Patients (n = 3991) with chronic heart failure, New York Heart Association (NYHA) functional class II to IV, and ejection fraction of 0.40 or less who were stabilized with optimum standard therapy.

INTERVENTIONS

Patients were randomized to metoprolol CR/XL, 25 mg once per day (NYHA class II), or 12.5 mg once per day (NYHA class III or IV), titrated for 6 to 8 weeks up to a target dosage of 200 mg once per day (n = 1990); or matching placebo (n = 2001).

MAIN OUTCOME MEASURES

Total mortality or any hospitalization (time to first event), number of hospitalizations for worsening heart failure, and change in NYHA class, by intervention group; quality of life was assessed in a substudy of 741 patients.

RESULTS

The incidence of all predefined end points was lower in the metoprolol CR/XL group than in the placebo group, including total mortality or all-cause hospitalizations (the prespecified second primary end point; 641 vs 767 events; risk reduction, 19%; 95% confidence interval [CI], 10%-27%; P<.001); total mortality or hospitalizations due to worsening heart failure (311 vs 439 events; risk reduction, 31%; 95% CI, 20%-40%; P<.001), number of hospitalizations due to worsening heart failure (317 vs 451; P<.001); and number of days in hospital due to worsening heart failure (3401 vs 5303 days; P<.001). NYHA functional class, assessed by physicians, and McMaster Overall Treatment Evaluation score, assessed by patients, both improved in the metoprolol CR/XL group compared with the placebo group (P = .003 and P = .009, respectively).

CONCLUSIONS

In this study of patients with symptomatic heartfailure, metoprolol CR/XL improved survival, reduced the need for hospitalizations due to worsening heart failure, improved NYHA functional class, and had beneficial effects on patient well-being.

The euglycemic hyperinsulinemic clamp examination: variability and reproducibility

The aim was to examine the reproducibility of the euglycemic hyperinsulinemic clamp method. From a random population sample of 60-year-old clinically healthy men, 32 subjects with varying degrees of insulin sensitivity were recruited. Conventional 2-h clamp examinations were carried out at an interval of 2 weeks. Insulin was infused intravenously (priming for 10 min and thereafter 1.0 mU/kg body wt/min). Glucose was infused concomitantly aiming at a whole blood glucose of 5 mmol/L. The glucose infusion rate (GIR) was adjusted for body weight or fat free mass (FFM), the latter measured with dual-energy X-ray absorptiometry. During the final hour of each examination (60-120 min) the mean whole blood glucose concentrations were 5.06+/-0.15 and 5.09+/-0.17 mmol/L, respectively. Of the different time intervals studied, the glucose infusion rate during the final hour (GIR60-120) showed the highest correlation and lowest coefficient of variation (GIR60-120 adjusted by FFM: r=0.70, coefficient of variation=14.7%). Adjustment of GIR for weight instead of FFM underestimated insulin sensitivity in obese men. GIR60-120 adjusted for FFM tended to increase during the second examination. The measurement error was constant across all GIR. In summary, the euglycemic hyperinsulinemic clamp method has a coefficient of variation around 15%. The glucose infusion rate should be adjusted for fat free mass.

Computerized measurement of LDL particle size in human serum. Reproducibility studies and evaluation of LDL particle size in relation to metabolic variables and the occurrence of atherosclerosis

OBJECTIVES

The main aims of the present research project were to develop and evaluate a new software program for evaluation of LDL particle size applied to the gradient gel electrophoresis methodology without the use of previous ultracentrifugation, and to investigate the relationships among LDL particle size, metabolic variables and atherosclerosis, as measured by ultrasound, in subjects with different degrees of insulin resistance.

METHODS

LDL particle size was determined by polyacrylamide gradient gel electrophoresis.

RESULTS

Coefficient of variation for between-assay experiments was 0.3% (r = 0.99) for measurement of LDL peak particle size. LDL peak particle size was negatively correlated to serum triglycerides, apolipoprotein B, fasting insulin, BMI and diastolic blood pressure and positively correlated to HDL. Furthermore, subjects with moderate to large plaques in the carotid artery had smaller LDL particles compared to subjects without plaques.

CONCLUSIONS

This project resulted in a highly reproducible, computerized method for the analysis of LDL particle size. The data suggest that it is possible to assess LDL particle size in serum without the use of previous ultra-centrifugation. LDL particle size was associated with metabolic variables and the occurrence of moderate to large plaques in the carotid artery.

Adding ischaemic hand exercise during occlusion of the brachial artery increases the flow-mediated vasodilation in ultrasound studies of endothelial function

A non-invasive method has been introduced to study endothelial function by evaluating flow-mediated, endothelium-dependent vasodilation of the brachial artery. One weakness of this method is that the post-occlusion vasodilation response is very small in subjects above the age of 60 years, which is a problem when quantifying endothelial dysfunction above this age. We have therefore evaluated whether a higher post-occlusion flow stimulus and a larger vasodilation response can be achieved by adding ischaemic hand exercise during the occlusion of the brachial artery. The subject population was men (n = 12), aged 60 years, free from cardiovascular disease. B-mode ultrasound images for the measurement of lumen diameter of the brachial artery were recorded before and after reactive hyperaemia induced by occlusion of the artery. Blood flow velocity was recorded intermittently using a Doppler technique. Hyperaemia was induced in two different ways: first by occlusion only and then by adding ischaemic hand exercise during the occlusion. The results showed that flow velocity was higher and the duration of flow increase was longer after ischaemic hand exercise compared with occlusion only. Two minutes after cuff pressure release, the increase in blood flow velocity was significantly higher after ischaemic hand work compared with occlusion only (P < 0.01). The corresponding maximal lumen diameters after cuff pressure release were 4.63 +/- 0.35 and 4.45 +/- 0.34 respectively (P < 0.01). The flow-mediated vasodilation increased significantly from 2.24 +/- 2.00% after occlusion only to 7.42 +/- 3.32% after occlusion plus ischaemic hand exercise (P < 0.01). In conclusion, this study showed that a maximal endothelial-dependent vasodilation was not achieved after occlusion only in these 60-year-old men. Adding ischaemic hand exercise may therefore be of value when quantifying endothelial dysfunction in this age group.

Chlamydia pneumoniae but not cytomegalovirus antibodies are associated with future risk of stroke and cardiovascular disease: a prospective study in middle-aged to elderly men with treated hypertension

BACKGROUND AND PURPOSE

Several cross-sectional and prospective studies have indicated that high titers of antibodies to Chlamydia pneumoniae and cytomegalovirus (CMV) are associated with coronary heart disease. The aim of the present study was to examine whether elevated titers of antibodies to these pathogens are predictive of not only coronary but also cerebrovascular disease.

METHODS

Serum titers of antibodies to C pneumoniae (IgM, IgG, IgA, IgG immune complex) and CMV (IgG) were determined at baseline (n=130) and after 3.5 years (n=111) in a total sample of 152 men. All individuals had treated hypertension and at least 1 additional risk factor for cardiovascular disease (hypercholesterolemia, smoking, or diabetes mellitus) and constituted 93% of a randomly selected subgroup (n=164) of patients participating in a multiple risk factor intervention study.

RESULTS

Elevations of any or both of the IgA or IgG titers to C pneumoniae at entry or after 3.5 years were found in 84 cases (55%). Of those with high titers at entry, 97% remained high at the 3.5 year reexamination. After 6.5 years of follow-up, high titers to C pneumoniae at entry were associated with an increased risk for future stroke (relative risk [RR], 8.58; P=0.043; 95% CI, 1.07 to 68.82) and for any cardiovascular event (RR, 2.69; P=0.042; 95% CI, 1.04 to 6.97). A high serum titer of antibodies to CMV was found in 125 cases (85%), and this was not associated with an increased risk of future cardiovascular events.

CONCLUSIONS

Seropositivity for C pneumoniae, but not for CMV, was associated with an increased risk for future cardiovascular disease and, in particular, stroke.

[Study and treatment of heart failure require new approaches. Natriuretic peptides can be safe and simple diagnostic and outcome measures]

Analysis of plasma natriuretic peptides and related propeptide fragments may be a cost-effective aid to diagnostic evaluation and treatment follow-up in cases of heart failure. In diagnostic potential such variables may constitute first-line measures of high negative predictive value, allowing further examination, e.g. by echocardiography, in cases where values are above the respective cut-off levels. However, in many cases evaluation of published reports is rendered difficult by their omission of information on such pre-analytical variables as blood sampling and storage, and drug therapy. Moreover, different analytical methods may yield widely divergent results. Thus, before such assays are introduced in general use, their long-term validity needs to be ensured, for instance by consistency in calibration, and measurements need to be made in representative series of unselected patients for the determination of appropriate cut-off levels.