Lifetime and 10-year risks of cardiovascular mortality in relation to risk factors in middle and old age: 50-year follow-up of the Whitehall study of London Civil Servants

BACKGROUND

Cardiovascular disease (CVD)-related mortality has declined substantially in the United Kingdom (UK) in recent decades, but the continued relevance of conventional risk factors for prediction of CVD mortality throughout the life-course is uncertain. We compared the 10-year risks and lifetime risks of CVD mortality associated with conventional risk factors recorded in middle and old age.

METHODS

The Whitehall study was a prospective study of 19,019 male London civil servants (mean age 52 years) when enrolled in 1967-1970 and followed-up for 50 years for cause-specific mortality. In 1997, 7044 (83%) survivors (mean age 77 years) were re-surveyed. The 10-year and lifetime risks of CVD mortality were estimated by levels of CVD risk factors recorded in middle-age and old-age, respectively.

RESULTS

By July 2020, 97% had died (22%, 51% and 80% before age 70, 80 and 90 years, respectively) and 7944 of 17,673 deaths (45%) were from CVD. The 10-year and lifetime risks of CVD death increased linearly with higher levels of CVD risk factors recorded in middle-age and in old-age. Individuals in the top versus bottom 5% of CVD risk scores in middle age had a 10.3% (95% CI:7.2-13.4) vs 0.6% (0.1-1.2) 10-year risk of CVD mortality, a 61.4% (59.4-65.3) vs 31.3% (24.1-34.5) lifetime risk of CVD mortality and a 12-year difference in life expectancy from age 50 years. The corresponding differences using a CVD risk score in old-age were 11.0% (4.4-17.5) vs 0.8% (0.0-2.2) for 10-year risk and 42.1% (28.2-50.0) vs 30.3% (6.0-38.0) for lifetime risk of CVD mortality and a 6-year difference in life expectancy from age 70 years.

CONCLUSIONS

Conventional risk factors remained highly predictive of CVD mortality and life expectancy through the life-course. The findings highlight the relevance of estimation of both lifetime risks of CVD and 10-year risks of CVD for primary prevention of CVD.

Correlates and consequences of atrial fibrillation in a prospective study of 25 000 participants in the China Kadoorie Biobank

Aims

The prevalence of atrial fibrillation (AF) is positively correlated with prior cardiovascular diseases (CVD) and CVD risk factors but is lower in Chinese than Europeans despite their higher burden of CVD. We examined the prevalence and prognosis of AF and other electrocardiogram (ECG) abnormalities in the China Kadoorie Biobank.

Methods and results

A random sample of 25 239 adults (mean age 59.5 years, 62% women) had a 12-lead ECG recorded and interpreted using a Mortara VERITAS™ algorithm in 2013-14. Participants were followed up for 5 years for incident stroke, ischaemic heart disease, heart failure (HF), and all CVD, overall and by CHA2DS2-VASc scores, age, sex, and area. Overall, 1.2% had AF, 13.6% had left ventricular hypertrophy (LVH), and 28.1% had ischaemia (two-thirds of AF cases also had ischaemia or LVH). The prevalence of AF increased with age, prior CVD, and levels of CHA₂DS₂-VASc scores (0.5%, 1.3%, 2.1%, 2.9%, and 4.4% for scores <2, 2, 3, 4, and ≥5, respectively). Atrial fibrillation was associated with two-fold higher hazard ratios (HR) for CVD (2.15; 95% CI, 1.71-2.69) and stroke (1.88; 1.44-2.47) and a four-fold higher HR for HF (3.79; 2.21-6.49). The 5-year cumulative incidence of CVD was comparable for AF, prior CVD, and CHA₂DS₂-VASc scores ≥ 2 (36.7% vs. 36.2% vs. 37.7%, respectively) but was two-fold greater than for ischaemia (19.4%), LVH (18.0%), or normal ECG (14.1%), respectively.

Conclusion

The findings highlight the importance of screening for AF together with estimation of CHA₂DS₂-VASc scores for prevention of CVD in Chinese adults.

Global heterogeneity in folic acid fortification policies and implications for prevention of neural tube defects and stroke: a systematic review

Background

Folic acid (pteroylmonoglutamic acid) supplements are highly effective for prevention of neural tube defects (NTD) prompting implementation of mandatory or voluntary folic acid fortification for prevention of NTDs. We used plasma folate levels in population studies by country and year to compare effects of folic acid fortification types (mandatory or voluntary folic acid fortification policies) on plasma folate levels, NTD prevalence and stroke mortality rates.

Methods

We conducted systematic reviews of (i) implementation of folic acid fortification in 193 countries that were member states of the World Health Organization by country and year, and (ii) estimated population mean plasma folate levels by year and type of folic acid fortification. We identified relevant English language reports published between Jan 1, 1990 and July 31, 2023 using Google Scholar, Medline, Embase and Global Health. Eligibility criteria were observational or interventional studies with >1000 participants. Studies of pregnant women or children <15 years were excluded. Using an ecological study design, we examined the associations of folic acid fortification types with NTD prevalence (n = 108 studies) and stroke mortality rates (n = 3 countries).

Findings

Among 193 countries examined up to 31 July 2023, 69 implemented mandatory folic acid fortification, 47 had voluntary fortification, but 77 had no fortification (accounting for 32%, 53% and 15% of worldwide population, respectively). Mean plasma folate levels were 36, 21 and 17 nmol/L in populations with mandatory, voluntary and no fortification, respectively (and proportions with mean folate levels >25 nmol/L were 100%, 15% and 7%, respectively). Among 75 countries with NTD prevalence, mean (95% CI) prevalence per 10,000 population were 4.19 (4.11-4.28), 7.61 (7.47-7.75) and 9.66 (9.52-9.81) with mandatory, voluntary and no folic acid fortification, respectively. However, age-standardised trends in stroke mortality rates were unaltered by the introduction of folic acid fortification.

Interpretation

There is substantial heterogeneity in folic acid fortification policies worldwide where folic acid fortification are associated with 50-100% higher population mean plasma folate levels and 25-50% lower NTD prevalence compared with no fortification. Many thousand NTD pregnancies could be prevented yearly if all countries implemented mandatory folic acid fortification. Further trials of folic acid for stroke prevention are required in countries without effective folic acid fortification policies.

Funding

Medical Research Council (UK) and British Heart Foundation.

Calcium Supplements and Risk of CVD: A Meta-Analysis of Randomized Trials

Background

Vitamin D supplements may only be beneficial for the prevention of osteoporotic fractures when administered with calcium and in individuals with low blood levels of 25(OH)D, but possible hazards of calcium supplements on CVD cannot be excluded.

Objectives

We conducted a meta-analysis of all placebo-controlled randomized trials assessing the effects of calcium supplements alone or with vitamin D on CHD, stroke, and all-cause mortality.

Methods

A meta-analysis of 11 trials included 7 comparisons of calcium alone compared with control (n = 8634) and 6 comparisons of calcium plus vitamin D compared with control (n = 46,804). Aggregated study-level data were obtained from individual trials and combined using a fixed-effects meta-analysis. The main outcomes included MI, CHD death, any CHD, stroke, and all-cause mortality.

Results

Among trials of calcium alone (mean daily dose 1 g), calcium was not significantly associated with any excess risk of MI (RR, 1.15; 95% CI: 0.88, 1.51; n = 219 events), CHD death (RR, 1.24; 95% CI: 0.89, 1.73; n = 142), any CHD (RR, 1.01; 95% CI: 0.75, 1.37; n = 177), or stroke (RR, 1.15; 95% CI, 0.90, 1.46, n = 275). Among 6 trials of combined treatment, supplementation with calcium plus vitamin D was not significantly associated with any excess risk of MI (RR, 1.09; 95% CI: 0.95, 1.25; n = 854), CHD death (RR, 1.04; 95% CI: 0.85, 1.27; n = 391), any CHD (RR, 1.05; 95% CI: 0.93, 1.19; n = 1061), or stroke (RR, 1.02; 95% CI: 0.89, 1.17; n = 885). Likewise, calcium alone, or with vitamin D had no significant associations with all-cause mortality.

Conclusions

This meta-analysis demonstrated that calcium supplements were not associated with any significant hazard for CHD, stroke, or all-cause mortality and excluded excess risks above 0.3%-0.5% per year for CHD or stroke. Further trials of calcium and vitamin D are required in individuals with low blood levels of 25(OH)D for the prevention of fracture and other disease outcomes.

Random plasma glucose levels and cause-specific mortality among Chinese adults without known diabetes: an 11-year prospective study of 450,000 people

INTRODUCTION

We examined the associations between long-term usual random plasma glucose (RPG) levels and cause-specific mortality risks among adults without known diabetes in China.

RESEARCH DESIGN AND METHODS

The China Kadoorie Biobank recruited 512,891 adults (59% women) aged 30-79 from 10 regions of China during 2004-2008. At baseline survey, and subsequent resurveys of a random subset of survivors, participants were interviewed and measurements collected, including on-site RPG testing. Cause of death was ascertained via linkage to local mortality registries. Cox regression yielded adjusted HR for all-cause and cause-specific mortality associated with usual levels of RPG.

RESULTS

During median 11 years' follow-up, 37,214 deaths occurred among 452,993 participants without prior diagnosed diabetes or other chronic diseases. There were positive log-linear relationships between RPG and all-cause, cardiovascular disease (CVD) (n=14,209) and chronic kidney disease (CKD) (n=432) mortality down to usual RPG levels of at least 5.1 mmol/L. At RPG <11.1 mmol/L, each 1.0 mmol/L higher usual RPG was associated with adjusted HRs of 1.14 (95% CI 1.12 to 1.16), 1.16 (1.12 to 1.19) and 1.44 (1.22 to 1.70) for all-cause, CVD and CKD mortality, respectively. Usual RPG was positively associated with chronic liver disease (n=547; 1.45 (1.26 to 1.66)) and cancer (n=12,680; 1.12 (1.09 to 1.16)) mortality, but with comparably lower risks at baseline RPG ≥11.1 mmol/L. These associations persisted after excluding participants who developed diabetes during follow-up.

CONCLUSIONS

Among Chinese adults without diabetes, higher RPG levels were associated with higher mortality risks from several major diseases, with no evidence of apparent thresholds below the cut-points for diabetes diagnosis.

Blood pressure and cardiovascular diseases in Chinese adults with type 2 diabetes: A prospective cohort study

BACKGROUND

Controversy persists about the relationship of blood pressure with cardiovascular diseases (CVD) in diabetes and associated disease burden. We assessed these associations among Chinese adults with type 2 diabetes (T2D).

METHODS

In 2004-08, the China Kadoorie Biobank recruited >512,000 adults aged 30-79 years from 10 localities across China, including 26,315 with T2D (based on self-report or plasma glucose measurement) but no prior CVD, followed-up for ~9 years. Cox regression yielded adjusted HR for major CVD and all-cause mortality associated with 10 mmHg higher usual (longer-term average) SBP. Attributable fractions were estimated to assess cardiovascular mortality burden due to uncontrolled hypertension (SBP ≥130 mmHg or DBP ≥80 mmHg).

FINDINGS

Overall, 75.7% of participants had self-reported (24.8%) or screen-detected (50.9%) (SBP ≥130 mmHg or DBP ≥80 mmHg) hypertension. Among individuals with self-reported hypertension, 82.3% were treated, of whom 9.3% achieved control. There were positive log-linear associations of blood pressure with CVD, with no evidence of a threshold down to ~120 mmHg for usual SBP. Each 10 mmHg higher usual SBP was associated with HR of 1.28 (95% CI 1.25-1.30), 1.18 (1.15-1.21), 1.17 (1.15-1.19) and 1.45 (1.38-1.52) for cardiovascular death (n=1807), major coronary event (n=1190), ischaemic stroke (n=4362) and intracerebral haemorrhage (n=469), respectively. There was an apparent J-shaped association with all-cause mortality (n=4503). In this diabetes population, uncontrolled hypertension accounted for 39% of cardiovascular deaths.

INTERPRETATION

Uncontrolled hypertension is common in Chinese adults with T2D, resulting in substantial excess risks of CVD. Improved hypertension management could avoid a large number of cardiovascular-related deaths.

FUNDING

Kadoorie Foundation, Wellcome Trust, MRC, BHF, CR-UK, MoST, NNSF.

P2494Cardiovascular disease burden attributed to high blood pressure in Chinese adults with type 2 diabetes

Background

Cardiovascular diseases (CVD) are the most common cause of death among people with diabetes, reflecting in part co-existence with other CVD risk factors, including high blood pressure. However, controversy persists about the nature of the relationship of blood pressure with risk of CVD in individuals with diabetes, and about the associated disease burden.

Methods

We analysed data from 26,315 men and women aged 30–79 years with type 2 diabetes but no prior history of CVD, who were recruited into the China Kadoorie Biobank in 2004–2008 from 10 diverse areas in China. During ∼10 years' follow-up 1,190 major coronary events (MCE), 4,362 ischaemic stroke (IS), 469 intra-cerebral haemorrhage (ICH) events and 4,503 deaths (including 1,807 CVD deaths) were recorded. Usual systolic (SBP) and diastolic (DBP) blood pressure and uncontrolled hypertension were related to risks of incident CVD and all-cause mortality, after adjustment for relevant confounders.

Results

Overall, 75.7% of participants had prior doctor-diagnosed (24.8%) or screen-detected (67.7%) hypertension, compared with 54.3% among those without diabetes. The age-adjusted prevalence of hypertension was higher among men and in rural areas. Among those with previously diagnosed hypertension, 39.3% reported use of anti-hypertensive medications (on average, 1 agent) and 8.5% had controlled hypertension (<130/80 mmHg). Usual SBP was continuously and positively associated with the risk of CVD, with no evidence of a threshold throughout the range examined (120–180 mmHg). Each 10 mmHg higher SBP was associated with a 27% higher risk for CVD death (HR 1.27, 95% CI 1.25–1.30). Strong positive associations were also seen for MCE (1.16, 1.12–1.21), IS (1.15, 1.13–1.18), and ICH (1.46, 1.34–1.60). Overall, uncontrolled hypertension accounts for an estimated 39% (32–45%), 30% (21–38%), 24% (20–28%) and 48% (34–58%) of CVD deaths, MCE, IS and ICH, respectively, among Chinese adults with diabetes.

Conclusion

Hypertension is common but frequently undetected and uncontrolled among adults with type 2 diabetes in China. Effective diagnosis and management of hypertension among individuals with diabetes would be expected to achieve substantial reductions in CVD morbidity and mortality.

Acknowledgement/Funding

Wellcome Trust, MRC, BHF, CR-UK, Kadoorie Foundation, MoST, NSFC

Associations of Omega-3 Fatty Acid Supplement Use With Cardiovascular Disease Risks: Meta-analysis of 10 Trials Involving 77 917 Individuals

Question

Does supplementation with marine-derived omega-3 fatty acids have any associations with reductions in fatal or nonfatal coronary heart disease in people at high risk of cardiovascular disease?

Findings

This meta-analysis of 10 trials involving 77 917 participants demonstrated that supplementation with marine-derived omega-3 fatty acids for a mean of 4.4 years had no significant association with reductions in fatal or nonfatal coronary heart disease or any major vascular events.

Meaning

The results provide no support for current recommendations to use omega-3 fatty acid supplements for the prevention of fatal coronary heart disease or any cardiovascular disease in people who have or at high risk of developing cardiovascular disease.

Importance

Current guidelines advocate the use of marine-derived omega-3 fatty acids supplements for the prevention of coronary heart disease and major vascular events in people with prior coronary heart disease, but large trials of omega-3 fatty acids have produced conflicting results.

Objective

To conduct a meta-analysis of all large trials assessing the associations of omega-3 fatty acid supplements with the risk of fatal and nonfatal coronary heart disease and major vascular events in the full study population and prespecified subgroups.

Data Sources and Study Selection

This meta-analysis included randomized trials that involved at least 500 participants and a treatment duration of at least 1 year and that assessed associations of omega-3 fatty acids with the risk of vascular events.

Data Extraction and Synthesis

Aggregated study-level data were obtained from 10 large randomized clinical trials. Rate ratios for each trial were synthesized using observed minus expected statistics and variances. Summary rate ratios were estimated by a fixed-effects meta-analysis using 95% confidence intervals for major diseases and 99% confidence intervals for all subgroups.

Main Outcomes and Measures

The main outcomes included fatal coronary heart disease, nonfatal myocardial infarction, stroke, major vascular events, and all-cause mortality, as well as major vascular events in study population subgroups.

Results

Of the 77 917 high-risk individuals participating in the 10 trials, 47 803 (61.4%) were men, and the mean age at entry was 64.0 years; the trials lasted a mean of 4.4 years. The associations of treatment with outcomes were assessed on 6273 coronary heart disease events (2695 coronary heart disease deaths and 2276 nonfatal myocardial infarctions) and 12 001 major vascular events. Randomization to omega-3 fatty acid supplementation (eicosapentaenoic acid dose range, 226-1800 mg/d) had no significant associations with coronary heart disease death (rate ratio [RR], 0.93; 99% CI, 0.83-1.03; P = .05), nonfatal myocardial infarction (RR, 0.97; 99% CI, 0.87-1.08; P = .43) or any coronary heart disease events (RR, 0.96; 95% CI, 0.90-1.01; P = .12). Neither did randomization to omega-3 fatty acid supplementation have any significant associations with major vascular events (RR, 0.97; 95% CI, 0.93-1.01; P = .10), overall or in any subgroups, including subgroups composed of persons with prior coronary heart disease, diabetes, lipid levels greater than a given cutoff level, or statin use.

Conclusions and Relevance

This meta-analysis demonstrated that omega-3 fatty acids had no significant association with fatal or nonfatal coronary heart disease or any major vascular events. It provides no support for current recommendations for the use of such supplements in people with a history of coronary heart disease.

Sex-specific relevance of diabetes to occlusive vascular and other mortality: a collaborative meta-analysis of individual data from 980 793 adults from 68 prospective studies

BACKGROUND

Several studies have shown that diabetes confers a higher relative risk of vascular mortality among women than among men, but whether this increased relative risk in women exists across age groups and within defined levels of other risk factors is uncertain. We aimed to determine whether differences in established risk factors, such as blood pressure, BMI, smoking, and cholesterol, explain the higher relative risks of vascular mortality among women than among men.

METHODS

In our meta-analysis, we obtained individual participant-level data from studies included in the Prospective Studies Collaboration and the Asia Pacific Cohort Studies Collaboration that had obtained baseline information on age, sex, diabetes, total cholesterol, blood pressure, tobacco use, height, and weight. Data on causes of death were obtained from medical death certificates. We used Cox regression models to assess the relevance of diabetes (any type) to occlusive vascular mortality (ischaemic heart disease, ischaemic stroke, or other atherosclerotic deaths) by age, sex, and other major vascular risk factors, and to assess whether the associations of blood pressure, total cholesterol, and body-mass index (BMI) to occlusive vascular mortality are modified by diabetes.

RESULTS

Individual participant-level data were analysed from 980 793 adults. During 9·8 million person-years of follow-up, among participants aged between 35 and 89 years, 19 686 (25·6%) of 76 965 deaths were attributed to occlusive vascular disease. After controlling for major vascular risk factors, diabetes roughly doubled occlusive vascular mortality risk among men (death rate ratio [RR] 2·10, 95% CI 1·97-2·24) and tripled risk among women (3·00, 2·71-3·33; χ2 test for heterogeneity p<0·0001). For both sexes combined, the occlusive vascular death RRs were higher in younger individuals (aged 35-59 years: 2·60, 2·30-2·94) than in older individuals (aged 70-89 years: 2·01, 1·85-2·19; p=0·0001 for trend across age groups), and, across age groups, the death RRs were higher among women than among men. Therefore, women aged 35-59 years had the highest death RR across all age and sex groups (5·55, 4·15-7·44). However, since underlying confounder-adjusted occlusive vascular mortality rates at any age were higher in men than in women, the adjusted absolute excess occlusive vascular mortality associated with diabetes was similar for men and women. At ages 35-59 years, the excess absolute risk was 0·05% (95% CI 0·03-0·07) per year in women compared with 0·08% (0·05-0·10) per year in men; the corresponding excess at ages 70-89 years was 1·08% (0·84-1·32) per year in women and 0·91% (0·77-1·05) per year in men. Total cholesterol, blood pressure, and BMI each showed continuous log-linear associations with occlusive vascular mortality that were similar among individuals with and without diabetes across both sexes.

INTERPRETATION

Independent of other major vascular risk factors, diabetes substantially increased vascular risk in both men and women. Lifestyle changes to reduce smoking and obesity and use of cost-effective drugs that target major vascular risks (eg, statins and antihypertensive drugs) are important in both men and women with diabetes, but might not reduce the relative excess risk of occlusive vascular disease in women with diabetes, which remains unexplained.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union BIOMED programme, and National Institute on Aging (US National Institutes of Health).

Adiposity and Blood Pressure in 110 000 Mexican Adults

Previous studies have reached differing conclusions about the importance of general versus central markers of adiposity to blood pressure, leading to suggestions that population-specific adiposity thresholds may be needed. We examined the relevance of adiposity to blood pressure among 111 911 men and women who, when recruited into the Mexico City Prospective Study, were aged 35 to 89 years, had no chronic disease, and were not taking antihypertensives. Linear regression was used to estimate the effects on systolic and diastolic blood pressure of 2 markers of general adiposity (body mass index and height-adjusted weight) and 4 markers of central adiposity (waist circumference, hip circumference, waist:hip ratio, and waist:height ratio), adjusted for relevant confounders. Mean (SD) adiposity levels were: body mass index (28.7±4.5 kg/m²), height-adjusted weight (70.2±11.2 kg), waist circumference (93.3±10.6 cm), hip circumference (104.0±9.0 cm), waist:hip ratio (0.90±0.06), and waist:height ratio (0.60±0.07). Associations with blood pressure were linear with no threshold levels below which lower general or central adiposity was not associated with lower blood pressure. On average, each 1 SD higher measured adiposity marker was associated with a 3 mm Hg higher systolic blood pressure and 2 mm Hg higher diastolic blood pressure (SEs <0.1 mm Hg), but for the waist:hip ratio, associations were only approximately half as strong. General adiposity associations were independent of central adiposity, but central adiposity associations were substantially reduced by adjustment for general adiposity. Findings were similar for men and women. In Mexican adults, often overweight or obese, markers of general adiposity were stronger independent predictors of blood pressure than measured markers of central adiposity, with no threshold effects.

Body-mass index and all-cause mortality: individual-participant-data meta-analysis of 239 prospective studies in four continents

BACKGROUND

Overweight and obesity are increasing worldwide. To help assess their relevance to mortality in different populations we conducted individual-participant data meta-analyses of prospective studies of body-mass index (BMI), limiting confounding and reverse causality by restricting analyses to never-smokers and excluding pre-existing disease and the first 5 years of follow-up.

METHODS

Of 10 625 411 participants in Asia, Australia and New Zealand, Europe, and North America from 239 prospective studies (median follow-up 13·7 years, IQR 11·4-14·7), 3 951 455 people in 189 studies were never-smokers without chronic diseases at recruitment who survived 5 years, of whom 385 879 died. The primary analyses are of these deaths, and study, age, and sex adjusted hazard ratios (HRs), relative to BMI 22·5-<25·0 kg/m(2).

FINDINGS

All-cause mortality was minimal at 20·0-25·0 kg/m(2) (HR 1·00, 95% CI 0·98-1·02 for BMI 20·0-<22·5 kg/m(2); 1·00, 0·99-1·01 for BMI 22·5-<25·0 kg/m(2)), and increased significantly both just below this range (1·13, 1·09-1·17 for BMI 18·5-<20·0 kg/m(2); 1·51, 1·43-1·59 for BMI 15·0-<18·5) and throughout the overweight range (1·07, 1·07-1·08 for BMI 25·0-<27·5 kg/m(2); 1·20, 1·18-1·22 for BMI 27·5-<30·0 kg/m(2)). The HR for obesity grade 1 (BMI 30·0-<35·0 kg/m(2)) was 1·45, 95% CI 1·41-1·48; the HR for obesity grade 2 (35·0-<40·0 kg/m(2)) was 1·94, 1·87-2·01; and the HR for obesity grade 3 (40·0-<60·0 kg/m(2)) was 2·76, 2·60-2·92. For BMI over 25·0 kg/m(2), mortality increased approximately log-linearly with BMI; the HR per 5 kg/m(2) units higher BMI was 1·39 (1·34-1·43) in Europe, 1·29 (1·26-1·32) in North America, 1·39 (1·34-1·44) in east Asia, and 1·31 (1·27-1·35) in Australia and New Zealand. This HR per 5 kg/m(2) units higher BMI (for BMI over 25 kg/m(2)) was greater in younger than older people (1·52, 95% CI 1·47-1·56, for BMI measured at 35-49 years vs 1·21, 1·17-1·25, for BMI measured at 70-89 years; pheterogeneity<0·0001), greater in men than women (1·51, 1·46-1·56, vs 1·30, 1·26-1·33; pheterogeneity<0·0001), but similar in studies with self-reported and measured BMI.

INTERPRETATION

The associations of both overweight and obesity with higher all-cause mortality were broadly consistent in four continents. This finding supports strategies to combat the entire spectrum of excess adiposity in many populations.

FUNDING

UK Medical Research Council, British Heart Foundation, National Institute for Health Research, US National Institutes of Health.

Effects of homocysteine lowering with B vitamins on cognitive aging: meta-analysis of 11 trials with cognitive data on 22,000 individuals

BACKGROUND

Elevated plasma homocysteine is a risk factor for Alzheimer disease, but the relevance of homocysteine lowering to slow the rate of cognitive aging is uncertain.

OBJECTIVE

The aim was to assess the effects of treatment with B vitamins compared with placebo, when administered for several years, on composite domains of cognitive function, global cognitive function, and cognitive aging.

DESIGN

A meta-analysis was conducted by using data combined from 11 large trials in 22,000 participants. Domain-based z scores (for memory, speed, and executive function and a domain-composite score for global cognitive function) were available before and after treatment (mean duration: 2.3 y) in the 4 cognitive-domain trials (1340 individuals); Mini-Mental State Examination (MMSE)-type tests were available at the end of treatment (mean duration: 5 y) in the 7 global cognition trials (20,431 individuals).

RESULTS

The domain-composite and MMSE-type global cognitive function z scores both decreased with age (mean ± SE: -0.054 ± 0.004 and -0.036 ± 0.001/y, respectively). Allocation to B vitamins lowered homocysteine concentrations by 28% in the cognitive-domain trials but had no significant effects on the z score differences from baseline for individual domains or for global cognitive function (z score difference: 0.00; 95% CI: -0.05, 0.06). Likewise, allocation to B vitamins lowered homocysteine by 26% in the global cognition trials but also had no significant effect on end-treatment MMSE-type global cognitive function (z score difference: -0.01; 95% CI: -0.03, 0.02). Overall, the effect of a 25% reduction in homocysteine equated to 0.02 y (95% CI: -0.10, 0.13 y) of cognitive aging per year and excluded reductions of >1 mo per year of treatment.

CONCLUSION

Homocysteine lowering by using B vitamins had no significant effect on individual cognitive domains or global cognitive function or on cognitive aging.

Dicing with chance, life and death in systematic reviews and meta-analyses: D.I.C.E. 3, a simulation study

OBJECTIVES

To show the effects of chance on meta-analyses, and the potential dangers of being prompted to do a meta-analysis by one favourable trial.

DESIGN

In total, 100,000 trials were simulated and combined into 10,000 meta-analyses, using data from the control group of a cancer trial. Each participant record was randomly coded to simulate allocation to 'treatment' or 'control'.

SETTING

Simulated study.

PARTICIPANTS

De-identified records for 578 patients from the control group of a cancer trial, of whom 147 had died.

MAIN OUTCOME MEASURE

Time to death from any cause.

RESULTS

Of the 100,000 trials, 4897 (4.9%) were statistically significant at 2p < 0.05 and 123 (1.2%) of the 10,000 meta-analyses were significant at 2p < 0.01. The most extreme result was a 20% reduction (99% CI: 0.70-0.91; 2p = 0.00002) in the annual odds of dying in the 'treatment' group. If a meta-analysis contained at least one trial with a statistically significant result (at 2p < 0.05), the likelihood of the meta-analysis being significant (at 2p < 0.01) increased strikingly. For example, among the 473 meta-analyses in which the first trial in a batch of 10 was statistically significant (at 2p < 0.05), 18 (3.8%) favoured treatment at 2p < 0.01.

CONCLUSIONS

Chance can influence the results of meta-analyses regardless of how well they are conducted. Researchers should not ignore this when they plan a meta-analysis and when they report their results. People reading their reports should also be wary. Caution is particularly important when the results of one or more included studies influenced the decision to do the meta-analysis.

Effects of folic acid supplementation on overall and site-specific cancer incidence during the randomised trials: meta-analyses of data on 50,000 individuals

BACKGROUND

Some countries fortify flour with folic acid to prevent neural tube defects but others do not, partly because of concerns about possible cancer risks. We aimed to assess any effects on site-specific cancer rates in the randomised trials of folic acid supplementation, at doses higher than those from fortification.

METHODS

In these meta-analyses, we sought all trials completed before 2011 that compared folic acid versus placebo, had scheduled treatment duration at least 1 year, included at least 500 participants, and recorded data on cancer incidence. We obtained individual participant datasets that included 49,621 participants in all 13 such trials (ten trials of folic acid for prevention of cardiovascular disease [n=46,969] and three trials in patients with colorectal adenoma [n=2652]). All these trials were evenly randomised. The main outcome was incident cancer (ignoring non-melanoma skin cancer) during the scheduled treatment period (among participants who were still free of cancer). We compared those allocated folic acid with those allocated placebo, and used log-rank analyses to calculate the cancer incidence rate ratio (RR).

FINDINGS

During a weighted average scheduled treatment duration of 5·2 years, allocation to folic acid quadrupled plasma concentrations of folic acid (57·3 nmol/L for the folic acid groups vs 13·5 nmol/L for the placebo groups), but had no significant effect on overall cancer incidence (1904 cancers in the folic acid groups vs 1809 cancers in the placebo groups, RR 1·06, 95% CI 0·99–1·13, p=0·10). There was no trend towards greater effect with longer treatment. There was no significant heterogeneity between the results of the 13 individual trials (p=0·23), or between the two overall results in the cadiovascular prevention trials and the adenoma trials (p=0·13). Moreover, there was no significant effect of folic acid supplementation on the incidence of cancer of the large intestine, prostate, lung, breast, or any other specific site.

INTERPRETATION

Folic acid supplementation does not substantially increase or decrease incidence of site-specific cancer during the first 5 years of treatment. Fortification of flour and other cereal products involves doses of folic acid that are, on average, an order of magnitude smaller than the doses used in these trials.

FUNDING

British Heart Foundation, Medical Research Council, Cancer Research UK, Food Standards Agency.

Homocysteine and vascular disease: review of published results of the homocysteine-lowering trials

Moderately elevated homocysteine levels have been associated with a higher risk of cardiovascular disease in observational studies, but whether these associations are causal is uncertain. Randomized trials of dietary supplementation with B vitamins were set up to assess whether lowering homocysteine levels could reduce the risk of vascular disease. This review is based on a meta-analysis of published results of eight homocysteine-lowering trials for preventing vascular disease. The eight trials comprised a total of 37,485 individuals and provided comparisons of the effects of B vitamins on 5,074 coronary heart disease (CHD) events, 1,483 stroke events, 2,692 incident cancer events, and 5,128 deaths. Our meta-analysis assessed the effects of lowering homocysteine levels by about 25% for about 5 years. Allocation to B vitamins had no beneficial effects on any cardiovascular events, with hazard ratios (95% confidence intervals) of 1.01 (0.96-1.07) for CHD and 0.96 (0.87-1.07) for stroke. Moreover, allocation to B vitamins had no significant adverse effects on cancer [1.08 (0.99-1.17)], or for death from any cause [1.02 (0.97-1.07)]. Thus, supplementation with B vitamins had no statistically significant effects on the risks of cardiovascular events, total mortality rates, or cancer. A meta-analysis based on individual participant data from all available trials will assess the effects of lowering homocysteine levels on a broader range of outcomes, overall and in all relevant subgroups. However, available evidence does not support the routine use of B vitamins to prevent cardiovascular disease.

Effects of lowering homocysteine levels with B vitamins on cardiovascular disease, cancer, and cause-specific mortality: Meta-analysis of 8 randomized trials involving 37 485 individuals

Elevated plasma homocysteine levels have been associated with higher risks of cardiovascular disease, but the effects on disease rates of supplementation with folic acid to lower plasma homocysteine levels are uncertain. Individual participant data were obtained for a meta-analysis of 8 large, randomized, placebo-controlled trials of folic acid supplementation involving 37 485 individuals at increased risk of cardiovascular disease. The analyses involved intention-to-treat comparisons of first events during the scheduled treatment period. There were 9326 major vascular events (3990 major coronary events, 1528 strokes, and 5068 revascularizations), 3010 cancers, and 5125 deaths. Folic acid allocation yielded an average 25% reduction in homocysteine levels. During a median follow-up of 5 years, folic acid allocation had no significant effects on vascular outcomes, with rate ratios (95% confidence intervals) of 1.01 (0.97-1.05) for major vascular events, 1.03 (0.97-1.10) for major coronary events, and 0.96 (0.87-1.06) for stroke. Likewise, there were no significant effects on vascular outcomes in any of the subgroups studied or on overall vascular mortality. There was no significant effect on the rate ratios (95% confidence intervals) for overall cancer incidence (1.05 [0.98-1.13]), cancer mortality (1.00 [0.85-1.18]) or all-cause mortality (1.02 [0.97-1.08]) during the whole scheduled treatment period or during the later years of it. Dietary supplementation with folic acid to lower homocysteine levels had no significant effects within 5 years on cardiovascular events or on overall cancer or mortality in the populations studied.

National pholcodine consumption and prevalence of IgE-sensitization: a multicentre study

BACKGROUND

The aim of this study was to test, on a multinational level, the pholcodine (PHO) hypothesis, i.e. that the consumption of PHO-containing cough mixtures could cause higher prevalence of IgE antibodies to PHO, morphine (MOR) and suxamethonium (SUX). As a consequence the risk of anaphylaxis to neuromuscular blocking agents (NMBA) will be increased.

METHODS

National PHO consumptions were derived from the United Nations International Narcotics Control Board (INCB) database. IgE and IgE antibodies to PHO, MOR, SUX and P-aminophenyl-phosphoryl choline (PAPPC) were measured in sera from atopic individuals, defined by a positive Phadiatop test (>0.35 kU(A)/l), collected in nine countries representing high and low PHO-consuming nations.

RESULTS

There was a significant positive association between PHO consumption and prevalences of IgE-sensitization to PHO and MOR, but not to SUX and PAPPC, as calculated both by exposure group comparisons and linear regression analysis. The Netherlands and the USA, did not have PHO-containing drugs on the markets, although the former had a considerable PHO consumption. Both countries had high figures of IgE-sensitization.

CONCLUSION

This international prevalence study lends additional support to the PHO hypothesis and, consequently, that continued use of drugs containing this substance should be seriously questioned. The results also indicate that other, yet unknown, substances may lead to IgE-sensitization towards NMBAs.

Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies

BACKGROUND

The main associations of body-mass index (BMI) with overall and cause-specific mortality can best be assessed by long-term prospective follow-up of large numbers of people. The Prospective Studies Collaboration aimed to investigate these associations by sharing data from many studies.

METHODS

Collaborative analyses were undertaken of baseline BMI versus mortality in 57 prospective studies with 894 576 participants, mostly in western Europe and North America (61% [n=541 452] male, mean recruitment age 46 [SD 11] years, median recruitment year 1979 [IQR 1975-85], mean BMI 25 [SD 4] kg/m(2)). The analyses were adjusted for age, sex, smoking status, and study. To limit reverse causality, the first 5 years of follow-up were excluded, leaving 66 552 deaths of known cause during a mean of 8 (SD 6) further years of follow-up (mean age at death 67 [SD 10] years): 30 416 vascular; 2070 diabetic, renal or hepatic; 22 592 neoplastic; 3770 respiratory; 7704 other.

FINDINGS

In both sexes, mortality was lowest at about 22.5-25 kg/m(2). Above this range, positive associations were recorded for several specific causes and inverse associations for none, the absolute excess risks for higher BMI and smoking were roughly additive, and each 5 kg/m(2) higher BMI was on average associated with about 30% higher overall mortality (hazard ratio per 5 kg/m(2) [HR] 1.29 [95% CI 1.27-1.32]): 40% for vascular mortality (HR 1.41 [1.37-1.45]); 60-120% for diabetic, renal, and hepatic mortality (HRs 2.16 [1.89-2.46], 1.59 [1.27-1.99], and 1.82 [1.59-2.09], respectively); 10% for neoplastic mortality (HR 1.10 [1.06-1.15]); and 20% for respiratory and for all other mortality (HRs 1.20 [1.07-1.34] and 1.20 [1.16-1.25], respectively). Below the range 22.5-25 kg/m(2), BMI was associated inversely with overall mortality, mainly because of strong inverse associations with respiratory disease and lung cancer. These inverse associations were much stronger for smokers than for non-smokers, despite cigarette consumption per smoker varying little with BMI.

INTERPRETATION

Although other anthropometric measures (eg, waist circumference, waist-to-hip ratio) could well add extra information to BMI, and BMI to them, BMI is in itself a strong predictor of overall mortality both above and below the apparent optimum of about 22.5-25 kg/m(2). The progressive excess mortality above this range is due mainly to vascular disease and is probably largely causal. At 30-35 kg/m(2), median survival is reduced by 2-4 years; at 40-45 kg/m(2), it is reduced by 8-10 years (which is comparable with the effects of smoking). The definite excess mortality below 22.5 kg/m(2) is due mainly to smoking-related diseases, and is not fully explained.

Blood cholesterol and vascular mortality by age, sex, and blood pressure: a meta-analysis of individual data from 61 prospective studies with 55,000 vascular deaths

BACKGROUND

Age, sex, and blood pressure could modify the associations of total cholesterol (and its main two fractions, HDL and LDL cholesterol) with vascular mortality. This meta-analysis combined prospective studies of vascular mortality that recorded both blood pressure and total cholesterol at baseline, to determine the joint relevance of these two risk factors.

METHODS

Information was obtained from 61 prospective observational studies, mostly in western Europe or North America, consisting of almost 900,000 adults without previous disease and with baseline measurements of total cholesterol and blood pressure. During nearly 12 million person years at risk between the ages of 40 and 89 years, there were more than 55,000 vascular deaths (34,000 ischaemic heart disease [IHD], 12,000 stroke, 10,000 other). Information about HDL cholesterol was available for 150,000 participants, among whom there were 5000 vascular deaths (3000 IHD, 1000 stroke, 1000 other). Reported associations are with usual cholesterol levels (ie, corrected for the regression dilution bias).

FINDINGS

1 mmol/L lower total cholesterol was associated with about a half (hazard ratio 0.44 [95% CI 0.42-0.48]), a third (0.66 [0.65-0.68]), and a sixth (0.83 [0.81-0.85]) lower IHD mortality in both sexes at ages 40-49, 50-69, and 70-89 years, respectively, throughout the main range of cholesterol in most developed countries, with no apparent threshold. The proportional risk reduction decreased with increasing blood pressure, since the absolute effects of cholesterol and blood pressure were approximately additive. Of various simple indices involving HDL cholesterol, the ratio total/HDL cholesterol was the strongest predictor of IHD mortality (40% more informative than non-HDL cholesterol and more than twice as informative as total cholesterol). Total cholesterol was weakly positively related to ischaemic and total stroke mortality in early middle age (40-59 years), but this finding could be largely or wholly accounted for by the association of cholesterol with blood pressure. Moreover, a positive relation was seen only in middle age and only in those with below-average blood pressure; at older ages (70-89 years) and, particularly, for those with systolic blood pressure over about 145 mm Hg, total cholesterol was negatively related to haemorrhagic and total stroke mortality. The results for other vascular mortality were intermediate between those for IHD and stroke.

INTERPRETATION

Total cholesterol was positively associated with IHD mortality in both middle and old age and at all blood pressure levels. The absence of an independent positive association of cholesterol with stroke mortality, especially at older ages or higher blood pressures, is unexplained, and invites further research. Nevertheless, there is conclusive evidence from randomised trials that statins substantially reduce not only coronary event rates but also total stroke rates in patients with a wide range of ages and blood pressures.

Survival in relation to angina symptoms and diagnosis among men aged 70-90 years: the Whitehall Study

BACKGROUND

While the excess mortality associated with a diagnosis of angina, myocardial infarction in middle-aged individuals is well established, there is little available evidence on the natural history of angina in population-based studies of older people.

DESIGN

We conducted a 5-year follow-up of 6655 older men aged 67-90 years (mean age 77 years) who participated in the Whitehall Study of London Civil Servants.

METHODS

Survival was examined in relation to a diagnosis of angina or myocardial infarction and to angina symptoms in a population-based study of older men living in the United Kingdom in the late 1990s.

RESULTS

Compared with men without a diagnosis of myocardial ischaemia (n=5219), a diagnosis of angina alone (n=617), myocardial infarction alone (n=421) or both (n=398) were associated with about a threefold, fourfold and sixfold higher risk of death from coronary heart disease, respectively. Median expectation of life at age 70 years was reduced by about 2, 5 and 6 years for those with angina, myocardial infarction, or both, respectively. Current symptoms of angina among those without previously diagnosed angina, was associated with a 2-fold higher risk of coronary heart disease mortality than those without either diagnosis or symptoms.

CONCLUSIONS

Both angina symptoms and diagnosis have a significant adverse effect on survival among men aged 70-90 years highlighting the importance of diagnosis and appropriate treatment of angina in old age.

A phase I dose-escalation and pharmacokinetic (PK) study of a novel spectrum selective kinase inhibitor, XL647, in patients with advanced solid malignancies (ASM)

3044

Background: XL647 is an orally bioavailable small molecule inhibitor of multiple receptor tyrosine kinases involved in tumor cell growth, angiogenesis, and metastasis, including EGFR (erbB1), erbB2, VEGFR2/KDR, and EphB4. Methods: Patients (pts) with ASM were enrolled in successive cohorts to receive XL647 orally as a single dose on day 1 with PK sampling, followed by 5 continuous daily doses starting on day 4 with additional PK sampling. Pts then continued to receive XL647 for 5 consecutive days, followed by a break, with cycles repeating every 14 days. Tumor imaging was conducted at baseline, after the first 3 or 4 cycles, and then after every 4 cycles. Pts were allowed to stay on-study in the absence of unacceptable toxicity until evidence of disease progression. Results: A total of 37 pts have been treated across 9 dose levels to date: 0.06, 0.12, 0.19, 0.28, 0.39, 0.78, 1.56, 3.12, 4.68, and 7.0 mg/kg. One pt at 3.12 mg/kg had a dose limiting toxicity (DLT) of asymptomatic QTc prolongation on electrocardiogram, resulting in expansion of that cohort. The first two pts who received 7.0 mg/kg experienced DLTs of grade 3 diarrhea, requiring dose reduction. Both pts from the 7.0 mg/kg cohort tolerated 4.68 mg/kg well. Expansion of the 4.68 mg/kg cohort to 6 pts occurred without further DLTs and this is considered the maximum tolerated dose (MTD). One serious adverse event, grade 4 pulmonary embolism, was considered possibly related to study treatment in a pt dosed at 0.28 mg/kg. PK analysis indicates that XL647 shows approximately dose-proportional exposure, a mean time to maximal concentration (tmax) of 6–9 hours and an elimination half-life of 50–70 hours. To date, 1 pt (non-small cell lung cancer [NSCLC]) from cohort 1 had a partial response and 7 others (NSCLC [2], chordoma [2], adenoid cystic carcinoma, adrenocortical carcinoma, colorectal) have had prolonged stable disease (>3 months). Conclusions: XL647 has been well tolerated. An MTD of 4.68 mg/kg oral dosing for 5 consecutive days every 14 days has been established. Exploration of additional dosing schedules is ongoing, including continuous daily dosing.

[Table: see text]

A phase I trial of liposomal doxorubicin, paclitaxel and valspodar (PSC-833), an inhibitor of multidrug resistance

PURPOSE

The aim of this study was to determine (i) the maximum tolerated dose (MTD) of liposomal doxorubicin (L-DOX) and paclitaxel (DP), (ii) the MTD of DP plus valspodar (DPV) and (iii) pharmacokinetic (PK) interactions of valspodar with L-DOX and paclitaxel.

METHODS

Twenty-three patients with metastatic cancers received DP, followed 4 weeks later by DPV. Dose levels of DP were (mg/m2 for L-DOX/paclitaxel): 30/135 (n = 7), 30/150 (n = 4), 35/150 (n = 8) and 40/150 (n = 4). Dose levels of DPV were 15/70 (n = 10) and 15/60 (n = 10). Serial, paired PK studies were performed.

RESULTS

The MTD of DP was 40/150. For DPV at 15/70, five of 10 patients experienced grade 4 neutropenia. In the next cohort, a reduced dose of 15/60 was well tolerated. Valspodar produced reversible grade 3 ataxia in seven patients, requiring dose reduction from 5 to 4 mg/kg. Paired PK studies indicated no interaction between L-DOX and valspodar, and a 49% increase in the median half-life of paclitaxel. Two partial and one minor remissions were noted.

CONCLUSIONS

The use of valspodar necessitated dose reductions of DP, with neutropenia being dose limiting. Valspodar PK interactions were observed with paclitaxel but not L-DOX.

Treatment of CML using IFN-alpha: impact on quality of life

Treatment of chronic myeloid leukaemia (CML) with IFN-alpha (IFN) is known to confer significant survival benefit, but the drug's impact on quality of life (QoL) in CML is unclear. We describe a cross-sectional comparison of QoL in patients randomised to long-term treatment with IFN versus no IFN within the UK MRC CML 3 trial, assessing the long-term consequences and psychosocial side effects of IFN therapy. Patients completed the EORTC QoL QLQ-C30, an in-house leukaemia/IFN questionnaire, a brief assessment of sexual functioning and demographic details. In total, 163 eligible patients completed questionnaires (85% response). Patients receiving IFN reported significantly worse QoL for emotional, cognitive and social functioning, pain and dyspnoea (P<0.01), and marginally worse fatigue, nausea and vomiting (P<0.05). As expected from other IFN use, those on IFN experienced more flu-like and febrile symptoms and skin problems than those not on IFN. In all, 35% of patients stopped IFN before questionnaire completion. This made no material difference to the results, except that those continuing on IFN had slightly better self-assessed Global health/QoL than those who had stopped (P<0.03). IFN treatment adversely affected sexual health after allowing for age and gender. In conclusion, IFN treatment has a significant adverse impact on QoL. Patient awareness of the survival benefits and these QoL effects should enable better-informed decision-making. The impact on QoL of IFN dose, and of imatinib therapy versus IFN in early CP CML, are being investigated. QoL will need evaluating in future studies of combination treatment (IFN+imatinib).

A phase I trial of doxorubicin, paclitaxel, and valspodar (PSC 833), a modulator of multidrug resistance

PURPOSE

P-glycoprotein is an efflux pump for many drugs including doxorubicin and paclitaxel. This study evaluated the coadministration of these drugs with the P-glycoprotein inhibitor valspodar (PSC 833) with the aim of determining: (a) maximum tolerated doses (MTDs) of doxorubicin followed by paclitaxel (DP); (b) the MTD of DP combined with PSC 833 (DPV), without and with filgrastim (G-CSF); and (c) the pharmacokinetic interactions of PSC 833 with doxorubicin and paclitaxel.

EXPERIMENTAL DESIGN

For the first cycle, patients received doxorubicin as a 15-min infusion followed by paclitaxel as a 1-h infusion. For the second cycle, patients received reduced doses of DP with PSC 833 at 5 mg/kg p.o., four times a day for 12 doses.

RESULTS

Thirty-three patients with various refractory malignancies were enrolled and assessable. The MTD of DP without PSC 833 was 35 mg/m(2) doxorubicin and 150 mg/m(2) paclitaxel. The MTD of DPV without G-CSF was 12.5 mg/m(2) doxorubicin and 70 mg/m(2) paclitaxel. The dose-limiting toxicity for both DP and DPV was neutropenia without thrombocytopenia. With G-CSF, the MTD for DPV was 20 mg/m(2) doxorubicin and 90 mg/m(2) paclitaxel. No grade 4 nonhematological toxicities were observed. Five partial and two minor tumor remissions were observed. Paired pharmacokinetics with and without PSC 833 revealed substantial drug interactions with both doxorubicin and paclitaxel.

CONCLUSIONS

PSC 833 can be administered safely with doxorubicin and paclitaxel. The pharmacokinetic profiles of these drugs are significantly affected by PSC 833, requiring approximately 60% dose reductions for equivalent degrees of myelosuppression.

DICE 2: a further investigation of the effects of chance in life, death and subgroup analyses

In an investigation into how chance might influence the distribution of deaths in a randomised trial and the time of those deaths, and to highlight the possible dangers of subgroup analyses, 100 randomised controlled trials were simulated and 50 subgroup pairs were simulated for some of these trials. Each of 580 control patients from a colorectal cancer trial was randomly coded to simulate allocation to treatment or control, the main outcome measure being time to death. Not surprisingly, most of the 100 trials gave non-significant results. Four were conventionally significant with logrank 2p-values of less than 0.05. The most extreme result was associated with a logrank 2p-value of 0.003, showing an absolute reduction in four-year mortality of 40% (SD 15) for patients allocated to treatment. One of the simulated prognostic factors for this trial (subgroup 13) showed that mortality for one type of patient was non-significantly slightly increased by treatment, whereas treatment reduced four-year mortality by 64% (SD 16) among the other patients in the trial (2p = 0.00006). Similar, extreme results were found for a trial of borderline statistical significance overall. Chance can influence the overall results of any randomised controlled trial, regardless of how well it is conducted, and can play an even more powerful role in the results of subgroup analyses. This should be borne in mind both by trialists when reporting their results and by readers and reviewers of those reports.

Effects of timing of coil embolization after aneurysmal subarachnoid hemorrhage on procedural morbidity and outcomes

OBJECTIVE

To elucidate the effect of treatment timing on procedural clinical outcomes after aneurysmal subarachnoid hemorrhage (SAH) for patients treated by endosaccular coil embolization.

METHODS

A group of 327 patients who were consecutively treated, during a 46-month period, for ruptured intracranial aneurysms by coil embolization within 30 days after SAH were evaluated. Outcomes were assessed by comparing immediate pretreatment World Federation of Neurological Surgeons (WFNS) grades, 72-hour posttreatment WFNS grades, and modified Glasgow Outcome Scale scores at 6 months for patients treated within 48 hours (Group 1), 3 to 10 days (Group 2), or 11 to 30 days (Group 3) after SAH.

RESULTS

The three interval-to-treatment groups included 33, 38, and 29% of the patients, respectively. Before treatment, 70% of the patients in Group 1, 78% of those in Group 2, and 83% of those in Group 3 were in good clinical grades (i.e., WFNS Grade 1 or 2). After coil embolization, the WFNS grades were either unchanged or improved for 93.5% of the patients in Group 1, 89.5% of those in Group 2, and 91.5% of those in Group 3. After 6 months, 81.3% of the patients in Group 1 experienced good outcomes (modified Glasgow Outcome Scale scores of 1 or 2), as did 84% of those in Group 2 and 80% of those in Group 3. No statistical difference was demonstrated between the three groups when they were compared for these two variables.

CONCLUSION

The interval between endovascular treatment and SAH did not affect periprocedural morbidity rates or 6-month outcomes. Coil embolization should therefore be performed as early as possible after aneurysmal SAH, to prevent aneurysmal rerupture.

Phase I study of an antisense oligonucleotide to protein kinase C-alpha (ISIS 3521/CGP 64128A) in patients with cancer

Protein kinase C (PKC) is an attractive target in cancer therapy. It is overexpressed in a variety of cancers, and nonspecific inhibitors of PKC have demonstrated antitumor activity. Antisense oligonucleotides targeted against PKC-alpha, which have high specificity, can inhibit mRNA and protein expression as well as the growth of tumors in vitro and in vivo. This Phase I study sought to characterize the safety profile and to determine the maximum tolerated dose of antisense to PKC-alpha when administered by continuous infusion in patients. Patients with incurable malignancies received ISIS 3521, a 20-length phosphorothioate oligodeoxynucleotide specific for PKC-alpha. Treatment was delivered over a period of 21 days by continuous i.v. infusion followed by a 7-day rest period. Doses were increased from 0.5 to 3.0 mg/kg/day. Patients continued on the study until evidence of disease progression or unacceptable toxicity was detected. Between August 1996 and September 1997, 21 patients were treated in five patient cohorts. The maximum tolerated dose was 2.0 mg/kg/day. The dose-limiting toxicities were thrombocytopenia and fatigue at a dose of 3.0 mg/kg/day. Pharmacokinetic measurements showed rapid plasma clearance and dose-dependent steady-state concentrations of ISIS 3521. Evidence of tumor response lasting up to 11 months was observed in three of four patients with ovarian cancer. The recommended dose of ISIS 3521 for Phase II studies is 2.0 mg/kg/day when given over a period of 21 days. Side effects are modest and consist of thrombocytopenia and fatigue. Evidence of antitumor activity provides the rationale for Phase II studies in ovarian cancer and other malignancies.

Overcoming multidrug resistance: valspodar as a paradigm for nursing care

PURPOSE/OBJECTIVES

To review the mechanisms of multidrug resistance (MDR) in human cancer and the clinical use of MDR modulators to overcome or reverse P-glycoprotein (P-gp)-mediated MDR.

DATA SOURCES

Current literature, ongoing clinical trials, and clinical experience.

DATA SYNTHESIS

Agents, such as valspodar, that block the activity of P-gp can reverse or overcome MDR caused by overexpression of P-gp. The MDR modulator valspodar (PSC 833; Novartis Pharmaceuticals Corporation, East Hanover, NJ) is examined as a model for establishing nursing guidelines for this new class of therapeutic agents.

CONCLUSIONS

The dose of some chemotherapy agents must be modified with concurrent valspodar administration. Studies examining the safety and efficacy of valspodar as a prototype of MDR modulators provide the basis for establishing nursing care guidelines.

IMPLICATIONS FOR NURSING PRACTICE

Nursing care for the administration of valspodar includes understanding patient selection, criteria, dosing, and administration; side-effect management; patient monitoring and follow-up; and patient education.

Modulation and prevention of multidrug resistance by inhibitors of P-glycoprotein

Intrinsic and acquired multidrug resistance (MDR) in many human cancers may be due to expression of the multidrug transporter P-glycoprotein (Pgp), which is encoded by the mdr1 gene. There is substantial evidence that Pgp is expressed both as an acquired mechanism (e.g., in leukemias, lymphomas, myeloma, and breast and ovarian carcinomas) and constitutively (e.g., in colorectal and renal cancers) and that its expression is of prognostic significance in many types of cancer. Clinical trials of MDR modulation are complicated by the presence of multiple-drug-resistance mechanisms in human cancers, the pharmacokinetic interactions that result from the inhibition of Pgp in normal tissues, and, until recently, the lack of potent and specific inhibitors of Pgp. A large number of clinical trials of reversal of MDR have been undertaken with drugs that are relatively weak inhibitors and produce limiting toxicities at doses below those necessary to inhibit Pgp significantly. The advent of newer drugs such as the cyclosporin PSC 833 (PSC) provides clinicians with more potent and specific inhibitors for MDR modulation trials. Understanding how modulators of Pgp such as PSC 833 affect the toxicity and pharmacokinetics of cytotoxic agents is fundamental for the design of therapeutic trials of MDR modulation. Our studies of combinations of high-dose cyclosporin (CsA) or PSC 833 with etoposide, doxorubicin, or paclitaxel have produced data regarding the role of Pgp in the clinical pharmacology of these agents. Major pharmacokinetic interactions result from the coadministration of CsA or PSC 833 with MDR-related anticancer agents (e.g., doxorubicin, daunorubicin, etoposide, paclitaxel, and vinblastine). These include increases in the plasma area under the curve and half-life and decreases in the clearance of these cytotoxic drugs, consistent with Pgp modulation at the biliary lumen and renal tubule, blocking excretion of drugs into the bile and urine. The biological and medical implications of our studies include the following. First, Pgp is a major organic cation transporter in tissues responsible for the excretion of xenobiotics (both drugs and toxins) by the biliary tract and proximal tubule of the kidney. Our clinical data are supported by recent studies in mdr-gene-knockout mice. Second, modulation of Pgp in tumors is likely to be accompanied by altered Pgp function in normal tissues, with pharmacokinetic interactions manifesting as inhibition of the disposition of MDR-related cytotoxins (which are transport substrates for Pgp). Third, these pharmacokinetic interactions of Pgp modulation are predictable if one defines the pharmacology of the modulating agent and the combination. The interactions lead to increased toxicities such as myelosuppression unless doses are modified to compensate for the altered disposition of MDR-related cytotoxins. Fourth, in serial studies where patients are their own controls and clinical resistance is established, remissions are observed when CsA or PSC 833 is added to therapy, even when doses of the cytotoxin are reduced by as much as 3-fold. This reversal of clinical drug resistance occurs particularly when the tumor cells express the mdr1 gene. Thus, tumor regression can be obtained without apparent increases in normal tissue toxicities. In parallel with these trials, we have recently demonstrated in the laboratory that PSC 833 decreases the mutation rate for resistance to doxorubicin and suppresses activation of mdr1 and the appearance of MDR mutants. These findings suggest that MDR modulation may delay the emergence of clinical drug resistance and support the concept of prevention of drug resistance in the earlier stages of disease and the utilization of time to progression as an important endpoint in clinical trials. Pivotal phase III trials to test these concepts with PSC 833 as an MDR modulator are under way or planned for patients with acute myeloid leukemias, multiple myeloma, and ovarian carcinoma.

Communicating with staff nurses: support or hostility?

Communication researchers specializing in social support determine factors that influence and make up supportive encounters in the hospital environment. Effective communication strategies provide a vital dyad's link between nurse managers and staff nurses. Thus, supportive relationships are formed that can ease stressful situations and encourage innovative ideas.

Analysis of molecular breakpoint and m-RNA transcripts in a prospective randomized trial of interferon in chronic myeloid leukaemia: no correlation with clinical features, cytogenetic response, duration of chronic phase, or survival

Two hundred and nineteen cases of Ph+ve CML and 15 Ph-ve, BCR+ve CML cases have been analysed to determine the breakpoint site and its relationship to clinical features, cytogenetic response, duration of chronic phase and survival. 119 cases have had RNA analysis performed to determine the type of BCR/ABL transcript and have also been analysed in a similar way. Presenting features at diagnosis including age, sex, white-cell count and platelet count showed no significant difference for those with 5' and 3' breakpoints and those with either b2a2 or b3a2 BCR/ABL transcripts. However, in a subgroup of patients whose presenting white-cell count was < 100 x 10(9)/l, those with b3a2 transcript did have a significantly higher platelet count. Analysis by Sokal risk grouping showed no difference for 5' or 3' breakpoints but a trend for lower stage among those with b2a2 transcripts. No correlation was found either for genomic breakpoint site or BCR/ABL RNA transcript in terms of duration of chronic phase or survival. When stratified by randomized therapy, either interferon-alpha or standard chemotherapy, no difference was noted in relation to genomic breakpoint site or BCR/ABL transcript. Cytogenetic response was not related to the molecular findings.

Phase I trial of doxorubicin with cyclosporine as a modulator of multidrug resistance

PURPOSE

To study the effects of cyclosporine (CsA), a modulator of multidrug resistance (MDR), on the pharmacokinetics and toxicities of doxorubicin.

PATIENTS AND METHODS

Nineteen patients with incurable malignancies entered this phase I trial. Initially patients received doxorubicin alone (60 or 75 mg/m2) as a 48-hour continuous intravenous (i.v.) infusion. Patients whose tumors did not respond received CsA as a 2-hour loading dose of 6 mg/kg and a 48-hour continuous infusion of 18 mg/kg/d with doxorubicin. Target CsA levels were 3,000 to 4,800 ng/mL (2.5 to 4.0 mumol/L). Doxorubicin doses were reduced to 40% of the prior dose without CsA, and then escalated until myelosuppression equivalent to that resulting from doxorubicin alone was observed. Doxorubicin pharmacokinetics were analyzed with and without CsA.

RESULTS

Thirteen patients received both doxorubicin alone and the combination of doxorubicin and CsA. Mean CsA levels were more than 2,000 ng/mL for all cycles and more than 3,000 ng/mL for 68% of cycles. Dose escalation of doxorubicin with CsA was stopped at 60% of the doxorubicin alone dose, as four of five patients at this dose level had WBC nadirs equivalent to those seen with doxorubicin alone. Nonhematologic toxicities were mild. Reversible hyperbilirubinemia occurred in 68% of doxorubicin/CsA courses. The addition of CsA to doxorubicin increased grade 1 and 2 nausea (87% v 47%) and vomiting (50% v 10%) compared with doxorubicin alone. There was no significant nephrotoxicity. Paired pharmacokinetics were studied in 12 patients. The addition of CsA increased the dose-adjusted area under the curve (AUC) of doxorubicin by 55%, and of its metabolite doxorubicinol by 350%.

CONCLUSION

CsA inhibits the clearance of both doxorubicin and doxorubicinol. Equivalent myelosuppression was observed when the dose of doxorubicin with CsA was 60% of the dose of doxorubicin without CsA. Understanding these pharmacokinetic interactions is essential for the design and interpretation of clinical trials of MDR modulation, and should be studied with more potent MDR modulators.

Clinical trials of modulation of multidrug resistance. Pharmacokinetic and pharmacodynamic considerations

A growing body of evidence indicates that expression of the mdr1 gene, which encodes the multidrug transporter, P-glycoprotein, contributes to chemotherapeutic resistance of human cancers. Expression of this protein in normal tissues such as the biliary tract, intestines, and renal tubules suggests a role in the excretion of toxins. Modulation of P-glycoprotein function in normal tissues may lead to decreased excretion of drugs and enhanced toxicities. A clinical trial of etoposide with escalating doses of cyclosporine (CsA) as a modulator of multidrug resistance was performed. CsA was delivered as a 2-hour loading dose followed by a 60-hour intravenous infusion, together with etoposide administered as a short infusion daily for 3 days. Patients received one or more courses of etoposide alone before the combined therapy to establish their clinical resistance to etoposide and to study etoposide pharmacokinetics without and then with CsA. Plasma and urinary etoposide was measured by high-performance liquid chromatography and plasma CsA by a nonspecific immunoassay. Conclusions from the initial phase I trial with the use of CsA as a modulator of etoposide are: (1) Serum CsA steady-state levels of up to 4800 ng/ml (4 microM) could be achieved with acceptable toxicity. (2) Toxicities caused by the combined treatment included increased nausea and vomiting, increased myelosuppression, and hyperbilirubinemia, consistent with modulation of P-glycoprotein function in the blood-brain barrier, hematopoietic stem cell, and biliary tract. Renal toxicity was uncommon, but severe in two patients with steady-state plasma CsA levels above 6000 ng/ml. (3) CsA administration had a marked effect on the pharmacokinetics of etoposide, with a doubling of the area under the concentration-time curve as a result of both decreased renal and nonrenal clearance, necessitating a 50% dose reduction in patients with normal renal function and hepatic function. (4) The recommended dose of CsA is a 6-7 mg/kg loading dose administered as a 2-hour intravenous infusion followed by a continuous infusion of 18-21 mg/kg/day for 60 hours with adjustments in the infusion rate to maintain steady-state serum levels of 3000-4800 ng/ml (2.5-4.0 M). We are performing additional phase I trials combining CsA with single-agent doxorubicin and taxol, and the CsA analog PSC-833 with various multidrug-resistant-related cytotoxins.

Alteration of etoposide pharmacokinetics and pharmacodynamics by cyclosporine in a phase I trial to modulate multidrug resistance

PURPOSE

To determine the effects of high-dose cyclosporine (CsA) infusion on the pharmacokinetics of etoposide in patients with cancer.

PATIENTS AND METHODS

Sixteen patients were administered 20 paired courses of etoposide and CsA/etoposide. Etoposide was administered daily for three days, alone or with CsA, which was delivered by a loading dose and 3-day infusion. Etoposide was measured by high-performance liquid chromatography (HPLC) and serum CsA by nonspecific immunoassay. Etoposide pharmacokinetics included area under the concentration-time curve (AUC), total and renal clearance (CL), half-life (T1/2), and volume of distribution at steady state (Vss).

RESULTS

CsA concentrations more than 2,000 ng/mL produced an increase in etoposide AUC of 80% (P less than .001), a 38% decrease in total CL (P < .01), a > twofold increase in T1/2 (P < .01), and a 46% larger Vss (P = .01) compared with etoposide alone. CsA levels ranged from 297 to 5,073 ng/mL. Higher CsA levels (< 2,000 ng/mL v > 2,000 ng/mL) resulted in greater changes in etoposide kinetics: Vss (1.4% v 46%) and T1/2 (40% v 108%). CsA produced a 38% decrease in renal and a 52% decrease in nonrenal CL of etoposide. Etoposide with CsA levels > 2,000 ng/mL produced a lower WBC count nadir (900/mm3 v 1,600/mm3) compared with baseline etoposide cycles.

CONCLUSIONS

High-dose CsA produces significant increases in etoposide systemic exposure and leukopenia. These pharmacokinetic changes are consistent with inhibition by CsA of the multidrug transporter P-glycoprotein in normal tissues. Etoposide doses should be reduced by 50% when used with high-dose CsA in patients with normal renal and liver function. Alterations in the disposition of other multidrug resistance (MDR)-related drugs should be expected to occur with modulation of P-glycoprotein function in clinical trials.

Phase I trial of etoposide with cyclosporine as a modulator of multidrug resistance

PURPOSE

To determine the maximum-tolerated dose (MTD) of cyclosporine (CsA) infusion administered with etoposide for 3 days in patients with cancer.

PATIENTS AND METHODS

Of the 72 registered patients, 26 were treated initially with CsA and etoposide. Forty-six received etoposide alone until disease progression, and 31 of these proceeded to CsA and etoposide. CsA was administered as a 2-hour loading dose (LD) and as a 3-day continuous infusion (CI); doses were escalated from 2 to 8 mg/kg LD and 5 to 24 mg/kg/d CI.

RESULTS

Fifty-seven patients were treated with 113 cycles of CsA with etoposide. Steady-state serum CsA levels (nonspecific immunoassay) more than 2,000 ng/mL were achieved in 91% of the cycles at CsA doses > or = 5 mg/kg LD and > or = 15 mg/kg/d CI. The major dose-related toxicity of CsA was reversible hyperbilirubinemia, which occurred in 78% of the courses with CsA levels > 2,000 ng/mL. Myelosuppression and nausea were more severe with CsA and etoposide. Other CsA toxicities included hypomagnesemia, 60%; hypertension, 29%; and headache, 21%. Nephrotoxicity was mild in 12% and severe in 2% of the cycles. Tumor regressions occurred in four patients after the addition of CsA (one non-Hodgkin's lymphoma, one Hodgkin's disease, and two ovarian carcinomas). Biopsy procedures for tumors from three of the four patients who responded were performed, and the results were positive for mdr1 expression.

CONCLUSIONS

Serum CsA levels of up to 4 mumol/L (4,800 ng/mL) are achievable during a short-term administration with acceptable toxicities when administered in combination with etoposide. The CsA dose that is recommended in adults is a LD of 5 to 6 mg/kg, followed by a CI of 15 to 18 mg/kg/d for 60 hours. CsA blood levels should be monitored and the doses should be adjusted to achieve CsA levels of 2.5 to 4 mumol/L (3,000 to 4,800 ng/mL). Reversible hyperbilirubinemia may be a useful marker of inhibition by CsA of P-glycoprotein function. When used with high-dose CsA, etoposide doses should be reduced by approximately 50% to compensate for the pharmacokinetic effects of CsA on etoposide (Lum et al, J Clin Oncol, 10:1635-1642, 1992).

The use of probenecid as a chemoprotector against cisplatin nephrotoxicity

Probenecid inhibits cisplatin (CP) secretion in humans and protects against CP-induced nephrotoxicity in rats. The authors conducted a Phase I trial of escalating doses of CP using probenecid as a chemoprotector. Fifty-four courses of CP at doses ranging from 100 to 160 mg/m2 were given by 24-hour infusion to 36 patients. There was no renal impairment at any dose. Ototoxicity, however, became the dose-limiting toxicity; 14 patients experienced a 20 or greater decibel (dB) loss. Seven percent of courses were associated with a leukocyte count of less than 1.5 x 10/microliters, and 19% with a platelet count of less than 50 x 10(3)/microliters. Only three patients developed neurotoxicity. Correlating pharmacokinetic data and toxicity, the authors found that high cumulative dose, area under the curve (AUC) for unbound platinum, and cumulative AUC were associated with ototoxicity and peripheral neuropathy. It was concluded that probenecid may protect against CP nephrotoxicity and warrants further investigation. Its unique mechanism of action and lack of toxicity make it ideal to combine with other chemoprotectors.