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Biomedical subjects

John Chalmers

Publications and source records attributed to John Chalmers.

At least 19 recordsLinked to original sources
PubMed2025

Blood Pressure Lowering and Risk of Cancer: Individual Participant-Level Data Meta-Analysis and Mendelian Randomization Studies.

BACKGROUND: Pharmacologic blood pressure (BP) lowering is typically a lifelong treatment, and both clinicians and patients may have concerns about the long-term use of antihypertensive agents and the risk for cancer. However, evidence from randomized controlled trials (RCTs) regarding the effect of long-term pharmacologic BP lowering on the risk for new-onset cancer is limited, with most knowledge derived from observational studies. OBJECTIVES: The aim of this study was to assess whether long-term BP lowering affects the risk for new-onset cancer, cause-specific cancer death, and selected site-specific cancers. METHODS: Individual-level data from 42 RCTs were pooled using a one-stage individual participant data meta-analysis. The primary outcome was incident cancer of all types, and secondary outcomes were cause-specific cancer death and selected site-specific cancers. Prespecified subgroup analyses were conducted to assess the heterogeneity of the BP-lowering effect by baseline variables and over follow-up time. Cox proportional hazards regression, stratified by trial, was used for the statistical analysis. For site-specific cancers, analyses were complemented with Mendelian randomization, using naturally randomized genetic variants associated with BP lowering to mimic the design of a long-term RCT. RESULTS: Data from 314,016 randomly allocated participants without known cancer at baseline were analyzed. Over a median follow-up of 4 years (Q1-Q3: 3-5 years), 17,954 participants (5.7%) developed cancer, and 4,878 (1.5%) died of cancer. In the individual participant data meta-analysis, no associations were found between reductions in systolic or diastolic BP and cancer risk (HR per 5 mm Hg reduction in systolic BP: 1.03 [95% CI: 0.99-1.06]; HR per 3 mm Hg reduction in diastolic BP: 1.03 [95% CI: 0.98-1.07]). No changes in relative risk for incident cancer were observed over follow-up time, nor was there evidence of heterogeneity in treatment effects across baseline subgroups. No effect on cause-specific cancer death was found. For site-specific cancers, no evidence of an effect was observed, except a possible link with lung cancer risk (HR for systolic BP reduction: 1.17; 99.5% CI: 1.02-1.32). Mendelian randomization studies showed no association between systolic or diastolic BP reduction and site-specific cancers, including overall lung cancer and its subtypes. CONCLUSIONS: Randomized data analysis provided no evidence to indicate that pharmacologic BP lowering has a substantial impact, either increasing or decreasing, on the risk for incident cancer, cause-specific cancer death, or selected site-specific cancers.

epidemiology↗
PubMed2006

Prior events predict cerebrovascular and coronary outcomes in the PROGRESS trial.

BACKGROUND AND PURPOSE: The relationship between baseline and recurrent vascular events may be important in the targeting of secondary prevention strategies. We examined the relationship between initial event and various types of further vascular outcomes and associated effects of blood pressure (BP)-lowering. METHODS: Subsidiary analyses of the Perindopril Protection Against Recurrent Stroke Study (PROGRESS) trial, a randomized, placebo-controlled trial that established the benefits of BP-lowering in 6105 patients (mean age 64 years, 30% female) with cerebrovascular disease, randomly assigned to either active treatment (perindopril for all, plus indapamide in those with neither an indication for, nor a contraindication to, a diuretic) or placebo(s). RESULTS: Stroke subtypes and coronary events were associated with 1.5- to 6.6-fold greater risk of recurrence of the same event (hazard ratios, 1.51 to 6.64; P=0.1 for large artery infarction, P<0.0001 for other events). However, 46% to 92% of further vascular outcomes were not of the same type. Active treatment produced comparable reductions in the risk of vascular outcomes among patients with a broad range of vascular events at entry (relative risk reduction, 25%; P<0.0001 for ischemic stroke; 42%, P=0.0006 for hemorrhagic stroke; 17%, P=0.3 for coronary events; P homogeneity=0.4). CONCLUSIONS: Patients with previous vascular events are at high risk of recurrences of the same event. However, because they are also at risk of other vascular outcomes, a broad range of secondary prevention strategies is necessary for their treatment. BP-lowering is likely to be one of the most effective and generalizable strategies across a variety of major vascular events including stroke and myocardial infarction.

Aged↗
PubMed2006

Secondary prevention of stroke by blood pressure-lowering treatment.

High blood pressure is the most important modifiable risk factor for stroke, accounting for more than 50% of the population-attributable fraction for stroke. There is now strong evidence from randomized trials that blood pressure-lowering treatment is one of the most effective and generalizable strategies for secondary prevention of stroke. Once the patient with stroke has stabilized, all patients should receive blood pressure-lowering therapy, irrespective of their blood pressure levels. Combination therapy with an angiotensin-converting enzyme (ACE) inhibitor plus a diuretic is an established regimen, but an angiotensin II-receptor blocker may provide an alternative regimen in patients who do not tolerate an ACE inhibitor, especially in combination with a diuretic. For patients with previous stroke, goal blood pressures of < 130/80 mm Hg in hypertensive subjects and < 120/80 mm Hg in normotensive (or "prehypertensive") subjects should be achieved using combination blood pressure-lowering therapy.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2006

Lower target blood pressures are safe and effective for the prevention of recurrent stroke: the PROGRESS trial.

OBJECTIVE: To explore the likely optimum blood pressure (BP) level for patients with a history of cerebrovascular disease. METHODS: The Perindopril Protection Against Recurrent Stroke Study (PROGRESS) was a randomized, placebo-controlled trial that established the beneficial effects of BP lowering in 6105 patients with cerebrovascular disease. The present study comprises two series of post hoc analyses. The first was designed to investigate the effects of randomized treatment on recurrent stroke by baseline BP levels, and the second was a corresponding observational analysis investigating the association between achieved follow-up BP levels and recurrent stroke risk. RESULTS: Analyses of the randomized treatment comparisons showed that BP lowering with combination therapy produced similar risk reductions in each of four subgroups defined by baseline BP of less than 120, 120-139, 140-159, and 160 mmHg or greater (P homogeneity = 0.5). The effects of single-drug therapy were also comparable across these subgroups (P homogeneity = 0.2), but consistently greater benefits were observed with combination compared to single-drug therapy. The analyses of achieved follow-up BP showed that the lowest risk of recurrence was among the one-quarter of participants with the lowest follow-up BP levels (median 112/72 mmHg), and that risks rose progressively with higher follow-up BP levels. Minor side-effects were progressively more common at lower BP levels (P homogeneity = 0.04), but there was no excess of serious complications (all P homogeneity > 0.2). CONCLUSION: These analyses provide no evidence of a J-curve relationship between BP level and stroke risk among patients with cerebrovascular disease, and identify no patient group among whom more intensive BP lowering would not be expected to produce greater risk reductions.

Aged↗
PubMed2006

ADVANCE: breaking new ground in type 2 diabetes.

OBJECTIVE AND RATIONALE: ADVANCE (Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation) is a large-scale trial designed to investigate the benefits of blood pressure lowering and intensive glucose control in patients with type 2 diabetes, and to address a number of unresolved issues: whether blood pressure-lowering therapy and intensive glucose control therapy will reduce the risk of major vascular disease regardless of initial blood pressure or glucose concentration; whether more intensive glucose control targeting a haemoglobin A1c (HbA1c) level of 6.5% or less will confer greater protection against microvascular disease; and whether the benefits of the two interventions are additive. DESIGN AND METHODS: ADVANCE is a 2 x 2 factorial randomized clinical trial evaluating the risks and benefits of the low-dose fixed combination of perindopril and indapamide versus placebo to lower blood pressure and of an intensive gliclazide-MR-based glucose control regimen, targeting an HbA1c of 6.5% or less versus standard guidelines based therapy for glucose control. There are two primary outcomes: a composite macrovascular endpoint and a composite microvascular endpoint. RESULTS: A total of 12 878 participants from 215 centres in 20 countries entered a 6-week run-in phase between June 2001 and January 2003, and 11 140 patients were randomly assigned by March 2003. The average (SD) systolic and diastolic blood pressure fell from 145 (22)/81 (11) to 137 (20)/78 (10) mmHg during the 6-week run-in phase, during which participants received one tablet of open-labelled perindopril 2 mg/indapamide 0.625 mg. Of the 12 878 patients who entered the run-in, only 3.6% withdrew because of suspected intolerance to perindopril/indapamide. The study is half way through follow-up and both the study medications (perindopril 2 mg/indapamide 0.625 mg and gliclazide-MR) continue to be well tolerated. Completion is expected in 2007. CONCLUSION: Safe and effective blood pressure lowering with the fixed low-dose combination of perindopril and indapamide was confirmed during the run-in phase in 11 140 patients with type 2 diabetes, who were subsequently randomly assigned. Post-randomization study treatments have been well tolerated, and the completion of follow-up is scheduled in 2007.

Aged↗
PubMed2006

Diuretics: a modern day treatment option?

The choice of drugs to initiate therapy for the management of hypertension remains contentious and diuretics are central to this controversy. Because most of the major trials involve complex treatment algorithms and allow diverse background treatments, one of the greatest challenges lies in separating out true class-specific effects - for example, separating true class-specific effects of diuretics from those of beta blockers. Despite these difficulties, the evidence confirms that diuretics are at least as effective as the newer first line groups in preventing cardiovascular events. The main area of doubt lies in relation to the risk of renal outcomes and of metabolic outcomes, such as new onset diabetes - where the evidence suggests that drugs that inhibit the renin-angiotensin system may be more protective than all other drug classes. These issues are reflected in the most recent international guidelines, all of which include diuretics among the first-line drugs for the treatment of hypertension, although they do differ on the role of diuretics in the initiation of therapy. Diuretics remain important for treating hypertension, especially in combination with other drug classes. The particular place of diuretics in the rank order of drugs must be tailored to suit the clinical situation in the individual patient. This will vary from a preferred option, as in black patients or elderly patients with systolic hypertension, to a second-line option in patients at high risk of developing new onset diabetes.

Diuretics↗
PubMed2005

Associations of inflammatory and hemostatic variables with the risk of recurrent stroke.

BACKGROUND AND PURPOSE: Several prospective studies have shown significant associations between plasma fibrinogen, viscosity, C-reactive protein (CRP), fibrin D-dimer, or tissue plasminogen activator (tPA) antigen and the risk of primary cardiovascular events. Little has been published on the associations of these variables with recurrent stroke. We studied such associations in a nested case-control study derived from the Perindopril Protection Against Recurrent Stroke Study (PROGRESS). METHODS: Nested case-control study of ischemic (n=472) and hemorrhagic (n=83) strokes occurring during a randomized, placebo-controlled multicenter trial of perindopril-based therapy in 6105 patients with a history of stroke or transient ischemic attack. Controls were matched for age, treatment group, sex, region, and most recent qualifying event at entry to the parent trial. RESULTS: Fibrinogen and CRP were associated with an increased risk of recurrent ischemic stroke after accounting for the matching variables and adjusting for systolic blood pressure, smoking, peripheral vascular disease, and statin and antiplatelet therapy. The odds ratio for the last compared with the first third of fibrinogen was 1.34 (95% CI, 1.01 to 1.78) and for CRP was 1.39 (95% CI, 1.05 to 1.85). After additional adjustment for each other, these 2 odds ratios stayed virtually unchanged. Plasma viscosity, tPA, and d-dimer showed no relationship with recurrent ischemic stroke, although tPA was significant for lacunar and large artery subtypes. Although each of these variables showed a negative relationship with recurrent hemorrhagic stroke, none of these relationships achieved statistical significance. CONCLUSIONS: Fibrinogen and CRP are risk predictors for ischemic but not hemorrhagic stroke, independent of potential confounders.

Aged↗
PubMed2005

Effects of blood pressure lowering on cerebral white matter hyperintensities in patients with stroke: the PROGRESS (Perindopril Protection Against Recurrent Stroke Study) Magnetic Resonance Imaging Substudy.

BACKGROUND: The prevalence of white matter hyperintensities (WMHs) detected on cerebral MRI is associated with hypertension, but it is not known whether blood pressure lowering can arrest their progression. We report here the results of an MRI substudy of PROGRESS (Perindopril Protection Against Recurrent Stroke Study), a randomized trial of blood pressure lowering in subjects with cerebrovascular disease. METHODS AND RESULTS: The substudy comprised 192 participants who had a cerebral MRI both at baseline and after a mean follow-up time of 36 months (SD=6.0 months). At the first MRI, WMHs were graded with a visual rating scale from A (no WMH) to D (severe WMH). Participants were assigned to a combination of perindopril plus indapamide (or their placebos; 58%) or to single therapy with perindopril (or placebo). At the time of the second MRI, the blood pressure reduction in the active arm compared with the placebo arm was 11.2 mm Hg for systolic blood pressure and 4.3 mm Hg for diastolic blood pressure. Twenty-four subjects (12.5%) developed new WMHs at follow-up. The risk of new WMH was reduced by 43% (95% CI -7% to 89%) in the active treatment group compared with the placebo group (P=0.17). The mean total volume of new WMHs was significantly reduced in the active treatment group (0.4 mm3 [SE=0.8]) compared with the placebo group (2.0 mm3 [SE=0.7]; P=0.012). This difference was greatest for patients with severe WMH at entry, 0.0 mm3 (SE=0) in the active treatment group versus 7.6 mm3 (SE=1.0) in the placebo group (P<0.0001). CONCLUSIONS: These results indicate that an active blood pressure-lowering regimen stopped or delayed the progression of WMHs in patients with cerebrovascular disease.

Aged↗
PubMed2005

Perindopril-based blood pressure-lowering reduces major vascular events in patients with atrial fibrillation and prior stroke or transient ischemic attack.

BACKGROUND AND PURPOSE: Patients with atrial fibrillation have a high risk of stroke and other vascular events even if anticoagulated. The primary objective here is to determine whether routine blood pressure-lowering provides additional protection for this high-risk patient group. METHODS: This study was a subsidiary analysis of the Perindopril Protection Against Recurrent Stroke Study (PROGRESS)--a randomized, placebo-controlled trial that established the beneficial effects of blood pressure--lowering in a heterogeneous group of patients with cerebrovascular disease. A total of 6105 patients were randomly assigned to either active treatment (2 to 4 mg perindopril for all participants plus 2.0 to 2.5 mg indapamide for those without an indication for or a contraindication to a diuretic) or matching placebo(s). Outcomes are total major vascular events, cause-specific vascular outcomes, and death from any cause. RESULTS: There were 476 patients with atrial fibrillation at baseline, of whom 51% were taking anticoagulants. In these patients, active treatment lowered mean blood pressure by 7.3/3.4 mm Hg and was associated with a 38% (95% confidence interval [CI], 6 to 59) reduction in major vascular events and 34% (95% CI, -13 to 61) reduction in stroke. The benefits of blood pressure-lowering in patients with atrial fibrillation were achieved irrespective of the use of anticoagulant therapy (P homogeneity=0.8) or the presence of hypertension (P homogeneity=0.4). CONCLUSIONS: For most patients with atrial fibrillation, routine blood pressure-lowering is likely to provide protection against major vascular events additional to that conferred by anticoagulation.

Aged↗
PubMed2005

Plasma lipids predict myocardial infarction, but not stroke, in patients with established cerebrovascular disease.

AIMS: To evaluate the role of plasma lipids in recurrent vascular events, including stroke, among individuals with established cerebrovascular disease. METHODS AND RESULTS: Plasma total cholesterol, HDL cholesterol, and triglycerides were measured at baseline among individuals participating in the Perindopril Protection Against Recurrent Stroke (PROGRESS) study, a randomized clinical trial of blood pressure lowering among patients with previous stroke or transient ischaemic attack. A series of nested case-control studies were used to investigate the association between each of these lipid variables and the risk of subsequent haemorrhagic stroke, ischaemic stroke, myocardial infarction (MI), and heart failure. A total of 895 patients were selected as cases (83 haemorrhagic stroke, 472 ischaemic stroke, 206 MI, and 258 heart failure) and each was matched with one to three controls. After adjustment for other major cardiovascular risk factors, none of the lipid variables was associated with the risk of either stroke subtype. There were significant positive and negative associations for total cholesterol and HDL, respectively, with the risk of MI; the odds ratio comparing the highest and lowest thirds of each of these lipid variables was 2.00 (95% CI: 1.30-3.09) for total cholesterol and 0.58 (95% CI: 0.37-0.90) for HDL. HDL was inversely associated with the risk of heart failure; however, this result was of borderline statistical significance (P=0.05). CONCLUSION: Lipid variables are associated with the risk of MI, but not recurrent stroke, in patients with established cerebrovascular disease.

Aged↗
PubMed2005

Effects of different blood pressure-lowering regimens on major cardiovascular events in individuals with and without diabetes mellitus: results of prospectively designed overviews of randomized trials.

BACKGROUND: Blood pressure (BP) level is a major determinant of cardiovascular morbidity and mortality in individuals with diabetes mellitus. Several guidelines recommend lower BP goals and specific drug classes for these patients. The overviews reported herein were performed to formally compare the effects on cardiovascular events and death of different BP-lowering regimens in individuals with and without diabetes. METHODS: Twenty-seven randomized trials (N = 158 709 participants) that included 33 395 individuals with diabetes and 125 314 without diabetes contributed to these analyses. For each outcome and each comparison summary, estimates of effect and 95% confidence intervals were calculated for patients with and without diabetes using a random-effects model. The constancy of the effects of each treatment regimen in participants with and without diabetes was examined using chi(2) tests of homogeneity. RESULTS: Total major cardiovascular events were reduced to a comparable extent in individuals with and without diabetes by regimens based on angiotensin-converting enzyme inhibitors, calcium antagonists, angiotensin receptor blockers, and diuretics/beta-blockers (P > .19 for all by chi(2) test of homogeneity). There was limited evidence that lower BP goals produced larger reductions in total major cardiovascular events in individuals with vs without diabetes (P = .03 by chi(2) test of homogeneity). CONCLUSIONS: These overviews showed that the short- to-medium-term effects on major cardiovascular events of the BP-lowering regimens studied were broadly comparable for patients with and without diabetes. Different effects of regimens on intermediate renal outcomes not evaluated in these overviews may still provide a rationale for using specific drug classes in patients with diabetes.

Aged↗
PubMed2004

Effects of an angiotensin-converting enzyme inhibitor-based regimen on pneumonia risk.

Observational studies conducted among Asian populations suggest that the risk of pneumonia is substantially reduced among users of angiotensin-converting enzyme (ACE) inhibitors but not other blood pressure-lowering agents. We conducted analyses of the effects of ACE inhibitor therapy on pneumonia in 6,105 patients with a history of stroke or transient ischemic attack enrolled in a randomized trial conducted in Australasia, Europe, and Asia. Patients were randomly assigned perindopril-based active treatment or placebo. The effects of ACE inhibitors on pneumonia (fatal or nonfatal) were determined from Cox models fitted according to the principle of intention to treat. During a median follow-up of 3.9 years, 261 patients developed pneumonia. Overall, active treatment was associated with a nonsignificant 19% lower risk of pneumonia (95% confidence interval, -3 to 37; p = 0.09) compared with placebo. Active treatment significantly reduced the risk of pneumonia among participants of Asian ethnicity (47%, 14-67%; p = 0.01), with no significant effect among non-Asian participants (5%, -27 to 29%; p = 0.7) (p for homogeneity = 0.04). These findings substantially add to the body of evidence about the effects of these drugs on pneumonia but do not provide the definitive information required to inform clinical decisions about the prevention of pneumonia with ACE inhibitors.

Aged↗
PubMed2004

Perindopril-based blood pressure lowering in individuals with cerebrovascular disease: consistency of benefits by age, sex and region.

OBJECTIVE: To assess the consistency of the benefits of blood pressure lowering on secondary stroke risk by age, sex and geographic region of recruitment. DESIGN: Randomized, placebo-controlled trial. Participants were randomized to the angiotensin-converting enzyme (ACE) inhibitor perindopril (plus the diuretic indapamide if not indicated or contraindicated) or to placebo(s) over a mean follow-up of 3.9 years. Main analyses used Cox proportional hazards models on an intention-to-treat basis. Subgroup results were standardized for the proportion (42%) taking single-drug therapy. SETTING: A total of 172 centres in Asia, Australia, New Zealand and Europe. PARTICIPANTS: Patients (n = 6105) with a history of stroke or transient ischaemic attack, of whom 50% were aged over 65 years at baseline, 30% were women and 39% were from Asia. MAIN OUTCOME MEASURES: Stroke, coronary heart disease and major vascular events. RESULTS: Overall, treatment reduced stroke by 28% [95% confidence interval (CI) 17-38%] and major vascular events by 26% (16-44%), with separately significant reductions across subgroups defined by age (< or > or = 65 years), sex and region (Asia or not). Treatment was safe and well tolerated, and the absolute benefits were large; 5 years' treatment would be expected to avert at least one major vascular event among every 20 patients in all age, sex and region subgroups. There was some evidence of particularly large benefits among younger participants and those from Asia. CONCLUSIONS: Blood pressure lowering reduces secondary stroke risk, with large absolute benefits across groups defined by age, sex and geographic region.

Age Distribution↗
PubMed2004

Effects of perindopril-based blood pressure lowering and of patient characteristics on the progression of silent brain infarct: the Perindopril Protection against Recurrent Stroke Study (PROGRESS) CT Substudy in Japan.

Controversy persists as to whether reducing the blood pressure of patients with a history of stroke leads to an increased risk of silent brain infarct (SBI) and dementia. A total of 667 patients were randomized to receive the angiotensin-converting enzyme (ACE) inhibitor perindopril (4 mg daily), with or without the diuretic indapamide (2 mg daily) or matching placebo(s). Brain CT scanning was performed annually over the mean follow-up period of 3.9 years. Active treatment reduced the blood pressure (systolic/diastolic) by 5.2/2.6 mmHg over the follow-up period. A total of 119 new SBI were detected and 92% of them were lacunar type small infarcts. The frequency of reaching the primary end-point (recurrent symptomatic stroke or new SBI) was similar in the placebo group (26.5%) and in the active treatment group (25.9%). There was no significant difference in brain atrophy indices between two groups. In the subgroup with a history of large artery infarction, 7 out of 55 patients from the placebo group developed new SBI, while none of the 40 patients from the active treatment group did so (p = 0.020). The baseline diastolic blood pressure was significantly associated with the risk of new SBI (p = 0.004), but the stroke subtype was not. In conclusion, blood pressure-lowering with a perindopril-based regimen did not increase the risk of SBI and brain atrophy in patients with a history of stroke. The baseline diastolic blood pressure was an independent predictor of new SBI, but the index stroke subtype did not influence the risk of SBI.

Aged↗
PubMed2003

The ACE gene I/D polymorphism is not associated with the blood pressure and cardiovascular benefits of ACE inhibition.

The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene might have consequences for the risks of vascular diseases. We examined the ACE genotype and the effects of a perindopril-based blood pressure-lowering regimen on macrovascular events, dementia, and cognitive decline among hypertensive and nonhypertensive patients with a history of cerebrovascular disease. ACE I/D genotypes were measured in 5688 of 6105 individuals with previous stroke or transient ischemic attack who participated in the PROGRESS trial. The DD genotype was significantly (P<0.0001) less frequent in Asian subjects (Chinese and Japanese, 14.7%) than in non-Asian subjects (32.0%). Controlling for racial background, there were no associations between ACE genotypes and cerebrovascular disease history or cardiovascular risk factors, including baseline blood pressure. The ACE genotype was not associated with the long-term risks of stroke, cardiac events, mortality, dementia, or cognitive decline; neither did the ACE genotype predict the blood pressure reduction associated with the use of the ACE inhibitor perindopril. Similarly, there was no evidence that the ACE genotype modified the relative benefits of ACE inhibitor-based therapy over placebo. This study provides no evidence that in patients with cerebrovascular disease, knowledge of ACE genotype is useful for predicting either the risk of disease or the benefits of perindopril-based blood pressure-lowering treatment.

Adult↗