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Objective: To demonstrate how mixed models may be used to estimate treatment effects, and inform decisions on the need for monitoring initial response., Study Design and Setting: Mixed models were used to analyze data from the Perindopril Protection Against Recurrent Stroke Study (PROGRESS), which examined the effects of perindopril and indapamide in 6,105 patients at high risk of a cerebrovascular event., Results: The mean effect of perindopril was to lower blood pressure (BP) (systolic/diastolic) by 6/3 mmHg. The mean effects of perindopril/indapamide varied according to baseline BP, and lowering of BP ranged from 9/5 to 14/5 mmHg (for individuals with a baseline systolic BP <140 and >150 mmHg, respectively). We found no variation in the effects of treatment on BP for either perindopril alone or in combination with indapamide. The effects of treatment on the individual can be predicted from the mean effect of treatment for the group (perindopril) or baseline systolic BP subgroup (perindopril/indapamide)., Conclusion: Monitoring initial treatment response is unnecessary for antihypertensives similar to those examined in this study. To address this issue for other therapies, we suggest that trials should report estimates of treatment effects from mixed models, and the CONSORT statement should be expanded to include this item.

Objective: To determine the value of monitoring blood pressure by quantifying the probability that observed changes in blood pressure reflect true changes., Design: Analysis of blood pressure measurements of patients in the perindopril protection against recurrent stroke study (PROGRESS)., Setting: Randomised placebo controlled trial carried out in 172 centres in Asia, Australasia, and Europe., Participants: 1709 patients with history of stroke or transient ischaemic attack randomised to fixed doses of perindopril and indapamide. Measurements Mean of two blood pressure measurements in patients receiving treatment recorded to the nearest 2 mm Hg with a standard mercury sphygmomanometer at baseline and then at three months, six months, nine months, and 15 months and then every six months to 33 months., Results: There was no change in the mean blood pressure of the cohort during the 33 month follow-up. Six months after blood pressure was stabilised on treatment, if systolic blood pressure was measured as having increased by >10 mm Hg, six of those measurements would be false positives for every true increase of >or=10 mm Hg. The corresponding value for an increase of 20 mm Hg was over 200. Values for 5 mm Hg and 10 mm Hg increases in diastolic blood pressure were 3.5 and 39, respectively. The likelihood that observed increases in blood pressure reflected true increases rose with the time between measurements such that the ratio of true positives to false positives reached parity at 21 months., Conclusions: Usual clinical approaches to the monitoring of patients taking drugs to lower blood pressure have a low probability of yielding reliable information about true changes in blood pressure. Evidence based guidelines for monitoring treatment response are urgently required to guide clinical practice. Trial registration Australia and New Zealand Clinical Trial Registry.

Background and Purpose: There are few reports on proinflammatory cytokines and risk of primary or recurrent stroke. We studied the association of interleukin (IL)-6, IL-18, and tumor necrosis factor-alpha (TNF-alpha) with recurrent stroke in a nested case-control study derived from the Perindopril Protection Against Recurrent Stroke Study (PROGRESS)., Methods: We performed a nested case-control study of 591 strokes (472 ischemic, 83 hemorrhagic, 36 unknown subtype) 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: IL-6 and TNF-alpha, but not IL-18, were associated with risk of recurrent ischemic stroke independently of conventional risk markers. Adjusted odds ratios comparing the highest to lowest third of their distributions were 1.33 (95% CI, 1.00 to 1.78) for IL-6 and 1.46 (1.02 to 2.10) for TNF-alpha. No inflammatory marker was associated with hemorrhagic stroke risk. In multivariable models, IL-6 and TNF-alpha fully explained observed associations of C-reactive protein and fibrinogen with risk of ischemic stroke, but TNF-alpha retained borderline significance after full adjustment., Conclusions: Inflammatory markers associated with the acute-phase response (IL-6, TNF-alpha, C-reactive protein, and fibrinogen, but not IL-18) are associated with risk of recurrent stroke. These markers are dependent on each other in multivariable models, and once all were included, only TNF-alpha retained a borderline association. Markers of generalized inflammation of the acute-phase response are associated with recurrent stroke, rather than IL-6, C-reactive protein, or fibrinogen in particular.

Background: Patients with stroke or transient ischemic attack are at high risk of another stroke, and there is need for improved strategies to predict recurrent stroke., Objective: To assess the prognostic value of levels of soluble vascular cell adhesion molecule 1 (sVCAM-1), N-terminal pro-B-type natriuretic peptide (NT-proBNP), C-reactive protein, homocysteine, renin, and lipids and lipoprotein particle concentration and size in patients with previous stroke or transient ischemic attack., Design, Setting, and Participants: A nested case-control study of participants of the Perindopril Protection Against Recurrent Stroke Study was performed. The Perindopril Protection Against Recurrent Stroke Study was a placebo-controlled trial of a perindopril erbumine-based, blood pressure-lowering regimen that reduced ischemic stroke risk by 24% among individuals with previous stroke or transient ischemic attack. Each of 252 patients who experienced ischemic stroke during a mean follow-up of 3.9 years was matched to 1 to 3 control patients. Matching variables were age, sex, treatment allocated, region, and most recent qualifying event at randomization., Main Outcome Measures: Risk of ischemic stroke predicted by baseline levels of sVCAM-1, NT-proBNP, C-reactive protein, homocysteine, renin, and lipids and lipoprotein particle concentration and size., Results: Levels of sVCAM-1 and NT-proBNP predicted recurrent ischemic stroke. The odds ratio for patients in the highest, as compared with the lowest, quarter was 2.24 (95% confidence interval, 1.35-3.73) for sVCAM-1 level and 1.62 (95% confidence interval, 0.98-2.69) for NT-proBNP level, after adjustment for matching and other risk factors. Patients in the highest quarters for both sVCAM-1 and NT-proBNP levels had 3.6 times the risk of recurrent ischemic stroke compared with patients in the lowest quarters for both biologic markers. Level of sVCAM-1 was similarly predictive of ischemic stroke in patients allocated to placebo and perindopril-based therapy. Baseline plasma levels of C-reactive protein, homocysteine, renin, and lipids and lipoprotein particle concentration and size did not predict recurrent ischemic stroke risk., Conclusion: Measurement of sVCAM-1 and NT-proBNP levels provides prognostic information for recurrent ischemic stroke beyond traditional risk factors.

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.

Background: Analyses of the risks of stroke were conducted for subjects with and without diabetes, participating in a randomized, double-blind, placebo-controlled trial of a perindopril-based blood pressure lowering regimen in 6105 people with prior stroke or transient ischaemic attack (TIA), followed for a median of 3.9 years., Findings: Seven hundred and sixty-one patients had diabetes at baseline. Diabetes increased the risk of recurrent stroke by 35% (95% CI 10-65%) principally through an effect on ischaemic stroke (1.53, 95% CI 1.23-1.90). Active treatment reduced blood pressure by 9.5/4.6 mmHg in patients with diabetes and by 8.9/3.9 mmHg in patients without diabetes. The proportional risk reductions achieved for stroke in patients with diabetes, 38% (95% CI 8-58%), and patients without diabetes, 28% (95% CI 16-39%), were not significantly different (p homogeneity = 0.5). The absolute reduction in the risk of recurrent stroke in the patients with diabetes was equivalent to one stroke avoided among every 16 (95% CI 9-111) patients treated for 5 years., Conclusions: Diabetes is an important risk factor for stroke in patients with established cerebrovascular disease. Treatment with the ACE inhibitor perindopril with discretionary use of the diuretic indapamide produced reductions in the risk of recurrent stroke in patients with diabetes that were at least as great as those achieved in patients without diabetes.

Most clinicians monitor blood pressure to estimate a patient's response to blood pressure-lowering therapy. However, the apparent change may not actually reflect the effect of the treatment, because a person's blood pressure varies considerably even without the administration of drug therapy. We estimated random background within-person variation, apparent between-person variation, and true between-person variation in blood pressure response to angiotensin-converting enzyme inhibitors after 3 months. We used meta-analytic mixed models to analyze individual patient data from 28 281 participants in 7 randomized, controlled trials from the Blood Pressure Lowering Trialists Collaboration. The apparent between-person variation in response was large, with SDs for change in systolic blood pressure/diastolic blood pressure of 15.2/8.5 mm Hg. Within-person variation was also large, with SDs for change in systolic blood pressure/diastolic blood pressure of 14.9/8.45 mm Hg. The true between-person variation in response was small, with SDs for change in systolic blood pressure/diastolic blood pressure of 2.6/1.0 mm Hg. The proportion of the apparent between-person variation in response that was attributed to true between-person variation was only 3% for systolic blood pressure and 1% for diastolic blood pressure. In conclusion, most of the apparent variation in response is not because of true variation but is a consequence of background within-person fluctuation in day-to-day blood pressure levels. Instead of monitoring an individual's blood pressure response, a better approach may be to simply assume the mean treatment effect. [ABSTRACT FROM AUTHOR]