Interventions in the management of serum lipids for preventing stroke recurrence

An assessment of the cost-effectiveness of magnetic resonance, including diffusion-weighted imaging, in patients with transient ischaemic attack and minor stroke: a systematic review, meta-analysis and economic evaluation

BACKGROUND

Patients with transient ischaemic attack (TIA) or minor stroke need rapid treatment of risk factors to prevent recurrent stroke. ABCD2 score or magnetic resonance diffusion-weighted brain imaging (MR DWI) may help assessment and treatment.

OBJECTIVES

Is MR with DWI cost-effective in stroke prevention compared with computed tomography (CT) brain scanning in all patients, in specific subgroups or as 'one-stop' brain-carotid imaging? What is the current UK availability of services for stroke prevention?

DATA SOURCES

Published literature; stroke registries, audit and randomised clinical trials; national databases; survey of UK clinical and imaging services for stroke; expert opinion.

REVIEW METHODS

Systematic reviews and meta-analyses of published/unpublished data. Decision-analytic model of stroke prevention including on a 20-year time horizon including nine representative imaging scenarios.

RESULTS

The pooled recurrent stroke rate after TIA (53 studies, 30,558 patients) is 5.2% [95% confidence interval (CI) 3.9% to 5.9%] by 7 days, and 6.7% (5.2% to 8.7%) at 90 days. ABCD2 score does not identify patients with key stroke causes or identify mimics: 66% of specialist-diagnosed true TIAs and 35-41% of mimics had an ABCD2 score of ≥ 4; 20% of true TIAs with ABCD2 score of < 4 had key risk factors. MR DWI (45 studies, 9078 patients) showed an acute ischaemic lesion in 34.3% (95% CI 30.5% to 38.4%) of TIA, 69% of minor stroke patients, i.e. two-thirds of TIA patients are DWI negative. TIA mimics (16 studies, 14,542 patients) make up 40-45% of patients attending clinics. UK survey (45% response) showed most secondary prevention started prior to clinic, 85% of primary brain imaging was same-day CT; 51-54% of patients had MR, mostly additional to CT, on average 1 week later; 55% omitted blood-sensitive MR sequences. Compared with 'CT scan all patients' MR was more expensive and no more cost-effective, except for patients presenting at > 1 week after symptoms to diagnose haemorrhage; strategies that triaged patients with low ABCD2 scores for slow investigation or treated DWI-negative patients as non-TIA/minor stroke prevented fewer strokes and increased costs. 'One-stop' CT/MR angiographic-plus-brain imaging was not cost-effective.

LIMITATIONS

Data on sensitivity/specificity of MR in TIA/minor stroke, stroke costs, prognosis of TIA mimics and accuracy of ABCD2 score by non-specialists are sparse or absent; all analysis had substantial heterogeneity.

CONCLUSIONS

Magnetic resonance with DWI is not cost-effective for secondary stroke prevention. MR was most helpful in patients presenting at > 1 week after symptoms if blood-sensitive sequences were used. ABCD2 score is unlikely to facilitate patient triage by non-stroke specialists. Rapid specialist assessment, CT brain scanning and identification of serious underlying stroke causes is the most cost-effective stroke prevention strategy.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Interventions in the management of serum lipids for preventing stroke recurrence

BACKGROUND

Studies have shown that interventions which reduce total and low-density lipoprotein cholesterol levels also reduce coronary heart disease (CHD) and stroke events in those with a history of CHD. However, it is uncertain whether treatment to alter cholesterol levels can prevent recurrence of either stroke or subsequent cardiovascular events and whether differences in outcomes exist between classes of lipid-lowering therapy. This is an update of a Cochrane review first published in 2002.

OBJECTIVES

To investigate the effect of altering serum lipids pharmacologically for preventing subsequent cardiovascular disease and stroke recurrence in patients with a history of stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched December 2008), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2008), MEDLINE (1966 to December 2008) and EMBASE (1980 to December 2008). We contacted pharmaceutical companies known to produce a lipid-lowering agent for information on relevant publications or unpublished work.

SELECTION CRITERIA

Unconfounded randomised trials of participants aged 18 years and over with a history of stroke or transient ischaemic attack (TIA).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality and extracted data.

MAIN RESULTS

We included eight studies involving approximately 10,000 participants. The active interventions were pravastatin, atorvastatin, simvastatin, clofibrate, and conjugated oestrogen. Fixed-effect analysis showed no overall effect on stroke recurrence but statin therapy alone had a marginal benefit in reducing subsequent cerebrovascular events in those with a previous history of stroke or TIA (odds ratio (OR) 0.88, 95% confidence interval (CI) 0.77 to 1.00). There was no evidence that such intervention reduced all-cause mortality or sudden death (OR 1.00, 95% CI 0.83 to 1.20). Three statin trials showed a reduction in subsequent serious vascular events (OR 0.74, 95% CI 0.67 to 0.82).

AUTHORS' CONCLUSIONS

There is evidence that statin therapy in patients with a history of ischaemic stroke or TIA significantly reduces subsequent major coronary events but only marginally reduces the risk of stroke recurrence. There is no clear evidence of beneficial effect from statins in those with previous haemorrhagic stroke and it is unclear whether statins should be started immediately post stroke or later. In view of this and the evidence of the benefit of statin therapy in those with a history of CHD, patients with ischaemic stroke or TIA, with or without a history of established CHD, should receive statins.

Common Questions in Managing Hyperlipidemia

Hyperlipidemia is a serious disease that affects the health and well-being of many, and further complicates other chronic illnesses. When treating a patient who has a lipid disorder, it is wise to take a global approach to the problem by assessing the patient's history and risk factors, collaborating on developing a healthy lifestyle plan to which the patient can commit, and initiating appropriate therapy when indicated.

Patterns and effectiveness of lipid-lowering therapies in a managed care environment

OBJECTIVE

To investigate the effectiveness of statin therapy and to compare the effectiveness results of this study with the reported efficacy of the corresponding data from randomized clinical trials in a moderate-to-high risk coronary heart disease (CHD) managed care population.

METHODS

Subjects, > or = 18 years old, with a new hyperlipidemia diagnosis or a new prescription claim for a lipid-lowering medication (LLM) between January 1, 1999 and March 31, 2001 were followed for 12 months. Subjects were classified into six medication categories of LLM use based partly on efficacy levels on package inserts. CHD risk factors were measured in the 24-month period prior, and subjects were required to have an established CHD or a CHD-related condition, or have two or more CHD risk factors.

RESULTS

The study population consisted of 39,124 hyperlipidemic subjects with moderate-to-high CHD risk; 22,048 (56.4%) were untreated with LLMs. Absolute mean low-density lipoprotein cholesterol (LDL-C) reductions ranged from a 32 mg/dL decrease in the low-efficacy groups to a 57 mg/dL decrease in the high efficacy statin group; percent reductions ranged from a 19% reduction from baseline to a 32% reduction from baseline, respectively. Less than half of subjects (47%) reached LDL goals set forth by NCEP Adult Treatment Panel (ATP III) guidelines, however, the rate of reaching goal increased as statin efficacy increased.

CONCLUSIONS

While a dose-response relationship was observed, the effectiveness of statin therapy was less than stated in package labeling and only 72% of the users of the highest efficacy statins reached their ATP III goal. LLM use was inconsistent with that recommended by the NCEP ATP III CHD risk assessment. Hyperlipidemia treatment in the managed care setting remains in need of improvement.