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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Self-management of oral anticoagulant therapy: a systematic review and meta-analysis

TD Christensen, SP Johnsen, VE Hjortdal, and JM Hasenkam.

Review published: 2007.

CRD summary

This review concluded that, for highly selected patients, self-management of oral anticoagulant therapy appeared to be at least as good as, and possibly better than, conventional management. This conclusion may not be reliable given the quality of, and heterogeneity between, included trials and the potential publication bias.

Authors' objectives

To assess the efficacy and safety of self-management of oral anticoagulant therapy for patients on long-term treatment.

Searching

The Cochrane Central Register of Controlled Trials and PubMed were searched from 1951 to December 2005. Search terms were reported. Additional studies were sought through a review of personal files, by handsearching published reviews and by searching references of retrieved studies. There was no restriction on the basis of language.

Study selection

Randomised controlled trials (RCTs) assessing the efficacy of self-management of oral anticoagulant therapy in comparison with conventional management were eligible for inclusion. Eligible trials reported death through all causes, major complications, minor complications and time within therapeutic international normalised ratio target range.

In included trials, the participants were aged over 18 years of age and were on long-term oral anticoagulant therapy, with follow-up ranging from 4.6 to 24 months.

The authors did not state how the papers were selected for review or how many reviewers performed the selection.

Assessment of study quality

Two reviewers independently assessed trial quality using predefined criteria according to the use of adequate concealment of treatment group allocation and the use of the intention-to-treat principle. Disagreements were resolved through consensus.

Data extraction

Three investigators were contacted for additional detail regarding the results of their trial. Relative risks with 95% confidence intervals were calculated for dichotomous data (death and complication events), while mean differences with 95% confidence intervals were calculated for continuous data (time within therapeutic international normalised ratio range). Cross-over studies were included and analysed.

Two reviewers independently extracted the data with disagreements resolved through consensus.

Methods of synthesis

Trials were combined in a random-effects and fixed-effect models as appropriate. Sensitivity analysis was undertaken of high and low quality trials. Heterogeneity was assessed using an I2 test. Publication bias was assessed using a funnel plot.

Results of the review

Ten randomised controlled trials (RCTs) were included in the review (n=2,724 patients). Two of the trials were rated as high-quality.

For a number of outcomes patient self-management yielded improved outcomes in comparison with conventional management.

Death, all causes: For all trials, the relative risk for death was 0.48 (95% confidence interval (CI): 0.29 to 0.79; p=0.004). There was no heterogeneity between trials.

Major complications: For all trials, the relative risk for major complications was 0.58 (95% CI: 0.42 to 0.81; p=0.001). For high quality studies only, the relative risk was 0.47 (95% CI: 0.26, 0.84; p=0.01). There was no heterogeneity between trials.

Minor complications: For all trials the relative risk for minor complications was 0.76 (95% CI: 0.63 to 0.91; p=0.003). Restricting analyses to high quality studies the relative risk was 0.41 (95% CI: 0.31 to 0.54; p<0.00001).

Time within therapeutic international normalised ratio target range: For all trials, the weighted mean difference for therapeutic international normalised ratio target range range was 4.36% (95% CI: 2.87 to 5.86; p<00001). There was significant heterogeneity between trials and application of a random-effects model still yielded a significant result, weighted mean difference 6.53% (95% CI: 2.24 to 10.82; p=0.003). When the analysis was restricted to high quality trials the difference between the interventions was not significant.

The funnel plot suggested the presence of publication bias for trials analysing minor complications and time within therapeutic international normalised ratio target range

Authors' conclusions

In highly selected patients, self-management of oral anticoagulant therapy appeared to be at least as good as, and possibly better than, conventional management.

CRD commentary

The review addressed a well-defined question and undertook a reasonable search for trials, with no restriction placed on language. Only two databases were searched, which makes it possible that some relevant trials were not included in the review. The authors attempted to minimise bias and errors in reviewing the trials selected for inclusion. An assessment of the methodological quality of the included trials was undertaken and incorporated into the discussion of the results. The characteristics of the individual trials were presented clearly. Pooling appeared to have been appropriate statistically, but only two of the trials were considered to be of high quality. There was heterogeneity for some analyses and also substantial publication bias for analyses surrounding two of the outcomes considered. The authors’ use of heterogeneity to determine whether a fixed-effect or random-effects model should be applied to the data is questionable, but the use of sensitivity analysis for high and low quality studies was sensible. Despite being a well undertaken and reported study, in light of the uncertainty underpinning some of the results, the conclusions should be treated with caution.

Implications of the review for practice and research

Practice: The authors did not state implications for practice.

Research: The authors recommended that further good quality randomised controlled trials, with well defined clinical end points such as death and major complications, are needed.

Funding

Not stated.

Bibliographic details

Christensen T D, Johnsen S P, Hjortdal V E, Hasenkam J M. Self-management of oral anticoagulant therapy: a systematic review and meta-analysis. International Journal of Cardiology 2007; 118(1): 54-61. [PubMed: 16891008]

Indexing Status

Subject indexing assigned by NLM

MeSH

Administration, Oral; Anticoagulants /administration & dosage; Humans; International Normalized Ratio; Models, Statistical; Randomized Controlled Trials as Topic; Self Administration /statistics & numerical data; Thromboembolism /prevention & control

AccessionNumber

12007001704

Database entry date

26/08/2009

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 16891008

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