This review found that implantable cardioverter defibrillator advisories had mixed effects on patient outcomes. This conclusion was based on very few studies and weak methodology. It is likely that studies were missed in the search and the authors' conclusions should be treated with caution.

To study the impact of implantable cardioverter defibrillator warning advice (advisories) on patient-centred outcomes.

PubMed was searched for articles from 1980 to the present; search terms were reported. Bibliographies of retrieved articles were handsearched for additional material. All articles were entered into Web of Science to perform a citation search.

Empirical, quantitative studies that examined the impact of implantable cardioverter defibrillator advisories on patient-centred outcomes were eligible for inclusion.

Outcomes of interest were a mixture of generic and disease-specific measures including: an amalgam of distress (e.g. anxiety and depression), anxiety, depression, device acceptance, and quality of life. The time between receiving advisories and assessment varied from less than one month to over 24 months. Patient response rates varied from 70.1% to 100% or were not reported. Advisories were divided into three classes. Class I was a device defect that had a high likelihood of causing serious adverse health or death. Class II was a device defect causing temporary or medically reversible adverse health, or a low risk of serious adverse health. Class III was a device defect that was unlikely to cause adverse health.

The authors did not state how many reviewers performed the selection.

The authors did not state that validity assessment was performed.

Data were extracted into tables. Advisories, as described by the Heart Rhythm Society, were the same as 'recalls' as defined by the Food and Drug Administration. They were divided into three classes.

The authors did not state how many reviewers performed the extraction.

The studies were combined in narrative synthesis.

Six studies were included in the review (n=505 participants).

Class I advisory: All three studies reported no significant impact of advisories on patient outcomes (three studies, n=240; all case-control).

Class II advisory: Three studies (n= 265); one case-control, one prospective, and one prospective case-control. Two studies reported an increase in patient anxiety and one reported a decrease in confidence for patients and caregivers. One study reported no significant impact for advisories.

Class III advisory: No studies.

The impact of device advisories on patient-centred outcomes was mixed. Two prospective studies found increased anxiety over time, whilst four larger case-control studies found no impact.

This review addressed a clear research question. The inclusion and exclusion criteria were brief, which may hinder the reproduction of the study. Limited sources were searched and there were no specific attempts to locate unpublished studies, which introduced the potential for publication bias. The authors did not state how many reviewers were involved in the methodology, which may introduce bias and error. The validity was not assessed and the quality of the studies is unknown. A narrative synthesis was appropriate given the small number of studies and the heterogeneity between included studies. The methods of this review were weak and, given the paucity of studies, the small samples, different study designs, and lack of standardisation of outcomes, there were no definitive conclusions.

Overall, the authors' conclusions reflected the evidence presented. These conclusions should be treated with caution because of the weak methodology and lack of studies.

Practice: The authors did not state any implications for practice.

Research: The authors stated that patient-centred outcomes should form part of standard clinical practice. In further studies, these outcome data should be collected in a standardised manner.

Part funded by a VENI grant (451-05-001) awarded to Dr Pedersen from the Netherlands Organization for Scientific Research, The Hague, The Netherlands.

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.