This review concluded that there was reason to be generally optimistic regarding use of telehealth in Asia. The authors' conclusions were supported by the data presented, but should be interpreted with caution due to the poor quality of the evidence base, lack of generalisability and potential for missed studies of relevance to the review question.

To assess the efficacy of telehealth in Asia.

MEDLINE was searched for peer-reviewed English-language studies from January 1997 to June 2007. Search terms were reported. Additional studies were identified by handsearches of three telehealth-related journals and by checking reference lists of retrieved articles.

Studies of any design that assessed telehealth applications of any sort undertaken in at least one Asian country were eligible for inclusion. Outcomes included patient outcomes (such as increased access to health care services or improved quality of care) as well as administrative changes or economic effects.

Just over one third of the included studies were undertaken in Japan; two-thirds were conducted in urban settings. Just under half of the studies were hospital-based. All studies conducted in a home-based setting were undertaken in the more developed countries of the region (Japan, Taiwan and South Korea). Studies were conducted in a wide variety of disciplines that included radiology for orthopaedic and neurology problems, ophthalmology, pathology, emergency medicine and cardiology; nearly one quarter of studies included two or more disciplines. Just under half of the telehealth applications utilised store and forward telemedicine; slightly fewer used videoconferencing or combined store and forward technologies and videoconferencing. A third of studies used ISDN lines for telecommunication.

Two reviewers independently selected studies for inclusion in the review. Disagreements were resolved through consensus.

There was no formal assessment of study validity. The authors reported on a classification scheme by Jovell and Navarro-Rubio, where the strength of evidence was based on study design and use of controls; the level of evidence was rated from good to poor.

The authors did not state how the assessment was performed.

Data on study characteristics and outcomes were independently extracted by two reviewers. Disagreements were resolved by consensus.

A narrative synthesis by type of outcome (access to health care services, improved quality of care, cost-effectiveness, change management and policy issues) was presented. Differences between studies were discussed in the text.

A total of 109 studies (total n not reported, study size ranged from one to 511 patients) were included in the review. Most studies were described as poor by the authors with 75% identified as descriptive. Eight studies included a control group against which telehealth was compared; three of these were randomised controlled trials.

Improved quality of health care was reported in 40% of studies. Perceived ability of telehealth to provide for the patients' health-care needs was considered to be an important predictor of patient/provider satisfaction (seven studies). Improved access to health care and health-care services was reported in 20% of studies.

Thirteen studies assessed resource utilisation and cost. Videoconferencing resulted in higher costs than audio conferencing. Costs of any telehealth initiative was the main concern in Asian countries (five studies).

The findings gave a generally optimistic picture of telehealth in Asia, but there was a lack of good-quality studies and generalisability may be limited.

The review question was supported by broad inclusion criteria for study design, participants, interventions and outcomes. The literature search was restricted to English-language studies and used one database, which meant that relevant studies may have been missed and language biases could not be ruled out (for example, no studies were included from China). Appropriate steps were taken to reduce reviewer bias and error in the assessment of studies for inclusion and data extraction. Study quality was not formally assessed and so the reliability of the small included studies was unclear; the authors attributed levels of evidence based on type of study and acknowledged that most studies were poor quality. A narrative synthesis was appropriate given differences between the studies and only limited numerical data were reported, which made it difficult to draw conclusions. The authors' conclusions were supported by the data presented, but should be interpreted with caution due to the poor quality of the evidence base, lack of generalisability and potential for missed studies of relevance to the review question.

Practice: The authors stated that e-health or telehealth projects needed to include a concentrated effort from professionals, departments, institutions and governments. Sustainability would result only if a structure was in place from the start of the project to integrate all the telehealth processes into an existing health-care system.

Research: The authors stated that there was a need for methodologically-sound research-based studies that measured long-term health-related outcomes to provide reliable evidence for policy makers.

International Development and Research Centre, Canada (PANACeA project) and the University Research Council of the Aga Khan University, Karachi.

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.