One hundred studies (number of participants unclear) were included in the review.
Store-and-forward telemedicine (35 studies).
Diagnosis or management: the largest number of studies came from the specialty of dermatology, in which concordance varied widely, from 41 to 87% for complete agreement and from 51 to 96% for disease-category agreement. While one study found complete agreement in decision to biopsy, others found lesser concordance. Diagnostic accuracy studies typically compared telemedicine diagnosis with a 'gold' standard, often biopsy of a pigmented lesion. In these studies, telemedicine generally was nearly as good as face-to-face in terms of a correct diagnosis. Wound care studies demonstrated that some characteristics of skin wounds and ulcerations could be assessed effectively using store-and-forward telemedicine, though these studies lacked statistical power. Four out of 5 ophthalmology studies showed that a high accuracy of diagnosing diabetic retinopathy could be obtained.
Health outcomes: there were no studies that assessed health outcomes using store-and-forward telemedicine interventions.
Access to care: 5 studies reported evidence on the effect of store-and-forward techniques upon access to care. The methodological quality of these studies was generally low and it was not possible to draw any firm conclusions.
Home-based telemedicine (27 studies).
Diagnosis or management: 2 studies assessing diagnostic capabilities in the home in the areas of congestive heart failure assessment and pulmonary function monitoring found various levels of agreement and disagreement, depending on the specific observation.
Health outcomes: the studies were highly heterogeneous and had several limitations. Multifaceted interventions demonstrated more benefit than single interventions such as monitoring of blood sugar or blood-pressure. In most studies, it was not possible to assess whether improved outcomes were due to the increased level of care provided by dedicated clinical staff or to the telemedicine intervention.
Access to care: no studies were identified that examined the effect of home-based telemedicine services on access to care.
Office/hospital-based telemedicine (38 studies).
Diagnosis or management: the most frequently studied specialty was ophthalmology; other frequently studied specialties included neurology and psychiatry. The results demonstrated that some diagnostic assessments could be successfully administered via telemedicine.
Health outcomes: studies indicated that outcomes with telemedicine interventions were comparable to those using conventional clinical evaluations. However, most of these studies were limited by small sample sizes and/or other problems.
Access to care: methodologically weaker studies suggested that office/hospital-based telemedicine improved access to care for patients in rural locations in medical applications in which patient evaluations could be performed using standard teleconferencing equipment.