We can first classify current PHR solutions into freestanding (3rd party), provider-tethered, and integrated PHR systems [25]. Free-standing PHR systems are stand-alone software applications that help patients maintaining their personal health information. Provider-tethered solutions are implemented and made available by a single care institution.
In terms of number of users, the most successful PHR solutions belong to the latter category, with examples ranging
from the EPIC MyChart system [26], tethered from hospitals using the EPIC EHR, and MyHealtheVet [24], promoted by
the US Department of Veterans Affairs. Besides increasing efficiency, by reducing the need for patient data collection or
duplicate clinical exams, provider-tethered PHRs promote a more stickier relationship between the provider and the patient. At the same time, however, this type of PHRs do not address the space dimension in the continuity of care envisioned for PHRs. An interoperability problem remains, in fact, when the patient seeks care from a caregiver outside of the network of the provider of the PHR. Kaelber et al. have demonstrated theoretically that the large-scale deployment of such PHR systems would have significant economic drawbacks [27].
MyPHRMachines can be classified as an integrated PHR solution [25]. Integrated PHRs are free-standing solutions that
collect information from a variety of information sources, such as EMRs, insurance claims, pharmacy data, or data entered
directly by patients. Integrated solutions, such as Indivo X [28] or Microsoft HealthVault [29] are less successful in terms of
adoption when compared to provider-tethered solutions [26], [29]. Patients, in fact, are required to proactively experiment
with the technology without being pushed in doing so by a given provider. Moreover, the interoperability of the PHR with
other proprietary systems and, more generally, the provider willingness to trust and use the PHR, are not guaranteed.