In addition to the confidentiality of clinical information, we are concerned with its integrity and availability.
If information is corrupted, clinicians may take incorrect decisions which harm or even kill patients. If information is unreliable, in the sense that it could have been corrupted (even if it has not been), then its value as a basis for clinical decisions is diminished. There is also the medico-legal concern that healthcare professionals called to justify their actions may not be able to rely on computer records in evidence; and there has recently been controversy over whether it is enough to have an electronic record alone, or whether paper or microfiche records should be kept as a backup.
If information systems are unreliable in the simpler sense that information may occasionally be unavailable as a result of system failure or sabotage, then this also diminishes their value and restricts the use which may prudently be made of them.
It is therefore prudent to look for ways to guarantee integrity for certain records, and to prevent attacks which might impact system availability.