Learning from no-fault treatment injury claims to improve the safety of older patients.

New Zealand's treatment injury compensation claims data set provides an uncommon no-fault perspective of patient safety incidents. Analysis of primary care claims data confirmed medication as the leading threat to the safety of older patients in primary care and drew particular attention to the threat posed by antibiotics. For most injuries there was no suggestion of error. The no-fault perspective reveals the greatest threat to the safety of older patients in primary care to be, not error, but the risk posed by treatment itself. To improve patients' safety, in addition to reducing error, clinicians need to reduce patients' exposure to treatment risk, where appropriate.