Computers, confounding, clusters, consent, cost, COVID and consultation: how the Health and Disability Code impedes the learning health system.

The Health and Disability Code precludes any research involving a competent patient without the informed consent of the participant. A learning health system requires rigorous evaluation of both new and established clinical practice, including low-risk components of usual care pathways. When comparing two accepted practices, the only way to control for unknown confounders is by randomisation. In some limited circumstances, particularly when comparing groups or clusters of patients, this comparison can only practicably be undertaken without consent. The current Code impedes a learning health system and is detrimental to the health of New Zealanders. It urgently needs updating.