Individuals' human rights may have been breached in more than 500 cases where "do not resuscitate" decisions were made during the Covid pandemic, the care watchdog for England has said.
Some 508 'do not attempt resuscitation' (DNAR) decisions made since March 2020 were not agreed in discussion with the person or their family, a report found.
The Care Quality Commission is calling for improvements to care planning.
An NHS spokesman said decisions should be made in consultation with families.
The CQC has recommended that a ministerial oversight group be created to work with health and care providers, local government and the voluntary sector to deliver improvements.
It wants to see a consistent national approach to advance care planning, with staff training, accessible information for families and records of conversations and decisions agreed.
The findings come after the CQC was asked by the Department of Health and Social Care to conduct a rapid review of how DNAR decisions were used at the start of the coronavirus pandemic.
It followed concerns that decisions were being made without the involvement of patients or relatives, and that they were being applied in a blanket way to particular groups - to people with learning disabilities, for example.
An interim report published by the care watchdog in December found that doctors may have made "do not resuscitate" decisions on a blanket basis in the first wave of the pandemic.
An NHS spokesman said: "The NHS has repeatedly instructed local clinicians and services that the blanket DNA(CPR) decisions would be unacceptable - including on three separate occasions in less than a month at the start of the pandemic, and again last week - and that access to treatment and care for people should be and is made on an individual basis in consultation with family and carers."
DNAR orders refer to cardiopulmonary resuscitation (CPR).
In its latest report, the CQC said that a combination of "unprecedented pressure" on providers and "rapidly developing guidance" may have led to situations where DNAR decisions were incorrectly conflated with other clinical assessments.
There were examples of good practice but the regulator also found a "worrying picture" of poor involvement of people using services, poor record keeping, and a lack of oversight and scrutiny of the decisions being made.
However, it noted that the issues raised - such as the need for proper, consistent processes around timely conversations about people's care - pre-dated the pandemic.
The report includes evidence from seven Clinical Commissioning Groups (CCGs), responses from adult social care providers, a public survey and voluntary sector organisations.
Some 2,048 adult social care providers responded to the CQC, and said that 508 DNAR decisions made since 17 March 2020 had not been agreed in discussion with the person, their relative or carer.
Around a third (180) were still in place in December.
And, while responsibility for making DNAR decisions does not largely rest with adult social care providers, 119 providers said people in their care had been subject to blanket DNAR decisions since March 2020.
The CQC said the figures raised concerns about whether the providers making these decisions were at risk of breaching the Equality Act 2010.
Most providers of adult social care, and primary and secondary care, said they were not aware of inappropriate DNAR decisions.
But other stakeholders, service users, families and carers said blanket DNAR decisions had been proposed locally.
The regulator heard evidence that these decisions were "quickly challenged and retracted".
Rosie Benneyworth, chief inspector of Primary Medical Services and Integrated Care at the CQC, said: "It is vital we get this right and ensure better end-of-life care as a whole health and social care system, with health and social care providers, local government and the voluntary sector working together.
"Covid-19 has brought this to the fore but these are not new issues."
Age UK said the approach to advance care planning needed a "complete overhaul", with strengthened support for professionals and families with concerns.
It is also calling for a review so that any "hasty, ill-informed decisions" could be removed from older people's records.
Meanwhile, Dan Scorer, head of policy at the learning disability charity Mencap, said the review highlighted "the urgent need for better staff training and support to ensure the right of people with a learning disability, and their families, to be involved in decisions about care and treatment is upheld".