Hospital patients with learning disabilities face longer waits and mismanaged treatment due to a failure to understand them by nursing staff, says a new report.
In one case, a patient who had problems making herself understood was accused of being drunk by hard pressed hospital staff.
It is estimated that one in 50 people in England have some form of learning disabilities such as Down's syndrome.
Dr Irene Tuffrey-Wijne, senior research fellow in nursing at St George's, University of London and Kingston University, said: "People with learning disabilities are largely invisible within the hospitals, which meant that their additional needs are not recognised or understood by staff.
"Our study found many examples of good practice, but also many examples where the safety of people with learning disabilities in hospitals was at risk."
Dr Tuffrey-Wijne, a co-author of the study who works at the Faculty of Health, Social Care and Education, a partnership between the two universities, added: "The most common safety issues were delays and omissions of care and treatment.
"Some examples come down to basic nursing care like providing enough nutrition but other serious consequences were also seen in our study.
"These included delays in clinical investigations and treatment by staff unclear or unaware of what to do in certain situations when patients had trouble expressing their consent or opinions or lacked an understanding about what was required from them."
The study included questionnaire surveys, interviews and observation with senior hospital managers, clinical staff, patients and carers in all types of areas within hospitals in the NHS.
It found that the main barrier to better and safer care was a lack of effective ﬂagging systems, leading to a failure to identify patients with learning disabilities in the first place.
There was also a lack of understanding by nursing staff about learning disability issues and a lack of clear lines of responsibility and accountability for the care of each patient with learning disabilities.
Specialist nurses such as learning disability liaison nurses and ward managers with specific responsibility to advocate on behalf of patients with learning difficulties were recommended by the report.
The report, Identifying the factors affecting the implementation of strategies to promote a safer environment for patients with learning disabilities in NHS hospitals, published in the Health Services and Delivery Research journal, also recommended that the NHS investigate practical and effective ways of ﬂagging patients with learning disabilities across NHS services and within NHS hospitals while also providing for procedures to ensure that family and other carers are involved in the care of such patients.