The NHS has achieved its financial savings target, largely as a result of freezing wages, but other savings are being achieved by rationing patients' access to certain treatments, a committee of MPs has reported.

Treatments being rationed include cataract surgery and hip and knee replacements, and while these are described as being "of low clinical value," people waiting for these operations suffer pain and a poorer quality of life, says the Commons Committee of Public Accounts (CAP), which notes its "concern" at such rationing.

"Furthermore, the finances of some trusts are fragile, and there is a risk they may resort to simple cost-cutting rather than finding genuine efficiency savings," said the PAC's chair, Labour MP Margaret Hodge, reporting on the panel's inquiry into the NHS' progress in making efficiency savings, based on evidence from the Department of Health.

The NHS has to fundamentally change the way that healthcare is provided in order to secure the level of savings needed in the future, for example by moving services out of hospitals and into the community. However, the PAC is not satisfied that the Department and the NHS Commissioning Board are doing enough to help the NHS transform services, she said.

"In replying to us, they should set out a clear plan for delivering the level of savings required from service transformation, including how they intend to use financial incentives to encourage NHS bodies to work together," said Lady Hodge.

Local people are "understandably resistant" when proposals are made to close their local hospital or reduce the range of services it provides, and it is down to the Department to make a clear case for change from the patient's point of view, demonstrating the benefits in terms of the quality and safety of care as well as cost savings, she pointed out, and warned: "unless this is done urgently, the Department will continue to face resistance to change and the NHS will struggle to deliver the savings it needs."

The Department had reported to the PAC that the NHS made savings in 2011-12 of £5.8 billion - virtually all of that year's forecast of £5.9 billion. While this suggests that the Service has made a positive start towards achieving the "Nicholson Challenge" of up to £20 billion in efficiency savings in the four years to 2014-15, the MPs say that the data for 2011-12 is not fully reliable, as only 60% of the savings it claimed to have made during the period could be substantiated using national data.

At local level, Primary Care Trusts (PCTs) measure and report savings in different ways; for example, the costs associated with generating savings are often significant but are not consistently taken into account in reporting the savings achieved. Using national data, the Department was able to substantiate only £3.4 billion of the savings reported for 2011-12, the MPs report.

The NHS says that the quality of healthcare should not suffer as it pursues efficiencies, and they note that performance against a small number of headline indicators of quality, including waiting times and infection rates, was maintained in 2011-12. However, they are concerned that the need to make savings may be affecting wider areas of care quality which are not adequately measured.

The Service is seeking to make savings by reducing the demand for health services, particularly for acute hospital care. This is not intended to restrict patients' access to care, but there are widespread concerns, from patient groups as well as professional bodies, that access to treatments "of low clinical value" such as cataract and bariatric surgery, is being rationed. Such treatments can make a real difference to a patient's quality of life, and delaying them may also lead to greater cost in the longer term, the MPs warn, and they welcome the fact that the Department has started work with the Royal College of Surgeons and others to define appropriate thresholds of care.

Changing the way services are delivered means in some cases centralising services, as in the case of stroke care in London, or providing more community-based care, closer to people's homes. This is expected to lead to some hospitals reducing the range of services they provide and the closure of some departments - and even of whole hospitals - changes which are usually contentious. What might make clinical and financial sense is often not supported by local people, and the Department has not yet convinced the public or politicians of the need for major service change or demonstrated that alternative services will be in place, say the MPs.