People who wait longer for NHS treatment are significantly more likely to seek emergency care in the months after eventually receiving it, compared with those who are seen quickly.

People treated within 18 weeks of being on the waiting list made 18% fewer A&E visits per week in the three months following their treatment, compared to how often they visited A&E while waiting for treatment.

In contrast, people who waited over a year ended up making 31% more A&E visits in the three months following their care.

The Health Foundation, which carried out the research and shared the findings with the Sky News Data and Forensics Unit, say that the fact people need more emergency care after long waits for treatment “may indicate additional aftercare needs or decreased effectiveness of treatment following a longer wait”.

They analysed detailed patient-level data that had previously not been available for research use.

It complements new NHS data published last week which revealed the make-up of the waiting list for the first time, in terms of the gender, age, ethnicity and deprivation status of the patients on it.

Government targets being missed

One of the targets most commonly highlighted by the government is to ensure that, by the end of this parliament, fewer than 8% of patients wait longer than 18 weeks for treatment.

Currently, almost five times as many patients in England wait longer than that, with significant differences depending on where you live.

It’s the same in emergency care. The target is that fewer than 5% of people should wait longer than four hours at A&E. As it stands, one in four people wait longer than that.

The Health Foundation explained that, as well as patients having to live with the “consequences of debilitating conditions for longer”, long waits can also lead to “more complex, difficult and expensive treatment” being required.

They also “significantly increase consumption of pain relief medication”. In some cases, while waiting, conditions for the patient become permanent and untreatable.

The NHS has paid out more than £8.3bn in compensation claims for injury and deaths caused by delays in care since 2010, in addition to the extra cost to the NHS of more A&E and GP attendances.

Dr Hilary Williams, incoming clinical vice president of the Royal College of Physicians, told Sky News: “People’s health clearly deteriorates overall as they wait for treatment. For example, waiting for heart or knee treatment can lead to increased risk of worsening health due to inactivity.

“When patients are then waiting too long, their conditions can worsen and complications can occur, meaning people may end up needing emergency care even after their planned treatment. In other words, the issue with long waits isn’t just the delay itself, but the lasting health impacts that those longest waits can cause.

“Not only does this significantly impact individual patients, but it also adds further avoidable strain to an already overstretched workforce.”

Shorter waits for wealthier people, white people and men

Data released by the NHS for the first time last week also shows that women, Asian people, and those in more deprived areas are more likely to experience longer waits for NHS treatment, compared with men, white people and the least deprived.

The differences are not extreme – less than two percentage points between the top and bottom groups – but they are statistically significant.

Health Foundation analysis also reveals that Asian people are more likely to wait longer even after accounting for the age, frailty and deprivation level of patients.

The research addresses the reasons why people left the waiting list – fewer than half of people removed from the waiting list did so because they actually started treatment.

A third of people had a “decision not to treat”. This is a broad category that includes people who dropped off the NHS list to receive private care. It also includes cases where a clinician has decided that the patient’s condition can be treated in primary care.

About one in 12 people went on to “active monitoring” instead of treatment, meaning their symptoms are monitored by specialists but they are not due for further clinical intervention or diagnostics procedures.

In about one in 20 cases the patient declines treatment themselves. In about one in 200 cases, equivalent to 30,000 people on a waiting list of over six million, the patient dies while waiting for care.

A similar number are taken off the waiting list because they have missed appointments, although this figure is higher among people from more deprived areas.

Longest waits for oral surgery, shortest for elderly services

There are significant differences in wait time depending on what you’re waiting for.

More than half of patients waiting for mouth or jaw surgery wait longer than 18 weeks for treatment, compared with fewer than a third of patients referred for heart and lung or eye appointments.

The Health Foundation said that conditions that are less likely to lead to death, for example many of those associated with gynaecology or ear, nose and throat problems, had been de-prioritised as part of efforts to increase access to care after the pandemic.

They said that some treatments that typically required overnight stays had longer wait times, as capacity was more limited. In some cases, waits were longer because there was a shortage of specialists for that specific condition.

Discussing the findings of the research, Charles Tallack, Director of Research and Analysis at the Health Foundation, told Sky News: “Reducing the elective care waiting list is rightly a major government priority. But while long waits continue, it’s vital to understand the impact of those waits. The NHS should consider how to better support people on waiting lists who have higher needs and longer waiting times.

“To enable informed decisions, the NHS must make better use of the rich data already available on elective care. That includes improving the quality of data to answer questions like why people leave a waiting list – which is essential for truly understanding and addressing the backlog.”

Health and Social Care Secretary Wes Streeting said: “We inherited an NHS which after years of neglect had left all patients worse off – but some more than others.

“Sunlight is the best disinfectant. Only by being upfront and shining a light on inequalities can we begin to tackle the problem. We will give all patients the care they need when they need it as part of our Plan for Change.”

See how waits in your trust differ for cancer treatment, elective operations and emergency care with our table:

The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling we aim to better explain the world while also showing how our journalism is done.