Almost 5,000 people died while on a health service waiting list in Northern Ireland in the last year.
The number of deaths is increasing year on year, rising by almost 50% since 2014.
In the last five years more than 22,000 died while waiting for treatment, an investigation by this newspaper found.
The timeframe includes the three-year period when Stormont was not sitting. Some people died having been on a waiting list for up to five years.
Health officials said the deaths may not be linked in any way to being on a waiting list.
Yet the extent of people passing away before undergoing treatment or operations is another shocking revelation to emerge from a health system in the midst of crisis.
The most recent official figures show a record 306,180 people were on a waiting list as of September.
Strike action by nurses and other health staff has also piled pressure on the system.
This newspaper can reveal the full impact of the spiralling waiting times for appointments and surgery in our hospitals.
◊ 22,001 people died while on waiting lists across the five health trust areas in the last five years.
◊ The number of deaths has risen from 3,206 in 2014 to 4,699 in 2019 - a rise of 46.5%.
◊ On average, 12 people are dying every day while on a waiting list.
◊ In one health trust the number of deaths has more than trebled since 2014.
The figures were obtained by this newspaper after Freedom of Information requests.
Each health trust provided details of how many people had been removed from their waiting lists because they had died. The figures cover inpatient and outpatient cases.
In each case, they stressed that it was not possible to determine if a patient's death was linked in any way to the reason for them being on the waiting list.
A patient may have died for another, entirely separate reason and unrelated to the waiting list they were on at the time.
However, the figures give an insight into the thousands of people dying each year while waiting for procedures.
SDLP health spokesman Mark H Durkan MLA said the figures were "shocking".
"For someone to spend their final days on a health service waiting list is unacceptable," he said.
"These people - regardless of whether their death was as a result of being left on a list or not - will have spent their last months, or as is increasingly the case, their last years in agony and pain.
"They will have died waiting for treatment for conditions and that is not acceptable."
He added: "Often people, whether it is health professionals, politicians or the media, look at waiting lists and see figures.
"Yet each of these figures is a real person, many with a family, and a story like this really brings home the human tragedy behind the health crisis."
Three health trusts provided figures by financial year, two others by calendar year, and thus the figures will not be precisely comparable.
However, the five-year totals provided by the trusts show a total of 22,001 patients on a waiting list died.
The highest number of deaths was in the Belfast Trust, Northern Ireland's biggest.
Deaths rose by 41% between 2014/15 (1,056 deaths) and 2018/19 (1,494 deaths).
In the Northern Trust, the number of waiting list deaths trebled in five years - rising from 417 in 2015 to 1,261 in 2019. In several hundred cases across the various trusts, people died after waiting on a list for more than a year. In a handful of cases they had been waiting for up to five years.
Patricia McKeown from the health workers' union Unison said: "Apart from being profoundly sad, this is utterly unacceptable.
"We saw that horrendous report before Christmas that said a patient here can expect to wait up to 100 times longer than in England - how can you justify that?
"If there has been a 40% increase in deaths in the last five years, is that caused by these unduly long waiting times?"
Ms McKeown said data should be closely examined to spot trends.
"If it can be shown that waiting lists are increasing, and there is also an increase in people dying while on them, then there is a moral imperative to act and put it right," she added.
The Department of Health said: "The Department is acutely aware of the impact of growing waiting lists on patient care and the distress they cause.
"There is a concerted effort across the HSC to ensure the most urgent patients are prioritised and staff are working tirelessly to do this.
"It is important to note that, from the figures released, it is not possible to determine if a patient's death was linked in any way to the reason for being on the waiting list or to waits for any services.
"There is ongoing analysis to further understand the impact delays are having in the care and outcomes of patients and service users. Health Minister Robin Swann has identified tackling waiting lists as a top priority for his department. This will require a combination of sustained investment and transformation of how services are delivered."