More people died after being admitted to Doncaster and Bassetlaw Teaching Hospitals NHS Trust with pneumonia than any other condition, figures reveal.
New NHS data shows 500 people died after getting the infection in 2018, in which lung tissue becomes inflamed and fills with fluid.
It means that of the 2,700 deaths over the year in the trust's hospitals, or up to 30 days after patients were discharged, 19 per cent were linked to a diagnosis of pneumonia.
The British Lung Foundation (BLF) said that between five and 11 adults in every 100,000 get pneumonia each year in the UK, with over-65s particularly vulnerable.
A BLF spokesman said: “There are things people can do to reduce their risk of pneumonia, such as not smoking, and there are vaccinations available to protect those who are at higher risk."
The picture at Doncaster and Bassetlaw Teaching Hospitals NHS Trust is reflected across England, where more people also died after being diagnosed with pneumonia than any other condition.
Across England, around 15% of the 293,000 patients who died last year were initially diagnosed with the condition.
Nick Scriven, president of the Society for Acute Medicine, said the data confirmed "the massive stresses the health care system is under", and that it reflected an older and frailer hospital population.
Commenting on the pneumonia figures, he said: "The stress to the system is added to by the fact that this sort of illness is not one that is treated in 24 to 48 hours in the elderly, and often they will need longer times in hospital and then time recovering."
Mr Sewa Singh, Medical Director at DBTH, said: ‘’Pneumonia represents a real challenge not only for our Trust, but for the NHS as a whole. On a national level, it is one of the biggest issues that healthcare providers must contend with and, in that sense, our figures are very much in line with expectations
"Patient safety is a top concern for us at DBTH and we strive each and every day to provide an exceptional standard of care.
"In recent years, our mortality performance has continued to improve, with our Hospital Standardised Mortality Ratio (HSMR) going from 109 in 2015 to 93.3 in 2019, marking an improvement of 14.9 per cent. The expected HSMR is 100.”
The second most common initial diagnosis for deaths at Doncaster and Bassetlaw Teaching Hospitals NHS Trust was septicaemia, or blood poisoning, with 220 patients dying.
Acute cerebrovascular disease - a cause of stroke - was third, with 140 deaths.
Acute or unspecified kidney failure and heart failure were also common diagnoses.
NHS Digital, which released the data, said the reason a patient was admitted may not directly correspond to their cause of death.
Across England, the top five diagnoses resulting in deaths in or after hospital were:
Acute cerebrovascular disease (6%)
Heart failure (4%)
Aspiration pneumonitis (3%)
The death rate at the Doncaster and Bassetlaw Teaching Hospitals NHS Trust was categorised as “expected” in 2018, with the difference between the number of deaths and the total expected based on averages across England falling within the anticipated range.
However, the NHS says the rate should be looked at alongside other measures when judging the performance of a trust.