Almost 150 people die in poverty in Mid Sussex every year, according to estimates published for the first time.
End-of-life charity Marie Curie said it was "shocking" that more than 90,000 people across the UK pass away while living in poverty annually and called for urgent action from the Government.
And the findings could be an underestimate as research by Loughborough University on behalf of the charity analysed data from before both the coronavirus pandemic and the cost-of-living crisis.
The estimates suggest that 141 people in Mid Sussex died in 2019 having experienced poverty in the last year of their life – around 11% of the total number of deaths in the area.
They were among 10,107 annual deaths in poverty across the South East, and almost 93,000 throughout the whole of the UK.
More than 15% of the nearly 605,000 people who died in the UK in 2019 are estimated to have experienced poverty in the last year before their death.
Researchers modelled estimates using a combination of data from a survey which closely followed the lives of thousands of people from 2009 to 2019, and local figures on deprivation.
For most of the findings, the Social Metrics Commission's definition of poverty was used which examines how much someone’s resources, after housing costs, meets their needs – including "inescapable costs" such as childcare and disability.
Juliet Stone, from the Centre for Research in Social Policy at Loughborough University, said the cost of living is high and rising, making the physical and financial challenges for people with terminal illnesses even tougher.
She said: "The number of people dying in poverty has almost certainly risen even further since the period covered by our research and will only get higher in the coming months as the cost of living crisis deepens.”
They found that 68,000 (around three-quarters) of the people who died experiencing poverty were of pension age – representing 13% of the more than 500,000 deaths among this group.
Around 25,000 were of working age, but this equated to 28% of the 90,000 deaths in this cohort – making them more than twice as likely to die in poverty than those who live past pension age.
The research suggests women and people from minority ethnic groups are particularly vulnerable to poverty at the end of life.
Of the 141 deaths in poverty in Mid Sussex in 2019, 112 are estimated to be pensioners (9% of the group), and 30 working age (20%).
Marie Curie is calling for urgent action to give terminally ill people of working age access to their State Pension, and warned the benefits system is failing to keep working-age people out of poverty at the end of their lives.
Matthew Reed, chief executive of the charity, said: "No one wants to imagine spending the last months of their life shivering in a cold home, struggling to feed themselves, their children, and burdened with the anxiety of falling into debt.
"But for 90,000 people a year that is their reality.
"We are staggered to see the scale of poverty among dying people – it is shocking."
The charity is also calling for greater support with energy costs to be made available to all terminally ill people, regardless of their age, and for more support with the costs of childcare for terminally ill parents with young children.
The Department of Work and Pensions said those nearing the end of their lives can get fast-track access to a range of benefits without needing a face-to-face assessment or waiting period.
A DWP spokesman said policies announced in the Queen's Speech mean more people at the end of life will be able to access some benefits earlier.
He added: “The Government is taking decisive action to ease pressures on the cost of living, including spending £22 billion across the next financial year to support people with energy bills and cut fuel duty, and our £1 billion Household Support Fund is helping the most vulnerable with essential costs.”