Rheumatoid arthritis may be costing the UK economy almost £8 billion a year, a new report has claimed.
The figure is almost double a previously estimate of between £3.8 billion and £4.8 billion.
Alisa Bosworth, chief executive of the National Rheumatoid Arthritis Society (NRAS), which produced the report, said: "The scale of these losses is vast.
"Unless rheumatoid arthritis is diagnosed and treated early, the effects on long-term health can be disastrous, forcing people to leave work in the prime of their lives and placing families under significant financial strain."
Around 26,000 new cases of rheumatoid arthritis (RA) are diagnosed each year in England alone, and more than 690,000 people in the UK are believed to be living with the condition.
The auto-immune disease causes progressive destruction of the joints and can lead to severe disability.
It most commonly strikes during a person's working life, between the ages of 40 and 50. For this reason RA is recognised as a major economic burden.
The new figures were based on the numbers of sufferers, the long-term cost of treatment, and the amount of productive working life lost as a result of the disease.
Estimates for England were extrapolated to arrive at totals for the whole of the UK.
An employed person with RA has an average of 40 days' sick leave a year, compared with just 6.5 days for a healthy worker, said the report, entitled The Economic Burden of Rheumatoid Arthritis.
Ms Bosworth said it was vital that people with RA received treatment as soon as possible after developing symptoms.
The direct cost to the NHS of RA was put at less than £700 million in the report, but this was dwarfed by the wider costs to the UK as a whole.
The total economic burden was calculated to be £7,925,379,954. Productivity loss associated with newly-diagnosed cases of RA was assessed at almost £3 billion a year.