The charity this month completed the sale of its Blackpool hotel to local company Century Hotels for about £800,000. The three other hotels, two in Scotland and one in Poole, Dorset, have gone on the market for a combined total of £3.7m.
One person in Arthritis Care's head office, the general manager of hotels, will be made redundant as a result of the sell-off. The charity said that staff at the hotels would transfer their employment to the companies that bought the hotels under the Tupe regulations, but it would be for the new owners to determine what happened to the employees.
Martin Gregory, co-owner of Century Hotels, declined to comment.
Adrian Adams, a former board member who resigned at Arthritis Care's annual general meeting last year in protest at the hotel sell-off, said the charity should have sold only one hotel and used the money to overhaul the other three.
A spokeswoman for Arthritis Care said it would be using the money "for the benefit of the arthritis community".
She said: "We have just consulted members on plans for the next five years, and this income will help us in achieving them."
The charity was making "every effort" to support hotel staff through the changes, she added.