I M Chaney Antique Furniture has dated this piece to the 17th Century.

The single sectioned base is manoeuvred up and down by means of an adjustable ratchet mechanism. By altering this mechanism, the angle of the upholstered top can be manipulated to allow for ease of use and comfort.

Gout was a common affliction throughout the wealthy classes in the nineteenth century, common enough for James Gillray in 1799 to provide a caricature of its effects. Happily not so frequent today this stool is still a good looking and ultimately useful piece of furniture.
Measuring
H 39 cm
W 30 cm
D 36 cm
Condition
Leather original , one small rip at the front and a few age related scuffs.
I M Chaney Antique Furniture has dated this piece to the 17th Century.
You can view the stock and full dealer information on the I M Chaney Antique Furniture Profile Page