The Brit won bronze in Athens four years ago and came into the event as one of the favourites in the absence of reigning champ Carolina Kluft.
But the 31-year-old ended up 102 points off a bronze medal and 216 adrift of new champion Nataliia Dobrynska of the Ukraine.
Sotherton admitted: “If I had won gold or silver I’d have quit but I’ll do another year.
“I want to at least win the World Championship.”