Robert Michael Bennight had appealed his second-degree murder conviction in the 2007 death of 52-year-old Denise Fabbro.
Bennight, 61, claimed the trial judge made several errors, arguing he should have been allowed to challenge the jury for bias against people with mental illness.
Bennight suffered a brain injury in a 1983 car accident that left him with cognitive deficits, although he was found fit to stand trial.
Court heard after he attacked Fabbro, Bennight sat in his apartment in Vancouver's notorious Downtown Eastside for a while before calling 911 with a fabricated story.
Most of the bones in Fabbro's face were broken and she suffered severe trauma to her skull, neck and ribs.
Her injuries were believed to have been caused by repeated blows to her face and body with an object such as a hockey stick or a baseball bat.
Fabbro died of her injuries two months later in hospital.
The trial judge said it was unclear why Fabbro was in Bennight's apartment.
Bennight has a lengthy criminal record that includes at least 16 offences, including several assaults, carrying a concealed weapon and uttering threats to cause death or bodily harm.