The Police Investigations and Review Commissioner (Pirc) investigation into the case found officers were dispatched to his Edinburgh address within 35 minutes, but were diverted to another urgent incident.
It was not until later that police realised no-one had attended.
The Commissioner concluded the delay was caused by a “lack of ownership” of the initial call within Police Scotland.
Kate Frame added that medical opinion indicated the delay was unlikely to have had a significant impact on the seriousness of the man’s illness.
The incident unfolded on April 19 when an Edinburgh City Council neighbourhood support officer reported concerns for the man, who was the subject of regular welfare visits but had not been seen for a few days. There had also been no reply at his home address.
The Pirc report found that while the initial call to police was correctly prioritised as a Grade 2 incident, which requires a response within 15 minutes, officers were not dispatched for 35 minutes.
On the way to the call, those officers were diverted to another incident, and it was not until some time later that it was realised that no-one had attended and alternative officers were then dispatched.
When they arrived at the property later in the day, they found the man was seriously ill and he was taken to hospital for treatment.
His condition has since improved and he is now expected to make a full recovery.
Ms Frame said: “Fortunately in this case, the medical opinion suggests that the delay in the police attending is unlikely to have had a significant impact on the seriousness of the man’s illness.
“Police Scotland has since carried out a review of the circumstances and put new safeguards in place for dealing with this type of incident, which requires supervisors to more closely monitor the actions of staff.”