John Jackson was last seen before heading to the appointment at a facility on Almeda around 2 p.m., his wife told ABC13.
He was also due to visit Methodist Hospital in the Texas Medical Center, but never arrived.
Jackson is a Black man with black hair and brown eyes. He's 6-feet tall and weighs approximately 253 pounds.
He was last seen driving a red GMC Sierra pickup. He was wearing blue jeans, an orange long-sleeve shirt, a white undershirt and an Army green baseball cap.
If you have any information on Jackson's whereabouts, call the Houston Police Department's Missing Persons Unit at 832-394-1840.