Now, her family is considering a chilling question: Did a former nurse who has confessed to killing up to 40 patients in New Jersey and Pennsylvania have anything to do with making her ill?
Scores of others families are beset by similar fears.
"My sisters and I brought her into a medical facility believing it was best for her," said Klimko's daughter, Mary Ann Jones. "My worst fear is that something bad might have been done while she was in there that we had no control over."
The nurse, Charles Cullen, was working at the critical care unit of Somerset Medical Center in Somerville, N.J. at the time Klimko was being treated there.
The medication coursing through the 76-year-old woman's system was digoxin - the same drug Cullen allegedly used to kill a Roman Catholic Church official, who died June 28 at Somerset.
Klimko was called back to the hospital twice after test results turned up high levels of digoxin. She died Oct. 26 of congestive heart disease, at home.
Jones, 41, said that when she read about Cullen, "I just wanted to let them know that I wanted her file opened and investigated."
"It just sounded a little suspicious to me," she said.
Somerset County authorities are looking into Klimko's death. The county prosecutor's office has had more than two dozen inquiries about former patients in the hospital since the Cullen story broke.
Cullen, 43, is charged with killing Roman Catholic priest Florian J. Gall and attempting to kill another patient at Somerset Medical Center. He is being held on $1 million bail.
Authorities are reviewing patient records, trying to evaluate Cullen's claims that he administered fatal overdoses of heart medication to seriously ill patients to put them out of their misery.
He worked at nine hospitals and a nursing home over a 16-year career.
Dr. William Cors, chief medical officer at Somerset Medical Center, said he understands the families' concerns.
"I truly, truly empathize with that," he said.
Hunterdon Medical Center, in Raritan Township, N.J., has set up a hotline for people concerned their loved ones may have come in contact with Cullen there between 1994 and 1996.
At St. Luke's Hospital in Bethlehem, Pa., where Cullen worked for two years, about 10 calls had come in by late Tuesday, the day after the allegations were made public, spokeswoman Susan Schantz said.
"We want people to be able to talk with us. If you're asking me whether we've been besieged by calls, the answer is no. Not yet," Schantz said.
By John Curran