TORONTO - Not enough medical evidence exists to recommend that cardiologists screen all their heart patients for depression, says a new study.
That runs counter to the advice of the American Heart Association, which suggested in September that heart patients be asked two standard questions: In the past two weeks, have you had little interest or pleasure in doing things? Have you felt down, depressed or hopeless?
If the patients answer yes to either, then a questionnaire is recommended to further explore the problem.
But the study published Wednesday in a special edition of the Journal of the American Medical Association was launched long before the AHA recommendations came out.
The researchers did a systematic review of existing studies, and drew on more than 1,500 clinical studies, including 17 that were selected for detailed scrutiny.
Brett Thombs, a psychologist and assistant professor at McGill University, says they wanted to see if screening for depression helps patients.
"It became very, very clear that the evidence - it just wasn't there to suggest recommended screening at this point," he said in an interview Tuesday from Montreal.
"What we've found is that just kind of asking a set of questions from a questionnaire to all patients that come through the door won't benefit patients."
He said that if cardiologists use these questionnaires, probably about a third of their patients would screen positive, which means getting a score above a certain level that indicates the person might have depression.
"The next problem is that probably only about 40 per cent of those patients actually have depression," said Thombs.
"So we have cardiologists now in a situation where they have about a third of their practice they don't know if they have depression or not. Less than half do. None of these guidelines have articulated, and the AHA guidelines don't either, what happens next."
"One might say 'refer them,' but it's not clear to where they would be referred, and who would possibly pick up this major, major caseload of a third of the millions of cardiovascular patients across North America who have depression - what would happen then?"
One study in the review looked at treating major depression in heart disease with antidepressants, he said, and "getting treatment was only reducing the symptoms of depression between one and four per cent" compared with those given a placebo.
Rather, Thombs said those involved in his study, including Dr. Roy Ziegelstein of Johns Hopkins University, are calling for good clinical care.
"We'd advocate that physicians spend more time talking to their patients, that there's a light that goes on when they talk about mood changes that haven't gotten better after they have a heart attack, or they talk about not being able to make the kind of behavioural changes that they need to make, whether it's exercising or eating better."
Those things, he noted, are often highly related to the presence of depression in cardiac patients.
Screening everyone takes a lot of resources to try to find new cases that probably won't benefit much by being found, he said. Resources can be devoted to better treatment for the people who are known to have depression.
"It's a huge outlay of cost in a situation where only a small number of patients would benefit minimally," he said.
Regular exercise will improve the cardiovascular prognosis of patients, and this will also help with depression, he noted.
Besides McGill and Johns Hopkins, six other institutions around the world were involved in the study.
Dr. Brian Baker, a cardiac psychiatrist and a spokesman for the Canadian Heart and Stroke Foundation, says there's a strong association between patients with heart disease and depression.
"The question is where in the state of science are we with regards to 'does treatment help?' and 'should you screen for them?' That has not been shown. Does it mean it will never be shown? Of course not," he said in an interview.
Much depends on how screening is done, he said.
"If you do it on a mass basis, you probably get a lot of false positives and false negatives," he said.
"If you're doing it that you know the person, and you ask the question, 'have you felt down, and you had a lack of interest for most of the day for two weeks?' those people should be followed on."
"And if they have a major depression, you should treat them. If they have a moderate to severe depression, they must be treated."
