ONE-THIRD of patients diagnosed with latent tuberculosis in the last two years were not eligible for drug treatment after doctors decided the medication would do more harm than good.
Winnipeg Regional Health Authority statistics show 125 out of the 392 people who were diagnosed with latent tuberculosis between April 2011 and March 2012 were ineligible for drug treatment, a report obtained by a freedom-of-information request showed.
Another 128 patients declined drug treatment and 66 patients deferred treatment for the dormant variant of the respiratory disease.
Of the 392 patients diagnosed with "sleeping" TB, 100 were considered a high risk for developing the disease later, the report said.
Patients with active tuberculosis must take medication because they can spread the disease to other people through coughing, sneezing, spitting or even talking. However, sleeping TB is dormant and is not infectious.
About 10 per cent of people with sleeping TB will develop active disease at some point in their lives. Doctors have no way of knowing who will get sick and who won't, but conditions such as diabetes, HIV, malnutrition and substance abuse increase the likelihood the disease will activate.
Both sleeping and active TB can be cured with a nine-month course of drug treatment.
Dr. William Libich, a medical officer of health with the Winnipeg Regional Health Authority, said doctors must consider the fact a person is being offered medication to prevent a condition that, while potentially serious, may never occur. He said the main drug used to treat sleeping TB -- isoniazid -- can cause liver damage in older patients or those who abuse alcohol.
While patients are monitored throughout their drug treatment and told to abstain from drinking alcohol, Libich said some people continue to drink to the extent that putting them on isoniazid for sleeping TB is too great a risk.
Health officials focus on patients considered high-risk for developing active TB: people with HIV or AIDS, who have had active TB before and those who are immunosuppressed.
"There are many factors that need to be considered when making the decision to offer therapy to a client. Overall, the clinician needs to decide if the benefits of therapy outweigh the risks, and what the client's preferences are," Libich said.
Libich said the decision to offer drug treatment is challenging as there are some sleeping TB patients who are at a high risk of developing active TB, but are also at a high risk of complications from the medication.
Dr. Earl Hershfield, former TB control director for Manitoba, said he is confused why a patient's age could render them ineligible for treatment, noting people who are older than 40 and have a high risk of developing active TB should be treated.
Hershfield said only three to four per cent of patients treated for sleeping TB have side-effects related to their liver, and the symptoms typically clear up once treatment is complete.
"Ninety-six per cent of people, even people who are alcoholics, won't have any liver problems," he said.
Hershfield said he supports a person's right to deny treatment if they don't have an infectious disease.