Asthma and chronic obstructive pulmonary disease (COPD) patients who are treated with inhaled corticosteroids may face a significantly higher relative risk for both the development and progression of diabetes, new Canadian research suggests.
The warning stems from an analysis of data involving more than 380,000 respiratory patients in Quebec. Inhaler use was associated with a 34% increase in the rate of new diabetes diagnoses and diabetes progression, the researchers found.
What's more, asthma and COPD patients treated with the highest dose inhalers appear to face even higher diabetes-related risks: a 64% jump in the onset of diabetes and a 54% rise in diabetes progression.
"High doses of inhaled corticosteroids commonly used in patients with COPD are associated with an increase in the risk of requiring treatment for diabetes and of having to intensify therapy to include insulin," the study team noted.
Based on their results, researchers from McGill University and the Lady Davis Research Institute at Jewish General Hospital in Montreal suggest "patients instituting therapy with high doses of inhaled corticosteroids should be assessed for possible hyperglycemia and treatment with high doses of inhaled corticosteroids limited to situations where the benefit is clear."
Lead investigator Samy Suissa colleagues report their findings in the most recent issue of the American Journal of Preventive Medicine.
The research team wrote that despite the fact that inhalers are recommended for use solely by the most severely ill COPD patients, they are typically prescribed for a much broader pool that amounts to about 70% of all COPD patients.
The authors found that more than 30,000 of the COPD/asthma patients in their study developed a new diagnosis diabetes over the course of five and a half years of treatment. This amounted to a diabetes onset rate of a little more than 14.2 out of every 1,000 inhaler patients per year.
"These are not insubstantial numbers," Suissa said.
In addition, in the same timeframe nearly 2,100 patients already diagnosed with diabetes before using inhalers experienced a worsening of their disease that ultimately required upgrading their diabetes care from pills to insulin shots.
Lifestyle choices and diet a factor
Dr Stuart Weiss, an endocrinologist with the New York University Medical Center, suggested that concern should be directed more at the underlying causes of both diabetes and asthma/COPD rather than at inhalers themselves.
"I would say that a lot more attention should first be paid to the lifestyle choices, dietary-wise, that lead to the pro-inflammatory conditions that raise the risk for both type 2 diabetes as well as COPD and asthma," said Weiss.
"We don't look at asthma as being a dietary condition, but it absolutely is. Which means that in terms of diabetes and asthma risk, the body is reacting to similar stresses brought about by the over-consumption of over processed foods and the lack of consumption of green vegetables."
Noting that the underlying risk for both conditions is similar, Weiss said he suspected the steroids themselves should not bear all the blame. "What may be more at the root of this problem," he said, "is the fact that those who are most at risk for diabetes are the same people who have the worst asthma and COPD that requires steroid treatment in the first place."
"Yes, we do know that steroids increase insulin resistance and that people treated with steroids require more aggressive diabetes management," he conceded. "But if we don't generally take an approach that deals with the poor quality of food that people are routinely consuming, the incidence of both these diseases will continue to go up at a dramatic rate."
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