Non-tuberculous mycobacterial disease risk increased in COPD

By Mark Cowen, Senior medwireNews Reporter

Chronic respiratory disease is a significant risk factor for non-tuberculous mycobacterial (NTM) pulmonary disease, results from a French study show.

Claire Andréjak (Teaching Hospital Amiens) and team also found that the risk for NTM pulmonary disease is particularly increased among patients with chronic obstructive pulmonary disease (COPD) taking inhaled corticosteroids (ICSs).

"Clinicians should be aware of this association and use all available diagnostic tools to confirm or rule out definitive NTM pulmonary disease, including at least three sputum samples and a chest X-ray or chest CT [computed tomography] in patients with COPD and other chronic respiratory diseases," they comment in Thorax.

Using Danish registry data for the period 1997-2008, the team identified 332 patients with pulmonary NTM disease and 3320 controls matched for age-, gender-, and place of residence.

Of these, 50.3% of patients with NTM pulmonary disease and 6.2% of controls had chronic respiratory disease, with COPD being the most common disorder, affecting 42.2% and 4.8%, respectively.

After accounting for comorbidities and alcohol-related disorders, the team found that the presence of any chronic respiratory disease was associated with a 16.5-fold increased risk for NTM pulmonary disease.

The overall risk for NTM pulmonary disease was increased 15.7 fold in patients with COPD compared with individuals without any chronic respiratory disease. However, COPD patients taking ICSs had a significantly greater risk for NTM pulmonary disease than those with COPD who had never taken these medications, at adjusted odds ratios (ORs) of 29.1 and 7.6, respectively.

Furthermore, the risk for NTM pulmonary disease among COPD patients increased with higher ICS doses, from an adjusted OR of 28.1 in patients with a low-dose intake (<800?µg/day) to 47.5 in those with a high-dose intake (>800?µg/day).

The researchers also note that patients diagnosed with COPD within the previous 2 years had a higher risk for NTM pulmonary disease (OR=22.5) than those diagnosed more than 5?years previously (OR=12.9).

"Based on this study, it can be concluded that patients with chronic respiratory disease, particularly COPD treated with ICSs, are at highly increased risk of pulmonary NTM disease," write Andréjak et al.

They add: "These results could partly explain the parallel trends of increased incidence of NTM disease and of COPD."

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