Inhaled steroids may increase risk of NTM lung infections in elderly
Use of inhaled corticosteroid (ICS), particularly fluticasone, was associated with an increased risk of nontuberculous mycobacterial (NTM) lung infections in older people with obstructive lung disease, according to a population-based study in Canada.
“These infections are not particularly common but they are chronic and difficult to treat, and are associated with an increased risk of death. Treatment typically requires at least three antibiotics given for longer than a year and this can still fail to tackle the infection,” said lead author Dr Sarah Brode from the University of Toronto, Canada.
“Although [steroid inhalers] have also been shown to benefit patients with chronic obstructive pulmonary disease [COPD], they are less important in the management of this condition [compared with in asthma], and they may only provide more benefit than harm in a subset of COPD patients,” she added. “There is an ongoing debate on which patients with COPD should be treated with inhaled steroids.”
The population-based case-control study drew data from administrative databases involving 417,494 older adults (aged ≥66 years) who had been treated for obstructive lung disease (ie, asthma, COPD, or asthma-COPD overlap syndrome). Of these, 2,966 NTM lung disease cases and 327 tuberculosis (TB) cases were identified, who were matched to 11,851 and 1,308 controls, respectively. [Eur Respir J 2017;doi:10.1183/13993003.00037-2017]
Compared with nonusers, current ICS users were significantly more likely to have NTM lung infections (adjusted odds ratio [aOR], 1.86, 95 percent confidence interval [CI], 1.60–2.15). The association was especially significant for those using fluticasone (aOR, 2.09, 95 percent CI, 1.80–2.43), but not for those using budesonide (aOR, 1.19, 95 percent CI, 0.97–1.45).
In a post hoc analysis taking current budesonide users as the reference, current fluticasone use remained associated with significantly increased risk of NTM infections.
“The differential risk of lung infection posed by fluticasone and budesonide is likely due to differences in pharmacokinetic and pharmacodynamic properties,” suggested Brode and co-authors. “Fluticasone has a greater effect on glucocorticoid receptors, is more lipophilic, and has a longer half-life than budesonide.” [Eur Respir J 2006;28:1042-1050]
Based on data from 1-year cumulative ICS dose used, the association between incident NTM lung disease and ICS was dose-dependent.
However, current ICS use was not associated with increased risk of TB infections (aOR, 1.43, 95 percent CI, 0.95–2.16) in contrast to previous report, which the researchers believed could be due to insufficient power of the study with few TB cases.
“Clinicians should consider this risk when prescribing ICSs to patients with obstructive lung disease and if they are needed, strive to use the lowest effective dose,” said Brode and co-authors.
“We think this is particularly relevant for patients with COPD who may have other risk factors for NTM-PD (ie, bronchiectasis, emphysema or prior sputum positive for NTM) and/or in whom the potential benefits of ICS are unclear (eg, a patient with infrequent exacerbations) … or those who have already had an infection of this type in the past,” they added.