Add-on azithromycin deemed cost-effective in patients with COPD exacerbations

Key takeaways:

• Azithromycin added to inhaled triple therapy in those with COPD and a recent exacerbation history was cost-effective.
• This added therapy was not cost-effective for those without an exacerbation in the last year.

For patients with COPD who experienced an exacerbation in the last 12 months, add-on azithromycin therapy was deemed cost-effective, according to results published in Annals of the American Thoracic Society.

“Contemporary guidelines provide conditional recommendations for azithromycin use in patients defined as frequent exacerbators,” Safa Ahmadian, BSc, of the Respiratory Evaluation Sciences program at the University of British Columbia, and colleagues wrote. “Our findings support this current recommendation but also suggests that add-on azithromycin might be cost-effective in patients with any positive exacerbation history in the previous 12 months.

“Ultimately, extending the eligibility of azithromycin in patients with COPD can provide significant health benefits to this population,” Ahmadian and colleagues added.

In this study, Ahmadian and colleagues assessed simulated patients (average age, 66 years) with COPD who experienced exacerbations even after receiving maximal inhaled triple therapy to determine whether add-on low-dose maintenance azithromycin therapy is cost-effective over 20 years through a validated Canadian COPD policy model.

Researchers classified a lower exacerbation rate as the benefit of the therapy in the model.

After dividing the cohort according to exacerbation history, researchers observed the incremental cost-effectiveness ratio (ICER) per quality-adjusted life-years (QALYs) gained in each group vs. a reference group who only received inhaled triple therapy. An annual discount rate of 1.5% was applied to future costs and health outcomes.

During the 20-year period, those with at least one exacerbation in the past 12 months had total costs of $49,732, 7.65 QALYs per patient and 10.95 exacerbations with use of azithromycin.

The reference group had lower costs ($48,436) and QALYs (7.62 per patient) but a higher exacerbation rate (11.86). Between the two groups, the ICER for azithromycin was $43,200 per QALY gained, which suggested that the therapy is cost-effective based on the set willingness-to-pay threshold ($50,000-$100,000/QALY), according to researchers.

Among those with at least two moderate exacerbations or at least one severe exacerbation in the past 12 months, researchers found that use of azithromycin therapy resulted in costs of $54,285, 7.15 QALYs per patient and 12.87 exacerbations. Similar to the above comparison, the reference group had lower costs ($53,576) and QALYs (7.07 per patient) but a higher total number of exacerbations (13.92).

Compared with the reference group, the ICER for azithromycin in patients with frequent exacerbations was $8,862 per QALY gained.

Researchers found that azithromycin use in the group that did not experience an exacerbation in the last year vs. the reference group was not cost-effective.

Lastly, sensitivity analysis in the group with at least one recent exacerbation revealed that a heightened relative risk of cardiovascular death, hearing loss and antimicrobial resistance, all of which are frequent adverse events of azithromycin, meant ICERs went above the established willingness-to-pay threshold.

Future studies on this topic may consider other dosing regimens of azithromycin, according to researchers.

“Azithromycin was modeled as daily use in our study, but it is also prescribed less frequently (eg, three times per week), with evidence suggesting that its efficacy is similar to daily azithromycin,” Ahmadian and colleagues wrote. “As this regimen reduces costs (and potentially improves adherence), it might provide a more favorable cost-effectiveness profile than those reported in this study.”