SMIs Linked to Reduced Exacerbations, Readmissions in COPD

Investigators using real-world data found that patients receiving treatment from slow mist inhalers (SMIs) had fewer exacerbations and hospitals readmissions compared with patients using dry powder inhalers (DPIs).

Patients with chronic obstructive pulmonary disease (COPD) who use soft mist inhalers (SMIs) over dry powder inhalers (DPIs) were found to have fewer COPD-related exacerbations and readmissions, especially severe exacerbations, according to a recent study.

The study, published in the International Journal of Chronic Obstructive Pulmonary Disease, is one of the few studies comparing the effects of using long-acting muscarinic antagonists (LAMAs) in SMIs versus DPIs and is the first to use a US-based cohort, according to the authors.

Additionally, the real-world aspect of the study allowed for inclusion of patients with COPD who are often excluded from research trials.

Patients with COPD rely on prescription inhaled long-acting bronchodilators, such as LAMAs, to help them manage their symptoms, maximize lung function, and improve quality of life. Globally, COPD is a leading cause of death that affects at least 170 million people.

Although some previous research has reported that there are no statistically significant differences in mortality and time to first exacerbation between SMIs and DPIs, there is scarce data on the real-world comparisons of the 2 inhaler types.

The study was a noninterventional retrospective database analysis using data entered into the Optum Research Database from September 1, 2013 through July 31, 2019.

Patients enrolled in the study had to have LAMA treatment using a SMI or DPI initiated between September 1, 2014 and June 30, 2018, were over the age of 40, and enrolled in a Medicare Advantage Part D program from 1 year prior to the trial through the end of the follow-up period. Patients were followed until they discontinued the treatment; switched to a different LAMA; disenrolled from the health plan; after 1 year; or at the end of the study.

In total, data on 28,240 patients was used in the analysis, with the SMI cohort containing 5360 patients and the DPI cohort containing 22,880. All of the patients in the SMI cohort had tiotropium bromide as the LAMA used in the inhaler. In the DPI cohort, 86% (19,644) of patients were using tiotropium bromide, 13% (2893) used umeclidinium bromide, 1% (337) used aclidinium bromide, and less than 1% (6) used glycopryrolate as their index LAMA.

The mean age of the patients was 72 years old in the SMI cohort and 73 years in the DPI cohort; a bit more than half (52%) were female. The majority of clinical characteristics, including their baseline comorbidity burdens and COPD severity scores, were similar between the 2 cohorts. Each cohort contained at least 50% of patients who had metabolic syndrome, hypertension, and dyspnea.

Patients in the SMI cohort had a significantly lower weighted mean number of COPD-related exacerbations than the DPI cohort (0.054[0.082] per patient per month [PPPM] vs 0.059[0.088] PPPM, P < .001). Additionally, the SMI cohort had a significantly lower weighted mean number of severe exacerbations compared with the DPI cohort (0.030[0.058] PPPM vs 0.034 ± 0.065 PPPM, P < .001).

“This finding is noteworthy, as the main driver of cost increases in COPD-related healthcare over recent years is treatment for moderate to severe exacerbations,” wrote the investigators in their report.

During the follow-up period, fewer COPD-related hospitalizations were found among the SMI cohort (369) than the DPI cohort (1786). Forty-seven (12.7%) of the hospitalizations in the SMI cohort and 359 (20.1%) in the DPI cohort resulted in an all-cause readmission within 30 days of discharge.

After hospitalizations, readmissions were less likely to occur among patients in the SMI cohort (12.7%) compared with those in the DPI cohort (20.1%, P = .001). After controlling for covariates, the SMI cohort had a lower adjusted odd of readmission after hospitalization than the DPI cohort (OR, 0.656; 95% CI, 0.460-0.937; P = .020).

Investigators said that all-cause readmissions are an important outcome to measure because they identify areas within a hospital system that signal issues with quality of care, which can affect the amount of money that hospitals with excessive readmissions can receive.

“Readmission rates reflect an important measure of health-care burden and quality of care,” wrote the investigators.


Singer D, Bengtson LGS, Elliott C, Buikema AP, Franchino-Elder J. Healthcare resource utilization, exacerbations, and readmissions among Medicare patients with chronic obstructive pulmonary disease after long-active muscarinic antagonist therapy initiation with soft mist versus dry powder inhalers. Int J Chron Obstruct Pulmon Dis. Published online December 7, 2020. doi: 10.2147/COPD.S284678