Adherence to Inhaled Therapy and Its Impact on Chronic Obstructive Pulmonary Disease (COPD)

Magdalena Humenberger; Andreas Horner; Anna Labek; Bernhard Kaiser; Rupert Frechinger; Constanze Brock; Petra Lichtenberger; Bernd Lamprecht


BMC Pulm Med. 2018;18(163) 

In This Article


Out of 592 hospitalized patients with COPD and discharged with a guideline conform inhaled therapy in 2012, complete data was available of 476 cases in the database of the Upper Austrian Health Insurance (OÖGKK). 54 subjects died within 6 months after discharge and 65 had no prescription for permanent inhaled medication and were therefore excluded (Figure 1).

Figure 1.

Study population

Out of 357 patients, 65.8% were male and 34.2% were female, with a mean age of 66.5 years and a mean FEV1 of 55.0%pred. 55% had GOLD spirometry class I – II COPD and 45% had GOLD spirometry class III – IV COPD. Overall, 35.3% were current smokers, 57.4% former smokers and only 3.9% were never smokers. In 77.0% of all cases, inhaled triple therapy (LAMA + LABA + ICS) was prescribed at the time of discharge (for other inhaled therapies see Table 1). 74.2% had an additional prescription for SAMA and/or SABA, as inhaled therapy on demand. 17% of all subjects were on long-term oxygen therapy. There was no significant difference between men and women concerning age, FEV1, smoking status or long-term oxygen therapy. However, significantly more male patients were treated with triple therapy (83.0% vs 65.6%; p < 0.001).

33.6% of 357 patients showed complete adherence to their therapy (33.2% in men, 34.4% in women), with a mean age of 67.0 years and a mean FEV1 of 49.2% predSubjects with complete adherence to therapy had a significantly lower FEV1 compared to those with low adherence (49.2%pred. vs 59.2%pred., respectively; p < 0.001). (for further baseline characteristics by adherence see Table 2).

Among all 357 patients, complete adherence was noted in 44.9% of GOLD spirometry category IV participants, while only 19.4% of GOLD spirometry category I were noted to be completely adherent (Figure 2).

Figure 2.

Adherence by stage of COPD, n = 357

Using the medication possession ratio (MPR), to describe adherence, the overall mean MPR was 0.565. Hence, on average patients were adherent in 56.5% of all months during the observation period.

Male patient had slightly higher MPRs than females (0.568 vs 0.558, respectively; p = 0.883). MPRs by GOLD spirometry class I – IV were 0.486, 0.534, 0.609 and 0.755, respectively. These differences were statistically highly significant (p = 0.002). Former smokers had a higher mean MPR (0.610) compared to smokers (0.510) and never smokers (0.464) (p = 0.021). Patients on triple therapy (LABA + LAMA + ICS) were, statistically not significant, more adherent compared to patients on other therapy regimes (0.584 vs 0.499, respectively; p = 0.089).

Table 3 shows the results of a binary univariate and multivariate logistic regression analysis of factors independently associated with exacerbations leading to hospitalizations during the observation period. The risk of exacerbations leading to hospitalization was 10-fold higher in GOLD stage IV compared to GOLD stage I (OR 10.69; CI 2.99; 38.24) in univariate analysis. In the univariate and multivariate analysis, an inverse association between adherence to therapy and exacerbations leading to hospitalization was observed. Subjects with low adherence had a reduced risk of exacerbations (not significant in multivariate analysis; OR 0.58; 95% CI (0.33; 1.02)); for details see Table 3).