**4.3 Factors related to the characteristics of the therapy**

The number of medications and the dosing frequency have been linked with adherence. According to our evaluations, the dosing frequency of respiratory drugs is one of the most important factors affecting non-adherence in patients with COPD (Agh et al., 2011; WHO, 2003). As a partial result of the daily drug doses, a significant difference has been shown in the adherence rates between the different respiratory drug classes (Apter et al., 1998; Breekveldt-Postma et al., 2007; Laforest et al., 2010). Tiotropium, a once-daily inhaled drug, may enhance adherence compared with other inhaled respiratory medications that are dosed more times daily. We also found that polypharmacy is another common cause of poor adherence (Agh et al., 2011); complicated treatment regimens may frustrate the patients, which may lead to non-adherence (van der Palen et al., 1999).

adherence to non-drug therapy as well; a poor COPD prognosis has been identified as one

Most prior studies have found that gender does not influence the level of patient cooperation (Agh et al., 2011; Apter et al., 1998; Corden et al., 1997; Turner et al., 1995). Adherence differences between men and women reported in the literature may be caused by psychological factors (Laforest et al., 2010). The prevalence of anxiety and depression are higher in women with COPD, and these psychiatric comorbidities have been independently

In general, drug-taking behaviour is related to age; older patients seem to be more adherent. Patients of advanced age are more likely to adhere to therapy that requires adjustments in daily life (Agh et al., 2011). However, memory loss and cognitive impairment, which are associated with both age and COPD duration, may adversely affect adherence (Incalzi et al.,

Social support can also influence patient adherence. Stable family life has been found to improve adherence to medication regimens (Tashkin, 1995; Turner et al., 1995). Furthermore, the study by George et al. (George et al., 2006b) indicates that patients with a good relationship with family and friends may live longer and may quit smoking with a higher success rate.

Better quality of life has been considered a trigger for non-adherence (Agh et al., 2011). Decision-making regarding patient adherence is a personal trade-off between the efficacy of the therapy and the negative effects that it generates. Adherence to COPD therapy can reduce the clinical symptoms and improve the patient's quality of life. However, COPD treatment regimens require adjustments in daily life, such as smoking cessation and exercise programs, and can cause side effects as well. Therefore, the interruption of drug therapy can temporarily also increases the patient's quality of life. Therapy in newly diagnosed COPD patients may significantly improve quality of life; however, the change in quality of life may be much smaller in patients treated previously for longer durations (Soumerai et al., 1991). From the patient's perspective, the benefits from the increase in the quality of life during the complication-free period can outweigh the effects of the worsening disease symptoms (Agh

The number of medications and the dosing frequency have been linked with adherence. According to our evaluations, the dosing frequency of respiratory drugs is one of the most important factors affecting non-adherence in patients with COPD (Agh et al., 2011; WHO, 2003). As a partial result of the daily drug doses, a significant difference has been shown in the adherence rates between the different respiratory drug classes (Apter et al., 1998; Breekveldt-Postma et al., 2007; Laforest et al., 2010). Tiotropium, a once-daily inhaled drug, may enhance adherence compared with other inhaled respiratory medications that are dosed more times daily. We also found that polypharmacy is another common cause of poor adherence (Agh et al., 2011); complicated treatment regimens may frustrate the patients,

of the most demotivating factors to quit smoking (George et al., 2006b).

linked with non-adherence ( Bosley et al., 1995; DiMatteo et al., 2000).

**4.2 Factors related to the characteristics of the patient** 

**4.3 Factors related to the characteristics of the therapy** 

which may lead to non-adherence (van der Palen et al., 1999).

1997).

et al., 2011).

Patient cooperation is better with oral medication than with inhaled drugs (James et al., 1985; Tashkin et al., 1991). Adherence with inhaled drugs may be compromised by inadequate inhaler technique (Garcia-Aymerich et al., 2000; Shrestha et al., 1996). Furthermore, better adherence with oral theophylline can also be due to the simplicity of the dosing regimens (Kelloway et al., 1995).

Other factors, such as adverse effects and medication costs, are also important. Medication cost is one of the greatest barriers to achieving adequate adherence (Cramer et al., 2007, Jung et al., 2009). Side effects or concerns about side effects from medications can reduce adherence as well (Dolce et al., 1991; Rand et al., 1995). For example, patients with COPD often confuse the side effects of ICS with those of anabolic steroids, which may decrease their cooperation willingness (Boulet, 1998).

#### **4.4 Factors related to the characteristics of the health-care provider–patient relationship**

Effective COPD management requires a good relationship between health-care providers and the patients. Quality of communication is related to adherence. Adherent patients report better overall communication with their providers (Blais et al., 2004). Education during the consultation and providing more information about the therapy may improve adherence (Raynor, 1992), as it reduces the risk of forgetting the providers' recommendations and the likelihood of misunderstandings between providers and patients. Previous studies suggest that immediately after the consultation, patients recall less than 50% of the information conveyed by their provider (DiMatteo, 1991).

The type of caregiver also influences adherence. Medication adherence may increase if the prescribing physician is a specialist instead of a general practitioner (Lau et al., 1996). Furthermore, periodic visits, closer follow-up and hospitalisation may also have increasing effects on patient cooperation (Breekveldt-Postma et al., 2007).
