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

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

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., 1997).

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 et al., 2011).
