[1] Med Univ Sofia, Dept Org & Econ Pharm, Fac Pharm, Sofia, Bulgaria
[2] Univ Groningen, Univ Med Ctr Groningen, Groningen Res Inst Asthma & COPD GRIAC, Dept Gen Practice, Groningen, Netherlands
[3] Univ Groningen, Dept Pharm, Unit Pharmacotherapy Epidemiol & Econ, Groningen, Netherlands
[4] Univ Groningen, Univ Med Ctr Groningen, Inst Sci Hlth Aging & healthcaRE SHARE, Groningen, Netherlands
[5] Univ Groningen, Univ Med Ctr Groningen, Dept Epidemiol, Groningen, Netherlands
[6] Univ Groningen, Univ Med Ctr Groningen, Dept Gen Practice, Groningen, Netherlands
[7] Med Univ, Dept Propaedeut Internal Dis, UMHAT Alexandrovska, Sofia, Bulgaria