[1] Immanuel Hosp Berlin, Dept Internal & Complementary Med, Berlin, Germany
[2] Charite, Berlin, Germany
[3] Humboldt Univ, Freie Univ Berlin, Berlin, Germany
[4] Berlin Inst Hlth, Inst Social Med Epidemiol & Hlth Econ, Konigstr 63, D-14109 Berlin, Germany