[1] Univ Cologne, Dept Med, Ctr Hlth Serv Res Cologne ZVFK, Cologne, Germany
[2] Univ Cologne, Div Med Sociol, Inst & Policlin Occupat & Social Med, Cologne, Germany
[3] Univ Hosp Cologne, CIO, Cologne, Germany
[4] Univ Bonn, LIMES Life & Med Sci Bonn, Program Unit Mol Immune & Cell Biol, D-5300 Bonn, Germany
[5] Univ Hosp Cologne, Dept Internal Med Mol Tumour Biol & Tumour Immuno, Cologne, Germany