[1] German Diabet Ctr, Inst Hlth Serv Res & Hlth Econ, Dusseldorf, Germany
[2] Heinrich Heine Univ Dusseldorf, Inst Hlth Serv Res & Hlth Econ, Med Fac, Ctr Hlth & Soc, Dusseldorf, Germany
[3] German Ctr Diabet Res DZD, Neuherberg, Germany
[4] Heinrich Heine Univ Dusseldorf, Inst Gen Practice, Med Fac, Cochrane Metab & Endocrine Disorders Grp, Dusseldorf, Germany
[5] Heinrich Heine Univ Dusseldorf, Inst Hlth Serv Res & Hlth Econ, German Diabet Ctr DDZ, Leibniz Inst Diabet Res, Aufm Hennekamp 65, D-40225 Dusseldorf, Germany