[1] Univ Groningen, Univ Med Ctr Groningen, Div Nephrol, Dept Internal Med, Groningen, Netherlands
[2] Isala Clin, Diabet Ctr, Zwolle, Netherlands
[3] Langerhans Med Res Grp, Zwolle, Netherlands
[4] Univ Groningen, Univ Med Ctr Groningen, Dept Internal Med, Groningen, Netherlands
[5] Univ Groningen, Univ Med Ctr Groningen, Dept Gen Practice, Groningen, Netherlands
[6] BRAHMS GmbH, Thermo Fisher Sci, Hennigsdorf, Germany