1. Department of General Internal Medicine (R.F.S., J.W.M.L.), 6525GA Nijmegen, The Netherlands
2. Department of Family Medicine (C.B.), 6525GA Nijmegen, The Netherlands
3. Methodology, Information Management, and Statistics Expertise Group (J.M.), 6525GA Nijmegen, The Netherlands
4. Department of Endocrinology (H.J.L.M.T.), Radboud University Nijmegen Medical Centre, 6525GA Nijmegen, The Netherlands
5. Department of Internal Medicine III (J.W.M.L.), University Hospital Carl Gustav Carus, Dresden, 01307 Germany