Faculty of Health Sciences – Department of Clinical Medicine Too much medicine? A study investigating unwarranted regional variation and use of medical care Ingvild Mathiesen Rosenlund A dissertation for the degree of Philosophiae Doctor – March 2019 TABLE OF CONTENTS ACKNOWLEDGEMENTS ..................................................................................................................... 3 ABBREVIATIONS ................................................................................................................................. 5 LIST OF PAPERS ................................................................................................................................... 6 SUMMARY ............................................................................................................................................. 7 1. PREFACE ............................................................................................................................................ 8 2. INTRODUCTION ............................................................................................................................... 9 2.1 Too muCh mEdiCinE ................................................................................................................ 9 2.2 ExtEnt of ovErusE .................................................................................................................... 9 2.3 MeasurEment of ovErusE ...................................................................................................... 10 2.3.1 DirECt mEasurEs of ovErusE .............................................................................................. 10 2.3.2 Regional variation as an indirECt mEasurE of ovErusE ..................................................... 10 2.4 DrivErs of ovErusE ................................................................................................................ 12 2.4.1 LaCk of EvidEnCE .............................................................................................................. 12 2.4.2 Shortcomings of medical guidelines ................................................................................ 13 2.4.3 Early diagnosis ................................................................................................................. 14 2.4.4 DiagnostiC intEnsity of imaging diagnostiCs .................................................................... 15 2.4.5 EconomiC inCEntivEs ........................................................................................................ 16 2.4.6 DefEnsivE mEdicinE .......................................................................................................... 16 2.5 Norwegian publiC hEalth ...................................................................................................... 17 2.6 BaCkground for thE individual papErs .................................................................................. 17 2.6.1 CT for suspECtEd urolithiasis (papEr 1) ............................................................................ 17 2.6.2 RoutinE pElviC Examinations (papEr 2) ............................................................................ 18 2.6.3 DivErtiCular disEasE (papEr 3) .......................................................................................... 18 3. AIMS OF THE STUDY .................................................................................................................... 19 4. MATERIALS AND METHODS ...................................................................................................... 20 4.1 CT for suspECtEd urolithiasis (papEr 1) ................................................................................ 20 4.1.1 Study population and data collection ............................................................................... 20 4.1.2 VariablEs .......................................................................................................................... 20 4.1.3 Statistical analysis ............................................................................................................ 20 4.2 RoutinE pElviC Examinations (papEr 2) ................................................................................. 21 4.2.1 Study population and data collection ............................................................................... 21 4.2.2 VariablEs .......................................................................................................................... 21 4.2.3 Statistical analysis ............................................................................................................ 22 1 4.3 DivErtiCular disEasE (papEr 3) .............................................................................................. 22 4.3.1 Study population and data collection ............................................................................... 22 4.3.2 VariablEs .......................................................................................................................... 22 4.3.3 Statistical analysis ............................................................................................................ 23 4.4 EthiCs .................................................................................................................................... 23 5. MAIN RESULTS .............................................................................................................................. 24 5.1.1 CT for suspECtEd urolithiasis (papEr 1) ............................................................................ 24 5.1.2 RoutinE pElviC Examinations (papEr 2) ............................................................................ 24 5.1.3 DivErtiCular disEasE (papEr 3) .......................................................................................... 25 6. GENERAL DISCUSSION ................................................................................................................ 27 6.1 MethodologiCal ConsidErations ............................................................................................ 27 6.2 Methodologic considerations related to the individual papers ............................................. 28 6.2.1 CT for suspECtEd urolithiasis (papEr 1) ............................................................................ 28 6.2.2 Variation studiEs with data from the Norwegian Patient Registry (paper 2 and 3) ......... 30 6.2.3 RoutinE pElviC Examinations (papEr 2) ............................................................................ 31 6.2.4 DivErtiCular disEasE (papEr 3) .......................................................................................... 32 6.3 DisCussion of main findings ................................................................................................. 33 6.3.1 CT for suspECtEd urolithiasis (papEr 1) ............................................................................ 33 6.3.2 RoutinE pElviC Examinations (papEr 2) ............................................................................ 35 6.3.3 DivErtiCular disEasE (papEr 3) .......................................................................................... 38 6.4 Further studies ...................................................................................................................... 39 6.5 ConsEquEnCEs for CarE .......................................................................................................... 40 7. CONCLUSIONS ............................................................................................................................... 42 REFERENCES ...................................................................................................................................... 43 2 ACKNOWLEDGEMENTS I did the presEnt work betwEEn 2013 and 2019 at the DEpartmEnt of CliniCal MEdiCine, FaCulty of HEalth SCiEncEs, UiT The ArctiC University of Norway. I would not have beEn ablE to carry out this thesis without the help and support from many. I am deEply gratEful. I am most gratEful to my main supervisor, Arthur Revhaug. You have generously supportEd – and challEnged mE, in a wEll-balancEd way. You have always made timE for mE, even when you had more than enough on your platE. I am very thankful that you open-mindedly and Curiously wantEd to investigatE the subjECt of this thesis together with mE. I have greatly benefittEd from your ExperiEncE as a resEarcher, supervisor, physiCian, and health care organizEr. I appreCiatE all our talks. I am vEry thankful to Olav HElge Førde, my co-supervisor. I could not have carriEd out this work without your knowlEdge in epidemiology and your experiEncE in health sErviCEs resEarCh. Also, thanks for advising mE to do a PhD the very first timE wE mEt. Linda LEivsEth, I am very happy CentEr for CliniCal DocumEntation and Evaluation designatEd you as my co-author for paper 2 and 3. Your careful and detail-oriEntEd work has both improved this thesis and also taught mE how high mEthodologiCal standards can be implEmEntEd in praCtiCE. I am very thankful. Thanks to Arthur, Olav HElge, and Linda for making mEthodologiCal debatEs thorough, loud, and somEtimEs intEnsEly frustrating, but still humorous and rewarding. Thanks to Ingard NilsEn for your expertisE in gyneCology and contributions as co-author for paper 2. Thanks to Johannes Walsøe for tEChniCal support and Anna Bågenholm for radiologiCal ExpertisE for paper 1. Thanks to GEir Hoff