Validering av kvalitetsregisterdata vad duger data till? Anders Ekbom, Professor Karolinska Institutet Institutionen för medicin Solna Enheten för klinisk epidemiologi Karolinska Universitetssjukhuset
GiGo-studier!? Anders Ekbom 20 maj 2013 2
Kajsa Warg: Man tar det man har! Anders Ekbom 20 maj 2013 3
Felaktiga data Missvisande data Missing data Anders Ekbom 20 maj 2013 4
BIRGER STRANDELL, STOCKHOLM The association of pernicious anemia and cancer in the same individual has, as is well known, attracted great interest for a long time. Thirty to fourty cases of this kind are previously reported in the literature. In hospital material in Stockholm and Örebro, which comprises 3,684 cases of cancer and 686 cases of pernicious anemia, both diseases were present in the same individual in 26 cases. In this material, therefore, cancer is five times as frequent in the pernicious anemia material as in pernicious anemia in the cancer material. Cancer of the stomach occurs in half of the total cases of cancer in this series, but in 4/5 of the cases with pernicious anemia and cancer, a fact which must be considered of special significance. The first disease to develop is pernicious anemia. After some time the cancer develops. It is evident that the course of the diseases must generally be as follows. 1) An atrophy of the gastric muccosa membrane develops and thereby calls forth a severe change in the physiology of the stomach. 2) This manifest itself, among other ways, through the development of achylia gastrica, and later on through the development of pernicious anemia. 3) Finally this atrophy supplies the basis for the development of a cancer of the stomach. Here in Sweden at least, therefore, we now have to deal with a new problem in pernicious anemia: the subsequent development of cancer of the stomach. The paper is published in full in Nordisk Med. Tidskrift. 32, 1937, p.1316. Anders Ekbom 20 maj 2013 5
PROF H.I. KARSNER, CLEVELAND, OHIO There will appear shortly in the American Journal of the Medical Sciences an article by one of my assistants, Dr J.R. Kahn, which proves that gastric ulcer does not occur in the course of pernicious anemia. In this study the cases of pernicious anemia were not caused by dibotriocephalus cancer, disease of the bones or other known agent. There were primary cases, with typical blood and clinical pictures, which responded to specific treatment. All were proven to have achylia. In about 1,000 cases, observed in Cleveland, Cincinnati and New York not one had gastric ulcer or gastric cancer in association with pernicious anemia. Anders Ekbom 20 maj 2013 6
Tvärsnittsstudie Cohortstudie Anders Ekbom 20 maj 2013 7
Kohortstudier Exponerade Insjuknade Ej exponerade Ej insjuknade Anders Ekbom 20 maj 2013 8
Incidenta och/eller prevalenta? Anders Ekbom 20 maj 2013 9
Lowenfels AB, et al. N Engl J Med. 1993;328(20):1433-7 Anders Ekbom 20 maj 2013 10
Confounding by indication! Anders Ekbom 20 maj 2013 11
Relative risk of cancer and of lymphoma in patients with RA, according to patient characteristics Non-Hodgkin s lymphoma Obs Exp SIR (95% CI) All patients (n=76,527) 458 242.9 1.89 (1.72-2.07) Yrs from first discharge with RA <1 72 20.9 3.44 (2.69-4.33) 1-4 136 70.9 1.92 (1.61-2.27) 5-9 109 63.3 1.72 (1.41-2.08) 10-19 124 67.9 1.83 (1.52-2.18) Ekström K, et al. Arthritis Rheum. 2003;48(4):963-70 Anders Ekbom 20 maj 2013 12
Non-differential misclassification of exposure Differential misclassification of exposure Anders Ekbom 20 maj 2013 13
Non-differential classification of exposure Skapar inga falska samband! Kan dölja sanna samband! Anders Ekbom 20 maj 2013 14
Differential classification of exposure Havoc! Anders Ekbom 20 maj 2013 15
Björnådal L, et al. Scand J Rheumatol. 2002;31(2):66-71 Anders Ekbom 20 maj 2013 16
Den höga överdödligheten skapar efter en tid en allt större andel icke-exponerade! Anders Ekbom 20 maj 2013 17
Inklusionskriterier 1. Lika för alla 2. Lika över tid 3. Lika oberoende av kön och ålder Anders Ekbom 20 maj 2013 18
Spöken 1. Äkta spöken 2. Förklädda spöken 3. Förrymda spöken Anders Ekbom 20 maj 2013 19
Vad göra? 1. Prevalens alternativt kumulativ incidens 2. Täckningsgrad (?) 3. Algoritm där ålder finns med Anders Ekbom 20 maj 2013 20
Täckningsgrad Gold standard: Operativa ingrepp Kroniska tillstånd? Vi behöver en ny definition! Anders Ekbom 20 maj 2013 21
Vad jämför vi? 1. Processmått 2. Outcomes Anders Ekbom 20 maj 2013 22
Processmått 1. Tid till intervention Definiera! 2. Farmakologisk intervention Case mix; ålder 3. Laboratorievärden Medelvärde; andel över/under cut off Anders Ekbom 20 maj 2013 23
Differential 1. Selektion 2. Uppföljningssystem Anders Ekbom 20 maj 2013 24
Outcomes Case mix Confounding ex RA och lymfom Anders Ekbom 20 maj 2013 25
Baecklund E, et al. Arthritis Rheum. 2006;54(3):692-701 Anders Ekbom 20 maj 2013 26
Missing data Create a) average b) algoritm Skip Anders Ekbom 20 maj 2013 27
SES Etnicitet Anders Ekbom 20 maj 2013 28
Slutsats Det finns fallgropar, det perfekta datasetet är en utopi, men med rätt metodik kan man testa de flesta hypoteser! Anders Ekbom 20 maj 2013 29