VARIATION IN HEALTH CARE AND OUTCOME Principles and examples

Transcription

1 VARIATION IN HEALTH CARE AND OUTCOME Principles and examples Symposium September 2014 Peter Vedsted Peter Hjertholm The Research Unit for General Practice Research Centre for Cancer Diagnosis in Primary Care CaP Aarhus University Denmark

2 The aim of this section Using descriptive analyses of variation we can: Demonstrate how health care activity and outcome vary Describe principles for looking at variation in health care Using inferential analyses of variation we can: Demonstrate how we may use variation to make inference about effect of health care activities Discuss implications for how we can develop the health care research using variation in everyday clinical practice

3 Clinical work = variation People, diseases, biology and conditions differ THUS, we will see variation in activity and outcome HOWEVER, is all variability warranted?

4 Ex: number of COPD-patients at hospital General practice in Liverpool

5

6

7 Wennberg s original findings Tonsillectomy example: A 19% probability of having tonsils removed before age 20. However, this vary from 16% to 66%

8 Question: What are the possible reasons for such variation in clinical activity?

9 Case-mix example: gender Vedsted

10 Case-mix example: age Vedsted

11 Explanations of variation John Appleby et al. Variations in health care. The good, the bad and the inexplicable. The King s Fund,

12 Wennberg J (2010) Tracking Medicine: A Researcher s Quest to Understand Health Care. Oxford University Press.

13 Effective care: Three ways to describe variation We have evidence of the effect and e.g. guidelines Variation = poor quality Preference-sensitive care: Different treatments are equal the patient can choose Variation = strong opinions among health care professionals (and patients) Supply-sensitive care : The higher supply, the higher use Variation = overuse, higher costs and side effects

14 Clinical work = variation Some variation we can account for (e.g. case-mix) How much variation is due to processes that we can influence? AND, are there consequences of variation? Processes VARIATION In activity Outcome

15 Variation in activity at different levels Individual patients (Clinical epidemiology) Health care provider/teams (GP, practice, hospital) Neighbourhoods Regions Health services research Public health Countries

16 Variation in colonoscopy per 10,000 in UK NHS ATLAS OF VARIATION

17 Question: Can we use variation in aggregated measures of activity to study optimal health care? What type of study design will that often be?

18 Ethics, already implemented and resources Sometimes we have to use variation and an observational study Ethics: Time to cancer diagnosis (or other serious disease) Already implemented activity Medication for infection, investigations, follow-up A randomised study is not affordable/possible Resection rate for cancer (e.g. small-cell lung cancer) The natural experiment

19 BUT then we might introduce Confounding by indication E.g. doctors select patients based on severity Problems with ecologic studies and ecologic falacy We use an aggregated measure of exposure and estimate the association with individual or aggregated outcome Sometimes confusion about cause and effect We do not know who got the pill and who took it

20 Examples

21 The gatekeeper and cancer survival Vedsted & Olesen. Br J Gen Pract 2011;DOI: /bjgp11X

22 Variability in cancer survival Møller H et al. British Journal of Cancer. 2009;101, S110 4

23 Adverse effect of the gatekeeper system? Vedsted & Olesen. Br J Gen Pract 2011;DOI: /bjgp11X

24 The use of PSA in general practice and outcome

25 PSA tests IRR=1.00 IRR=1.52 IRR= 2.02 IRR=3.56 PSA test rates adjusted for age, calendar-year, educational level, ethnic origin and marital status

26 PSA and diagnostic procedures = 95% CI IRR of diagnostic procedures

27 PSA and PC incidence IRR of prostate cancer

28 PSA and stage Disease stage at diagnosis

29 PSA and treatment of PC

30 PSA and mortality

31 Comments to Peter?

32 Summary We see large variation in health care and outcome We can try to explain variability in health care with trivial casemix etc. BUT what is the effect of the variation? And we can use variation to study effect of clinical activity However, we have important methodological challenges We need further development of these And we need much more research using variation in activity