Health Numeracy: Explaining risk in numbers patients can use. Kirtly Parker Jones MD

Transcription

1 Health Numeracy: Explaining risk in numbers patients can use Kirtly Parker Jones MD

2 Learning Objectives List three different numerical means of presenting risk Describe three graphical methods of presenting risk Identify at least 3 factors that influence patients perceptions of risk

3 Disclosures This presentation has been created in part by the Association of Reproductive Health Professionals (ARHP to see more you can go to arhp.org and go to CORE slide set) I like arithmetic

4 Arithmetic Two plus Three equals? If there was a 50% decrease in the number of people who answered the question incorrectly, what would be the subsequent percent of people who answered the question correctly?

5 Weather Class.. If there is a 50% chance of rain today and a 50% chance of rain tomorrow.. What is the chance that it will rain today AND tomorrow? What is the chance that it will rain today OR tomorrow?

6 What do oncologists tell patients? The 5 year survival of stage 4 ovarian cancer is 12% Aggressive chemotherapy can increase the 5 year survival of ovarian cancer by 50% What is the chance if surviving stage 4 ovarian cancer for 5 years if a patient undergoes aggressive chemotherapy? What do you think the patient hears?

7 Know your numbers Expressing Risk

8 Risk Calculations Causality Weigh pros and cons Degree to which attributable Hennekens CH. Epidemiology in Medicine

9 Associations vs. Causality An association does not always mean exposure caused outcome It could be due to random chance or bias Grimes DA. Lancet

10 Commonly Used Risk Calculations Absolute Risk Attributable Risk Relative Risk

11 Absolute Risk The percentage of people in a group who experience a discrete event Number of events experienced Total exposure time of people at risk New York Academy of Medicine Misselbrook D. Fam Practice

12 Example of Absolute Risk Of 100,000 women on third-generation OCs, 30 will develop venous thromboembolism (VTE) per year. Absolute risk 30 per 100,000 woman-years Mills A. Hum Reprod Bromham D, O Brien T

13 Attributable Risk The difference in risk between those exposed and those not exposed Reflects extra risk associated with exposure Risk in exposed Risk in unexposed BMJ Collections

14 Attributable Risk: Example 1 Risk of cancer in smokers: 100 per 100,000 Risk of cancer in nonsmokers: 10 per 100,000 = Attributable risk: 90 more cancers per 100,000

15 Relative Risk Frequency of the outcome in the exposed group divided by the frequency of the outcome in the unexposed group Frequency Exposed Frequency Unexposed Grimes DA. Lancet Hennekens CH. Epidemiology in Medicine

16 Interpreting Relative Risk Compared with unexposed group: Relative Risk = 1 Relative Risk > 1 Relative Risk < 1 No increased risk in exposed group Increased risk in exposed group Decreased risk in exposed group Hennekens CH. Epidemiology in Medicine

17 Relative Risk: Example 1 Absolute Risk: 3rd-Generation OCs 30 per 100,000 woman-years Absolute Risk: 2nd-Generation OCs 15 per 100,000 woman-years = Relative Risk: 2 Mills A. Hum Reprod

18 Relative Risk: Example 2 Risk of cesarean delivery with elective induction of labor Risk of cesarean delivery with spontaneous onset of labor Relative risk with induction: Grimes DA. Lancet Relative risk = = 2 20% 10% 20% 10% more

19 Relative Risk: Example 3 Risk of infection after cesarean delivery with prophylactic antibiotics Risk without prophylactic antibiotics: Relative risk: = 0.5 Grimes DA. Lancet Relative risk = 6 12 = 0.5 6% 12% 6% 12% more

20 Ridiculous Relative Risk Chance of getting heads is 1:2 with a normal penny In two headed penny, the chance is 2:2 Relative risk is 2 But..you are always going to get head Not everyone fits the stats

21 Know how to communicate numbers Communicating About Risk

22 Tools: Numerical Data Try different ways to explain numerical data: women You Three of every 10 develop nausea. have a 30% chance of having nausea. Gigerenzer G, Edwards A. BMJ more

23 Tools: Numerical Data (continued) Avoid shifting denominators in proportions: Headache developed in 1 of every 333 women. of Headache developed in 3 every 1,000 women. Gigerenzer G, Edwards A. BMJ Grimes DA, Snively GR. Obstet Gynecol more

24 Tools: Numerical Data (continued) Use absolute risk: OC use increases the risk of heart attack 2.5-fold. Heart attacks occur in 4.2 of every 1 million OC users and 1.7 of every 1 million nonusers. Gigerenzer G, Edwards A. BMJ Farley TMM, Collins J, Schlesselman JJ. Contraception Sloman SA. Organizational Behavior and Human Decision Processes

25 Tools: Descriptive Terms Risk level High <1 in 100 Moderate 1 10 in 1,000 Low 1 10 in 10,000 Very low 1 10 in 100,000 Minimal 1 10 in 1 million But your patient needs to know the numbers, too Calman KC. BMJ Berry DC, et al. Drug Saf

26 Tools: Risk Comparisons Annual risk of death (per 100,000) Skydiving 100 Driving 20 Pregnancy 11.5 Riding a bicycle 0.8 Airplane crash 0.4 Using OCs* 0.06 *Nonsmoker, age Bennett P. In: Risk Communication and Public Health. 1999; Chang J, et al. MMWR Harvard Center for Risk Analysis Schwingl PJ, et al. Am J Obstet Gynecol Trussell J, Jordan B. Contraception

27 Incidence of VTE per 100,000 woman-years Comparative Risks of VTE Pregnancy Highdose OC Shulman LP. J Reprod Med Chang J. In: Surveillance Summaries Low-dose OC General Population

28 Tools: Diagrams Categories table Numbers and categories table Paling Perspective Scale Paling Palette

29 Tools: Categories Typical Success Rate More Effective* Effective Less Effective Sterilization (male & female) Implants Birth control pills (combined & mini pill) Barrier methods Spermicide Hormone shot Natural methods Intrauterine device (hormonal) Intrauterine device (copper) Adapted from Steiner MJ, et al. Obstet Gynecol

30 Tools: Numbers and Categories More Effective* Typical Success Rate Typical Pregnancy Rate Lowest Expected Pregnancy Rate Sterilization (male & female) % % Implants 0.05% 0.05% Hormone shot 3% 0.3% Intrauterine device (hormonal) 0.2% 0.2% Intrauterine device (copper) 0.8% 0.6% Effective Birth control pills (combined & mini pill) 8% 0.3% Less Effective Barrier methods 15 16% 2 6% Spermicide 29% 18% Natural methods 25% 3 5% Steiner MJ, et al. Obstet Gynecol Trussell J, et al. Ardent Media, 2007.

31 Teaching Methods Affect Knowledge Hormone Shot vs. Pill 20% 29% 37% Pill vs. Condom 15% 14% 27% Categories Numbers & categories (WHO) Numbers FDA Steiner MJ. Obstet Gynecol

32 Tools: Paling Palette 1,000 Women Paling J. BMJ

33 Absolute Risk of Breast Cancer in the General Population Each 50-year-old woman has approximately a 2.8% chance of developing breast cancer by age 60 years This translates to an absolute risk of 2.8 per 100 women All Women Aged 50 Years in the General Population Risk for Breast Cancer by Age 60 Years In 100 women, 2.8 are at risk American Cancer Society, Surveillance Research, Breast Cancer Facts and Figures Available at: http//

34 Absolute Risk of Breast Cancer After 5 Years of HT WHI results indicate an HR for breast cancer of 1.26 after 5 years of HT use (a 26% increase in risk) 1 This translates into an absolute risk of 3.5 per 100 users Risk of Breast Cancer by Age 60 Years After 5 Years of HT Use (Assuming a 26% Increase in Risk) 3.5 of 100 women who are HRT users are at risk (<1 additional woman over baseline risk) 1 Writing Group for the Women s Health Initiative Investigators. JAMA. 2002;288:

35 1 pregnancy per 100 women in 1 year WHO Decision Aid on Contraceptive Effectiveness Most Effective Implants, female sterilization, vasectomy, IUD Injectables, lactational amenorrhea method, pills, patch, vaginal ring ~30 pregnancies per 100 women in 1 year Least Effective Male condom, female condom, diaphragm, sponge, fertility awareness based methods Withdrawal, spermicides Adapted from World Health Organization, 2006.

36 Communicating Contraceptive Effectiveness Given only effectiveness category information, women overestimated pregnancy risk When later shown percentage tables, majority reported rate accurately Authors recommend category tools with general range of risk shown within each category Steiner MJ. Obstet Gynecol

37 Cardiovascular Adverse Events: Screening for Risk Factors Deaths per million woman-years among women age Venous thromboembolism Ishemic stroke Hemorrhagic stroke Myocardial infarction Smoker OC User Farley TMM, Collins J, Schlesselman JJ. Contraception Smoker OC User BP Checked 3

38 Overall correct response rate as a function of numeracy and graphical format. Hamstra D A et al. Med Decis Making 2014;35:27-36

39 Guidance Understand risk and how to communicate it Ensure a trusting environment conducive to conversation Put risks in context Remember cultural, literacy, and developmental issues Remember that discussing risk may make it salient Pro Choice Public Education Project more

40 Guidance (continued) When providing information about risk, discuss risk reduction Remember to present absolute risk Use different forms of numerical data to explain risk Be aware of framing effects Use risk comparisons with care Have multiple, complementary tools available Pro Choice Public Education Project

41 Know Yourself and Your Patient

42 Decision Aid for Risk Communication Clarify situation Provide information Clarify patient s values Screen for implementation problems O Connor A, Legare F, Stacey D. BMJ

43 A misperception of risks may unnecessarily limit choices Risk perception is affected by a number of factors Clinicians should consider relevant factors and expert guidance about risk communication Several tools are available to aid risk communication

44 Communicating Risk: How-To s What to ask: What to consider: What to use: What to do: Patient needs & concerns Relevant factors Tools Provide guidance

45 Patient Needs & Concerns How important is it to avoid pregnancy right now? Do you want (or need) your use of contraception to be private? Do you have concerns about a particular contraceptive? What side effects are you willing to accept? Are you comfortable with methods that require insertion in the vagina?

46 Risk & Health Decisions Decisions about risk are not technical, but value decisions. Baker B. In: Risk Communication and Public Health

47 Mammography numbers For every 2,000 women age 50 to 70 who are screened for 10 years, one woman will be saved from dying of breast cancer, 10 will have their lives disrupted unnecessarily by overtreatment. Nordic Cochrane Center Collaborative, 2006

48 Mammography Numbers repeated screening starting at age 50 saves about 1.8 (overall range, ) lives over 15 years for every 1000 women screened. Keen JD. BMC Medical Informatics and Decision Making 2009

49 Media Influence + Widespread dispersion of reproductive health information Misperception of contraceptive risks Grimes DA. In: Oral Contraceptives and Breast Cancer

50 Perception & Interpretation of Risk Individual Risk Presentation Characteristics of the Risk

51 Characteristics of the Risk People worry more about risks that: The individual cannot control Are involuntary Are associated with particular dread Are novel or unfamiliar Result from man-made sources Are more easily recalled Harvard Center for Risk Statistics Bennett P. In: Risk Communication and Public Health

52 Weighing the Risks & Benefits Burkman R. Am J Obstet Gynecol

53 Guidance for Risk Communication Understand risk and how to communicate it Establish a trusting environment conducive to conversation Put risks in context Remember cultural, literacy, social, and developmental issues Remember that discussing risk may make it salient Lipkus IM. Med Decis Making Pro Choice Public Education Project more

54 Guidance for Risk Communication (cont d) When providing information about risk, discuss risk reduction Remember to present absolute risk Use numeric, verbal, and visual formats to convey health risk Be aware of framing effects Use risk comparisons with care Have multiple, complementary tools available Lipkus IM. Med Decis Making Pro Choice Public Education Project

55 Using numbers your patient can use Know your numbers Know how to present your numbers Know your patient