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

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Presentation on theme: "Health Numeracy: Explaining risk in numbers patients can use Kirtly Parker Jones MD."— Presentation transcript:

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

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

10 Commonly Used Risk Calculations Absolute Risk Attributable Risk Relative Risk

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

12 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 Example of Absolute Risk

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

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

15 Risk from 3rd-generation OCs 30 VTE per 100,000 woman-years Risk from 2nd-generation OCs 15 VTE per 100,000 woman-years – = Attributable Risk: 15 more VTE per 100,000 woman-years Attributable Risk: Example 2

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

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

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

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

20 = 0.5 Risk of infection after cesarean delivery with prophylactic antibiotics 6% Risk without prophylactic antibiotics: 12% Relative risk: 6% 12% Relative risk = 6  12 = 0.5 Grimes DA. Lancet more… Relative Risk: Example 3

21 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 Relative risk isn’t useful without absolute risk

22 Know how to communicate numbers Communicating About Risk

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

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

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

26 Risk level Calman KC. BMJ Berry DC, et al. Drug Saf High<1 in 100 Moderate1–10 in 1,000 Low1–10 in 10,000 Very low1–10 in 100,000 Minimal1–10 in 1 million Tools: Descriptive Terms But your patient needs to know the numbers, too

27 Annual risk of death (per 100,000) Bennett P. In: Risk Communication and Public Health. 1999; Chang J, et al. MMWR Harvard Center for Risk Analysis. 2006’ Schwingl PJ, et al. Am J Obstet Gynecol Trussell J, Jordan B. Contraception Skydiving100 Driving20 Pregnancy11.5 Riding a bicycle0.8 Airplane crash0.4 Using OCs*0.06 *Nonsmoker, age 15–34 Tools: Risk Comparisons

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

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

30 More Effective*Effective † Less Effective ‡ Sterilization (male & female) Birth control pills (combined & mini pill) Barrier methods ImplantsSpermicide Hormone shotNatural methods Intrauterine device (hormonal) Intrauterine device (copper) Typical Success Rate Adapted from Steiner MJ, et al. Obstet Gynecol Tools: Categories

31 Typical Success Rate Typical Pregnancy Rate Lowest Expected Pregnancy Rate More Effective* Sterilization (male & female)0.5–0.15%0.5–0.1% Implants0.05% Hormone shot3%0.3% Intrauterine device (hormonal)0.2% Intrauterine device (copper)0.8%0.6% Effective † Birth control pills (combined & mini pill)8%0.3% Less Effective ‡ Barrier methods15–16%2–6% Spermicide29%18% Natural methods25%3–5% Steiner MJ, et al. Obstet Gynecol Trussell J, et al. Ardent Media, Tools: Numbers and Categories

32 Steiner MJ. Obstet Gynecol Teaching Methods Affect Knowledge CategoriesNumbers & categories (WHO) Numbers FDA

33 Tools: Paling Perspective Scale INCREASED RISK Risk of death from vaccination Risk of smallpox Death from smallpox if not vaccinated post- exposure Death from smallpox if vaccinated post- exposure 1 in 2 million 1 in 100 million (or less) 1 in 1.7 billion 1 in 100 billion Paling J. BMJ

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

35 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 2001–2002. Available at: http//www.cancer.org/downloads/STT/BrCaFF2001.pdf.

36 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) 1 Writing Group for the Women’s Health Initiative Investigators. JAMA. 2002;288: of 100 women who are HRT users are at risk (<1 additional woman over baseline risk)

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

38 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 Communicating Contraceptive Effectiveness

39 Farley TMM, Collins J, Schlesselman JJ. Contraception Smoker OC User Smoker OC User BP Checked 3 Deaths per million woman-years among women age 30–34 Cardiovascular Adverse Events: Screening for Risk Factors Venous thromboembolism Ishemic stroke Hemorrhagic stroke Myocardial infarction

40 Medical student attitudes toward the doctor– patient relationship Medical Education Volume 36, Issue 6, pages , 31 MAY 2002 DOI: /j x Volume 36, Issue 6,

41 Attitudes re: patient centered care through medical school

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

43 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… Guidance

44 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 Guidance (continued)

45 Know Yourself and Your Patient

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

47 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

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

49 “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?” Patient Needs & Concerns

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

51 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

52 Mammography Numbers repeated screening starting at age 50 saves about 1.8 (overall range, 0.9–2.7) lives over 15 years for every 1000 women screened. Keen JD. BMC Medical Informatics and Decision Making 2009

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

54 Perception & Interpretation of Risk IndividualRisk Presentation Characteristics of the Risk

55 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 Characteristics of the Risk

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

57 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… Guidance for Risk Communication

58 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 Guidance for Risk Communication (cont’d)

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


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