Prognosis

1. Prognosis HINF 371 - Medical Methodologies Session 9

2. Objective • Understand prognosis and factors determining prognosis • Review PRO-Act-Ive over a case

3. Reading • Mar CD, Doust J, Glasziou (2006) Chapter 5: Fine Art of Prognostication, in Clinical Thinking: Evidence, Communication and Decision-Making, Blackwell Publishing and BMJ Books, USA • Mar CD, Doust J, Glasziou (2006) Chapter 6: Making Clinical Management Decisions, in Clinical Thinking: Evidence, Communication and Decision-Making, Blackwell Publishing and BMJ Books, USA • http://www.cdc.gov/nchs/products/pubs/pubd/lftbls/life/1966.htm

4. Prognosis • Each condition have their own natural progression • Our decision is what would happen if we did nothing • If an intervention is recommended, then what are the options • Which options are preferrable by the patient

5. Comparison of life expectancies

6. Median Absolute risk difference in Mortality or survival What is the big deal? We will all die anyway. Rule of Thumb: Mortality doubles every 6 years

7. But we are able to make changes for our prognosis

8. Determining Prognosis • Estimating the severity of illness • Likely duration of the illness to date • Extrapolate forward in future • Independent factors – Age, physical condition • Dependent factors – estrogen receptors in breast cancer, smoking in COPD • Risk factors – susceptability to disease – systemic Lupus Erythematosus

9. Patterns of Diagnosis • Spontaneously remitting: cold, sprain, • Recurrent – intermittent: migraine, asthma • Chronic (non-progressive): ulcerative colitis, rheumatoid arthritis, anxiety • Progressive: COPD, cancers,

10. Use of Pro-Act-IveCase Madison is 22-month-old girl who has been unwell for the past 48 hours. She has been unhappy, crying occasionally, has a fever, is not eating or drinking well and is waking up and crying several times through the night. She has two older siblings, who are at primary school and are well. Both parents work full-time and she goes to child-care centre near her mother’s work on weekdays. Madison has generally been a well child, but she had a similar episode about 6 months ago that took a week to resolve. Her immunization is up-to-date. On examination, she is not dehydrated, her temperature is 37.8 degrees and the only abnormality of note is a right dull red tympanic membrane.

11. Problem and Reframing • P=define the problem • Unhappy child, sick and probably ottis media • R=reframe the problem • Family is sleepless • Mother works casually, can’t earn money if can’t go to work or needs to pay for child care • Mother worried about hearing loss or limitations in language development • Wants solutions to eliminate these episodes • Disease is self-limiting, may have complications of infection of nearby bones or tissues, in chronic state may create hearing loss • Parents probably expect antibiotics – but problems with over use of antibiotics

12. Objectives • Minimize symptoms • Minimize duration of illness • Reduce risk of complications • Reduce the risk of spread of the illness to other family members • Reduce the use of antibiotics

13. Act • A=consider all alternatives • Do nothing • Provide pain relief • Provide antibiotic • Provide prescription and let family decide • Seek further solutions e.g. myringotomy

14. Act • Consider consequences of each alternative and estimate the changes • Asked focussed question • Patient • Intervention • Comparator • Outcome • Search for evidence (Medline, Cochrane Library, Clinical evidence by BMJ, UpToDate) • Appraise the evidence • Apply evidence to the individual patient • Evaluate the process What is the effect of antibiotics compared with nothing on pain in a 2 year old with acute otitis media

15. Apply evidence to the patient • Determine the possible beneficial and harmful effects of treatment • Antibiotics – some reduction of pain 2-7 days, no change in 24 hrs 7 percent absolute reduction, 30 percent relative risk reduction, 67 percent relative risk, number needed to treat 14. • No effect on risk of occurrence, ear perforation, abnormal hearing, • Side effects of antibiotics: vomiting, diarrhoea, allergic reaction, antibiotic resistance – 1 every 17 • Determine if there is a predictable variation in the relative effects of treatment between sub-group of patients • Younger children <2 years • Children otitis media at both sides • Seriously unwell (e.g. high fewer) • Examine if effects vary with risk level • Indigenous communities • Estimate the predicted benefits and harms for an individual patient • Maddison is <2 years • But has low risk of pain

16. Trade-offs • T: Identify Trade-offs • Pain is the only problem • Illness complications are quite low • Antibiotic versus ordinary pain killers • Antibiotic resistance versus pain

17. Ive • I: integrated the evidence and the values • The evidence doesn’t identify significant benefits for antibiotic use • But mother may be happy that antibiotics is prescribed • V: optimize the expected value • No alternative is optimal • Maddison is <2 but not seriously unwell. • E: explore assumptions and evaluate uncertainty • How certain we are about the estimates of benefit and harm • What would be the effect of variation – sensitivity analyses

18. Heuristics of case • Overall few short-term benefits and no long-term benefit of antibiotics for otitis media. Major problem is increase in antibiotic resistance. Not wise to prescribe antibiotics • Pain killers may be able provide same short-term benefits with fewer potential harms • Some children may benefit from antibiotics – high risk of complications, indigenous children, seriously unwell children with bilateral illness, high fewer.

19. What would you do?