Prognosis Prognosis HINF 371 - Medical MethodologiesHINF 371 - Medical Methodologies

Session 9Session 9

Objective Objective

Understand prognosis and Understand prognosis and factors determining prognosisfactors determining prognosis

Review PRO-Act-Ive over a caseReview PRO-Act-Ive over a case

ReadingReading

Mar CD, Doust J, Glasziou (2006) Chapter 5: Mar CD, Doust J, Glasziou (2006) Chapter 5: Fine Art of Prognostication, in Clinical Fine Art of Prognostication, in Clinical Thinking: Evidence, Communication and Thinking: Evidence, Communication and Decision-Making, Blackwell Publishing and Decision-Making, Blackwell Publishing and BMJ Books, USABMJ Books, USA

Mar CD, Doust J, Glasziou (2006) Chapter 6: Mar CD, Doust J, Glasziou (2006) Chapter 6: Making Clinical Management Decisions, in Making Clinical Management Decisions, in Clinical Thinking: Evidence, Communication Clinical Thinking: Evidence, Communication and Decision-Making, Blackwell Publishing and Decision-Making, Blackwell Publishing and BMJ Books, USAand BMJ Books, USA

http://www.cdc.gov/nchs/products/pubs/pubhttp://www.cdc.gov/nchs/products/pubs/pubd/lftbls/life/1966.htmd/lftbls/life/1966.htm

Prognosis Prognosis

Each condition have their own Each condition have their own natural progressionnatural progression

Our decision is what would Our decision is what would happen if we did nothinghappen if we did nothing

If an intervention is If an intervention is recommended, then what are the recommended, then what are the optionsoptions

Which options are preferrable by Which options are preferrable by the patientthe patient

Comparison of life Comparison of life expectancies expectancies

AgeAge NumbNumber of er of survivsurvivorsors

Number Number of of people people dying dying before before the next the next ageage

The The proportiproportion on survivinsurvivingg

The The proportiproportion of on of dying dying before before next agenext age

CoefficieCoefficient of nt of variationvariation

Number Number of life of life years years livedlived

Number Number of life of life years years lived lived beyond beyond

Life Life expectaexpectancy at ncy at age age

Coefficient Coefficient of of variation variation of life of life expectancexpectancyy

Males-22Males-22

Males-79Males-79

98,8698,8655

57324

9494

3185

0.99905

0.94444

0.00095

0.05556

19.6

3.7

98818

55731

5620852

503092

56.85

8.78

0.15

0.77

Females-Females-2222

Females-Females-7979

99,2299,2244

71261

4040

2481

0.99960

0.96519

0.00040

0.03481

30.7

4.0

99203

70020

6096433

760225

61.44

10.67

0.14

0.59

What is the big deal? We What is the big deal? We will all die anyway.will all die anyway.

Median

Absolute risk difference in Mortality or

survival

Rule of Thumb: Mortality doubles every 6 years

But we are able to make But we are able to make changes for our prognosischanges for our prognosis

Determining PrognosisDetermining Prognosis

Estimating the severity of illnessEstimating the severity of illness Likely duration of the illness to dateLikely duration of the illness to date Extrapolate forward in futureExtrapolate forward in future

Independent factors – Age, physical Independent factors – Age, physical conditioncondition

Dependent factors – estrogen receptors Dependent factors – estrogen receptors in breast cancer, smoking in COPDin breast cancer, smoking in COPD

Risk factors – susceptability to disease – Risk factors – susceptability to disease – systemic Lupus Erythematosussystemic Lupus Erythematosus

Patterns of DiagnosisPatterns of Diagnosis

Spontaneously remitting: cold, Spontaneously remitting: cold, sprain, sprain,

Recurrent – intermittent: migraine, Recurrent – intermittent: migraine, asthmaasthma

Chronic (non-progressive): ulcerative Chronic (non-progressive): ulcerative colitis, rheumatoid arthritis, anxietycolitis, rheumatoid arthritis, anxiety

Progressive: COPD, cancers, Progressive: COPD, cancers,

Use of Pro-Act-IveUse of Pro-Act-IveCaseCase

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.

Problem and ReframingProblem and Reframing

P=define the problemP=define the problem Unhappy child, sick and probably ottis mediaUnhappy child, sick and probably ottis media

R=reframe the problemR=reframe the problem Family is sleeplessFamily is sleepless Mother works casually, can’t earn money if can’t Mother works casually, can’t earn money if can’t

go to work or needs to pay for child carego to work or needs to pay for child care Mother worried about hearing loss or limitations in Mother worried about hearing loss or limitations in

language developmentlanguage development Wants solutions to eliminate these episodesWants solutions to eliminate these episodes Disease is self-limiting, may have complications of Disease is self-limiting, may have complications of

infection of nearby bones or tissues, in chronic infection of nearby bones or tissues, in chronic state may create hearing lossstate may create hearing loss

Parents probably expect antibiotics – but Parents probably expect antibiotics – but problems with over use of antibioticsproblems with over use of antibiotics

ObjectivesObjectives

Minimize symptomsMinimize symptoms Minimize duration of illnessMinimize duration of illness Reduce risk of complicationsReduce risk of complications Reduce the risk of spread of the Reduce the risk of spread of the

illness to other family membersillness to other family members Reduce the use of antibioticsReduce the use of antibiotics

ActAct

A=consider all alternativesA=consider all alternatives Do nothingDo nothing Provide pain reliefProvide pain relief Provide antibioticProvide antibiotic Provide prescription and let family Provide prescription and let family

decidedecide Seek further solutions e.g. Seek further solutions e.g.

myringotomymyringotomy

ActAct

Consider consequences of each Consider consequences of each alternative and estimate the changesalternative and estimate the changes Asked focussed questionAsked focussed question

PatientPatient InterventionIntervention ComparatorComparator OutcomeOutcome

Search for evidence (Medline, Cochrane Search for evidence (Medline, Cochrane Library, Clinical evidence by BMJ, Library, Clinical evidence by BMJ, UpToDate)UpToDate)

Appraise the evidenceAppraise the evidence Apply evidence to the individual patientApply evidence to the individual patient Evaluate the processEvaluate the process

What is the effect of antibiotics compared with nothing on pain in a 2 year old with acute otitis media

Apply evidence to the Apply evidence to the patientpatient

Determine the possible beneficial and harmful effects of Determine the possible beneficial and harmful effects of treatmenttreatment Antibiotics – some reduction of pain 2-7 days, no change in 24 hrs 7 Antibiotics – some reduction of pain 2-7 days, no change in 24 hrs 7

percent absolute reduction, 30 percent relative risk reduction, 67 percent absolute reduction, 30 percent relative risk reduction, 67 percent relative risk, number needed to treat 14.percent relative risk, number needed to treat 14.

No effect on risk of occurrence, ear perforation, abnormal hearing,No effect on risk of occurrence, ear perforation, abnormal hearing, Side effects of antibiotics: vomiting, diarrhoea, allergic reaction, Side effects of antibiotics: vomiting, diarrhoea, allergic reaction,

antibiotic resistance – 1 every 17 antibiotic resistance – 1 every 17 Determine if there is a predictable variation in the relative Determine if there is a predictable variation in the relative

effects of treatment between sub-group of patientseffects of treatment between sub-group of patients Younger children <2 yearsYounger children <2 years Children otitis media at both sidesChildren otitis media at both sides Seriously unwell (e.g. high fewer)Seriously unwell (e.g. high fewer)

Examine if effects vary with risk levelExamine if effects vary with risk level Indigenous communitiesIndigenous communities

Estimate the predicted benefits and harms for an individual Estimate the predicted benefits and harms for an individual patientpatient Maddison is <2 yearsMaddison is <2 years But has low risk of painBut has low risk of pain

Trade-offsTrade-offs

T: Identify Trade-offsT: Identify Trade-offs Pain is the only problemPain is the only problem Illness complications are quite lowIllness complications are quite low Antibiotic versus ordinary pain Antibiotic versus ordinary pain

killerskillers Antibiotic resistance versus painAntibiotic resistance versus pain

Ive Ive

I: integrated the evidence and the valuesI: integrated the evidence and the values The evidence doesn’t identify significant benefits The evidence doesn’t identify significant benefits

for antibiotic usefor antibiotic use But mother may be happy that antibiotics is But mother may be happy that antibiotics is

prescribedprescribed V: optimize the expected valueV: optimize the expected value

No alternative is optimalNo alternative is optimal Maddison is <2 but not seriously unwell.Maddison is <2 but not seriously unwell.

E: explore assumptions and evaluate E: explore assumptions and evaluate uncertaintyuncertainty How certain we are about the estimates of benefit How certain we are about the estimates of benefit

and harmand harm What would be the effect of variation – sensitivity What would be the effect of variation – sensitivity

analysesanalyses

Heuristics of caseHeuristics of case

Overall few short-term benefits and no long-term Overall few short-term benefits and no long-term benefit of antibiotics for otitis media. Major benefit of antibiotics for otitis media. Major problem is increase in antibiotic resistance. Not problem is increase in antibiotic resistance. Not wise to prescribe antibioticswise to prescribe antibiotics

Pain killers may be able provide same short-term Pain killers may be able provide same short-term benefits with fewer potential harmsbenefits with fewer potential harms

Some children may benefit from antibiotics – high Some children may benefit from antibiotics – high risk of complications, indigenous children, seriously risk of complications, indigenous children, seriously unwell children with bilateral illness, high fewer.unwell children with bilateral illness, high fewer.

What would you do?What would you do?