prognosis hinf 371 - medical methodologies session 9
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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
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.
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