Lectures 13&14 - More on study design: The key challenges to medicine

Question 1

why undertake systematic review?

Answer 1

• data quantity
• data quality

a review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, to collect and analyse data from the studies that are included in the review

Question 2

what are the main advantages of a systematic approach?

Answer 2

• transparent process because of the explicit methods in identifying and rejecting studies
• a meta-analysis increases the power of the study and enhances the precision of estimates of treatment effects, accounting for sample size and uncertainties
• systematic reviews demonstrate the lack of adequate evidence so identify areas where further studies are needed

Question 3

what is the 1st stage in a systematic review?

Answer 3

• planning the review: research question must be clearly defined

Question 4

what is the 2nd stage in a systematic review?

Answer 4

• identification of research: defined search criteria and thorough search of all published literature
• selection of studies: inclusion and exclusion criteria should be defined
• study quality assessment: use recognised or user-defined criteria to establish whether biases are likely to exist in the study

Question 5

what is the 3rd stage in a systematic review?

Answer 5

• reporting and dissemination: study details must be extracted from each eligible study along with the effect estimate, details should be tabulated and an overall effect should be determined by combining data

Question 6

what are the advantages of a meta-analysis?

Answer 6

• generates a pooled overall risk estimate
• produces a more reliable and precise estimate of effect
• explores differences (heterogeneity) between studies
• identifies whether a publication bias is occurring

Question 7

what are the limitations of a meta-analysis?

Answer 7

• publication bias
• labour intensive
• inconsistency of results
• low study quality

Question 8

what is the most common way of visually summarising the results of a meta-analysis?

Answer 8

forest plot

Question 9

what is publication bias?

Answer 9

the greater likelihood of research with statistically significant results to be published in the peer-reviewed literature in comparison to those with null/non-significant results

Question 10

what is the most common way of visually summarising publication bias in meta-analyses?

Answer 10

funnel plot

- shows whether there is a link between study size and the effect estimate

Question 11

what is heterogeneity?

Answer 11

studies that are trying the answer the same question will still differ in ways with respect to exact population, interventions/exposure, outcomes and designs used

Question 12

what is the most common way of visually summarising heterogeneity?

Answer 12

galbraith (radical) plots

Question 13

what are the limitations of a systematic review?

Answer 13

• if there are too few studies matching the eligibility criteria the systematic review may be pointless
• if the quality of studies included are poor the findings of the review may be compromised
• publication bias

Question 14

what is Cochrane?

Answer 14

an organisation involving a large number of international researchers and clinicians to organise medical research in a systematic way

Question 15

what is PRISMA?

Answer 15

Preferred Reporting Items for Systematic Reviews and Meta-Analyses

evidence-based minimum set of items for reporting in systematic reviews and meta-analyses

Question 16

what must be considered when critically appraising systematic reviews and meta-analyses in particular?

Answer 16

• clear, predefined question
• comprehensive search
• quality of studies
• heterogeneity
• publication bias
• PRISMA guidelines

Question 17

what are achievements of healthcare so far?

Answer 17

1) longevity

2) access to health services

Question 18

describe how longevity is an achievement of healthcare

Answer 18

people are living longer (however this also presents problems):

• life expectancy for females is 84yo in UK
• males is 80yo in UK
• health life expectancy = people living without disability, and in the UK the average of this is 63yo
• improvements in global child mortality rates
• HOWEVER: reduced life expectancy in Syria and Iraq due to wars

Question 19

describe how access to health services is an achievement of healthcare

Answer 19

• free healthcare = NHS
• brazil has greatly increased primary care over 2 decades
• HOWEVER: money is needed to pay for healthcare in some Arab countries (e.g. Egypt)

Question 20

what are challenges to medicine so far?

Answer 20

• strength of evidence
• unhealthy behaviours
• burden of disease
• ageing population
• shortage of human resources
• organisation of health services
• quality, safety, effectiveness
• information, technology, people power
• medical advances: use and misuse

Question 21

describe how strength of evidence is a challenge to medicine

Answer 21

• half of scientific literature may be untrue

- reliability of research findings and systems of evidence

Question 22

describe how unhealthy behaviour is a challenge to medicine

Answer 22

• inequalities in smoking prevalence due to different exposures in different ethnic groups
• smoking/drinking/eating unhealthily
• childhood obesity
• NHS spends a lot of money on treating unhealthy behaviours

Question 23

describe how burden of disease is a challenge to medicine

Answer 23

• CHD

- mental illnesses

Question 24

describe how an ageing population is a challenge to medicine

Answer 24

• increasing life expectancy
• people live longer so more older people in population who require resources
• many non-communicable/chronic diseases/disabilities

Question 25

describe how a shortage of human resources is a challenge to medicine

Answer 25

• not enough doctors
• junior doctor contract = many graduates choosing not to work for the NHS
• US have more supply than demand so may attract UK doctors
• health care professionals suffer due to lack of support

Question 26

describe how the organisation of health services is a challenge to medicine

Answer 26

• many countries have weak public health, hospital based healthcare and primary care

Question 27

describe how quality, safety and effectiveness are challenges to medicine

Answer 27

• 20-40% of health spending is wasted:
• ineffective treatment
• misuse
• no evidence
• incompetent healthcare professionals
• A&E costs 4a more than a GP visit

Question 28

describe how information, technology and people power are challenges to medicine

Answer 28

• influence of social media

- GPs reliance on taking emails and sending texts

Question 29

describe how medical advances are challenges to medicine

Answer 29

• unit costs
• unmet needs
• longevity
• adaptations and errors