Lectures 13&14 - More on study design: The key challenges to medicine Flashcards
why undertake systematic review?
- 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
what are the main advantages of a systematic approach?
- 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
what is the 1st stage in a systematic review?
- planning the review: research question must be clearly defined
what is the 2nd stage in a systematic review?
- 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
what is the 3rd stage in a systematic review?
- 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
what are the advantages of a meta-analysis?
- 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
what are the limitations of a meta-analysis?
- publication bias
- labour intensive
- inconsistency of results
- low study quality
what is the most common way of visually summarising the results of a meta-analysis?
forest plot
what is publication bias?
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
what is the most common way of visually summarising publication bias in meta-analyses?
funnel plot
- shows whether there is a link between study size and the effect estimate
what is heterogeneity?
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
what is the most common way of visually summarising heterogeneity?
galbraith (radical) plots
what are the limitations of a systematic review?
- 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
what is Cochrane?
an organisation involving a large number of international researchers and clinicians to organise medical research in a systematic way
what is PRISMA?
Preferred Reporting Items for Systematic Reviews and Meta-Analyses
evidence-based minimum set of items for reporting in systematic reviews and meta-analyses
what must be considered when critically appraising systematic reviews and meta-analyses in particular?
- clear, predefined question
- comprehensive search
- quality of studies
- heterogeneity
- publication bias
- PRISMA guidelines
what are achievements of healthcare so far?
1) longevity
2) access to health services
describe how longevity is an achievement of healthcare
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
describe how access to health services is an achievement of healthcare
- 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)
what are challenges to medicine so far?
- 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
describe how strength of evidence is a challenge to medicine
- half of scientific literature may be untrue
- reliability of research findings and systems of evidence
describe how unhealthy behaviour is a challenge to medicine
- 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
describe how burden of disease is a challenge to medicine
- CHD
- mental illnesses
describe how an ageing population is a challenge to medicine
- increasing life expectancy
- people live longer so more older people in population who require resources
- many non-communicable/chronic diseases/disabilities
describe how a shortage of human resources is a challenge to medicine
- 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
describe how the organisation of health services is a challenge to medicine
- many countries have weak public health, hospital based healthcare and primary care
describe how quality, safety and effectiveness are challenges to medicine
- 20-40% of health spending is wasted:
- ineffective treatment
- misuse
- no evidence
- incompetent healthcare professionals
- A&E costs 4a more than a GP visit
describe how information, technology and people power are challenges to medicine
- influence of social media
- GPs reliance on taking emails and sending texts
describe how medical advances are challenges to medicine
- unit costs
- unmet needs
- longevity
- adaptations and errors
