EBP

in NNT what do you do

round up

In NNH what do you do

round down

what do clinical end points reflect

survival or symptomactic status of patient

whats per protocol analysis

include only those events that occur while participant is complying with intervention

whats intention to treat

all included regardless of adherance

whats a non-inferiority design

to evaluate where trt is ‘not inferior’ to standard trt

what are systematic reviews

summarise studies

using structured, reproducible method

asses bias, confounding, study design issues

whats a meta analysis

statistical method for combinding the results of a number of studies

whats a fixed meta analysis

treatment affect the same in all studies - variation due to sampleing

whats a random effect metanalysis

heterogenicity

big studies don’t dominate as much

how to test for heterogeneity

cochran’s Q test

what is satisfaction called in economics

utility

what is health economics

the study of attempts to allocate limited healthcare resources among unlimited wants and needs to achieve the maximum health benefit for society

what are the two perspectives

healthcare system - only costs and benefity relivetnat to the healthcare system

society - costs and benefits to the whole of society

what are unidimensional benefits

don’t consider quality of life

can’t compare cost effectivness of interventions measured in units

what is QALY

generic measure of disease burden including the quanity (years) and quality of life (0-1)

one QALY = one year in perfect health

cost-minimisation analysis - just compares cost

cost consequence analysis - costs and benefits not compared mathematically in terms of numerical values

cost effectiveness plane

whats cost effectiveness analysis

costs and benefitys of two intervnetions

calculte the cost of each extra ‘unit of benefit’

calculated using ICER

whats cost utility analysis

subtype of cost effectivness analysis where benefits measured in QALYs

ICER = how many £ for each extra QALY

NICE cost effectivness threshold

25,000 - 30,000 per QALY

what are the two ways to carry out economic evaluation

trial based - collect costs alongside RCTs

economic modelling - decision tree, markov model

problems with trial based economic evaluation

follow up rarely long enough

can only compare treatments used in trial

costs vary between counties

does not use all the availbale info

whats the severity modifier

high everity - 1.7 times weighting for benefits

medium severity - 1.2 times weighting for benefity

no severity weight - 1 times

for highly specialised technology appraisals what are thresholds

<10 QALYS - 100,000 per QALY

11-29 QALYS - 100,000-300,000 per QALY

>30 QALYs gained - 300,000 per QALY

What are managed access programmes

allow people to use drugs whilst uncertainties about clinical or cost effectivness of the new treaments whilst collecting data

how long are managed access programmes and what two funding sources are there

5 years

cancer drugs fung

innovative medicines fund

what does non-differential misclassification do

underestimate effect for two exposure categories

whats a confounder

the distorition of risk estimate due to the mixture of the people in the study and population- a risl factor for the disease and is correlated with the exposure independent of disease

how to control confounding

randomisation

restriction

matching - pair cases with control

stratified analysis - separate out factors

multi variant analysis

strengths of cohort studies

efficent for rare exposures

multiple effects can be studies

less prone to bias

can calculate IR,RR

limitations of cohort studies

can have difficulties with loss to FUP

may have problems with bias

in case-control studies where should the controls come from

must be at risk of outcome but not have the outcome under study

what is bias

the introduction of a systematic error in the study

advvantages of case- control studies

results avialble quickly, cheaply

good for rare diseases with long latency

disadvantages of case control studies

inefficent for rare exposures

cant’ calculate indcidence or prevelance #

more prone to bias than cohort

what controls to use in case-control studies

hosptial controls - easy to recruit, might not come from same population

community controls - more representatvie, harder to recruit

two methods for drug safety evaluation

spontaneous reporting eg yellow card scheme

systematic evaluation

what are case reports

used in literature to report unsual medical occurances - cannot test for statistical association

3 types of adverse reaction

Type A - drug effect

Type B - patient reaction

Type C - where drug increases the frequency of spontaneous disease Type D - delayed reactions

what does proportional reporting ration do

compares how often a specific side effect is reported for ONE drug vs all drugs - shows assiciation

what 5 ways is drug safety studied in pregnant women

1. case-control studies

2. teratology information services

3. pregancy exposure registeries

4. electronic health data

5. clinical practice reasearch data link

issues with case-control studies in pregnancy

relies on maternal reoprting

doesn’t capture spontaneous losses

issues with pregnancy expoure registeries

self enrolment

loss to FUP

small numbers

strengths of electronic healthcare data

often provide representative sample

routinley recoreded

exposure data recorded prospectivly

internal comparators

limitations of electronic healthcare data

no OTC medicines or in patient prescirbing

dont know if medicine was taken