Health Pop Flashcards

Question

How do you work out confidence interval?

Answer 1

lower bound = observed value ÷ error factor | upper bound = observed value x error factor

Answer 2

deviation of the results from the truth via certain processes

Answer 3

error due to SYSTEMATIC differences in ways in which the two groups were collected

Answer 4

error due to systematic misclassification of subjects in the group

Answer 5

studies with statistically significant or favourable results are more likely to be published

Answer 6

``` Recall bias Information bias Publish bias Healthy worked effect Selection bias Allocation bias ```

Answer 7

recruiting disease FREE individuals and classifying them according to EXPOSURE status then followed up for extended periods, disease progress monitored and incidence rates (IR) are calculated

Answer 8

rare exposure or diseases which take a long time to develop

Answer 9

disease free individuals recruited and followed up 'look to the future'

Answer 10

disease free individuals recruited then exposure status calculated from historical documentation and followed up can be prone to recall bias use IR

Answer 11

when you have sub cohorts within your original group then compare exposed and unexposed within your within the cohort use IRR

Answer 12

exposed population compared against reference population e.g. general population use SMR to remove cofounders

Answer 13

recruiting disease free individuals (control) and diseased individuals (control) and their exposure status determined (recorded) then word out the odds ratio (a x d) / (b x c)

Answer 14

2 things are equal / no difference

Answer 15

strong suggestion that the null hypothesis is false (statistically significant)

Answer 16

observed findings consistent with null hypothesis (2 things are equal) (NOT true, just consistent, so can't reject)

Answer 17

p>0.05, can't reject null hypothesis

Answer 18

null hypothesis = 1 being exposed will give the same odds for developing the disease as unexposed (being exposed will give the odds of developing the disease for the odds calculated)

Answer 19

for rare diseases number of controls usually 5x amount of cases, controls easier to find - minimising EF (more control, less error - more representative of the population of the disease being rare)

Answer 20

pros: good for rare EXPOSURES cons: expensive, time-consuming (esp. if disease has long latent period - takes long time to develop) but can calculate absolute risk opportunity to look for different potential outcomes at once from varying exposures

Answer 21

good for rare DISEASE opportunity to look for different EXPOSURES cheap and quick (pt already have the disease) can't obtain absolute risks heavily affected by recall + selection bias

Answer 22

1. selection bias - participants not representing general population e.g. diseased and control from the same ward (heart disease), SIMILAR risk factors / exposures 2. recall bias - exposure status incorrectly determined - due to retrospective (looking back to history to determine exposure)

Answer 23

confounders | matching up same band controls with similar details

Answer 24

identify a source of eligible pts allocate participants to treatment fairly - randomisation follow up participants in identical ways minimise losses to follow up (try and follow up often) and maximised compliance with treatment (follow the treatment plan given) analyse data obtained and results

Answer 25

used to remove any confounders that may be present in the study, known or unknown

Answer 26

neither the patient nor the doctor now which treatment they are on - removing selection bias (doctors are more likely to place healthy patients in new drug groups and show more positive results for the new drug to produce statistically significant results)

Answer 27

if no current treatment already in place for disease in question to remove placebo effect from the trial

Answer 28

loss of randomisation as the patients who remain in the trail are normally ones who are predisposed to or have the disease, so want a cure

Answer 29

intention to treat analysis | ignores noncompliance, withdrawal, and anything that happens after randomisation

Answer 30

to determine whether causal-effect relationship has been established (once confounders, bias and chance have been removed)

Answer 31

1. STRENGTH of association: stronger association, more likely to be causal 2. SPECIFICITY of association: outcome associated with specific factor (mesothelioma caused by asbestos) 3. CONSISTENCY of association: association occurs in other studies too

Answer 32

1. temporal sequence: causative factor precedes outcome (cause before outcome) 2. Dose response: increasing exposure increases outcome 3. Reversibility: removing causative factor reduces risk of outcome

Answer 33

1. Coherence of theory: observed observation confirms current scientific thinking 2. Biological plausibility: biological mechanism support theory 3. Analogy: study more likely if there is a link with another study

Answer 34

follow up participants at appropriate times no coercion or inducements (don't force anything!) honest to patients

Answer 35

1. simplify instructions 2. patient allowed to ask any questions they have 3. made simple and accessible for patients measuring blood test urine samples etc.

Answer 36

1. clinical equipoise - reasonable, certain which drug is better for patient, not subjecting patient to less effective treatment 2. scientifically robust - in search for good of the general population 3. ethical recruitment - recruitment for region where drug will take affect (all factors taken in - side effects etc.) 4. valid consent - participants given sufficient knowledge cooling off period

Answer 37

an overview of primary studies that used explicit and reproducible method large amount of studies identified and narrowed down with the most relevant and credible studies should be transparent, reproducible and explicit (stated clearly)

Answer 38

quantitive synthesis of primary studies within systematic review (continuos outcome e.g. long term effects) provides overall value with associated confidence intervals results shown via forest plots

Answer 39

1. fixed effects model | 2. random effects model

Answer 40

assumes that the studies used are homogenous and any variation between data comes from within - study variation (study estimating SAME effect size)

Answer 41

assumes the studies are heterogeneous and variation between the data comes from between - study variation and in between study variation (study estimating SIMILAR effect size)

Answer 42

quality of primary studies AND publication bias | should use published AND unpublished trial

Answer 43

a study is more likely to be published if the results are statistically significant or has a large sample size - results will be biased

Answer 44

using funnel plot well shaped and balanced systematic review - funnel shape in its studies when plotted a biased systematic review will vary in shape

Answer 45

explicit methods can reduce bias and exclusion of poor quality studies meta-analysis provides overall figure for the studies large amounts of information can be assimilated quickly by healthcare professionals reduction in time between research discovery and implementation of clinical use uses evidence based practice guidelines (quick, large amount of information assimilated, short time period between discovery and use of treatment)

Answer 46

1. Necessary: cause BEFORE disease 2. Specific: cause ABSENT in other diseases 3. Sufficient: cause ALONE can cause disease

Answer 47

the study of the distribution and determinants of health-related states or even in specified populations, and the application of this study to the control of health problems

Answer 48

any form of planned experiment which involves patients and is designed to elucidate the most appropriate method of treatment of future patients

Answer 49

``` reproducible controlled - comparison of interventions fair - unbiased without confounding autonomy - patient has a say pt able to withdraw anytime ```

Answer 50

even if the therapy is irrelevant to the patient's condition, the patient's attitude to his or her illness and indeed the illness itself, ay be improved by a feeling that something is being done about it