Term Test 1 Flashcards
define EBVM
the conscientious and judicious use of the current best evidence in the health care of individuals and populations…. combining clinical expertise with the best available external clinical evidence from systematic research
in a nutshell, EBVM combines (2)
clinical expertise and best available research
EBVM can be applied to what 3 types of clinical decisions
1) diagnostic decisions
2) treatment decisions
3) preventative health decisions
what is an example of EBVM in diagnostic decisions
tests and test performance
what is an example of EBVM in treatment decisions
interventions and strength of evidence
what is an example of EBVM in preventative health decisions
herd health or wellness and causation
what two types of studies are synthesis studies
SRs and MAs
what are the 6 parts to a BestBET
1) clinical scenario
2) PICO question aka 3 part question
3) literature search
4) evidence
5) comments
6) bottom line
what types of studies are hypothesis-testing studies
observational and experimental studies
what types of studies are observational studies
case-control, cohort and cross-sectional studies
what types of studies are experimental studies
experiments and RCTs
what type of observational study can establish a temporal sequence
cohort studies
how are cohort study results usually expressed
risk ratio
you can determine _________ risk in a cohort study
absolute
when are cohort studies not useful
rare diseases
how are the results of a case-control study expressed
odds ratio
what cannot be calculated from a case-control study
relative risk, true prevalence/incidence, absolute risk
what is an advantage of a case-control study
good for rare outcomes and is cheap and quick
what does PICO stand for
patient/problem, intervention, control, outcome
what are some issues with using medical records as evidencd
1) completeness
2) quality
3) case definition
4) follow-up
if using medical records as evidence we must consider:
- case definition needed for incidence and prevalence
- complications need to be recorded
- probability of success relies on follow-up and outcomes
what is key for case definition
consistency across clinicians and clinics
what is the biggest issue in practice with finding evidence
not having access and ability to find the right articles
describe whether the following boolean operators narrow or broaden your search:
or:
and:
not:
or: broadens search
and: narrows search
not: narrows search
what are 3 databases for animal health and which is the best
1) CAB direct (best)
2) Agricola
3) PubMed/Medline
What sections of a journal article pertain to relevance and what sections pertain to quality
Relevance:
- title
- authors
- abstract/conclusion
Quality:
- materials and methods (objectives, data, outcomes
- conclusions
we tend to remember what types of cases
best and worst
why is having a clearly defined case definition important
it is needed to determine incidence and prevalence
are case reports/case series useful for decision making
no
what are case reports/case series useful for
generating questions for future research, describing rare cases, raising awareness
what are the 7 Hill’s Criteria for Causation
1) dose-response
2) temporal sequence
3) biological plausibility
4) reversal
5) repeatability
6) rule-out other potential causes
7) strength of association (OR and RR)
case control studies are best for rare _________ and cohort studies are best for rare _________
conditions/diseases; risk factors
what observational study type is best for arguing causation
cohort
are RCTs or laboratory experiments more controlled
laboratory experiments
what is a key aspect of intervention/experimental studies
random allocation of subjects to groups
T/F intervention studies support a causal relationship
T
every explanatory study needs 2 things:
hypothesis and objective
what is the p value
likelihood of the observed difference between the groups, given that the null hypothesis is true OR likelihood of the observed differences corresponding to no difference
what are measures of association
measure of the magnitude/strength of the relationship between E and O as a relative effect; the ratio of two estimates of disease frequency
what observational study designs can use:
1) RR
2) OR
1) RR: cross-sectional and cohort
2) OR: all study types
what are chi-square tests used for
to determine whether two categorical variables are related
how is RR calculated
risk of disease in exposed group / risk of disease in non-exposed group
[a/(a+b)] / [c/(c+d)]
is RR or OR more commonly reported in an observational study
OR
what does MERIDIAN stand for
MEnagerie of Reporting guIDelines Involving ANimals
what is the purpose of MERIDIAN
to establish guidelines for a variety of types of animal research in order to make it easier to assess quality
how can we determine if randomization worked
check the groups for similarity… age, breed, parity, species, severity of condition, etc.
what is the aim of a non-inferiority trial?
to demonstrate no difference between groups for outcome measures
what 7 things should be on every controlled trial checklist
1) objectives and hypothesis
2) sample size calculation
3) random allocation
4) did randomization work
5) blinding and placebo
6) effect size
7) limitations and survival bias
what is an important consideration with diagnostic accuracy
we estimate Sp and Sn by comparing to what we call the reference standard, which we assume to be “gold standard”
no test is actually perfect so we need to account for this so as not to over or under estimate the accuracy of a new test
what does STROBE-VET stand for
strengthening the reporting of observational studies in epidemiology - vet extension
define the type of observational study:
comparison of past histories of animals that have a disease with those in a comparable group of undiseased animals
case-control
define the type of observational study:
simultaneous classification of a group of animals according to disease status and risk factors
cross-sectional
define the type of observational study:
most useful for rare outcomes
case-control
define the type of observational study:
cannot calculate true incidence/prevalence and RR
case-control
define the type of observational study:
among observational studies is the best to argue causation
cohort
define the type of observational study:
ID two groups of animals (one with the risk factor and one without) and subsequent follow-up over time to determine if disease develops
cohort
what are 3 types of bias possible to see in narrative reviews
1) selection bias
2) information bias
3) publication bias
what is a systematic review
review of a clearly formulated question that uses systematic and explicit methods to identify, select, appraise and summarize relevant research
the systematic review team includes what two experts
content and methodological
the answer to the review question in a systematic review is a
NUMBER
what 4 types of studies are included in a systematic review
1) intervention studies (RCTs)
2) prevalence/incidence/proportion studies
3) diagnostic test accuracy studies
4) observational studies
T/F you can draw conclusions from scoping reviews
F
what are scoping reviews good for
- finding gaps in the literature to help guide future research
- assessing feasibility of a full systematic review
- planning primary research or systematic reviews
what are the 9 steps to a systematic review
1) define review question
2) develop review protocol
3) comprehensive search for studies
4) select relevant studies
5) collect data from relevant studies
6) assess relevant studies for bias
7) synthesize results
8) present results
9) interpret results
what is the most important step in a systematic review
defining the review question
what are the 4 types of review questions
1) prevalence/incidence (PO)
2) diagnostic test accuracy (PIT)
3) etiology (PECO)
4) intervention (PICO)
what types of characteristics can explain variability between studies used in systematic reviews
population characteristics, intervention/comparator, outcomes
what are the 4 ways to present data from a systematic review
1) narrative synthesis
2) meta-analysis
3) pair-wise meta-analyiss
4) network meta-analysis
what is I^2 a test of
heterogeneity (higher number means there is a lot of differences between the studies)
interpret the following I^2 values:
- 30-50%:
- 50-80%:
- 80-100%:
30-50% is moderate
50-80% is substantial
>80% is considerable
how can we explore heterogeneity
by subgroup analysis and meta-regression
T/F narrative synthesis and narrative review are the same thing
F
what is the who, what, where of infectious disease control
health and disease is a balance of host, environmental and agent factors
what is disease caused by and how do we control disease
disease is the result of a combination of risk factors, we control disease through management/manipulation of these risk factors
Describe the following:
- between agent and host
- between agent and environment
- between host and environment
- between agent and host: RESISTANCE
- between agent and environment: EXPOSURE
- between host and environment: STRESS
what is infectious vs contagious
infectious: caused by or communicated by microorganisms in the tissue (about agent)
contagious: capable of being transmitted from individual to individual (about transmission)
what is the relationship between contagious and infectious
contagious is always infectious, but infectious is not always contagious
contagious diseases are spread by __________ whereas infectious diseases are spread by ____________
contact; infectious agents
Match the following:
1) epidemic
2) sporadic
3) pandemic
4) endemic
a) predictable long-term balance between agent and host
b) agent is present but disease occurs infrequently and is not readily predictable
c) gross imbalance between agent and host, usually during initial exposure
d) a global epidemic
1) c
2) b
3) d
4) a
is coliform mastitis contagious or infectious
infectious
is s. aureus mastitis contagious or infectious
both
what is a necessary vs sufficient cause
necessary: must be present to cause disease; always a component of a sufficient cause
sufficient: always produces disease; usually a group of host, agent and environment factors
what is the Reed Frost equation and what are the components
Ct = S(1-Qct)
Ct = number of cases over time
S = number of susceptible individuals
1-Qct = probability of adequate contact
what are the 3 overarching ways to approach infectious disease control
1) eliminate
2) prevent
3) control
how can we eliminate infectious disease (3)
1) eradicate infected animals
2) vaccinate at-risk animals
3) test and slaughter and vaccination
what are the 3 ways to eradicate infected animals as a form of infectious disease elimination
1) depopulate all animals
2) test and slaughter (high Sp)
3) treatment
which of the approaches to infectious disease elimination will cause the disease to ‘die out’
test and slaughter and vaccination
what are the 3 options for preventing disease as a method of disease control
1) increase resistance
2) decrease exposure
3) decrease stress
what are ways to decrease exposure
- biosecurity (closed herds)
- reduce contact
what are ways to enhance resistance
- vaccination
- genetics (long-term)
- nutrition (Vitamin E and selenium)
what are 3 methods of disease control through strategic/routine medication
1) metaphylaxis
2) medicated feed
3) fleas
4) heartworm
what is metaphylaxis
treatment of a group of animals without evidence of disease but who were in close contact with other animals that are showing evidence of disease
how do we decide whether to control infectious disease through elimination vs prevention vs control
risk-based decision
what are the two components of risk
probability and magnitude
what 3 things can influence magnitude of risk
1) zoonotic potential
2) economic impact
3) distribution (endemic, epidemic, pandemic, sporadic)
define biosecurity
the protection of people, animals and ecological systems against disease and other biological threats
how is biosecurity achieved
through systems that protect people, animal and plant industries and the environment from the ENTRY, ESTABLISHMENT and SPREAD of diseases
management/prevention of what 3 disease categories forms the basis of Canadian Biosecurity
1) foreign disease
2) endemic disease
3) zoonotic disease
define disease surveillance
continuous investigation of a population to detect the occurrence of disease for control purposes; can be active or passive
what are the 2 biggest challenges for preventing the introduction of foreign diseases
1) movement of animals within and across borders
2) many commodities
what are the two approaches to managing risk when developing biosecurity protocols for endemic diseases
1) all peril
2) targetted
what are some challenges to on-farm biosecurity programs
1) acceptance across commodity groups for all peril vs targeted approaches
2) hard to measure success of programs (lack of a challenge)
3) programs built on biological plausibility rather than evidence
what are the main targets of biosecurity for endemic diseases
herd-herd and animal-animal transmission
how do farms get introduction of a new endemic disease
1) animal movement
2) dirty equipment
what are some benefits of targetted vs all peril approach
1) can be maintained
2) can be cost-effective
3) is focused and defined
what are the 6 steps to a targetted biosecurity approach for endemic diseases
1) identify disease of concern
2) determine current prevalence of disease
3) limit animal movement
4) implement a prevention program
5) monitor compliance
6) review annually
what is a tool that can be used to help farmers reduce the risks of endemic diseases and improve biosecurity
RAMP - risk assessment and management plan
what are 3 challenges to zoonotic disease control
1) many pathogens cause both animal and human disease
2) some pathogens that may cause the most risk to humans may not cause disease in animals
3) some pathogens that make animals sick may not be zoonotic or may not be easily detectable
what are 7 methods to manage zoonotic disease risk
1) limit introduction of infectious disease
2) limit movement of animals within and between farms
3) treat or cull sick animals
4) collect meat and milk products hygienically
5) pasteurize milk products
6) maintain potable water
7) wash your hands
in regards to tests and test interpretation, what variables stay constant and what variables can change based on true prevalence of disease
constant: Sn and Sp
changes: NPV, FN, PPV
what are 10 things to consider when assessing vaccine efficacy
1) was there a laboratory and field RCT
2) were controls current or historical
3) how were the animals challenged
4) were outcome measures meaningful
5) was underlying biology and physiology considered
6) were other biases considered
7) were groups randomly assigned
8) was there blinding
9) how likely were the findings due to chance
10) how do the animals in the trial differ from your practice
define vaccine
a substance used to stimulate antibody production and provide immunity against 1 or several diseases, prepared from the agent, its products, or a synthetic substitute treated to act as an antigen without stimulating disease
what is the purpose of a vaccine
to prime the immune system so that the animal can better defend itself against infection with the agent when it is challenged
what are some desirable outcomes of vaccination
1) less animals get sick
2) animals get less sick
3) animals get sick for less time
4) fewer animals die
5) the vaccinated animal produces protective antibodies
