MISC Flashcards
Mode of action of tramadol
Mu opioid agonist
Serotonin and noradrenaline reuptake inhibition
Mode of action of tapentadol
Mu opioid agonist
Noradrenaline reuptake inhibition
Which analgesia should be avoided with TCA, SSRI, SNRI, MAOI
Tramadol - risk of serotonin syndrome
Do positive/negative predictive values or sensitivity/specificity depend on the prevalence?
Predictive values
Sensitivity = out of everyone who has X, how many people tested positive for X?
Predictive values = out of the people who test positive for X, how many actually have X? (so if X was less common, the predictive value would be lower)
How to calculate the likelihood ratio
+LR = sensitivity/(1-specificity)
-LR = (1-sensitivity)/specificity
What is the T-test good at testing
T-test is comparing means
So it’s good for continuous variables which are normally distributed
What is the Chi-squared test
It tests the null hypothesis that the variables are independent
It’s used for categorical (discrete) data
Data is usually 2 columns and 2 rows
What is Fisher’s exact test used for
Also tests the null hypothesis in a 2x2 table
It is used for the same situations as Chi-squared but in studies of smaller sample size
Type I error vs Type II error in stats
Type I error - rejecting the null hypothesis when it is correct (the P value is not low enough)
Type II error - do not reject the null hypothesis when it is wrong (insufficient numbers)
When is logistic regression used?
How is the likelihood of the outcome predicted?
To predict whether variables have an effect on a binary outcome
Odds ratio is used to predict the likelihood
Cross section study
Patient population/sample at 1 time point
Provides association, not cause
How are patients selected in cohort study and what kind of diseases is it good for studying
Patient selected based on exposure, followed prospectively
Good for uncommon exposures
What is the outcome of a cohort study
Risk ratios
How are patients selected for a case-control study and what kind if diseases is it good for studying?
Patients selected on basis of disease
Good for uncommon diseases
What is the outcome of a cohort study
Odds ratios
How to calculate NNT
1/ARR
Commencement of thromboprophylaxis after spinal anaesthesia
6-8 hours post catheter removal
What is the difference between categorical/nominal and ordinal data
Ordinal is like categorical but there is a clear order between the categories
What is the difference between ANOVA and Chi-squared test
ANOVA is used for testing the mean between multiple populations (like T-test but for multiple groups)
Chi-squared is to test the independence of categorical data
What is the difference between Cox proportional-hazards model and Kaplan-Meier curve?
Cox proportional hazards model looks like multiple variables that may affect the outcome
cluster RCT
randomisation of groups “e.g. schools, hospitals”
lose statistical power
network meta-analysis
also called multi-treatment comparison meta-analysis
best way to assess where there is multiple treatments for 1 condition
which group of patients obtain the most benefits (have the lowest NNT) for an intervention
highest risk group
mild diseases need the largest NNT
what results markers (e.g. ARD, NNT, RR, RRR) changes depending on the risk group?
ARD and NNT, not RR and RRR
of note NNH does not change based on the risk group because it’s an inherent risk of the intervention
