Stats and such

Question 1

exposure odds ratio

Answer 1

diseased/healthy exposed divided by diseased/healthy unexposed

Question 2

Interpretation of an odds ratio

Answer 2

under the rare disease assumption (100%), we can substitute odds for risk, and odds ration for relative risk

Question 3

What is the relationship between prevalence and incidence

Answer 3

Prevalence=Incidence x disease duration

Question 4

What is the target population

Answer 4

Population to which inferences from the study are to be made.

Question 5

Source population

Answer 5

Population from which study subjects (cases and non-cases) are selected

Question 6

Effect modification

Answer 6

Effect modification is when the effect of A on B depends on C
e.g. the effect of smoking on laryngeal cancer is greater in men than in women EM
as opposed to, the effect of coffee on laryngeal cancer is confounded by smoking

Question 7

Measures of disease frequency

Answer 7

Measures of disease frequency describe the absolute risk of a disease.
Prevalence,
Incidence rate/Incidence density, and
cumulative incidence/incidence proportion

Question 8

measure of association

Answer 8

Risk ratio (relative risk , incidence rate ratio), A tool to compare disease rates in two populations
Odds ratios
Risk difference (attributable risk)
The population attributable risk (rate) (PAR) is the risk in the total study population that is attributable to the presence of the exposure

Question 9

Logistic regression

Answer 9

Logistic regression can describe the relationship between a categorical outcome (response variable) and a set of covariates (predictor variables). The categorical outcome may be binary (e.g., presence or absence of disease) or ordinal (e.g., normal, mild and severe). The predictor variable(s) may be continuous or categorical.

Question 10

Type 1 error

Answer 10

incorrect rejection of a true null hypothesis. (False positive result)

Question 11

Type 2 error

Answer 11

is the failure to reject a false null hypothesis (incorrect acception of a false null hypothesis) (false negative result)

Question 12

4 Measures of variability

Answer 12

There are four different measures of variability, the range, interquartile range, variance, and standard deviation.

Question 13

Variance

Answer 13

The average squared difference of the deviance from the mean
1,2,3,4,5
medel 3
-2  -> 4
-1  -> 1
0  -> 0
1  -> 1
2 -> 4
= 10
10/n-1 = 10/4= 2,5

Question 14

Standard deviation

Answer 14

square root of the variance

Question 15

Sensitivity, specificity, PPV, NPV

Answer 15

Sensitivity=sant testpositiva/alla sant positiva
specificity=sant testnegativa/alla sant negativa
PPV= sant Testpositiva/ alla testpositiva
NPV= Sant Testnegativa/ alla testnegativa

Question 16

Whats the difference between paulines study and yours

Answer 16

Basically the same incidence for TNFi (66 vs 62)
I have an active comparator
Dramtic increase in melanoma age-standardized incidence (doubling since 2000, 5 times higher than 1975), almost no change in metastatic melanom and death from melanoma
In the european collaborative project, the inidence rate in Swedish TNFi treated was double that of UK-treated (the two largest registers)
No increase of in situ melanoma in paulines study

Question 17

Active comparator important in your studies (stuyd 3)

Answer 17

Results were very stable comparing the different bionaive comparators

Question 18

Potentiell bias i both TMX/AI

Answer 18

Samtidigt kan det ju finnas orsaker kopplade till ledvärk som gör att man 1) byter preparat, 2) alternativt att om man inte har utvecklat jobbig ledvärk av ett av preparaten så är man kanske mer villig att testa det andra också.

Question 19

Adjustments in the cc study

Answer 19

Betr brca som riskfaktor för senare RA är det eg inte lika viktigt att justera, vår fråga är ju här om OR för brca före RA liknar HR för RA efter brca, oavsett om det förstnämnda är confoundat eller ej.

Question 20

Genetic overlap

Answer 20

Both RA and Breast cancer are gentically complex diseases. GWAS studies have indeed identified many candidate genes, but the effect sizes are generally quite small

Question 21

R2

Answer 21

proportion of the variance in the dependent variable that is predictable from the independent variable(s

Question 22

AIC

Answer 22

AKaika information criterion, a measure of the fit of the model, comparing two models, lower value is better

Question 23

Hazard Hazard ratio

Answer 23

Instantaneous risk, ratio of the hazard rates

Question 24

Properties of the normal distribution

Answer 24

Normal distributions are symmetric around their mean.
The mean, median, and mode of a normal distribution are equal.
68% of the area of a normal distribution is within one standard deviation of the mean.
Approximately 95% of the area of a normal distribution is within two standard deviations of the mean.

Question 25

Channeling between bDMARDs

Answer 25

We see that mortality is higher in non-TNFi cohorts, especially among those that start a non-TNFi as their first bDMARD.
We also see that there is channeling of patients concerning the risk of malignancy (most of which is handled by age/sex + disease severity), but we see that when we compare tnfi switchers to second tnfi or non-tnfi, there is very little channeling beyond age/sex

Question 26

Compliance vid TMX-behandling

Answer 26

I en registerstudie var 30% ickekompliant

Question 27

Biverknignar AI TMX

Answer 27

TMX, svettningar trombos

AI, ledvärk, osteoporos, torrhet i slidan,