lets make a marker board formula list for step - shigatox22

[ArchivalUser]

c'mon guys i think this is really useful n will help our brains have memory for the more impt things ...

lets make a list of impt formulas

if u guys respond but the subject name like bistat forumla or pharm forumula n we will come up with a high yeild formula list!!


thanks

[ArchivalUser]

BIOSTATS:

PREVALANCE estimates----- INCIDENCE X (DISEASE DURATION)


PPV=TP/TP+FP

NPV=TN/TN+FN

SPECIFICITY=TN/TN+FP

SENSITIVITY=TP/TP+FN

ODDS ratio=AD/BC

RR=A/(A+B) divided C/(C+D)


ATTRIBUTABLE RISK= A/A+B (-) C/C+D ..INVERSE OF FRACTION IS NNT OR numbr needed to harm

[ArchivalUser]

hi shigatox22 ..nice effort

correction : NNT and NNH are diff

NNH= 1/ AR ( attributable risk ) ie. {a/a+b}- {c/c+d}

NNT = 1/ARR (Absolute risk reduction ) ie (rate in control) - (rate in treatment /exposed)

how i remember to avoid confusion is tht No. Needed to HARM has 'AR' in it so it is associated with AR attributable risk ( not abs risk reduction which is ARR)

[ArchivalUser]

hmm kaplan guy says AR and ARR is the same thing.....AR asses actual RISK of disease.....and ARR asses actual RISK REDUCTION of disease


as NNT asses how many ppl to affect to 1 life

n as NNH asses how many ppl to harm to affect 1 life


basically the equations are identical for AR n ARR but.......


AR=Incidence in exposed group (-) incidence in unexposed group


thus

ARR= Incidence in tx group (-) Incidence in placebo(control) group

[ArchivalUser]

RELATIVE RISK REDUCTION=

INCIDENCE in tx group (-) INCIDENCE in control(placebo) group DIVIDED by INCIDENCE

IN control(placebo) group

[ArchivalUser]

i know the actual definition is diff but were just worried at this point of memorizing the forumulas cuz it should be expected that everyone knows how to apply it to a question




CORRECT ME IF UM WRONG PPL

[ArchivalUser]

bump

[ArchivalUser]

You are right.

Relative Risk Reduction (RRR) = Absolute Risk Reduction (ARR)/Control Event Rate (CER)

[ArchivalUser]

ARI= absolute risk increase, AR= Absolute risk, RR= relative risk, ARR=absolute risk reduction, RRR= relative risk reduction, ARP = Attributable risk percent, (AR) control = AR of control


NNH = 1/ ARI
NNT = 1/ ARR
ARI = Event rate of treatment - event rate of control
ARR = Event rate of control - event rate of treatment
Event rate of treatment = Events/ total treatment arm subjects
RRR = ((AR)control - (AR)treatment ) / (AR) control
ARP = (Risk in exposed - Risk in unexposed)/ Risk in exposed
ARP = (RR-1)/RR

ARP is the attributable risk percent that represents the excess risk in the exposed population that can be attribute to the risk factor.

[ArchivalUser]

thanks lets keep it goin guys