PASI

[Alberto]

DaveW escribió en mensaje
<20000326232243...@ng-bj1.aol.com>...
>PASI is the Psoriasis Area and Severity Index (if I recall
correctly). It's
>a combined measurement of how much you're covered, how
scaly it is,
>how inflammed it is, etc., etc.. I'm not sure of exactly
what it measures,
>but it's *the* standard as far as comparing one psoriatic
to another goes. >So much so that if you read about a
psoriasis trial that *doesn't* use
>PASI as it's primary measurement tool, you can almost
immediately
>consider the results suspect. Even trials that use a
"modified PASI" are
>to be read very carefully (to see what they added or
subtracted from the
>standard PASI).
>I wonder if it's possible to come up with a sort of "home
PASI" that we
>could all do to get some standard comparison here on the
newsgroup.
>Guess we've gotta find out what's really in the standard
PASI, and figure
>out how to do at-home approximations. GMan? Since you're
*in* a
>trial using PASI right now, do you think you could convince
someone to
>get you the information? Is there anyone else around
here'd who'd have
>easy access to a "How to PASI" instruction sheet?
>
>- Dave W.

The index PASI is calculated in a different way according to
the parameters to measure in each study. An habitual and
standardized form it can be the following one:

The extension and severity is calculated in a separate way:

The extension (E) is evaluated for one of the following
corporal areas, superior extremities , trunk and inferior
extremities that correspond to 20%, 30% and 40% of the total
corporal surface and a scale is used from 0 to 6 points

0 = without affectation
1 = < 10 %
2 = 10-29 %
3 = 30-49 %
4 = 50-69 %
5 = 70-89 %
6 = 90-100 %

The severity of the psoriasic lesions registers in function
of the studied parameters, Itching, Erythema, Scaling,
Thickness, according to a scale of values from a total
absence of cutaneous affectation, until a maximum possible
severity according to the following chart:

0 = Total absence of cutaneous affectation.
1 = Slight affectation.
2 = Moderate affectation.
3 = Severe affectation.
4 = Maximum severity possible of affectation.

The index PASI is calculated independently for each
localization, according to the following formulas:

Arms: 0.2 (I+R+S+T) x E = X
Trunk: 0.3 (I+R+S+T) x E = Y
Legs: 0.4 (I+R+S+T) x E = Z

(I=Itching, R=Erythema, S=Scaling, T=Thickness, E=Extension)

The index PASI corresponds to the total sum, X+Y+Z, and it
can vary from a study to another.In this case from 0 to
86.4.

Sorry my english is not good enough to better explain.

Alberto