Table 2

 Pros and cons for selected tools to assess response to treatment

Psoriasis Area and Severity Index(PASI)National Psoriasis Foundation Psoriasis Score(NPF-PS)Physician static global assessment(PSGA)Overall lesion assessment(OLA)
BSA, body surface area; QoL, quality of life.
Pros Widely usedCorrelates with QoLSimpleSimple
Correlates to QoL, albeit poorlyDiscriminates when BSA is lowForces evaluator to step increments(not a continuous scale)Forces step increments(not a continuous scale)
Accepted by approving agenciesHas patient inputUses thickness of lesions
Thickness is predominate component
All elements are defined
Cons Not used by cliniciansIs not linearDoes not discriminate small changesDoes not discriminate small changes
FDA wants tool that reflects clinical useHas not been widely testedRange not robustRange not robust, correlation to PASI unknown
Does not discriminate when BSA is lowNot yet accepted by approving agencies nor clinicians
Upper end of scale not used