Prajapati et al.

Disease Activity

Disease activity in RA is a complex phenomenon, impossible to define and discern.

At the present time no single test of disease activity in RA is effective because

RA may cause various kinds of symptoms and signs. Thus, the disease activity

variables can be considered as surrogate markers for the in-self un-measurable

process. Clinical symptoms of disease activity are e.g. morning stiffness, fatigue,

pain, impaired function, and psychological and sleep disturbances. Clinical signs

include joint swelling and deformity, reduced objective function, low-grade

fever, osteoporosis and weight loss. Some of these symptoms and signs are used

to assess disease activity, e.g. the number of swollen and tender joints (Prevoo,

van‘t, Kuper, Van, Putte, Riel, 1995), graded, ungraded or weighted joint indices

(Ritchie, Boyle, McInnes, Jasani, Dalakos, Grieveson, 1968; Thompson, Silman,

Currey, 1987), pain and fatigue (Ferraz, Quaresma, Aquino, Atra, Tugwell,

Goldsmith, 1990), duration of morning stiffness and different scores for functional

decline (Fries, Pincus, Summey, Soraci, Wallston, Hummon, 1983). The patient’s

own global assessment of the disease activity is sometimes added. Laboratory

markers of disease activity are for instance acute phase proteins and ESR. In

some instances, clinical and laboratory markers for disease activity are combined,

including the patient’s global assessment of disease activity, into compound

indices of disease activity, e.g. the disease activity score (DAS) (Van der, 1990),

the Stoke index (Davis, 1990), Simplified Disease Activity Index (SDAI) and

Rheumatoid Arthritis Disease Activity Index (RADAI). The first three instruments

includes measurements of clinical and laboratory marker and the patient’s and

physician’s global assessments of disease activity but the last one i.e. RADAI

is self-administered questionnaire used by the patient to assess own disease

activity.

Disease activity Response criterias: There are three standard response criteria

being used widely in clinical trial of RA are (Gestel, 1996; Lipsky, 2000)

(i)

American college of rheumatology (ACR) criteria (Felson, Anderson,

Boers, Bombardier, 1993; Arnett, 1988)

(ii) European League Against rheumatism (EULAR) criteria (DAS-28

score) (Prevoo, Hof, Kuper, Van, Van de Putte, Van Riel, 1995; Gestel et

al., 1996)

(iii)

Paulus criteria (Paulus, Egger, Ward, Williams, 1990)

(i) American college of Rheumatology (ACR) criteria : Overall patient’s clinical

response of therapy is assessed by ACR improvement criteria. The ACR20

criterion is developed to define improvement in rheumatoid arthritis. The primary

efficacy variable is rate at which the intention to treat sample achieves 20%

improvement in ACR core set variables (ACR20). To be considered an ACR20%

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Int. J. Bioinformatics and Biological Sci.: v.2 n.1&2, p. 85-94. March & June 2014