Disease severity and domain-specific arthritis self-efficacy: relationships to pain and functioning in patients with rheumatoid arthritis.
OBJECTIVE
To examine the degree to which disease severity and domains of self-efficacy (pain, function, and other symptoms) explain pain and functioning in rheumatoid arthritis (RA) patients.


METHODS
Patients (n = 263) completed the Arthritis Impact Measurement Scales 2 to assess pain and functioning (physical, affective, and social), the Arthritis Self-Efficacy Scale to assess 3 self-efficacy domains (pain, physical function, and other). Disease severity was assessed with C-reactive protein level, physician's rating, and abnormal joint count. Structural equation modeling was used to examine 3 hypotheses: does disease severity have a direct relationship with pain and each area of functioning, does disease severity have a direct relationship with each arthritis self-efficacy domain, and do the self-efficacy domains mediate the relationship between disease severity and RA pain and each area of functioning.


RESULTS
Disease severity was related to pain, physical functioning, and each self-efficacy domain (beta = 0.28-0.56, P < 0.001). Each self-efficacy domain was related to its respective domain of functioning (e.g., self-efficacy for pain was related to pain; beta = 0.36-0.54, P < 0.001). Self-efficacy mediated the relationship between disease severity and pain and functioning (beta = 0.12-0.19, P < 0.001). Self-efficacy for pain control and to perform functional tasks accounted for 32-42% of disease severity's total effect on their respective outcomes (e.g., self-efficacy for pain control accounted for 32% of disease severity's total effect on pain). Variance accounted for by the total model was 52% for pain, 53% for physical functioning, and 44% for affective and social functioning.


CONCLUSIONS
Disease severity and self-efficacy both impact RA functioning, and intervening in these areas may lead to better outcomes.
Somers
Tamara J
TJ
Duke University Medical Center, Durham, North Carolina 27705, USA.
Shelby
Rebecca A
RA
Keefe
Francis J
FJ
Godiwala
Neha
N
Lumley
Mark A
MA
Mosley-Williams
Angelia
A
Rice
John R
JR
Caldwell
David
D
D000203:Activities of Daily Living / Q000523:psychology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000150:complications / Q000175:diagnosis* / Q000523:psychology; D010147:Pain Measurement / Q000379:methods; D020377:Self Efficacy; D012720:Severity of Illness Index; D055815:Young Adult