The NOAR Damaged Joint Count (NOAR-DJC): a clinical measure for assessing articular damage in patients with early inflammatory polyarthritis including rheumatoid arthritis.
OBJECTIVE
To evaluate the reliability and validity of the Norfolk Arthritis Register Damaged Joint Count (NOAR-DJC) in patients with early inflammatory polyarthritis (IP).


METHODS
The NOAR-DJC examines deformity in 51 joints. Deformity is defined as inability to adopt the anatomical position, reduction in range of movement by at least one-third, and/or surgical alteration of the joint. Reliability was investigated by assessing intra- and inter-observer agreement in 40 and 32 patients, respectively. Validity was assessed by correlating the NOAR-DJC with the eroded joint count (criterion validity), the Health Assessment Questionnaire (HAQ) (convergent construct validity) and tender and swollen joint counts (divergent construct validity) and by discriminating between those who did and did not satisfy criteria for rheumatoid arthritis (discriminant validity).


RESULTS
The intraclass correlation coefficient for the intra- and inter-rater studies were 0.88 [95% confidence interval (CI) 0.79, 0.94, P<0.00001] and 0.74 (95% CI 0.53, 0.86, P<0.00001), respectively. Correlations with eroded joint counts and HAQ scores after 5 yr follow-up were r(s) = 0.42 (95% CI 0.35, 0.49, P<0.01) and r(s) = 0.45 (95% CI 0.4, 0.5, P<0.01), respectively. Correlations with tender and swollen joint counts were weak (r(s) = 0.28 and r(s) = 0.33).


CONCLUSIONS
The NOAR-DJC is a quick, reliable and valid tool for assessing articular damage in patients with early IP.
Norfolk Arthritis Register, Norfolk and Norwich University Hospital, Colney Lane, Norwich, Norfolk NR4 7UY, UK. diane@fs1.ser.man.ac.uk
D K
DK
Bunn
L
L
Shepstone
L M
LM
Galpin
N J
NJ
Wiles
D P M
DP
Symmons
D000293:Adolescent; D000328:Adult; D000368:Aged; D001168:Arthritis / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology; D018450:Disease Progression; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010808:Physical Examination / Q000379:methods; D016059:Range of Motion, Articular; D012720:Severity of Illness Index