M. Bukhari

The performance of anti–cyclic citrullinated peptide antibodies in predicting the severity of radiologic damage in inflammatory polyarthritis: Results from the Norfolk Arthritis Register

Objective Anti–cyclic citrullinated peptide (anti-CCP) antibodies are a stronger predictor of the severity of rheumatoid arthritis than is rheumatoid factor (RF). Their role in predicting outcome in unselected patients with new-onset inflammatory polyarthritis (IP) has not been examined. The aims of this study were to examine the role of baseline RF and anti-CCP antibodies in determining the likelihood of patients having erosions at presentation or in predicting future radiologic damage, and to determine whether anti-CCP antibodies or RF is sufficiently robust to be clinically useful in guiding treatment decisions in early IP. Methods Patients were recruited from the Norfolk Arthritis Register. Logistic regression models were fitted to test the ability of anti-CCP antibodies and RF to predict erosions. Further models were investigated to examine the role of anti-CCP antibodies in patients stratified by RF status. Results The presence of anti-CCP antibodies at baseline was strongly associated with both prevalent erosions (odds ratio [OR] 2.53 [95% confidence interval (95% CI) 1.48–4.30]) and developing erosions at 5 years (OR 10.2 [95% CI 6.2–16.9]). These ORs were higher than those for RF (OR 1.63 [95% CI 0.94–2.82] and OR 3.4 [95% CI 2.2–5.2], respectively). The likelihood ratio (LR) for the prediction of prevalent erosions and erosions at 5 years was highest in the RF−subgroup (LR 2.2 and 5.8, respectively). However, 27% of anti-CCP−patients had developed erosions by 5 years. Conclusion Despite their strong association with the presence, development, and extent of erosions, anti-CCP antibodies alone are not a sufficiently accurate measure upon which to base clinical treatment decisions. Knowledge of anti-CCP antibody status is most informative in RF−negative patients.

Time to first occurrence of erosions in inflammatory polyarthritis: Results from a prospective community‐based study

OBJECTIVE To examine the time of occurrence of first radiographic erosions in a cohort of patients with inflammatory polyarthritis. METHODS Patients were recruited through the Norfolk Arthritis Register, which follows up patients annually. Patients with features of rheumatoid arthritis (other than erosions) sufficient, together with erosions, to meet the American College of Rheumatology (formerly, the American Rheumatism Association) 1987 revised criteria were requested to undergo radiographic examinations of the hands and feet at the first and/or second annual followup visits. All patients were requested to undergo radiographic examinations at the fifth annual followup visit. The most recent erosion-free radiograph was identified for 416 eligible patients, and these data were used to derive the duration of disease since the recalled date of onset of first symptoms. The rate of occurrence of first erosions was then determined (as a cumulative prevalence and as an incidence rate using Poisson regression) from analysis of followup films. Patients were assumed to be free of erosions at symptom onset. RESULTS The cumulative prevalence of erosions in patients whose first film was obtained 12-24 months after disease onset was 36%, equivalent to an incidence rate of 24.5/1,000 patient-months. We identified 3 analysis groups of patients who were free of erosions based on films obtained 12-24 months, 24-36 months, and 36-60 months since the recalled date of onset of first symptoms. New erosions were observed in all 3 groups, with cumulative prevalences of 23%, 28%, and 47%, respectively. These were equivalent to first-erosion incidence rates/1,000 patient-months of 5.4 (95% confidence interval [95% CI] 3.8-83), 6.8 (95% CI 4.7-10.0), and 13.0 (95% CI 8.9-19.2), respectively. CONCLUSION Many patients with erosive disease first develop their erosions >2 years from disease onset.

Long-term stability of anti-cyclic citrullinated peptide antibody status in patients with early inflammatory polyarthritis

IntroductionThe utility of reassessing anti-cyclic citrullinated peptide (anti-CCP) antibody status later in disease in patients presenting with early undifferentiated inflammatory polyarthritis, particularly in those who test negative for both anti-CCP and rheumatoid factor (RF) at baseline, remains unclear. We aimed therefore to determine the stability of CCP antibody status over time and the prognostic utility of repeated testing in subjects with early inflammatory polyarthritis (IP).MethodsAnti-CCP and RF were measured at baseline and 5 years in 640 IP patients from the Norfolk Arthritis Register, a primary care-based inception cohort. The relation between change in anti-CCP status/titer and the presence of radiologic erosions, the extent of the Larsen score, and Health Assessment Questionnaire (HAQ) score by 5 years was investigated.ResultsWith a cut-off of 5 U/ml, 28% subjects tested positive for anti-CCP antibodies, 29% for RF, and 21% for both at baseline. Nine (2%) anti-CCP-negative patients seroconverted to positive, and nine (4.6%) anti-CCP-positive individuals became negative between baseline and 5 years. In contrast, RF status changed in 17% of subjects. However, change in RF status was strongly linked to baseline anti-CCP status and was not independently associated with outcome. Ever positivity for anti-CCP antibodies by 5 years did not improve prediction of radiographic damage compared with baseline status alone (accuracy, 75% versus 74%). A higher baseline anti-CCP titer (but not change in anti-CCP titer) predicted worse radiologic damage at 5 years (P < 0.0001), even at levels below the cut-off for anti-CCP positivity. Thus, a titer of 2 to 5 U/ml was strongly associated with erosions by 5 years (odds ratio, 3.6 (1.5 to 8.3); P = 0.003).ConclusionsRepeated testing of anti-CCP antibodies or RF in patients with IP does not improve prognostic value and should not be recommended in routine clinical practice.