Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Hand Osteoarthritis: A Predictor of Accelerated Progression in Knee OA?

Samuels1,  Jonathan, Petchprapa2,  Catherine, Carpenter2,  Elizabeth, Attur1,  Mukundan, Rybak2,  Leon, Krasnokutsky3,  Svetlana, Oh4,  Cheongeun

NYU Hospital for Joint Diseases, New York, NY
NYU Langone Medical Center, New York, NY
NYU Hospital for Joint Disease, New York, NY
New York University, New York, NY

Background/Purpose:

There is insufficient understanding regarding how generalized OA involving the hand and knee differs from isolated knee OA, which may result from other factors such as obesity or trauma. The purpose of these studies is to determine whether the presence of hand OA involving interphalangeal (IP) and first carpometacarpal (CMC) joints, alone or in combination, predicts progression of patients with symptomatic knee OA.

Methods:

Hand radiographs were obtained on 146 patients at NYUHJD who met ACR criteria for symptomatic knee OA, and who were enrolled in a two-year NIH-sponsored prospective study. The patients completed standardized fixed-flexion knee radiographs at baseline and 24 months, with progression of the signal (more painful) knee OA determined by >= 30% decrease change in joint space width (JSW) or >=1 grade increase in KL score. For each set of hand x-rays, 2 radiologists evaluated 18 IP joints and 2 CMC joints for joint space narrowing and/or osteophytes, and whether or not there was erosive change at the IP joints; we averaged the scores from the two readers whose scores provided excellent Kappa values.

Results:

We identified 79 percent of the knee OA patients to have at least 2.0 IP joints with OA (5% with erosive OA), and 53% with at least 1.0 1st CMC OA joint - both consistent with other studies in the literature. While the overall mean IP score was 5.6 and 1st CMC score was 0.9, Caucasians had significantly higher scores for IP and CMC (p=0.0019 and 0.0037). Knee progressors by JSW had higher IP scores approaching significance, 7.0 vs. 4.6 (p=0.11). Since the IP scores were not normally distributed, we further analyzed data by dichotomizing the study populations into two groups using 2 IP joints with OA as the cutoff point. When so analyzed, the presence of "hand OA" increased the odds ratio of knee OA progression to 2.5 (p=0.1797). This burden of IP OA also associated with a trend towards knee progression by delta KL increase. Conversely, knee progressors defined by a KL increase to a score of 3 or 4 over 24 months were 3.5 times as likely to have >=2 IP joints with OA (p=0.008) The 7 knee OA patients with radiographic evidence of erosive IP disease, as compared with the rest of the non-erosive IP OA patients and those without IP OA, had a higher percentage of knee OA progression >= 30% JSN (57% vs. 22% vs. 19%) approaching significance. None of the permutations involving the 1st CMC revealed significant differences in knee OA progression. In addition, while we had hypothesized that OA patients with prior knee trauma or surgery would have less hand OA given the external causation, we instead found no significant differences in hand OA prevalence in either of those analyses.

Conclusion:

In our completed pilot cohort, the quantitative "burden" of hand OA at the IP joint associates with the radiographic severity of knee OA and a trend towards more rapid progression of knee OA, by either JSN or increased KL grade. Erosive IP disease may be an even stronger predictor than non-erosive IP disease of accelerated progression of knee OA.

Funding:

This study is funded by NIAMS (R01- AR052873).

To cite this abstract, please use the following information:
Samuels, Jonathan, Petchprapa, Catherine, Carpenter, Elizabeth, Attur, Mukundan, Rybak, Leon, Krasnokutsky, Svetlana, et al; Hand Osteoarthritis: A Predictor of Accelerated Progression in Knee OA? [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1070
DOI:

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