Prevalence of total knee arthroplasty and its predictive factors in Japanese patients with rheumatoid arthritis: Analysis using the NinJa cohort

Abstract

Objectives. The aim of this study was to clarify the prevalence and the predictive factors for undergoing total knee arthroplasty (TKA) among patients with rheumatoid arthritis (RA).

Methods. The data of 1,134 patients with RA who were enrolled in the Japanese nationwide cohort database NinJa in 2003 and consecutively followed up until 2009 were analyzed.

Results. Seventy-six patients underwent TKA during the observation period. The yearly progression of the modified Health Assessment Questionnaire or mHAQ score from 2003 to 2004, but not the yearly progression of the Disease Activity Score in 28 Joints or DAS28 or patient visual analog scale (VAS) score, was significantly higher in the patients who underwent TKA than those who did not.

Multivariate analysis showed that knee involvement in the disease, high Steinbrocker stage (III or IV), and high patient VAS score at the time of enrollment were powerful predictive factors, with hazard ratios of 4.01, 3.71, and 1.20, respectively.

According to survival analysis with TKA as an endpoint, patients with knee involvement in the disease at the time of enrollment had a significantly worse 5-year survival rate than did those without knee involvement (83.5% vs. 97.0%, respectively).

Conclusion. Several factors were elucidated as predictive factors for undergoing TKA among patients with RA.

Keywords:

• Database analysis
• Predictive factors
• Rheumatoid arthritis
• Total knee arthroplasty

Acknowledgements

The authors thank Mayumi Yokoyama, who provided expert technical assistance. The authors acknowledge the assistance of the following clinicians who referred patients to NinJa: Kumiko Akiya, Tomiaki Asai, Noriyuki Chiba, Yoshito Eto, Kenji Ichikawa, Atushi Kaneko, Yojiro Kawabe, Toshihiro Matsui, Akinori Matsumori, Ryutaro Matsumura, Satoru Motokawa, Kunikazu Ogawa, Akira Okamoto, Koichiro Omura, Yusuke Ota, Yukihiko Saeki, Koichiro Saisho, Tomotaro Sato, Yoshiki Shiohira, Makoto Sueishi, Eichi Suemtsu, Yasuo Suenaga, Shoji Sugii, Takao Sugiyama, Koichiro Takahi, Norio Tamura, Takeharu Tonai, Issaku Toyohara, Hiroshi Tsutani, Hajime Yamagata, Hidetoshi Yanagida, Masayuki Yasuda, Yasuhiko Yoshinaga, and Shigeru Yoshizawa. This work was supported in part by Health and Labour Sciences Research Grants from the Ministry of Health, Labour and Welfare of Japan to Shigeto Tohma and the Research Grant of Health Care Regeneration Project in Josho Region, Nagano Prefecture, Japan to Sakae Tanaka.

Conflict of interest

None.