Association Between Central Sensitization and Increasing Prevalence of Nocturnal Knee Pain in the General Population with Osteoarthritis from the Iwaki Cohort Study

Eiji Sasaki; Seiya Ota; Daisuke Chiba; Yuka Kimura; Shizuka Sasaki; Masataka Ando; Yuji Yamamoto; Eiichi Tsuda; Yasuyuki Ishibashi

doi:10.2147/JPR.S318038

Association Between Central Sensitization and Increasing Prevalence of Nocturnal Knee Pain in the General Population with Osteoarthritis from the Iwaki Cohort Study

J Pain Res. 2021 Aug 13:14:2449-2458. doi: 10.2147/JPR.S318038. eCollection 2021.

Authors

Eiji Sasaki¹, Seiya Ota^{1

2}, Daisuke Chiba¹, Yuka Kimura¹, Shizuka Sasaki¹, Masataka Ando², Yuji Yamamoto¹, Eiichi Tsuda³, Yasuyuki Ishibashi¹

Affiliations

¹ Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
² Department of Social Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
³ Department of Rehabilitation Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.

Abstract

Purpose: Knee pain is associated with osteoarthritis (OA) and increases during this condition; however, its correlation with central sensitization (CS) in arthritis patients requires greater understanding. The present cross-sectional cohort study to explore the prevalence of knee OA, nocturnal knee pain and disability in general population and to examine the association of CS with sleep quality in Japanese general population.

Patients and methods: From among 1056 community-dowelling volunteers, 942 were enrolled as participants in this study. Bilateral weight-bearing anterior-posterior knee radiographs were classified by the Kellgren-Lawrence grade. Nocturnal knee pain and disability were assessed with self-reported questionnaires. Using the CS inventory with nine items (CSI-9), CS was defined as 10 points or higher. Sleep quality was scored using the Pittsburgh Sleep Quality Index (PSQI). Linear regression analysis, adjusted by age, sex, body mass index, Kellgren-Lawrence grade, nocturnal knee pain, and lifestyle habits, was performed to investigate the association of CS with PSQI.

Results: The prevalence of OA, nocturnal knee pain, and disability was 37.9%, 7.6%, and 6.2%, respectively. The mean CSI-9 score was 4.9 ± 4.4, with a CS prevalence of 14.0%. The mean PSQI score was 3.9 ± 2.4, which was correlated with the CSI-9 value. CS was not correlated with OA severity; however, nocturnal knee pain prevalence increased from 13.3% to 25.5% in knee OA patients with CS. The CSI-9 value correlated with PSQI total score and subscales.

Conclusion: Knee OA severity correlated with nocturnal pain and disability; however, its association with CS was unproven. The combined effect of knee OA and CS elevated nocturnal pain and disability, resulting in diminished sleep quality.

Keywords: central sensitization; epidemiology; knee osteoarthritis; nocturnal knee pain; sleep quality.

Grants and funding

The present study was supported in part by JST COI Grant Number JPMJCE1302, a Grant-in-Aid from the Japanese Society for the Promotion of Science (Nos. 21500676, 18K16606, 18K09091), the Health Labor Sciences Research Grant, a JOA-Subsidized Science Project Research from the Japanese Orthopedic Association (2018-4), and the Grant of Japan Orthopedics and Traumatology Research Foundation (No. 421).