Ab0136 Knee Pain and Hospitalisation Due to Comorbidities in a Swedish Population – A 25 Year Follow-Up Study

Background: Musculoskeletal pain is a common cause of medical attention. For chronic widespread pain (CWP), a relationship with serious medical comorbidities such as cardiovascular disease, psychiatric disease and cancer has been proposed. Osteoarthritis of the knee, a common cause of musculoskeletal pain, has been linked to cardiovascular risk factors such as the metabolic syndrome. Concomitant pain in other areas has not systematically been considered when studying this metabolic risk in osteoarthritis. Few studies seem to have investigated the risk of hospitalisation due to serious illness in patients with chronic knee pain. Objectives: The aim was to investigate whether chronic knee pain was associated with a higher risk of hospitalisation due to common comorbidities, among people with or without other chronic pain, in a 25 year follow-up of a general population. Methods: 2425 participants, aged 20-74 years, from the longitudinal cohort study EPIPAIN were included in 1995. The baseline survey included data on experiences of pain lasting for more than 3 months, recorded on a pain mannequin. Participants were divided into 6 pain groups; no chronic pain, chronic knee pain only, and chronic regional pain (CRP) or CWP with or without knee pain. CWP was defined according to WP2019¹. Main outcome was first hospitalisation due to different disease groups during follow-up time, with data from the national health care register. Associations between pain report and hospitalisation were investigated using Cox regression, controlling for age, sex, life style factors (including smoking) and previous hospitalisation. Results: Out of 324 participants with chronic knee pain, 22 had knee pain only. This group had an increased risk of care due to musculoskeletal disorders (HR 2.7; p=0.01) but not for any of the other diagnostic subgroups or all cause hospitalisation. Those with CWP with or without knee pain had a higher risk of hospitalisation due to ischemic cardiovascular disease (Table 1). Participants with CWP without knee pain also had increased risk of hospitalisation due to psychiatric disease (Table 1). The knee pain only group did not have any cases of hospitalisation due to infections, but all other pain groups had a significantly or nearly significantly increased risk (Table 1). Conclusion: Chronic knee pain was common in a general population. Knee pain only was uncommon and did not increase the risk of hospitalisation apart from care due to musculoskeletal disorders. Knee pain was usually associated with pain in other regions, and CWP (both with and without knee pain) increased the risk of hospitalisation for several diseases. This indicates the need for physicians to investigate the presence of concomitant CWP, and risk factors for e.g. cardiovascular disease, in patients seeking care for knee pain. REFERENCES: [1] Wolfe F, Butler SH, Fitzcharles M, Häuser W, Katz RL, Mease PJ, et al. Revised chronic widespread pain criteria: development from and integration with fibromyalgia criteria. Scand J Pain. 2019 Dec 18;20(1):77-86. Acknowledgements: NIL. Disclosure of Interests: None declared.