The prognostic factors affecting quality of life in patients with knee osteoarthritis: a cohort study

Abstract

Objective To investigate the quality of life (QOL) and risk factors for progression of knee osteoarthritis. Methods A prospective study of knee OA was conducted from April 2015 to August 2016. Two hundred and fifty patients with knee OA were recruited in this study and followed up for 18 months, during which there were five visits, i.e. baseline, 1st month, 6th month, 12th month and 18th month. QOL was assessed by the Arthritis Impact Measurement Scale 2 (AIMS2), which includes five dimensions (physical function, symptom, affect, social interaction and social role). Trajectories of QOL change were identified from a group-based trajectory model (PROC TRAJ). Risk factors associated with the QOL of OA were analyzed using chi square test followed by a multivariate logistic regression. Results Two hundred and thirty-nine participants had at least two follow-up visits. Each dimension of AIMS2 has deteriorated over time (Lower score indicates better health status): Physical function (1.9 points, (95%CI, 0.1 to 3.9; P=0.011), Symptom (2.0 points, 95%CI, 0.2 to 3.8; P=0.045), Affect (1.5 points, 95%CI 0.3 to 2.5; P=0.01), Social interaction (0.7 points, 95%CI, -0.1 to 1.5; P=0.065) and Social role (1.6 points, 95%CI, 0.5 to 2.7; P=0.01). Three trajectories of QOL were identified. Participants in Subgroup 1 (poor QoL; n=153) displayed bad QOL at baseline and deteriorated over time. Participants in Subgroup 2 (moderate QOL; n=65) developed or displayed moderate QOL over time. Participants in Subgroup 3 (good QOL; n=21) displayed good QOL at baseline and developed slightly better outcome over time. Baseline characteristics such as: female, higher body mass index, greater knee pain, longer duration of disease, lower education level, lower yearly income and more comorbidities were associated with the deterioration of QOL of knee OA. Conclusion Knee OA had impacts on patients' QOL. We identified three distinct trajectories of QOL change: good QOL group, moderate QOL group and poor QOL group. Baseline characteristics such as: female, higher body mass index, greater knee pain, longer duration of disease, lower education level, lower yearly income and more comorbidities were associated with the deterioration of QOL of OA. Key words: Osteoarthritis, knee; Quality of life; Root cause analysis