Trajectories and Risk Profiles of Pain in Persons with Radiographic, Symptomatic Knee Osteoarthritis: Data from the Osteoarthritis Initiative.
ABSTRACT Little is known about the temporal evolution of pain severity in persons with knee OA. We sought to describe the pain trajectory over 6 years in a cohort of subjects with radiographic, symptomatic knee OA.
We used data from the Osteoarthritis Initiative (OAI), a multi-center, longitudinal study of subjects with diagnosed radiographic evidence of knee OA. Pain was assessed at baseline and annually for 6 years. Our analysis cohort included subjects with symptomatic knee OA at baseline, defined as baseline Kellgren-Lawrence (KL) score >2 with WOMAC pain score >0. We used group-based trajectory modeling to identify distinct patterns of pain progression over 6-year follow-up. Factors examined included sex, race, education, comorbidities, age, body mass index (BMI), alignment, KL grade, and depression.
We used data from 1,753 OAI participants with symptomatic knee OA. Mean baseline WOMAC pain score was 26.5 (0-100,100 = worst) with standard deviation 19. Group-based trajectory modeling identified 5 distinct pain trajectories; baseline pain scores for each ranged from 15 to 62. None of the trajectories exhibited substantial worsening. One fifth of subjects in the two trajectories with the greatest pain underwent total knee replacement over follow-up. Higher KL grade, obesity, depression, medical comorbidities, female sex, non-white race, lower education, and younger age were associated with trajectories characterized by greater pain.
We found that knee pain changes little, on average, over six years in most subjects. These observations suggest knee OA is characterized by persistent rather than inexorably worsening symptoms.
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ABSTRACT: Objective: The authors aimed to characterize distinct trajectories of knee pain in adults who had, or were at high risk of, knee osteoarthritis using data from two population-based cohorts. Method: Latent class growth analysis was applied to measures of knee pain severity on activity obtained at 18-month intervals for up to 6 years between 2002 and 2009 from symptomatic participants aged over 50 years in the Knee Clinical Assessment Study (CAS-K) in the United Kingdom. The optimum latent class growth model from CAS-K was then tested for reproducibility in a matched sample of participants from the Osteoarthritis Initiative (OAI) in the United States. Results: A 5-class linear model produced interpretable trajectories in CAS-K with reasonable goodness of fit and which were labelled "Mild, non-progressive" (N = 201, 35%), "Progressive" (N = 162, 28%), "Moderate" (N = 124, 22%) "Improving" (N = 68, 12%), and "Severe, non-improving" (N = 15, 3%). We were able to reproduce "Mild, non-progressive", "Moderate", and "Severe, non-improving" classes in the matched sample of participants from the OAI, however, absence of a "Progressive" class and instability of the "Improving" classes in the OAI was observed. Conclusions: Our findings strengthen the grounds for moving beyond a simple stereotype of osteoarthritis as "slowly progressive". Mild, non-progressive or improving symptom trajectories, although difficult to reproduce, can nevertheless represent a genuinely favourable prognosis for a sizeable minority.Osteoarthritis and Cartilage 10/2014; 22(12). DOI:10.1016/j.joca.2014.09.026 · 4.17 Impact Factor
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ABSTRACT: In order to gain a better understanding of the timing of emergent symptoms of osteoarthritis, we sought to investigate the existence, duration and nature of a prodromal symptomatic phase preceding incident radiographic knee osteoarthritis (ROA). Data were from the incidence cohort of the Osteoarthritis Initiative (OAI) public use datasets. Imposing a nested case-control design, ten control knees were selected for each case of incident tibiofemoral ROA between 2004 and 2010 from participants aged 45-79 years. Candidate prodromal symptoms were WOMAC and KOOS subscale scores and individual items, available up to 4 years prior to the time of incident ROA. Multi-level models were used to estimate the length of the prodromal phases. The prodromal phase for subscale scores ranged from 29 months (KOOS Other Symptoms) to 37 months (WOMAC Pain). Pain and difficulty on activities associated with higher dynamic knee loading were associated with longer prodromal phases (e.g. pain on twisting/pivoting (39 months, 95% confidence interval: 13, 64) vs. pain on standing (25 months: 7, 42)). Our analysis found that incident ROA is preceded by prodromal symptoms lasting at least 2 to 3 years. This has potential implications for understanding phasic development and progression of osteoarthritis and for early recognition and management. Copyright © 2015. Published by Elsevier Ltd.Osteoarthritis and Cartilage 04/2015; 60(7). DOI:10.1016/j.joca.2014.12.026 · 4.17 Impact Factor
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ABSTRACT: We performed a systematic review of prognostic factors for the progression of symptomatic knee osteoarthritis (OA), defined as increase in pain, decline in physical function or total joint replacement. We searched for available observational studies up to January 2015 in Medline and Embase according to a specified search strategy. Studies that fulfilled our initial inclusion criteria were assessed for methodological quality. Data were extracted and the results were pooled, or if necessary summarized according to a best evidence synthesis. 1,392 articles were identified and 30 articles met the inclusion criteria. 38 determinants were investigated. Pooling was not possible due to large heterogeneity between studies. The best evidence synthesis showed strong evidence that age, ethnicity, body mass index (BMI), co morbidity count, magnetic resonance imaging (MRI) detected infrapatellar synovitis, joint effusion and baseline OA severity, both radiographic and clinical, are associated with clinical knee OA progression. There was moderate evidence showing that education level, vitality, pain coping subscale resting, MRI detected medial femorotibial cartilage loss and general bone marrow lesions (BMLs) are associated with clinical knee OA progression. However, evidence for the majority of determinants was limited (including knee range of motion (ROM) or markers) or conflicting (including age, gender and joint line tenderness). Strong evidence was found for multiple prognostic factors for progression of clinical knee OA. A large variety in definitions of clinical knee OA (progression) remains, which makes it impossible to summarize the evidence through meta-analyses. More research on prognostic factors for knee OA is needed using symptom progression as outcome measure. Remarkably, only few studies have been performed using pain progression as an outcome measure. The pathophysiology of radiographic factors and their relation with symptoms should be further explored.Arthritis research & therapy 06/2015; 17(1):152. DOI:10.1186/s13075-015-0670-x · 3.75 Impact Factor