Defining knee pain trajectories in early symptomatic knee osteoarthritis in primary care: 5-year results from a nationwide prospective cohort study (CHECK).

BACKGROUND: GPs have high consultation rates for symptoms related to knee osteoarthritis (OA). Many risk factors for symptomatic knee OA progression remain unknown. AIM: To define distinct knee pain trajectories in individuals with early symptomatic knee OA and determine the risk factors for these pain trajectories. DESIGN AND SETTING: Data were obtained from the multicentre prospective Cohort Hip and Cohort Knee study in the Netherlands. Participants with knee OA, according to the clinical criteria of the American College of Rheumatology, and a completed 5-year follow-up were included. METHOD: Baseline demographic, anamnestic, and physical examination characteristics were assessed. Outcome was annually assessed by the Numeric Rating Scale for pain. Pain trajectories were retrieved by latent class growth analysis. Multinomial logistic regression was used to calculate relative risk ratios. RESULTS: In total, 705 participants were included. Six distinct pain trajectories were identified with favourable and unfavourable courses. Statistically significant differences were found in baseline characteristics, including body mass index (BMI), symptom severity, and pain coping strategies between the different trajectories. Higher BMI, lower level of education, greater comorbidity, higher activity limitation scores, and joint space tenderness were more often associated with trajectories characterised by more pain at first presentation and pain progression--compared with the reference group with a mild pain trajectory. No association was found for baseline radiographic features. CONCLUSION: These results can help differentiate those patients who require more specific monitoring in the management of early symptomatic knee OA from those for whom a 'wait-and-see' policy seems justifiable. Radiography provided no additional benefit over clinical diagnosis of early symptomatic knee OA in general practice.

Effectiveness of diclofenac versus paracetamol in knee osteoarthritis: a randomised controlled trial in primary care.

BACKGROUND: The effectiveness of diclofenac versus paracetamol in primary care patients with pain caused by knee osteoarthritis is unclear. AIM: To assess the effectiveness of diclofenac compared with paracetamol over a period of 2, 4, and 12 weeks in patients with knee osteoarthritis. DESIGN AND SETTING: Randomised controlled trial in general practice. METHOD: There were 104 patients included in the study, they were aged ≥45 years consulting their GP with knee pain caused by knee osteoarthritis. Patients were randomly allocated to diclofenac (n = 52) or paracetamol (n = 52) for at least 2 weeks. Primary outcomes were daily knee pain severity, and knee pain and function measured with the Knee Injury and Osteoarthritis Outcome Score (KOOS). RESULTS: Over a period of 2- and 4-weeks follow-up, no significant difference in daily knee pain was found between the patient groups: estimated differences of 0.5 (95% CI = -0.2 to 1.3) and -0.2 (95% CI = -1.0 to 0.7), respectively. Over the 12-weeks follow-up, no significant differences were found between both groups for KOOS pain: estimated difference of -2.8 (95% CI = -10.7 to 5.1) and KOOS function of -2.7 (-10.6 to 5.0). CONCLUSION: Over a period of 2- and 4-weeks follow-up no significant difference in daily measured knee pain severity was found between primary care patients with knee osteoarthritis taking paracetamol or diclofenac. Also, over a period of 12-weeks follow-up no significant differences were found regarding KOOS pain and KOOS function between both groups. Patients more frequently reported minor adverse events after taking diclofenac (64%) than paracetamol (46%).

Latent class growth analysis successfully identified subgroups of participants during a weight loss intervention trial.

INTRODUCTION: Weight loss interventions often present small mean weight changes over time, despite the fact that a substantial proportion of the participants lost more weight. This effect is often leveled out by the substantial proportion of participants who gained weight during the trial. The aim of this study is to identify and describe distinct subgroups of participants with different weight change trajectories during and after a weight loss intervention. METHODS: We used data from a weight loss intervention that was part of a randomized controlled trial on the preventive effect of a tailor-made weight loss intervention and oral glucosamine sulfate on the incidence of knee osteoarthritis in 407 overweight women aged 50 to 60 years. Latent class growth analysis (LCGA) was used to identify subgroups of participants with different weight change trajectories over time. RESULTS: Using LCGA, we identified three subgroups with different trajectories of weight change, one large group (n = 298) with almost no change over time, and two smaller groups (both n = 48), of which one represents participants who steadily gained weight over time, whereas the other represents participants who steadily lost weight over time. Participants that had relatively low body weight around their 40th year of life and that gained weight in the year preceding the study were most likely to belong to the group that lost weight. CONCLUSION: LCGA was a suitable method to identify three distinct groups of participants with different trajectories of weight change. Low body weight at age 40 and weight gain in the year preceding the study were associated with a higher chance of membership of the group that lost weight. It seems weight loss that occurred during this weight loss intervention was mostly recently gained weight.

Longitudinal relation between weight change and quality of life in a community-based population: a prospective cohort study.

BACKGROUND: Previous cross-sectional studies revealed that obesity is associated with lower health-related quality of life (HRQOL). This study aimed to investigate the longitudinal association between 5-year weight change and HRQOL. METHODS: Data from 2414 Dutch men and women was collected. HRQOL was measured with the RAND-36. Weight change was calculated as change in weight between 1998 and 2003. Using generalized estimation equations, we primarily analyzed the influence of weight change on HRQOL for the total population and additionally, by change groups (weight losers, weight maintainers and weight gainers) using regression analysis. All analyses were stratified for gender. RESULTS: After 5 years, 598 men (50%) and 646 women (54%) maintained their weight, 177 men (15%) and 163 women (14%) lost >2.5 kg and 410 men (35%) and 379 women (32%) gained >2.5 kg. Longitudinal associations of 5-year weight change and HRQOL were found for mental component score (MCS) in women (ß = 0.13; 95% CI: 0.02-0.24), and physical component score (PCS) in men (ß = -0.09; 95% CI: -0.17 to -0.00) and women (ß = -0.10; 95% CI: -0.19 to -0.01). Categorizing for 5-year weight change showed that weight gainers and weight losers did not significantly differ from weight maintainers on both MCS and PCS for both men and women. CONCLUSION: Weight change over 5 years leaded to a slight, though significant reduction on the PCS in both genders. In women, we found a positive association between weight change and MCS.

Defining discriminative pain trajectories in hip osteoarthritis over a 2-year time period.

BACKGROUND: Although pain due to osteoarthritis (OA) generally deteriorates over time, there is a large individual variation in the course of pain. This study examines the different longitudinal trajectories of patients with hip pain due to OA. METHODS: Data from a previously performed randomised controlled trial were used to investigate the course of pain over 2 years in 222 patients with clinically and radiographically determined hip OA. Pain was measured with a visual analogue scale (0-100). Latent class growth analysis was used to determine the number of trajectories of patients with hip pain due to OA. RESULTS: Analyses yielded five trajectories of pain due to hip OA. Trajectory 1 ('mild pain'; n=69) consists of patients with stable mild pain. Patients in trajectory 2 ('moderate pain'; n=31) fluctuated slightly between moderate and severe pain levels. Trajectory 3 ('always pain'; n=32) consists of patients with severe pain. Patients in trajectory 4 ('regularly progressing'; n=48) started with mild pain and progressed slowly to moderate pain. Trajectory 5 ('highly progressing'; n=42) patients also started with mild pain but quickly progressed to severe pain over 2 years. Compared with the 'mild pain' group, patients in the 'always pain' group had more severe radiographic hip OA, morning stiffness and decreased range of motion. The 'highly progressing' group had more severe radiographic hip OA and morning stiffness. CONCLUSIONS: Latent class growth analysis applied to longitudinal data of patients with hip OA identified five distinct trajectories of pain. More studies are needed to externally validate these findings.

Effectiveness of diclofenac versus acetaminophen in primary care patients with knee osteoarthritis: [NTR1485], DIPA-trial: design of a randomized clinical trial.

BACKGROUND: Osteoarthritis is the most frequent chronic joint disease which causes pain and disability of especially hip and knee. According to international guidelines and the Dutch general practitioners guidelines for non-traumatic knee symptoms, acetaminophen should be the pain medication of first choice for osteoarthritis. However, of all prescribed pain medication in general practice, 90% consists of non-steroidal anti-inflammatory drugs compared to 10% of acetaminophen. Because general practitioners may lack evidence showing a similar efficacy of acetaminophen and non-steroidal anti-inflammatory drugs, we present the design of a randomized open-label trial to investigate the efficacy of a non-steroidal anti-inflammatory drug (diclofenac) compared with acetaminophen in new consulters with knee osteoarthritis in general practice. METHODS/DESIGN: Patients aged 45 years or older consulting their general practitioner with non-traumatic knee pain, meeting the clinical American College of Rheumatology criteria, and with a pain severity score of 2 or higher (on a 0-10 scale), will be randomly allocated to either diclofenac (maximum daily dose of 150 mg) or acetaminophen (maximum daily dose of 3000 mg) for 2 weeks and, if required, an additional 1-2 weeks, with a total follow-up period of 12 weeks. The primary outcomes are knee pain measured with a daily diary, and pain and function measured with the Knee Injury and Osteoarthritis Outcome Score (KOOS) at baseline, and at 3, 6, 9, and 12-weeks follow-up. Secondary outcomes are patients' perceived recovery, quality of life, medical, patient, and productivity costs, compliance to therapy, co-interventions, and adverse reactions. DISCUSSION: The successful completion of this trial would lead to a better understanding of which medication should be used in the treatment of primary care patients with mild knee osteoarthritis. TRIAL REGISTRATION: Dutch trial registry NTR1485.