Arthrosis is the most common chronic disease of the joints and is observed daily in clinical practice. The condition can manifest itself in any joint, but most commonly occurs in the knees and hips. This is reflected in the fact that OA in these joints is projected to be the ninth leading cause of years of disability by 2030.
Joint pain is the hallmark of osteoarthritis and arguably the main cause of disability, but the way we view diasbilicity in arthritis is changing. Fatigue has recently emerged as an important and widespread symptom for people with osteoarthritis and could be a major contributor to the high disability rates associated with the disease. This leads to the immediate question: How do we treat fatigue in OA?
Discover new insights into Patellofemoral OA
A new systematic review was published in the journal Rheumatology Advances in Practice in which an attempt was made to identify and evaluate factors that are related to fatigue in people with hip and / or knee osteoarthritis.
Methods
This systematic review followed the PRISMA guidelines and the protocol was registered with PROSPERO in July 2019. Both are hallmarks of a good systematic review. A quick review of the PROSPERO database shows that the authors followed their protocol as intended.
A total of five databases were searched from the beginning to March 2020. These were the core collections AMED, CINAHL, MEDLINE, ProQuest and Web of Science. The search strings were adapted for each database, created by an experienced systematic examiner and can be found in the additional information of the article.
Articles were included in the review if they were peer-reviewed, including hip and / or knee osteoarthritis diagnosed on the basis of radiological evidence or a clinical diagnosis based on ACR criteria or KL classification, and measured fatigue using outcome measures such as the SF-36 vitality framework. When studies included joint replacement, published and reviewed in non-English, or excluded gray literature.
"Two individual factors (age and BMI) showed moderate indications of no connection with fatigue."
The data were extracted by two authors, with a third available if consensus had to be reached. Item quality was assessed using the National Heart, Lung, and Blood Institute (NHLBI) quality assessment tool. This tool rates studies with a high, moderate, or low risk of bias and is similar to the Cochrane Risk of Bias tool, but is used less frequently because it does not assess wear bias.
The results of this study were presented as a narrative synthesis to report factors that were or were not associated with fatigue. Two authors grouped and classified identified factors into individual, disease-specific, psychosocial, behavioral and biological groups using the bio-behavioral conceptual framework of fatigue in OA.
The best evidence synthesis and ranking system was used to assess the level of evidence supporting the associations found in the results. The details of how this was achieved are quite complex and a breakdown can be found in the full text of the article in the supplementary information.
Results & clinical take-away
A total of 24 studies were included in the results, in which a total of 9475 patients with knee and / or hip osteoarthritis took part. Of the 24 studies, nineteen were rated as high quality, four as moderate, and one as poor quality. Sample sizes varied widely between studies of 3815 or 68, and the most common measure of fatigue score was the visual anaogue scale, which was used in a third of the studies.
Interestingly, when looking at individual factors age and BMI showed moderate evidence of no connection with fatigue which probably contradicts the assumptions of many clinicians. Race, educational level, and gender are not associated with fatigue. However, higher comorbidity rates are moderately related to fatigue, which is nonsensical and is consistent with the concepts of frailty and the burden of disease.
16 studies examined the relationship between disease-specific factors and fatigue in order to further investigate the burden of disease. There was moderate evidence to support the relationship between severe pain and increased fatigue. Interestingly, there was no evidence of an association between poorer radiological severity and fatigue, which reinforces the importance of the correlation of radiology with clinical presentation.
Brief summary of the factors associated with fatigue in OA of the lower extremities
Age and BMI showed moderate evidence of no connection with fatigue
Worse x-ray evidence is not related to the degree of fatigue
Signs of a depression are associated with higher rates of fatigue
Not surprisingly, low physical activity is related to higher rates of fatigue
A high level of pain is associated with a higher level of fatigue
Eleven studies examined the connection between psychological factors and fatigue. There are strong indications of a connection between depressive symptoms and a higher degree of tiredness . This probably explains why low self-reported physical function is associated with higher rates of fatigue. Not surprisingly, low rates of physical activity are associated with higher rates of fatigue.
Given the strengths and weaknesses of this study, the fact that only articles were written in English limits the practical applicability of behavioral factors in clinical practice, and it cannot be ignored that some factors may not be identified at all were because of this.
Fatigue results were not validated for hip or knee OA, which probably explains why the VAS was the most frequently used tool in the included studies. This will have had some impact on the synthesis results, but in clinical practice it is likely that VAS is the most commonly used tool.
In terms of how you can use this information in clinical practice, the current evidence strongly suggests that the treatment of hip and knee fatigue can be based on modifiable factors such as physical activity, physical function, pain and OA depressive symptoms must be used in a targeted manner
