Association of blood pressure with knee cartilage composition and structural knee abnormalities: data from the osteoarthritis initiative

Blood pressure is associated with knee pain severity in middle-aged and elderly individuals with or at risks for osteoarthritis: data from the Osteoarthritis Initiative

BACKGROUND

Hypertension is a common comorbidity of osteoarthritis (OA). Joint pain is the main clinical manifestation of OA. Knowledge about the relationship between hypertension and OA pain is limited. This study aimed to investigate whether blood pressure parameters are associated with knee pain severity in individuals with or at risks for OA.

METHODS

Our sample consisted of 2598 subjects (60.7% female, aged 45-79 years) collected from the Osteoarthritis Initiative. Blood pressure parameters included blood pressure stage, systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (PP). Radiographic evaluation using Kellgren-Lawrence system and pain severity evaluation using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Numeric Rating Scale (NRS) were performed for right knee. Linear regression was used to examine the relationship between blood pressure parameters and knee pain severity.

RESULTS

For the overall sample, blood pressure stage, SBP, and PP were positively correlated with WOMAC and NRS pain scores when adjusting for age, sex, and body mass index (BMI) (p ≤ 0.024) and were inversely correlated with KOOS score (p ≤ 0.004). After further adjusting for all covariates, PP remained a positive correlation with WOMAC score (p = 0.037) while other associations between blood pressure parameters and pain scores did not reach the statistical significance. In female, higher blood pressure stage, SBP, and PP were significantly associated with increased WOMAC and NRS scores and decreased KOOS score after adjustments of age and BMI (p ≤ 0.018). When adjusting for all covariates, the correlations of PP with WOMAC, KOOS and NRS scores remained significant (p = 0.008-0.049). In male sample, SBP was positively correlated with WOMAC score when adjusting for age and BMI (p = 0.050), but other associations between blood pressure parameters and pain scores were not statistically significant. No significant correlation was observed in male when further adjusting for other covariates.

CONCLUSIONS

Increased PP is a risk factor for knee pain and mainly affects females, which suggested that controlling PP may be beneficial in preventing or reducing knee pain in females with or at risks for OA.

Research Progress on the Pathogenesis of Knee Osteoarthritis

Knee osteoarthritis (KOA) is a chronic joint bone disease characterized by inflammatory destruction and hyperplasia of bone. Its main clinical symptoms are joint mobility difficulties and pain, severe cases can lead to limb paralysis, which poses major pressure to the quality of life and mental health of patients, but also brings serious economic burden to society. The occurrence and development of KOA is influenced by many factors, including systemic factors and local factors. The joint biomechanical changes caused by aging, trauma and obesity, abnormal bone metabolism caused by metabolic syndrome, the effects of cytokines and related enzymes, genetic and biochemical abnormalities caused by plasma adiponectin, etc. all directly or indirectly lead to the occurrence of KOA. However, there is little literature that systematically and comprehensively integrates macro- and microscopic KOA pathogenesis. Therefore, it is necessary to comprehensively and systematically summarize the pathogenesis of KOA in order to provide a better theoretical basis for clinical treatment.

Epidemiology of osteoarthritis

OBJECTIVE

To summarize the current state of the evidence regarding osteoarthritis (OA) prevalence, incidence and risk factors at the person-level and joint-level.

DESIGN

This was a narrative review that took a comprehensive approach regarding inclusion of potential risk factors. The review complements prior reviews of OA epidemiology, with a focus on new research and emerging topics since 2017, as well as seminal studies.

RESULTS

Studies continue to illustrate the high prevalence of OA worldwide, with a greater burden among older individuals, women, some racial and ethnic groups, and individuals with lower socioeconomic status. Modifiable risk factors for OA with the strongest evidence are obesity and joint injury. Topics of high interest or emerging evidence for a potential association with OA risk or progression include specific vitamins and diets, high blood pressure, genetic factors, metformin use, bone mineral density, abnormal joint shape and malalignment, and lower muscle strength/quality. Studies also continue to highlight the heterogenous nature of OA, with strong interest in understanding and defining OA phenotypes.

CONCLUSIONS

OA is an increasingly prevalent condition with worldwide impacts on many health outcomes. The strong evidence for obesity and joint injury as OA risk factors calls for heightened efforts to mitigate these risks at clinical and public health levels. There is also a need for continued research regarding how potential person- and joint-level risk factors may interact to influence the development and progression of OA.

Machine learning to predict incident radiographic knee osteoarthritis over 8 Years using combined MR imaging features, demographics, and clinical factors: data from the Osteoarthritis Initiative

OBJECTIVE

To develop a machine learning-based prediction model for incident radiographic osteoarthritis (OA) of the knee over 8 years using MRI-based cartilage biochemical composition and knee joint structure, demographics, and clinical predictors including muscle strength and symptoms.

DESIGN

Individuals (n = 1,044) with baseline Kellgren Lawrence (KL) grade 0-1 in the right knee from the Osteoarthritis Initiative database were analyzed. 3T MRI at baseline was used to quantify knee cartilage T₂, and Whole-Organ Magnetic Resonance Imaging Scores (WORMS) were obtained for cartilage, meniscus, and bone marrow. The outcome was set as true if a subject developed KL grade 2-4 OA in the right knee over 8 years (n = 183) and false if the subject remained at KL 0-1 over 8 years (n = 861). We developed and compared three models: Model 1: 112 predictors based on OA risk factors; Model 2: top ten predictors based on feature importance score from Model 1 and clinical relevance; Model 3: Model 2 without the imaging predictors. We compared the models using the area under the ROC curve derived from hold-out data.

RESULTS

The 10-predictor model (Model 2, that includes cartilage and meniscus WORMS scores and cartilage T₂) had a slightly lower AUC (0.772) compared to the model with 112 predictors (Model 1: AUC = 0.792, p = 0.739); and had a significantly higher AUC compared to the model without MR imaging predictors (Model 3, AUC = 0.669, p = 0.011).

CONCLUSIONS

A 10-predictor model including MRI parameters coupled with demographics, symptoms, muscle, and physical activity scores provides good prediction of incident radiographic OA over 8 years.

Hemodynamic stress shapes subchondral bone in osteoarthritis: An emerging hypothesis

Osteoarthritis (OA) is no longer regarded as a simple wear-and-tear problem of articular cartilage. Instead, OA is a whole joint disorder involving both cartilaginous and non-cartilaginous tissues such as subchondral bone and synovium. Among them, subchondral bone undergoes constant remodeling in response to the changes of mechanical environment. Current understanding of subchondral bone disturbance in OA is limited to its link with an altered local mechanical loading as a result of ligament or meniscus injury. Very recently, hypertension, the most common vascular morbidity, has been emerged as an independent risk factor of OA. It might suggest a plausible role of systemic hemodynamic mechanical stress in subchondral bone remodeling and the pathogenesis of OA. However, their relationship remains not fully understood. Based on our preliminary clinical observation on the association of hemodynamic parameters with subchondral bone mass and microstructure in late-stage knee OA patients, we formulate a vascular etiology hypothesis of OA from a mechanobiology perspective. Noteworthily, hemodynamic stress associated with subchondral bone mineral density; yet compressive mechanical loading does not. Furthermore, hemodynamic parameters positively correlated with subchondral plate-like trabecular bone volume but negatively associated with rod-like trabecular bone volume. In contrast, compressive mechanical loading tends to increase both plate-like and rod-like trabecular bone volume. Taken together, it warrants further investigations into the distinct role of hemodynamic or compressive stress in shaping subchondral bone in the pathophysiology of OA.

The Translational potential of this article

This work provides a new insight, from the angle of biomechanics, into the emerging role of vascular pathologies, such as hypertension, in the pathogenesis of OA. It might open up a new avenue for the development of a mechanism-based discovery of novel diagnostics and therapeutics.

Cardiovascular Drugs and Osteoarthritis: Effects of Targeting Ion Channels

Osteoarthritis (OA) and cardiovascular diseases (CVD) share many similar features, including similar risk factors and molecular mechanisms. A great number of cardiovascular drugs act via different ion channels and change ion balance, thus modulating cell metabolism, osmotic responses, turnover of cartilage extracellular matrix and inflammation. These drugs are consumed by patients with CVD for many years; however, information about their effects on the joint tissues has not been fully clarified. Nevertheless, it is becoming increasingly likely that different cardiovascular drugs may have an impact on articular tissues in OA. Here, we discuss the potential effects of direct and indirect ion channel modulating drugs, including inhibitors of voltage gated calcium and sodium channels, hyperpolarization-activated cyclic nucleotide-gated channels, β-adrenoreceptor inhibitors and angiotensin-aldosterone system affecting drugs. The aim of this review was to summarize the information about activities of cardiovascular drugs on cartilage and subchondral bone and to discuss their possible consequences on the progression of OA, focusing on the modulation of ion channels in chondrocytes and other joint cells, pain control and regulation of inflammation. The implication of cardiovascular drug consumption in aetiopathogenesis of OA should be considered when prescribing ion channel modulators, particularly in long-term therapy protocols.

Hypertension meets osteoarthritis - revisiting the vascular aetiology hypothesis

Osteoarthritis (OA) is a whole-joint disease characterized by subchondral bone perfusion abnormalities and neovascular invasion into the synovium and articular cartilage. In addition to local vascular disturbance, mounting evidence suggests a pivotal role for systemic vascular pathology in the aetiology of OA. This Review outlines the current understanding of the close relationship between high blood pressure (hypertension) and OA at the crossroads of epidemiology and molecular biology. As one of the most common comorbidities in patients with OA, hypertension can disrupt joint homeostasis both biophysically and biochemically. High blood pressure can increase intraosseous pressure and cause hypoxia, which in turn triggers subchondral bone and osteochondral junction remodelling. Furthermore, systemic activation of the renin-angiotensin and endothelin systems can affect the Wnt-β-catenin signalling pathway locally to govern joint disease. The intimate relationship between hypertension and OA indicates that endothelium-targeted strategies, including re-purposed FDA-approved antihypertensive drugs, could be useful in the treatment of OA.