Osteoarthritis Linked to Rapid Worsening of Severe Long-Term Conditions: Study

Osteoarthritis, a condition where the protective cartilage on the ends of bones deteriorates, may more than double the risk of rapid progression to multiple severe long-term conditions, known as multimorbidity, according to a 20-year study published in the open-access journal RMD Open. The study reveals four distinct speeds of progression to multimorbidity, highlighting the impact of osteoarthritis on overall health.

The research suggested that persistently low levels of physical activity, a high-calorie diet, and chronic low-grade inflammation may explain the link between osteoarthritis and the increased risk of developing other long-term conditions.

Around 70% of those with osteoarthritis are likely to have other long-term conditions, but the speed and severity of their development were previously unclear. To investigate this, researchers analyzed continuously collected healthcare data which included around 1.4 million residents. They focused on individuals aged 40 or older and were newly diagnosed with osteoarthritis between 2008 and 2009. These cases were matched with two people of the same age and sex who did not have osteoarthritis.

During the study period, 5,318 people were newly diagnosed with knee osteoarthritis, 2,479 with hip osteoarthritis, 988 with hand osteoarthritis, 714 with osteoarthritis in other joints, and 499 with generalized osteoarthritis.

Out of the total participants, 1,296 did not develop any other long-term condition, while 28,242 did. Four distinct patterns of progression emerged: mild multimorbidity late progression (class 1), mild multimorbidity early progression (class 2), moderate multimorbidity (class 3), and severe multimorbidity (class 4). Initially, the average number of long-term conditions was low (one or none) in all four classes. Those in class 1 progressed the slowest to developing multiple long-term conditions, with an average of around three conditions by the end of the tracking period. In contrast, those in class 4 progressed the fastest, accumulating an average of around ten long-term conditions.

The severity of each long-term condition was assessed using the disability weighting from the Global Burden of Disease (GBD) study. Disability levels mirrored the categorization, being lowest in class 1 and highest in class 4, where over half (57%) of participants had died by the end of the tracking period. Osteoarthritis prevalence was also lowest in class 1 (29%) and highest in class 4 (42%).

Osteoarthritis was associated with a 29% increased risk of class 1 membership but more than doubled the risk for class 4 membership. Despite this, the presence of osteoarthritis alone was a poor predictor of any class of membership. Age remains a significant factor in developing long-term conditions, but the study found that the correlation between osteoarthritis and multimorbidity extended beyond age.

The findings underscored the importance of addressing lifestyle factors such as physical activity and diet in managing osteoarthritis and preventing the rapid progression of other severe long-term conditions.

Reference: Dell’Isola, A., Recenti, F., Englund, M., & Kiadaliri, A. (2024). Twenty-year trajectories of morbidity in individuals with and without osteoarthritis. RMD Open. doi.org/10.1136/rmdopen-2024-004164