Heavy Disease Burden of Knee Osteoarthritis Reported Over Past Decades

Knee osteoarthritis (OA) has become more prevalent from 1990 to 2019, with increases in overall incidence, years lived with disability (YLD), and age-standardized disease rates, according to study results published in Arthritis Care and Research.

Researchers analyzed the prevalence, incidence, YLD, and associated risk factors for knee OA from 1990 to 2019.

Data were taken from the Global Burden of Diseases, Injuries, and Risk Factors 2019 study, which estimates worldwide prevalence, incidence, mortality, YLD, years of life lost, and years adjusted for disability, as stratified by sex and age, among numerous diseases since 1990. Patients diagnosed with knee OA (defined as radiologically-confirmed symptomatic OA around the knee joint) were included in the analysis.

Knee OA was prevalent among approximately 364,600,000 people worldwide in 2019, accounting for 4.9% of all diseases among the global population. The age-standardized prevalence estimate was 4376.0 per 100,000 population, with an increase of 7.5% between 1990 and 2019. There were around 29,500,000 incident cases, with an age-standardized incident rate increase of 6.2% from 1990 to 2019.

The highest prevalence of knee OA was found among high-income Asian Pacific, East Asian, and Australasian regions, with age-standardized rates of 5662.9, 5123.3, and 4903.7 per 100,000 population.

The lowest prevalence of knee OA was found among Central Asian, Southeast Asian, and Central European regions, with age-standardized rates of 2908.0, 3317.7, and 3413.7 per 100,000 population.

The highest age-standardized incidence of knee OA was found among high-income Asian Pacific, east Asian, and Australasian regions, while the lowest rates were found among Central Asian, Southeast Asian, and Central European regions.

The largest increases in age-standardized prevalence of knee OA between 1990 and 2019 were found among Andean Latin American (12.9% increase), southern Latin American (12.7% increase), and Southeast Asian (12.4% increase) regions, while the lowest increases were found among high-income North American (1.8% decrease), high-income Asian Pacific (2.6% increase), and Central Sub-Saharan African (4.3% increase) regions.

Women showed higher prevalence rates for knee OA vs men across all age groups, with rates of 5161.4 vs 3510.2 per 100,000 population, respectively (women-to-men ratio, 1.47). Asia had the highest women-to-men ratio for prevalence of knee OA at 1.7.

The burden of knee OA tended to increase along with rising sociodemographic level.

Between 1990 and 2019, the high-middle sociodemographic index (SDI) regions saw the greatest rise in age-standardized YLD rates (12.5% increase). The burden of disease among high and high-middle SDI regions was greater than those of other sociodemographic levels.

Globally, 22.4% of YLDs as a result of knee OA were attributed to high body mass index (BMI).

This study is limited by potential missing data from certain countries and time periods. Additional limitations included varying research methodologies and lack of tools to assess contributing factors beyond BMI.

The study authors concluded, “Continuous monitoring of the burden of [knee] OA is of great significance for establishing appropriate public prevention policies and raising public awareness, especially in high- and high-middle SDI regions.”