Abstract
Objectives:
Osteoarthritis (OA) represents a leading source of disability in Germany’s aging population, with knee OA contributing the highest burden. This study aimed to evaluate long-term trends in OA incidence, prevalence, and disability-adjusted life years (DALYs) from 1990 to 2021 and forecast these trends to 2040. We investigated disparities by age, sex, and OA subtype to inform national musculoskeletal health policy.
Methods:
We conducted a retrospective secondary analysis using the Global Burden of Disease (GBD) 2021 database. Disease burden was measured via age-standardized incidence rate (ASIR), prevalence rate (ASPR), and DALYs (ASDaR). Disease definitions followed GBD criteria based on Kellgren-Lawrence grades 2–4 confirmed radiographically and symptomatically. Temporal trends were examined using Joinpoint regression using the National Cancer Institute’s software, reporting estimated annual percentage change (EAPC). Future trends were projected using Bayesian Age-Period-Cohort (BAPC) modeling with integrated nested Laplace approximation (INLA). Correlations between OA burden and the Sociodemographic Index (SDI) were evaluated using Pearson’s r.
Results:
Between 1990 and 2021, Germany experienced a 36% increase in OA incidence (from 579,625 to 787,712 cases) and a 49% rise in DALYs. Males had a 50% increase in incidence, 73% in prevalence, and 74% in DALYs, compared to females with 28%, 36%, and 37% increases, respectively. The ASIR, ASPR, and ASDaR all exhibited significant upward trends (EAPC: 0.15%, 0.11%, and 0.11%, respectively). Knee OA remained the dominant subtype, with incidence rising from 377,450 to 518,788 cases (37%), followed by hip OA (47%). Hand OA showed a decline in ASIR and ASPR in males (EAPC: -0.11% and -0.09%). The OA burden correlated strongly with SDI (r > 0.88, p < 0.001). Notably, DALY rates exceeded global averages in all age groups except 45–59 (Figure 1). Joinpoint regression revealed statistically significant increases in ASIR during 1990–1994, 1994–2000, 2000–2005, 2010–2015, and 2019–2021, while a decline was observed from 2005–2010 and stability from 2015–2019. Projections to 2040 predict ASIR will remain stable with a slight increase while ASPR is expected to rise initially, decline temporarily, and increase again around 2030 (Figure 2).
Conclusion:
The OA burden in Germany has increased markedly, particularly among older adults and males. Knee OA emerged as the most dominant and disabling subtype. The observed temporal patterns and projections to 2040 suggest a slight plateauing but persistent increase in age-standardized incidence. With the aging population and medical workforce shortages, sustainable solutions will require targeted prevention, early detection, and investment in conservative and surgical OA management strategies. These insights should drive immediate policy action since without intervention, OA will keep disabling millions and overwhelm Germany’s healthcare system and economy by 2040.
