Epidemiology and treatment of pain associated with osteoarthritis of the knee in Germany: A retrospective health claims data analysis.

Objective: Osteoarthritis of the knee (knee OA) is a serious joint disease leading to pain and reduced quality of life. Pharmacological treatments include anti-inflammatories, analgesics, intraarticular hyaluronic acid, and intraarticular corticosteroids while for severe knee OA, knee replacement is an option. This study examined the incidence, prevalence, patient characteristics, and uptake of medical and surgical treatments in knee OA patients in Germany. Design: A non-interventional, retrospective health claims data analysis with anonymized data from the InGef database was performed. Patients ≥18 years were analyzed cross-sectionally for each year 2015-2020. Newly diagnosed patients in 2015 were also longitudinally analyzed until end of 2020. Results: Annual knee OA prevalence increased from 7.07 ​% in 2015 to 7.39 ​% in 2020. Annual incidence proportions ranged from 1.71 ​% in 2015 to 1.46 ​% in 2020. Knee replacement was the most common surgery, with rising patient numbers (e.g., 7918 patients in 2015 and 8975 patients in 2019). Approximately 62 ​% of patients newly diagnosed in 2015 received prescription pharmacological pain treatment during follow-up. Most (96.95 ​%) received non-opioid analgesics, followed by weak opioids (8.14 ​%) and strong opioids (3.00 ​%) as first-line treatment (combinations possible). Knee surgery was performed in 16.6 ​% of patients during follow-up. Median time from first diagnosis until surgery was 346 days for any knee surgery and 564 days for knee replacement. Conclusions: The number of patients with knee OA in Germany is steadily rising, along with an increasing number of surgical interventions, especially knee replacement. Time until first surgery and knee replacement is relatively short, even for newly diagnosed patients.