Medication use and comorbidities in an increasingly younger osteoarthritis population: an 18-year retrospective open-cohort study

OBJECTIVES: As understanding of the pathogenesis and treatment strategies for osteoarthritis (OA) evolves, it is important to understand how patient factors are also changing. Our goal was to examine demographics and known risk factors of patients with OA over time. DESIGN: Open-cohort retrospective study using electronic health records. SETTING: Large US integrated health system with 7 hospitals, 2.6 million outpatient clinic visits and 97 300 hospital admissions annually in a mostly rural geographic region. PARTICIPANTS: Adult patients with at least two encounters and a diagnosis of OA or OA-relevant surgery between 2001 and 2018. Because of geographic region, over 96% of participants were white/Caucasian. INTERVENTIONS: None. PRIMARY AND SECONDARY OUTCOME MEASURES: Descriptive statistics were used to examine age, sex, body mass index (BMI), Charlson Comorbidity Index, major comorbidities and OA-relevant prescribing over time. RESULTS: We identified 290 897 patients with OA. Prevalence of OA increased significantly from 6.7% to 33.5% and incidence increased 37% (from 3772 to 5142 new cases per 100 000 patients per year) (p<0.0001). Percentage of females declined from 65.3% to 60.8%, and percentage of patients with OA in the youngest age bracket (18–45 years) increased significantly (6.2% to 22.7%, p<0.0001). The percentage of patients with OA with BMI ≥30 remained above 50% over the time period. Patients had low comorbidity overall, but anxiety, depression and gastro-oesophageal reflux disease showed the largest increases in prevalence. Opioid use (tramadol and non-tramadol) showed peaks followed by declines, while most other medications increased slightly in use or remained steady. CONCLUSIONS: We observe increasing OA prevalence and a greater proportion of younger patients over time. With better understanding of how characteristics of patients with OA are changing over time, we can develop better approaches for managing disease burden in the future.