National cohort study aimed to investigate the impact of comorbidities (number and type of comorbidities) on health utility state change in lower lim osteoarthritis (hip and knee OA).

The concept of health utility state was developed by economists to explain individual choices and preferences for health states. It is expressed as the "desirability or preference that individuals exhibit for the condition". This health utility state can be measured indirectly using health-relation quality of life questionnaires.

Chronic diseases such as OA are known to be associated with impairment of quality of life. Given that OA prevalence increases with age, OA is often associated with other diseases (comorbidities). A cross-sectional study showed that comorbidities are associated with lower health utility state in OA. Investigation of longitudinal impact of comorbidities on health utility state change is need.

Main objective: Determine the impact of comorbidities on change in health utility state among patients with lower limb OA.

Secondary objective: Determine the Minimal Clinically important Difference in health utility state among patients with lower limb OA.

The COMUTAR study uses longitudinal data from the Knee and Hip Osteoarthritis Longitudinal Assessment (KHOALA) cohort study. Health utility state is measured indirectly using Medical Outcome Study Short Form-36 quality of life questionnaire Comorbidities are assessed using the Functional Comorbidity Index

Inclusion Criteria:

• age: 40-75 years
• Uni or bilateral lower limb osteoarthritis (OA) according to the American College of Rheumatology (ACR) and European league against rheumatism (EULAR) criteria

Exclusion Criteria:

• Hip or knee prothesis
• Antecedent of osteotomy
• Severe comorbidity
• Adult under legal protection

Population-based

Open to partnership