The Bristol 'OA500 study': progression and impact of the disease after 8 years.

OBJECTIVE: To study the natural history of peripheral joint osteoarthritis (OA) and assess its impact over eight years in a prospective study of 500 patients.
METHODS: 500 consecutive patients with peripheral joint OA were recruited from a hospital-based rheumatology clinic. All were invited for review 3 and 8 years after entry. Joint sites involved, pain severity, change in index joints, global change in the condition, use of medication, surgery and walking aids were all recorded at each visit, and after eight years disability was assessed by the health assessment questionnaire (HAQ) and anxiety and depression by the Hospital anxiety and depression scale (HAD).
RESULTS: At eight-year review, 349 patients were seen: 90% of those remaining alive. Outcome was heterogeneous. Sixty patients (17.2%) reported worsening in all three subjective parameters (pain, index joint and global change) compared with 22 (6.3%) who improved in all three parameters. Using this definition of worsening or improvement, strong baseline predictors of clinical outcome did not emerge. For further description, the group was split according to the index joint sites involved at entry to the study, there being 111 with knee OA alone, 87 with hand and knee OA, 72 with hand disease alone, and 29 with hip disease alone. Forty-four percent of those with lone hand disease at entry had acquired significant knee or hip OA 8 years later. The mean HAQ and HAD scores at 8 years were high, especially in those with knee disease, indicating significant disability as a result of the disease. Those with knee or knee and hand disease had the worst outcome in all parameters recorded. The data showed a general decrease in use of NSAIDs over the eight years, but an increase in utilization of analgesics, surgery (especially for hip disease) and walking aids.
CONCLUSIONS: Patients with peripheral joint OA of sufficient severity to lead to hospital referral have a heterogeneous, but generally bad outcome over 8 years, the disease resulting in high levels of physical disability, anxiety and depression, with a high level of utilization of healthcare resources, including joint replacement, drugs and walking aids. The results were consistent with previous suggestions that peripheral joint OA in older people is characterized by the slow acquisition of new joint sites. Progression and outcome may depend on a complex set of psychosocial factors, as well as biological ones.