Objectives — To assess how people with arthritis evaluate and calibrate their complex medication regimens. Building on these findings, to explore how the concept of concordance helps to describe a patient-provider partnership model which can aid optimum medication regimen selection, calibration and management of chronic conditions.

Method — A longitudinal study of 689 patients diagnosed with osteoarthritis (OA) or rheumatoid arthritis (RA) was conducted to identify patient perceptions, decision-making and behaviour related to their medication management. Face to face interviews with the Brief Medication Questionnaire, health quality of life questionnaires (AIMS2 and SF-36) and telephone interviews were conducted in waves centered around patient visits every six months for two years. Data about medication regimens were abstracted from the clinic medication profile record for each visit.

Setting — Three rheumatology clinics in the United States: a university clinic, a private clinic and a Veterans Administration clinic.

Key findings — About half of the patients in the sample had complex regimens with eight or more medications at any one time. The majority of physicians altered patients' medication orders every six months. The majority of patients reported that they evaluated the effectiveness and side effects of individual medicines based largely on symptoms. There were 248 reported deviations in the scheduled medications at baseline and the majority (61 per cent) were intentional, largely based on symptoms.

Conclusion — Providers and patients each had unique expertise and were engaged in a dynamic process of calibrating patients' ever-changing regimens. In the absence of a perfect static regimen for patients, the concept of concordance productively reflects the partnership and mutual respect needed for ongoing medication regimen selection, calibration and management for a long-term condition.