Polymyalgia rheumatica (PMR) is a systemic inflammatory disease that affects elderly people. It is characterized by pain and morning stiffness in the shoulders, pelvic girdles and neck. Glucocorticoids are the mainstay of the treatment. In clinical practice, the disease activity of PMR and corresponding treatment changes are based on the presence of symptoms and inflammatory markers. The interpretation of these abnormalities can be surprisingly difficult, especially when they are not consistent. In 2004, Leeb and Bird developed a composite score for measurement of disease activity in PMR, called the polymyalgia rheumatica activity score. It consists of 5 domains: morning stiffness time, ability to elevate the upper limbs, physician's global assessment, pain and CRP level. However, high-quality evidence on the measurement properties is lacking and there is still no consensus on the optimal cut off point. Based on a Delphi study with physicians and patients OMERACT defines laboratory markers of systemic inflammation, pain, stiffness and physical function as the four inner core of domains considered mandatory for clinical trials of PMR, most frequently measured by erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP), visual analogue scale (VAS) for pain, morning stiffness time and Health Assessment Questionnaire-Disability Index (HAQ-DI) respectively. Patient's global fatigue was strongly recommended to measure in PMR as well. Recently, a PMR-specific patient-reported outcome measure was developed, called the PMR impact scale. However, outcome measures in PMR studies lack consistency and there is no high-quality evidence on the measurement properties. In addition, the evolution of these patient reported outcomes is not known.