Current evidence for therapeutic interventions and prognostic factors in polymyalgia rheumatica: a systematic literature review informing the 2015 European League Against Rheumatism/American College of Rheumatology recommendations for the management of polymyalgia rheumatica

To summarise evidence on therapeutic interventions and prognostic factors in polymyalgia rheumatica (PMR). A systematic literature review was conducted using Ovid Medline, Embase, PubMed, CINAHL, Web of Science and the Cochrane Library (1970 through April 2014). Quality of evidence (QoE) of identified studies was appraised by Grading of Recommendations Assessment, Development and Evaluation (GRADE) (interventions) and the Quality In Prognosis Studies (QUIPS) methodologies (prognostic factors). Out of 10 931 titles identified, 52 articles were finally selected. A single study indicated that an initial prednisone dose of 20 mg/day is associated with a lower short-term relapse rate than 10 mg/day but at the cost of a higher rate of adverse events. Another study suggested a comparable efficacy of intramuscular methylprednisolone and oral glucocorticoids (GCs) with lower cumulative GC doses and less weight gain in the former group. Moderate to high QoE (1-2 studies) indicated a benefit of methotrexate in remission rates and cumulative GC doses in early PMR. Anti-tumour necrosis factor a agents are ineffective for PMR treatment. Among prognostic factors, female sex, high erythrocyte sedimentation rate (ESR) and peripheral arthritis were associated in some studies with a higher relapse risk. Women and patients with high ESR also appeared to have a longer duration of treatment. Several studies of varying quality, however, failed to prove these associations. In PMR, evidence for initial GC doses and subsequent tapering regimens is limited. Intramuscular methylprednisolone and methotrexate may be effective GC sparing agents. Female sex, high ESR and peripheral arthritis at disease outset are potential risk factors for a worse prognosis.