Joint involvement in sarcoidosis: systematic review and meta-analysis of prevalence, clinical pattern and outcome.

Objectives: To characterize joint involvement (JI) in sarcoidosis, a systematic search of MEDLINE, EMBASE and Cochrane Library was conducted from inception to July 2022 for publications reporting its prevalence, pattern, treatment and outcome.

Methods: The pooled prevalence estimates (PPE) with 95% CI were calculated using binomial distribution and random effects. Meta-regression method was used to examine factors affecting heterogeneity between studies.

Results: Forty-nine articles were identified comprising a total of 8574 sarcoidosis patients, where 12% presented with JI (95% CI 10, 14; I2 = 0%). The PPE for sarcoid arthritis (SA) was 19% (95% CI 14, 24; I2 = 95%), and 32% (95% CI 13, 51; I2 = 99%) for arthralgia. Heterogeneity was due to higher JI prevalence reported in Western Asia and the Middle East, in rheumatology clinics and via surveys. Sample size of SA varied from 12 to 117 cases. Ankles were most frequently affected (PPE 80%) followed by knees and wrists. Monoarthritis was uncommon (PPE 1%; 95% CI 0, 2; I2 = 55%). Acute SA prevailed (PPE 79%; 95% CI 72, 88; I2 = 69%) with an equal proportion of oligo and polyarthritis and was frequently accompanied by erythema nodosum (PPE 62%; 95% CI 52, 71; I2 = 16%). Chronic SA was predominantly polyarticular with a higher frequency of the upper extremity joints affected. Most common non-articular manifestations with SA included fever (52%), erythema nodosum (41%), hilar adenopathy (86%) and interstitial lung disease (23%) of which one-third required corticosteroids and/or immunosuppressants.

Conclusion: SA occurred early in the disease with a PPE of 19% and most frequent pattern of acute oligo- or polyarthritis predominantly affecting the lower extremity large joints.