Table 2. Characteristics of included participants.
| Study | Number of included participants | Gout/control participants | Number of involved joints or locations | Joints or locations with positive/negative PLM result for MSU | Mean age (gout/control) (years) | Male: female (gout/control) | Duration of gout | SUA level (Mean±SD) | Conditions of control participants |
|---|---|---|---|---|---|---|---|---|---|
| Ogdie, 2017 [14] | 824 | 416/408 | 1191 | NA | 60.2±14.6/59.5±16.0 | 363:53/222:186 | NR | 0.466±0.138 mmol/L | CPPD, clinically suspected gout, OA, RA, spondyloarthropathies, undifferentiated inflammatory arthritis, septic arthritis, systemic lupus erythematosus, and other |
| Das, 2017 [15] | 92 | 62/30 | NR | NA | 49.13±9.1/47.6±10.6 | 60:2/29:1 | 58.48±36.4 months (range 12–144 months) | 7.69±1.6 mg/dl | RA, OA and healthy individuals |
| Elsaman, 2016 [16] | 100 | 47/53 | 131 | 71/60 | 55.06±6.42/NR | 30:17/25:28 | NR | NR | CPPD, non-CRA |
| Loffler, 2015 [17] | NR | NR | 216 | 74/142 | 69±12/NR | NR | NR | NR | CPPD, non-CRA such as RA, PSA, septic arthritis, OA, hemarthrosis, reactive joint effusion after overexertion and others |
| Zufferey, 2015 [18] | 109 | 60/49 | NR | NA | 65±12/NR | 55:5/NR | <10 days | NR | CPPD, non-CRA |
| Leng, 2014 [19] | 68 | 32/36 | NR | NA | 56.7±15.2/50.8±17.9 | 30:2/10:26 | 9.0±4.5 years | 0.614±0.119 mmol/L | CPPD, OA, RA, HADD, synovial chondroma |
| Lamers-Karnebeek, 2014 [20] | 54 | 26/28 | NR | NA | 63.5/55.0 | 25:1/13:15 | new onset | 0.52 mmol/L | CPPD, reactive arthritis, poly-arthritis eci, ankle arthritis in Loffgren triad, OA, discrete synovitis in PMR, PSA, undifferentiated arthritis |
| Gruber, 2014 [21] | 21 | NA | 37 | 12/2 | 55.2±13.6 | NA | acute and chronic | NR | NA |
| Naredo, 2014 [22] | 133 | 91/42 | NR | NA | 56.4±11.5/56.6±13.5 | NR | 87.4(1–480) months | 9±1.9 mg/dl | RA, spondyloarthritis and healthy subjects |
| Bergner, 2013 [23] | 113 | 39/74 | 113 | 39/74 | NR | NR | NR | NR | CPPD, non-CRA |
| Ottaviani, 2012 [24] | 103 | 53/50 | NR | NA | 59.7±15.8/59.5±15.3 | 49:4/40:10 | 9.2±10.7 years | 0.657±0.145 mmol/L | PSA, RA, CPPD, OA |
| Thiele, 2007 [25] | 46 | 23/23 | 70 | 37/33 | 59.9±16.1/NR | 17:6/8:15 | >6 months (except one) | NR | CPPD, retrocalcaneal bursitis, inflammatory oligoarthritis, sarcoidosis, RA, lateral epicondylitis, OA, FMS, PSA, muscle fiber tear, bursitis, tendinitis |
| Nalbant, 2003 [26] | 23 | 10/13 | 40 | 20/20 | 61.3±8.45/54.54±7.01 | NR | 10.7±3.13 years | NR | RA |
PLM, polarized light microscopy; CPPD, chondrocalcinosis; HADD, hydroxyapatite deposition disease; non-CRA, non-crystal-related inflammatory joint disease; RA, rheumatoid arthritis; PSA, psoriatic arthritis; OA, osteoarthritis; FMS, fibromyalgia; PMR, polymyalgia rheumatica; NA, not available; NR, not reported