Subgroups | Number of study | Mean difference | 95% CI | P |
---|---|---|---|---|
Unit of measure | ||||
 U/L | 3 | 2.13 | 0.11, 4.16 | 0.04 |
 μg/ml | 6 | 1.00 | 0.37, 1.63 | 0.002 |
Disease severity | ||||
 K-L 1 VS K-L 2 | 3 | 0.79 | 0.34, 1.25 | 0.0007 |
 K-L 1 VS K-L 3 | 3 | 1.08 | 0.44, 2.60 | 0.16 |
 K-L 1 VS K-L 4 | 3 | 1.61 | 0.57, 2.65 | 0.002 |
 K-L 2 VS K-L 3 | 6 | 0.44 | 0.04, 0.85 | 0.03 |
 K-L 2 VS K-L 4 | 7 | 0.61 | 0.17, 1.05 | 0.007 |
 K-L 3 VS K-L 4 | 5 | 0.41 | 0.15, 0.68 | 0.002 |