Table 3.
Subgroup analyses of the association between KL-6 and HP in this meta-analysis.
| Subgroup | NO. of studies | Sample | Standard mean difference (95% CI) | P for Heterogeneity | I2 | P Value between groups | ||
|---|---|---|---|---|---|---|---|---|
| HP | Controls | |||||||
| Type of Allergen | ||||||||
| Bird-related HP | 7 | 252 | 200 | 1.33 [0.98,1.68] | P=0.02 | 61% | P<0.0001 | |
| Fungi-related HP | 2 | 17 | 67 | 1.31 [0.78,1.84] | P=0.79 | 0% | P<0.0001 | |
| FLD | 1 | NA | NA | NA | NA | NA | NA | |
| MWL | 2 | 9 | 66 | 4.12 [2.09,6.15] | P=0.06 | 71% | P<0.0001 | |
| Mixed | 5 | 250 | 153 | 3.54 [1.68,5.39] | P<0.0001 | 97% | P=0.0002 | |
| Conditions of Pulmonary fibrosis | ||||||||
| Fibrotic HP | 7 | 277 | 218 | 3.28 [1.89,4.67] | P<0.0001 | 96% | P<0.0001 | |
| Non-fibrotic-HP | 3 | 39 | 87 | 1.81 [0.83,2.80] | P=0.01 | 77% | P=0.0003 | |
| Mixed | 8 | 233 | 438 | 2.73 [1.53,3.93] | P<0.0001 | 96% | P<0.0001 | |
| Ethnic | ||||||||
| Caucasian | 11 | 272 | 184 | 1.75 [1.21,2.29] | P<0.0001 | 84% | P<0.0001 | |
| Asian | 7 | 277 | 472 | 4.53 [2.66,6.40] | P<0.0001 | 98% | P<0.0001 | |
| Specimen types | ||||||||
| Serum | 17 | 529 | 646 | 2.85 [2.09,3.62] | P<0.0001 | 95% | P<0.0001 | |
| Plasm | 1 | NA | NA | NA | NA | NA | NA | |
| Assay approach | ||||||||
| ELISA | 13 | 338 | 471 | 2.24 [1.47,3.01] | P<0.0001 | 94% | P<0.0001 | |
| CLEIA | 3 | 191 | 143 | 5.13 [0.35,9.9] | P<0.0001 | 98% | P=0.04 | |
| Mixed | 2 | 20 | 42 | 3.62 [0.54,6.69] | P=0.003 | 89% | P=0.02 | |
NA, not applicable; HP, Hypersensitivity pneumonitis; FLD, Farmer’s lung disease; MWL, Mushroom worker’s lung; ELISA, Enzyme linked-immuno-sorbent assay; CLEIA, chemiluminescence immunoassay assay.