Table 2.
Clinical and laboratory parameters in IIM patients with or without elevated serum AREG/HB-EGF levels.
| AREG | HB-EGF | |||||
|---|---|---|---|---|---|---|
| Normal (n = 30) | Elevated (n = 7) | p Value | Normal (n = 31) | Elevated (n = 6) | p Value | |
| Female, n (%) | 21 (70.0) | 5 (71.4) | 1.00 | 22 (71.0) | 4 (66.7) | 1.00 |
| Age, years (range) | 58 (50–68) | 71 (63–77) | 0.064 | 59 (51–71) | 61 (57–68) | 0.76 |
| Disease duration, month (range) | 21 (8–93) | 7 (1–18) | 0.001 | 16 (7–84) | 18 (9–41) | 0.79 |
| Untreated, n (%) | 11 (36.7) | 3 (42.9) | 1.00 | 11 (35.5) | 3 (50) | 0.65 |
| ILD, n (%) | 21 (70.0) | 5 (85.7) | 0.08 | 7 (22.6) | 3 (50) | 0.31 |
| CK, U/L | 69 (46–639) | 186 (42–1571) | 0.43 | 65 (73–192) | 2451 (850–6009) |
0.16 |
| Elevated CK, n (%) | 10 (34.5) | 3 (42.9) | 0.69 | 7 (23.3) | 6 (100) | <0.001 |
| KL-6, U/mL (range) | 453 (259–644) | 634 (550–900) | 0.27 | 557 (321–687) | 248 (231–617) | 0.93 |
| Elevated KL-6, n (%) | 9 (40.9) | 5 (83.3) | 0.16 | 13 (54.2) | 1 (25.0) | 0.60 |
| %VC, % (range) | 83 (68–102) | 71 (57–87) | 0.23 | 77 (64–90) | 100 (92–105) | 0.14 |
| %DLCO, % (range) | 76 (65–94) | 70 (57–78) | 0.24 | 74 (64–85) | 94 (85–99) | 0.16 |
| AREG, pg/mL (range) | 16.8 (11.6–25.2) |
46.5 (45.1–48.6) |
<0.001 | 20.1 (11.7–31.9) |
24.6 (16.3–29.4) |
0.50 |
| HB-EGF, pg/mL (range) | 78.7 (49.5–116.6) |
78.4 (69.5–115.6) |
0.59 | 70.9 (50.8–90.6) |
223 (157–269) | 0.0055 |
Data are reported as median (IQR) unless stated otherwise. Numbers may not add up to the expected total since data were not available for some variables. The upper limits of normal range of CK: 248 U/L (male), 153 U/L (female); KL-6: 500 U/mL. Elevated levels of serum AREG was defined as ≥40 pg/mL based on the finding that the serum AREG levels of any patient with disease controls (SSc and RA) did not exceed 40 pg/mL. Elevated levels of serum HB-EGF (≥133.2 pg/mL) was defined as greater than those of the mean for HC plus 2SD. Disease duration was defined as the duration from the diagnosis of IIM to the serum sample collection. IIM: idiopathic inflammatory myopathy; SSc: systemic sclerosis; RA: rheumatoid arthritis; ILD: interstitial lung disease; CK: creatine kinase; KL-6: Sialylated carbohydrate antigen Krebs von den Lungen-6; VC: vital capacity; DLCO: carbon monoxide diffusing capacity; AREG: amphiregulin; HB-EGF: heparin-binding epidermal growth factor. Each clinical parameter in the normal group and the elevated group of AREG/HB-EGF was analyzed using unpaired t-test for continuous variables and Fisher’s exact test for categorical variables.