Table 1. Characteristics of included studies investigating patients with versus without ILD.
| With ILD | Without ILD | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| First author, Country, Year | Study design | Disease | N. | Male (%) | Mean age | NLR (Mean ± SD) | N. | Male (%) | Mean age | NLR (Mean± SD) | NOS/AHRQ |
| Achaiah, UK., 2022 [31] | cohort | ILD | 1259 | 602 (47.8) | 65.39 | 3.92±5.22 | 355 | 203 (57.2) | 63.4 | 4.46±5.79 | 8 |
| Atilla, Turkey, 2016 [22] | case-control | SSc | 34 | 9 (26.5) | NR | 3.66 ± 1.32 | 25 | 6 (24) | NR | 2.85 ± 1.12 | 8 |
| Bai, China, 2021 [13] | cohort | IIM | 133 | 44 (33.1) | 50 | 5.7861±4.1821 | 153 | 47 (30.7) | 47 | 5.5248±3.8169 | 9 |
| Chen, China, 2019 [19] | case-control | RA | 103 | 24 (23.3) | 60.94 | 5.55±7.88 | 198 | 39 (19.7) | 59.80 | 3.40±3.17 | 9 |
| García-Núñez, Spain, 2022 [8] | case-control | silicosis | 91 | 91 (100) | 40.48 | 2.5252±1.2348 | 22 | 22 (100) | 36.4 | 1.60±0.50 | 6 |
| Ha, Korea, 2018 [34] | case-control | IIM | 101 | NR | NR | 1.495± 0.761 | 96 | NR | NR | 1.225±0.902 | 7 |
| Jung, Korea, 2017 [21] | case-control | SSc | 40 | NR | NR | 6.13±9.18 | 48 | NR | NR | 2.12±1.71 | 7 |
| Karataş, Turkey, 2019 [18] | case-control | silicosis | 573 | NR | 40 | 3.295±4.9868 | 222 | NR | 35 | 2.2049±2.7982 | 8 |
| Kim, Korea, 2020 [17] | cross-section | SSc | 54 | NR | NR | 2.2455±1.272 | 60 | NR | NR | 1.6195±0.5469 | 8† |
| Man, Romania, 2022 [5] | case-control | ILD | 36 | 20 (55.6) | 64 | 2.7177±1.4978 | 161 | 33 (20.5) | 40 | 2.0721±0.7481 | 6 |
| Ruta, Romania, 2020 [15] | case-control | IPF/CTD | 42 | 25 (59.5) | 62.28 | 2.8229±1.1604 | 50 | 24 (48) | 55.04 | 2±1.05 | 7 |
| Xu, China, 2022 [29] | case-control | RA | 284 | 105 (37.0) | 68.95 | 4.37 ± 3.29 | 1215 | 274 (22.6) | 57.95 | 3.84 ± 2.77 | 7 |
| Yang, China, 2017 [20] | case-control | DM | 18 | 9 (50) | 51.39 | 5.54 ± 1.60 | 55 | 24 (43.6) | 50.05 | 4.16 ± 1.73 | 8 |
| Zhang, China, 2021 [11] | cohort | PSS | 71 | 12 (16.9) | 60.8 | 2.12±0.4 | 146 | 11 (7.5) | 56.4 | 1.64±0.3 | 6 |
| Zinellu, Italy, 2020 [14] | cross-section | IPF | 73 | 22 (30.1) | 69.64 | 2.3949±0.5899 | 62 | 19 (30.6) | 67.35 | 1.9159±0.63 | 7† |
† The methodological quality of cross-sectional studies was evaluated by the Agency for Healthcare Research and Quality(AHRQ).
NLR,neutrophil-to-lymphocyte ratio;ILD,interstitial lung diseases;N., number; SD, standard deviation; NOS, the modified Newcastle-Ottawa Quality Assessment Scale; AHRQ, the Agency for Healthcare Research and Quality; NR, no report; SSc, systemic sclerosis; IIM, idiopathic inflammatory myopathy; RA, rheumatoid arthritis; IPF, idiopathic pulmonary fibrosis; CTD, connective tissue diseases; DM, dermatomyositis, PSS, primary Sjogren’s syndrome.