TABLE 1

Characteristics of studies investigating the association between neutrophil-to-lymphocyte ratio (NLR) on admission and adverse outcomes in acute exacerbations of chronic obstructive pulmonary disease

First author, year, countryStudy designSample sizeSettingOutcomeOR (95% CI)AUC (95% CI)Cut-offSensitivity (%)Specificity (%)Additional findings
Kumar, 2017, Australia [25]R181EDMortality0.95# (0.84–1.08)NRNRNRNRNLR in survivors versus nonsurvivors: 7±8 versus 13±10, p=0.004
Yao, 2017, China [26]R303WardMortalityNR0.803 (NR)6.240.810.69NLR in survivors versus nonsurvivors: 7±8 versus 15±10, p<0.001
Rahimirad, 2017, Iran [27]R174WardMortality3.586# (1.69–7.60)0.717 (0.623–0.811)40.870.4NLR in survivors versus nonsurvivors: 8±8 versus 17±18, p<0.001
Aksoy, 2018, Turkey [28]R2727WardMortality1.13# (0.46–2.78)NRNRNRNRNLR in survivors versus nonsurvivors: 7 (4–12) versus 10 (4–19), p=0.07
Ergun, 2018, Turkey [29]P132ICUMortalityNRNRNRNRNRNLR in survivors versus nonsurvivors: 18±23 versus 24±32, p=0.65
Teng, 2018, China [30]R904WardMortality1.067# (1.039–1.095)0.737 (0.661–0.814)8.130.610.75NLR significantly higher in nonsurvivors, p<0.001
Liu, 2019, China [31]R622EDMortality2.05# (1.21–3.48)0.742 (0.554–0.881)4.190.710.74NLR in survivors versus nonsurvivors: 3±7 versus 8±10, p<0.001
Yilmaz, 2019, Turkey [32]R171ICUMortality1.902# (1.108–3.266)NR3.180.710.72NLR in survivors versus nonsurvivors: 2.8±1.4 versus 3.5±1.9, p=0.037
Ardestani, 2020, Iran [33]R829NRMortality1.08# (1.02–1.14)0.7 (0.67–0.73)6.90.610.73NLR in survivors versus nonsurvivors: 6±5 versus 11±10, p<0.001
Luo, 2021, China [34]R533WardMortality3.87# (1.29–10.3)0.801 (NR)6.740.830.71NLR in survivors versus nonsurvivors: 8±6 versus 15±13, p<0.001
Yao, 2021, China [35]R146WardMortality1.01# (0.999–1.022)0.83 (0.761–0.899)16.830.690.65NLR in survivors versus nonsurvivors: 12 (6–25) versus 22 (11–40), p<0.001
Karauda, 2021, Poland [36]R275WardMortalityNR0.96 (0.93–0.99)13.21.000.93NR
Teng, 2018, China [30]R906WardICU1.046# (1.023–1.068)0.676 (0.607–0.744)8.130.540.77NLR significantly higher in patients admitted to ICU, p<0.001
Teng, 2018, China [30]R906WardIMV1.042# (1.019–1.066)0.732 (0.656–0.807)10.3450.540.85NLR significantly higher in patients requiring IMV, p<0.001
Sun, 2021, China [37]R212WardNIMVF10.783# (2.069–56.194)0.858 (0.785–0.931)8.90.690.88NLR in NIMV success versus failure: 4 (3–6) versus 14 (7–17), p<0.001
Zuo, 2019, China [38]R185NRPH1.161# (0.924–1.458)0.701 (0.629–0.766)4.6590.810.6NLR in patients without versus with PH: 4 (3–6) versus 6 (5–12), p<0.001
Wang, 2022, China [39]P598WardLHS0.981# (0.963–0.999)NRNRNRNRNLR in patients with normal, mildly prolonged and significantly prolonged hospital stay: 4.6±6.0, 6.0±8.1 and 5.5±5.3, p=0.006
Esmaeel, 2017, Egypt [40]P80WardDeath/ICU1.2# (0.9–1.5)0.642 (0.526–0.746)3.40.890.49NR
Gòmez-Rosero, 2021, Colombia [41]P610WardDeath/ICU3.0# (1.7–5.4)NRNRNRNRNLR in survivors/non-ICU admitted versus nonsurvivors/ICU admitted: 5 (3–10) versus 8 (5–14), p<0.001
Lu, 2021, China [42]R282WardDeath/ICU/IMV41.85# (9.57–306.74)0.883 (0.771–0.894)10.230.620.92NLR in survivors/non-ICU admitted/not requiring IMV versus nonsurvivors/ICU admitted/requiring IMV: 5 (3–8) versus 11 (8–16), p<0.001

AUC: area under the curve; CI: confidence interval; ED: emergency department; ICU: intensive care unit; IMV: invasive mechanical ventilation; LHS: length of hospital stay; OR: odds ratio; NIMV: noninvasive mechanical ventilation; NIMVF: noninvasive mechanical ventilation failure; NR: not reported; P: prospective; PH: pulmonary hypertension; R: retrospective. #: from multivariate analysis. : median and interquartile range.