Table 1 Sensitivity analysis of the data before and after interpolation
Variable | Before interpolation (n = 636) | After interpolation (n = 636) | Statistical magnitude | P |
|---|---|---|---|---|
Gender, n (%) |  |  | χ2 = 0.000 | 1.000 |
 Male | 425 (66.82) | 425 (66.82) |  |  |
 Female | 211 (33.18) | 211 (33.18) |  |  |
Age, mean ± SD | 70.82 ± 9.88 | 70.82 ± 9.88 | t = 0.000 | 1.000 |
Height, mean ± SD | 1.67 ± 0.07 | 1.67 ± 0.07 | t = 0.000 | 1.000 |
Weight, mean ± SD | 65.50 ± 8.44 | 65.50 ± 8.44 | t = 0.000 | 1.000 |
Acute exacerbation in previous 1 year, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 430 (67.61) | 430 (67.61) |  |  |
 Yes | 206 (32.39) | 206 (32.39) |  |  |
Smoking status, n(%) |  |  | χ2 = 0.000 | 1.000 |
 Never smoked | 321 (50.47) | 321 (50.47) |  |  |
 Smoked before | 93 (14.62) | 93 (14.62) |  |  |
 Smoker at present | 222 (34.91) | 222 (34.91) |  |  |
  Daily amount of smoking, M (Q1, Q3) | 0.00 (0.00, 15.00) | 0.00 (0.00, 15.00) | Z = 0.000 | 1.000 |
  Duration of smoking, M (Q1, Q3) | 0.00 (0.00, 30.00) | 0.00 (0.00, 30.00) | Z = 0.000 | 1.000 |
LAMA, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 479 (75.31) | 479 (75.31) |  |  |
 Yes | 157 (24.69) | 157 (24.69) |  |  |
SAMA, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 634 (99.69) | 634 (99.69) |  |  |
 Yes | 2 (0.31) | 2 (0.31) |  |  |
LABA, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 413 (64.94) | 413 (64.94) |  |  |
 Yes | 223 (35.06) | 223 (35.06) |  |  |
SABA, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 555 (87.26) | 555 (87.26) |  |  |
 Yes | 81 (12.74) | 81 (12.74) |  |  |
PDE4I, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 617 (97.01) | 617 (97.01) |  |  |
 Yes | 19 (2.99) | 19 (2.99) |  |  |
ICS, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 422 (66.35) | 422 (66.35) |  |  |
 Yes | 214 (33.65) | 214 (33.65) |  |  |
Congestive heart-failure, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 572 (89.94) | 572 (89.94) |  |  |
 Yes | 64 (10.06) | 64 (10.06) |  |  |
Diabetes, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 498 (78.30) | 498 (78.30) |  |  |
 Yes | 138 (21.70) | 138 (21.70) |  |  |
Hypertension, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 280 (44.03) | 280 (44.03) |  |  |
 Yes | 356 (55.97) | 356 (55.97) |  |  |
Atrial fibrillation, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 596 (93.71) | 596 (93.71) |  |  |
 Yes | 40 (6.29) | 40 (6.29) |  |  |
Combined with other diseases, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 432 (67.92) | 432 (67.92) |  |  |
 Yes | 204 (32.08) | 204 (32.08) |  |  |
Systolic blood pressure, Mean ± SD | 133.46 ± 17.34 | 133.46 ± 17.34 | t = 0.000 | 1.000 |
Diastolic blood pressure, Mean ± SD | 78.73 ± 10.82 | 78.73 ± 10.82 | t = 0.000 | 1.000 |
Respiratory rate, Mean ± SD | 19.28 ± 2.53 | 19.28 ± 2.53 | t = 0.000 | 1.000 |
Temperature, mean ± SD | 36.86 ± 0.56 | 36.86 ± 0.56 | t = 0.000 | 1.000 |
Heart rate, mean ± SD | 81.65 ± 11.35 | 81.65 ± 11.35 | t = 0.000 | 1.000 |
Hb, mean ± SD | 132.50 ± 17.34 | 132.51 ± 17.26 | t =  − 0.002 | 0.998 |
RBC, mean ± SD | 4.33 ± 0.55 | 4.33 ± 0.55 | t = 0.046 | 0.963 |
WBC, M (Q1, Q3) | 6.89 (5.51, 8.97) | 6.90 (5.53, 8.93) | Z =  − 0.027 | 0.979 |
PLT, M (Q1, Q3) | 188.00 (151.00, 235.75) | 188.50 (151.75, 235.00) | Z =  − 0.043 | 0.966 |
NEUT, M (Q1, Q3) | 4.67 (3.52, 6.65) | 4.68 (3.53, 6.65) | Z =  − 0.044 | 0.965 |
Percentage of neutrophils, mean ± SD | 70.51 ± 11.70 | 70.54 ± 11.65 | t =  − 0.052 | 0.959 |
LYM, M (Q1, Q3) | 1.28 (0.90, 1.80) | 1.29 (0.91, 1.80) | Z =  − 0.079 | 0.937 |
Percentage of lymphocytes, M (Q1, Q3) | 19.40 (12.40, 27.30) | 19.43 (12.47, 27.13) | Z = 0.019 | 0.985 |
MONO, M (Q1, Q3) | 0.44 (0.33, 0.60) | 0.44 (0.33, 0.60) | Z =  − 0.066 | 0.947 |
Percentage of monocytes, M (Q1, Q3) | 6.30 (4.90, 8.10) | 6.30 (4.90, 8.00) | Z = 0.045 | 0.964 |
EOS, M (Q1, Q3) | 0.10 (0.03, 0.19) | 0.10 (0.03, 0.19) | Z =  − 0.036 | 0.971 |
Percentage of eosinophils, M(Q1, Q3) | 1.50 (0.40, 2.90) | 1.46 (0.40, 2.90) | Z = 0.018 | 0.986 |
RDW, mean ± SD | 13.20 ± 1.07 | 13.20 ± 1.05 | t =  − 0.020 | 0.984 |
ALT, M (Q1, Q3) | 15.45 (10.93, 23.00) | 15.50 (11.00, 23.00) | Z =  − 0.027 | 0.978 |
AST, M (Q1, Q3) | 18.00 (14.00, 23.17) | 18.00 (14.00, 23.10) | Z =  − 0.026 | 0.979 |
TBIL, M (Q1, Q3) | 9.30 (6.65, 13.35) | 9.35 (6.70, 13.30) | Z =  − 0.013 | 0.989 |
ALB, mean ± SD | 39.88 ± 4.68 | 39.89 ± 4.67 | t =  − 0.035 | 0.972 |
BUN, M (Q1, Q3) | 5.44 (4.44, 6.68) | 5.44 (4.45, 6.68) | Z =  − 0.014 | 0.989 |
Cr, M (Q1, Q3) | 76.00 (64.10, 93.90) | 76.20 (64.40, 93.75) | Z =  − 0.037 | 0.971 |
Uric acid, M (Q1, Q3) | 288.00 (226.00, 352.00) | 288.50 (226.00, 352.00) | Z =  − 0.009 | 0.993 |
Hypersensitive C-reactive protein, M (Q1, Q3) | 8.30 (2.00, 38.00) | 8.40 (2.00, 36.67) | Z =  − 0.655 | 0.512 |
mMRC grade, n (%) |  |  | Z = 0.000 | 1.000 |
 0 | 1 (0.16) | 1 (0.16) |  |  |
 1 | 138 (21.70) | 138 (21.70) |  |  |
 2 | 279 (43.87) | 279 (43.87) |  |  |
 3 | 189 (29.72) | 189 (29.72) |  |  |
 4 | 29 (4.56) | 29 (4.56) |  |  |
FEV1, M (Q1, Q3) | 1.60 (1.10, 2.21) | 1.60 (1.10, 2.21) | Z = 0.000 | 1.000 |
FVC, M (Q1, Q3) | 2.26 (1.66, 3.64) | 2.26 (1.66, 3.64) | Z = 0.000 | 1.000 |
FEV1/FVC, mean ± SD | 67.25 ± 13.27 | 67.25 ± 13.27 | t = 0.000 | 1.000 |
FEV1 in predicted value FEV1, mean ± SD | 55.33 ± 17.82 | 55.33 ± 17.82 | t = 0.000 | 1.000 |
Use of systemic glucocorticoid, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 472 (74.21) | 472 (74.21) |  |  |
 Yes | 164 (25.79) | 164 (25.79) |  |  |
Antibacterial agents, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 13 (2.04) | 13 (2.04) |  |  |
 Yes | 623 (97.96) | 623 (97.96) |  |  |
Oxygen therapy, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 126 (19.81) | 126 (19.81) |  |  |
 Yes | 510 (80.19) | 510 (80.19) |  |  |
Mechanical ventilation, n (%) |  |  | χ2 = 0.000 | 1.000 |
 No | 628 (98.74) | 628 (98.74) |  |  |
 Noninvasive ventilation | 8 (1.26) | 8 (1.26) |  |  |
Group, n (%) |  |  | χ2 = 0.000 | 1.000 |
 Non-readmission group | 449 (70.60) | 449 (70.60) |  |  |
 Readmission group | 187 (29.40) | 187 (29.40) |  |  |
BMI, mean ± SD | 23.48 ± 2.95 | 23.48 ± 2.95 | t = 0.000 | 1.000 |
CAT score, mean ± SD | 20.28 ± 5.34 | 20.28 ± 5.34 | t = 0.000 | 1.000 |