Table 1.
Baseline Characteristics of Patients with COPD and Correlation Coefficients with mCRP and pCRP
| Characteristics | Patients with COPD (N = 38) | Non-COPD Control Persons (N = 18) | Correlation with mCRP (rho) | Correlation with pCRP (rho) |
|---|---|---|---|---|
| Age (y) | 65 ± 6 | 65 ± 6 | 0.162 | 0.122 |
| Sex (N [%male]) | 28 [74] | 14 [78] | – | – |
| BMI (kg/m2) | 25.8 ± 4.7 | 26.4 ± 3.0 | -0.200 | 0.040 |
| BMI ≥ 30 kg/m2 (N [%]) | 7 [18] | 2 [11] | – | – |
| Fat mass index (kg/m2)† | 7.2 (5.4–9.1) | 6.6 (6.1–8.5) | -0.281 | -0.010 |
| Lean mass index (kg/m2)† | 18.6 (15.7–20.1) | 19.4 (17.7–20.0) | -0.115 | 0.000 |
| FEV1 (%predicted) | 55.6 ± 14.0* | 104.8 ± 10.2 | 0.213 | -0.017 |
| FEV1/FVC (%) | 50.5 ± 11.9* | 73.2 ± 6.1 | 0.189 | -0.259 |
| TLC (%predicted) | 117.3 ± 16.2 | – | -0.134 | -0.078 |
| RV (%predicted) | 177.7 ± 40.6 | – | -0.244 | -0.293 |
| DLCO SB (%predicted) | 52.3 (44.6–63.3) | – | 0.085 | -0.121 |
| GOLD Stage: I, II, III, IV (N [%]) | 3 [8], 21 [55], 13 [34], 1 [3] | – | – | – |
| Hospitalization in last year: 0, 1, >1 (N [%]) |
32 [84], 5 [13], 1 [3] | 18 [100], 0 [0], 0 [0] | – | – |
| Smoking: NS, EX, S (N [%]) | 1 [3], 21 [55], 16 [42]* | 7 [39], 11 [61], 0 [0] | – | – |
| mMRC (points) | 1 (0–1)* | 0 (0–0) | -0.322 | -0.054 |
| CAT (points) | 14 ± 6* | 5 ± 4 | -0.271 | -0.152 |
| CCI (points) | 2 (1–3)* | 0 (0–1) | -0.274 | 0.086 |
| 6MWD (m) | 505 ± 76* | 664 ± 64 | 0.193 | -0.012 |
| 6MWD < 357 m (N [%]) | 0 [0] | 0 [0] | – | – |
| PA (steps/day)‡ | 4499 (3402–8198)* | 7024 (6505–9198) | 0.004 | -0.128 |
| PA < 5000 steps/day (N [%])‡ | 19 [56]* | 1 [6] | – | – |
| mCRP (mg/L) | 0.66 (0.38–1.03)* | 0 (0–0.29) | – | 0.076 |
| pCRP (mg/L) | 1.85 (1.05–4.20)* | 0.75 (0.30–2.18) | 0.076 | – |
Notes: rho = Spearman correlation coefficient, rho < 0.3 = weak correlation; rho = 0.3–0.7 = moderate correlation; rho > 0.7 = strong correlation. *Significant P < 0.05; †Sample size is n = 37 patients with COPD for this outcome; ‡Sample size is n = 34 patients with COPD for this outcome.
Abbreviations: COPD, Chronic Obstructive Pulmonary Disease; mCRP, monomeric C-reactive Protein; pCRP, native pentameric C-reactive Protein; BMI, Body Mass Index; FEV1, Forced Expired Volume in one second; FVC, Forced Vital Capacity; TLC, Total Lung Capacity; RV, Residual Volume; DLCO SB, Diffusion capacity of the Lung for Carbon Monoxide Single Breath; GOLD, Global initiative for Chronic Obstructive Lung Disease; NS, Non-Smoker; EX, EX-smoker; S, Smoker; mMRC, modified Medical Research Council scale for dyspnea; CAT, COPD Assessment Test; CCI, Charlson Comorbidity Index; 6MWD, Six-Minute Walking Distance; PA, Physical Activity. y, years; N, number; kg, kilogram; m, meter; %, percentage; mg/L, milligram per litre.