Table 1. Baseline characteristics of ARDS patients involved in the study*
Table 1
Baseline characteristics of ARDS patients involved in the study*
Characteristics | 28-day survivor (N = 2316) | 28-day death (N = 891) | P value |
| 2316 | 891 | |
Clinical parameters | | | |
Age,years | 61.03 ± 0.34 | 66.99 ± 0.51 | 0.000 |
Gender | | | |
Female,n(%) | 894(38.6) | 370(41.53) | 0.129 |
Male,n(%) | 1422(61.4) | 521(58.47) | |
Comorbidities,n(%) | | | |
COPD,n(%) | 138(5.96) | 76(8.53) | 0.009 |
CHD,n(%) | 253(10.92) | 83(9.32) | 0.183 |
Diabetes,n(%) | 610(26.34) | 204(22.90) | 0.045 |
Hypertension,n(%) | 1140(49.22) | 387(43.43) | 0.003 |
Carcinoma,n(%) | 455(19.65) | 247(27.72) | 0.000 |
CKD,n(%) | 400(17.27) | 200(22.45) | 0.001 |
Berlin classificationn,n(%) | | | 0.000 |
Mild,n(%) | 1110(47.93) | 281(31.54) | |
Moderate,n(%) | 989(42.70) | 415(46.58) | |
Severe,n(%) | 217(9.37) | 195(21.89) | |
Baseline vital data | | | |
SBP,mmHg | 88.07 ± 0.24 | 83.24 ± 0.69 | 0.000 |
DBP,mmHg | 46.34 ± 0.15 | 44.59 ± 0.45 | 0.000 |
MBP,mmHg | 55.28 ± 15.87 | 50.59 ± 27.01 | 0.000 |
Respiratory rate,beats/minute | 28.58 ± 7.35 | 30.33 ± 7.74 | 0.000 |
Heart rate,beats/minute | 107.24 ± 0.44 | 113.52 ± 0.78 | 0.535 |
Temperature,°C | 37.28 ± 0.02 | 36.94 ± 0.04 | 0.000 |
SPO2,% | 87(86,96) | 86(83,94) | 0.001 |
PEEP,cmH2O | 5(5,10) | 8(5,10) | 0.000 |
Ventilation status | | | 0.000 |
Invasive,n(%) | 1189(51.3) | 735(82.5) | |
Non-Invasive,n(%) | 1127(48.7) | 156(17.5) | |
Laboratory parameters | | | |
RBC,×10^9/L | 3.84 ± 0.01 | 3.73 ± 0.03 | 0.000 |
WBC,×10^9/L | 15.45 ± 0.20 | 18.13 ± 0.55 | 0.000 |
Platelets count,×10^9/L | 165(118,223) | 153(86,226) | 0.000 |
BE,mmol/L | -6.51 ± 0.19 | -10.18 ± 0.21 | 0.000 |
Hemoglobin,g/dL | 10.16 ± 0.05 | 9.83 ± 0.08 | 0.000 |
Lactate,mmol/L | 2.30(1.50,3.60) | 3.70(2.10,7.60) | 0.000 |
Serum Creatinine,mg/dL | 1.10(0.80,1.65) | 1.70(1.10,2.80) | 0.000 |
Glucose,mg/dL | 162(129,204) | 183(138,263) | 0.000 |
Serum urea nitrogen,mg/dL | 21(14,32) | 33(22,51) | 0.000 |
RDW,% | 14.6(13.6,15.9) | 15.5(14.2,17.3) | 0.000 |
PT,s | 15(13.2,18.7) | 18.5(14.0,24.4) | 0.000 |
PTT,s | 33.7(28.9,46.5) | 42.8(31.7,58.6) | 0.000 |
PaO2/FiO2, mmHg | 190.74 ± 1.37 | 161.51 ± 2.34 | 0.000 |
PaCO2,mmHg | 48(43,56) | 50(42,60) | 0.133 |
Scoring systems | | | |
APSIII | 53.03 ± 0.50 | 78.07 ± 1.00 | 0.000 |
SOFA | 7.45 ± 0.07 | 10.69 ± 0.14 | 0.000 |
Outcomes | | | |
Length of ICU stay,days | 6.84 ± 0.17 | 5.61 ± 0.18 | 0.000 |
Length of hospital stay,days | 14.43 ± 0.28 | 7.40 ± 0.23 | 0.000 |
Duration of MV,hours | 30.3(12.1,86.0) | 45.0(18.0,106.0) | 0.000 |
*Data are displyed as mean ± SD,median (IQR) or n(%). The total percentage may not be accurately 100% because of rounding of values . |
*Data are displyed as mean ± SD,median (IQR) or n(%). The total percentage may not be accurately 100% because of rounding of values.
“Note: Because of Table 1 is larger than one A4,so it is placed at the end of the“Acknowledgements””
A total of 3207 patients with ARDS were finally enrolled in this study,the baseline characteristics of participants according to survival situation at day 28 are shown in Table 1.Of these patients, 891 (27.8%) died within 28 days.No statistically significant difference were found between the two groups in gender,heart rate,the presence of CHD,PaCO2(all P > 0.05).Compared to the survivors,patients who died within 28 days were older and were more likely to be with moderate-severe ARDS(P = 0.000),and be mechanically ventilated(82.5% vs. 52.3%, P = 0.000),and has longer duration of MV[45.0(18.0,106.0) vs.30.3(12.07,85.90),P = 0.000].In terms of the baseline vital data, deaths had lower blood pressure, PaO2/FiO2(161.51 ± 2.34 vs. 190.74 ± 1.37,P = 0.000) but higher PEEP level[8(5, 10) vs. 5(5, 10),P = 0.000].Besides, PLT was significantly lower in non-survivors[153(86,226) vs.164.5(118,223),P = 0.000]who had higher PT,PTT,RDW,lactate,SOFA and APSIII scores(P = 0.000) compared with survivors.
Table 2
Outcomes of ARDS patients across different levels of PLT*
Outcomes | Patients | PLT ×10^9/L | P |
PLT ≤ 100 | PLT 101–200 | PLT 201–300 | PLT > 300 |
Patients, n | 3207 | 633 | 1518 | 729 | 327 | — |
ARDS | | | | | | 0.054 |
Mild,n(%) | 1391(43.37%) | 260(41.07%) | 694(45.72%) | 311(42.66%) | 126(38.53%) | |
Moderate,n(%) | 1404(43.78%) | 296(46.76%) | 644(42.42%) | 318(43.62%) | 146(44.65%) | |
Severe,n(%) | 412(12.85%) | 77(12.16%) | 180(11.86%) | 100(13.72%) | 55(16.82%) | |
28-day ICU mortality,n(%) | 891(27.78%) | 254(40.13%) | 350(23.06%) | 185(25.38%) | 102(31.19%) | 0.001 |
60-day ICU mortality,n(%) | 1002(31.24%) | 282(44.55%) | 394(25.96%) | 210(28.81%) | 116(35.47%) | 0.000 |
90-day ICU mortality,n(%) | 1062(33.12%) | 290(45.81%) | 420(27.67%) | 226(31%) | 126(38.53%) | 0.000 |
ICU-LOS ,day | 6.50 ± 7.39 | 6.64 ± 7.36 | 6.12 ± 7.38 | 6.85 ± 7.44 | 7.21 ± 7.26 | 0.031 |
Hospital-LOS,day | 12.48 ± 12.41 | 13.19 ± 14.65 | 12.15 ± 12.10 | 12.06 ± 10.93 | 13.58 ± 12.12 | 0.088 |
Duration of MV,hour | 35.53 (14.00,93.00) | 39.00 (15.00,100.50) | 30.92 (11.68,88.60) | 37.00 (16.21,92.06) | 44.00 (16,95.92) | 0.006 |
* Data are displayed as the mean ± SD,median (IQR) and n (%).
These 3207 patients were subdivided into four groups in Table 2 in accordance with baseline PLT count.No statistically significant difference in terms of the stratification of ARDS between these groups.1391 patients suffered from mild ARDS, and 1816 patients suffered from moderate to severe ARDS,the proportion of moderate ARDS patients in PLT ≤ 100 group was higher than that compared with other three groups (P > 0.05).Overall,patients with lower PLT(PLT ≤ 100)have the highest 28-day mortality(P = 0.001),the similar trends were datected in 60-day and 90-day mortality (all P = 0.000). Furthermore, ICU-LOS and duration of MV in patients with PLT > 300 are longer compared to all other three groups(P = 0.031 and P = 0.006).
The Kaplan–Meier Survival estimates for 28-,60-,90-day mortality stratified by PLT levels.
Kaplan-Meier curves constructed for 28-,60-,90-day mortality of these four PLT stratas among ARDS patients also showed significantly worse survival among patients in the PLT ≤ 100 group (Fig. 2)(all logrank P = 0.001).
Table 3
COX regression analysis for 28-day morality in different models
Status | Model 1* | Model 2† | Model 3‡ |
HR (95%CI) | P-value | HR (95%CI) | P-value | HR (95%CI) | P-value |
Continuous | | | | | | |
PLT (×10^9) | 0.999 (0.998-1.000) | 0.002 | 0.999 (0.998-1.000) | 0.002 | 0.999 (0.998–0.999) | 0.001 |
Categories | | | | | | |
PLT ≤ 100 | 1(Ref) | NA | 1(Ref) | NA | 1(Ref) | NA |
PLT 101–200 | 0.520 (0.442–0.611) | 0.000 | 0.517 (0.440–0.608) | 0.000 | 0.522 (0.443–0.613) | 0.000 |
PLT 201–300 | 0.579 (0.479-0.700) | 0.000 | 0.585 (0.484–0.707) | 0.000 | 0.572 (0.472–0.692) | 0.000 |
PLT > 300 | 0.717 (0.570–0.902) | 0.005 | 0.702 (0.557–0.883) | 0.003 | 0.681 (0.541–0.859) | 0.001 |
*Model 1 No covariates were adjusted.
†Model 2 Adjusted for age, sex.
‡Model 3 Adjusted for age,sex,COPD, CHD, diabetes,hypertension, carcinoma,CKD.
As demonstrates in the Table 3,at the unadjusted Cox proportional hazards regression model 1,PLT ≤ 100×10^9 was associated with significantly increased risk for 28-day mortality [HR for PLT 101–200×10^9,PLT 201–300×10^9,PLT > 300×10^9 were 0.520(95%CI,0.433–0.613,P = 0.000), 0.579(95%CI,0.479-0.700,P = 0.000),0.717(95%CI,0.570–0.902,P = 0.005) respectively].After further adjustment for age,sex,as shown in model 2,the adjusted hazard ratios (aHR) for PLT 101–200×10^9,PLT 201–300×10^9,PLT > 300×10^9 were 0.517(95%CI,0.440–0.608,P = 0.000),0.585(95%CI,0.484–0.707,P = 0.000),0.702(95%CI,0.557–0.883,P = 0.003) respectively.In the fully adjusted models,PLT ≤ 100×10^9 remained consistently correlate with higher 28-day mortality in ARDS patients[aHR for PLT 101–200×10^9,PLT 201–300×10^9,PLT > 300×10^9 were 0.522(95%CI,0.443–0.613,P = 0.000), 0.572(95%CI,0.472–0.692,P = 0.000), 0.681(95%CI,0.541–0.859,P = 0.001) respectively].
Forest plot of association between PLT level and 28-day mortality in subgroups.
In our cohort,subgroup analysis was performed and it was observed that in most subgroups, the PLT ≤ 100×10^9 group was associated with a higher risk of 28-day mortality. Consistent correlation were retained in various subgrous stratified by age, gender, carcinoma,diabetes,hypertension,,and CKD.For participants with CHD, the risk of mortality increased in both PLT 201–300×10^9 group and PLT > 300×10^9 group compared with PLT ≤ 100×10^9[HR for PLT 201–300×10^9 and PLT > 300,respectively:1.490(95%CI,0.760–2.918,P = 0.245),1.964(95%CI,0.774,4.983,P = 0.155)],similar interactions were obtained between PLT 201–300×10^9 and the presence of COPD[HR = 1.059(95%CI,0.545–2.060,P = 0.865)],but the differences in both subgroups were not statistically significant (P > 0.05 for interaction)(Fig. 3).
As shown in Fig. 4,ROC curve analyses were further conducted to evaluate the predictive value of the PLT,RDW,PT,and PTT. It was demonstated that the area under the receiver operating characteristic curve of the PLT to predict 28-day mortality was 0.55 (95% CI,0.53–0.57,P < 0.0001). PT showed the largest area under the curve(AUC = 0.66,95%CI,0.64–0.68,P < 0.0001), followed by PTT(AUC = 0.64 ,95%CI,0.62–0.66,P < 0.0001),RDW(AUC = 0.63,95%CI,0.61–0.66,P < 0.0001) and then platelet count.