Table 1.
Demographic and clinical characteristics of the study population ≥70 years old by type of respiratory support.a
| Variables | All patients (N = 1525) | Non-invasive respiratory support (N = 554) | Invasive mechanical ventilation (N = 971) | p-value |
|---|---|---|---|---|
| Age, median (Q1; Q3), years | 74 (72; 77) | 74 (72; 78) | 74 (72; 76) | 0.055 |
| Age ≥80 years, n (%) | 136 (9) | 84 (15) | 52 (5) | <0.001 |
| Male sex, n (%) | 1037 (68) | 372 (67) | 665 (69) | 0.639 |
| BMI, median (Q1; Q3), kg/m2 | 27.8 (25.5; 31.1) | 28 (25.3; 31) | 27.8 (25.6; 31.1) | 0.810 |
| BMI, n (%) | 0.679 | |||
| Underweight (<18.5 kg/m2) | 8 (1) | 4 (1) | 4 (0.5) | – |
| Normal weight (≥18.5 - <25 kg/m2) | 268 (20) | 103 (22) | 165 (20) | – |
| Pre-Obese (≥25 - <30 kg/m2) | 636 (48) | 227 (47) | 409 (48) | – |
| Obese (≥30 kg/m2) | 410 (31) | 144 (30) | 266 (32) | – |
| Comorbidities, n (%) | ||||
| Active smoker | 60 (4) | 20 (4) | 40 (5) | 0.535 |
| Hypertension | 1063 (70) | 385 (69) | 678 (70) | 0.869 |
| Diabetes mellitus | 501 (33) | 187 (34) | 314 (32) | 0.571 |
| Dyslipidemia | 561 (37) | 206 (37) | 355 (37) | 0.822 |
| Chronic heart disease | 330 (22) | 134 (24) | 196 (20) | 0.069 |
| Chronic liver disease | 44 (3) | 13 (2) | 31 (3) | 0.343 |
| Chronic lung disease | 273 (18) | 116 (21) | 157 (16) | 0.019 |
| Chronic renal failure | 157 (10) | 74 (13) | 83 (9) | 0.003 |
| Immunosuppression | 51 (3) | 31 (6) | 20 (2) | <0.001 |
| Nursing-home, n (%) | 39 (3) | 19 (3) | 20 (2) | 0.117 |
| Previous 30 days admission, n (%) | 69 (5) | 28 (5) | 41 (4) | 0.450 |
| Days from first symptoms to hospital admission, median (Q1; Q3) | 7 (4; 9) | 6 (4; 9) | 7 (4; 9) | 0.692 |
| Days from hospital admission to ICU admission, median (Q1; Q3) | 2 (0; 4) | 2 (0; 5) | 2 (0; 4) | 0.002 |
| Symptoms at hospital admission, n (%) | ||||
| Fever | 1168 (78) | 417 (76) | 751 (79) | 0.120 |
| Dry cough | 871 (58) | 312 (57) | 559 (59) | 0.461 |
| Productive cough | 219 (15) | 82 (15) | 137 (14) | 0.781 |
| Dyspnoea | 1043 (69) | 373 (68) | 670 (70) | 0.309 |
| Fatigue | 629 (42) | 232 (42) | 397 (42) | 0.899 |
| Muscle pain | 381 (26) | 134 (25) | 247 (26) | 0.485 |
| Diarrhoea | 277 (18) | 99 (18) | 178 (19) | 0.746 |
| Confusion | 107 (7) | 24 (4) | 83 (9) | 0.002 |
| Characteristics on ICU admission | ||||
| Glasgow Coma Scale, median (Q1; Q3) | 15 (15; 15) | 15 (15; 15) | 15 (14; 15) | <0.001 |
| APACHE-II score, median (Q1; Q3) | 14 (12; 18) | 13 (11; 15) | 15 (12; 21) | <0.001 |
| APACHE-II APS component, median (Q1; Q3) | 8 (6; 12) | 7 (5; 9) | 10 (6; 15) | <0.001 |
| SOFA score, median (Q1; Q3) | 5 (4; 8) | 4 (3; 5) | 7 (4; 8) | <0.001 |
| SOFA hemodynamic component, median (Q1; Q3) | 0 (0; 4) | 0 (0; 0) | 4 (0; 4) | <0.001 |
| SOFA renal component, median (Q1; Q3) | 0 (0, 1) | 0 (0, 0) | 0 (0, 1) | 0.005 |
| Temperature, median (Q1; Q3), °C | 36.5 (36; 37.3) | 36.5 (36; 37.1) | 36.6 (36; 37.5) | 0.020 |
| Respiratory rate, median (Q1; Q3), breaths per min | 25 (20; 30) | 27 (23; 32) | 24 (20; 30) | <0.001 |
| Arterial blood gasses at ICU admission | ||||
| PaO2/FiO2 ratio, median (Q1; Q3) | 107.8 (79; 154.1) | 96 (73.8; 141) | 113.8 (82; 162) | <0.001 |
| PaO2/FiO2 ratio, n (%) | <0.001 | |||
| Severe (<100) | 553 (45) | 202 (54) | 351 (42) | <0.001 |
| Moderate (≥100 - <200) | 504 (41) | 146 (39) | 358 (42) | 0.233 |
| Mild (≥200 - <300) | 126 (10) | 20 (5) | 106 (13) | <0.001 |
| No ARDS (≥300) | 39 (3) | 9 (2) | 30 (4) | 0.285 |
| pH, median (Q1; Q3) | 7.40 (7.33; 7.45) | 7.45 (7.41; 7.47) | 7.36 (7.29; 7.43) | <0.001 |
| PaCO2, median (Q1; Q3), mmHg | 40 (34; 47) | 35.3 (32; 40) | 42.7 (36; 50) | <0.001 |
| Laboratory findings at ICU admission | ||||
| Haemoglobin, median (Q1; Q3), g/dL | 13 (11.6; 14.2) | 13.3 (11.8; 14.3) | 13 (11.5; 14.1) | 0.044 |
| Leucocyte count, median (Q1; Q3), 109/L | 9.5 (6.8; 13.1) | 8.5 (6.1; 11.6) | 10.1 (7.4; 13.9) | <0.001 |
| Lymphocyte count, median (Q1; Q3), 109/L | 0.6 (0.4; 0.88) | 0.62 (0.45; 0.9) | 0.6 (0.4; 0.87) | 0.040 |
| Neutrophil count, median (Q1; Q3), 109/L | 8.2 (5.6; 11.7) | 7.3 (5.1; 10) | 8.8 (6.1; 12.7) | <0.001 |
| Neutrophil-to-lymphocyte ratio, median (Q1; Q3) | 13 (7.8; 22) | 11.1 (6.6; 18) | 14.7 (8.8; 24.8) | <0.001 |
| Monocyte count, median (Q1; Q3), 109/L | 0.37 (0.2; 0.57) | 0.34 (0.2; 0.55) | 0.39 (0.21; 0.59) | 0.096 |
| Platelet count, median (Q1; Q3), 109/L | 224 (172; 291) | 220 (173; 293) | 225 (172; 290) | 0.713 |
| D-dimers, median (Q1; Q3), ng/mL | 1278 (697; 3800) | 1049 (580; 2250) | 1525 (780; 5131) | <0.001 |
| Ferritin, median (Q1; Q3), ng/mL | 1033 (578; 1714) | 977 (528; 1643) | 1095 (620; 1750) | 0.256 |
| C-reactive protein, median (Q1; Q3), mg/L | 138 (69; 230) | 109 (61; 197) | 152 (73; 249) | <0.001 |
| C-reactive protein ≥150 mg/L, n (%) | 652 (46) | 198 (38) | 454 (51) | <0.001 |
| C-reactive protein-to-lymphocyte ratio, median (Q1; Q3) | 213 (92; 395) | 174 (71; 343) | 237 (106; 429) | <0.001 |
| IL-6, median (Q1; Q3), pg/mL | 94.2 (37; 202) | 82 (27.5; 175.8) | 105 (39.3; 222) | 0.069 |
| Serum creatinine, median (Q1; Q3), mg/dL | 0.91 (0.71; 1.2) | 0.86 (0.7; 1.12) | 0.95 (0.73; 1.24) | 0.001 |
| LDH, median (Q1; Q3), U/L | 485 (377; 657) | 424 (342; 554) | 540 (411; 709) | <0.001 |
| Evolution of type of respiratory support, n (%)a | – | |||
| Non-invasive respiratory support at ICU admission & Conventional oxygen therapy at day 3 of ICU admission or end of MV | 15 (1) | 15 (3) | 0 (0) | – |
| Non-invasive respiratory support at ICU admission & Non-invasive respiratory support at day 3 of ICU admission or end of MV | 214 (14) | 214 (41) | 0 (0) | – |
| Non-invasive respiratory support at ICU admission & Invasive MV at day 3 of ICU admission or end of MV | 288 (19) | 288 (56) | 0 (0) | – |
| Invasive MV at ICU admission & Conventional oxygen therapy, Non-invasive respiratory support or Invasive MV at day 3 or end of MV | 971 (65) | 0 (0) | 971 (100) | – |
| Ventilatory setting and pulmonary mechanics at MV start | ||||
| Tidal volume/PBW, median (Q1; Q3), mL/kg | 7.1 (6.4; 7.9) | 6.9 (6.3; 7.8) | 7.1 (6.5; 7.9) | 0.024 |
| Respiratory rate, median (Q1; Q3), breaths per min | 20 (18; 24) | 21 (18; 24) | 20 (18; 24) | 0.862 |
| PEEP, median (Q1; Q3), cmH2O | 12 (10; 14) | 12 (10; 14) | 12 (10; 14) | 0.064 |
| FiO2, median (Q1; Q3),% | 80 (60; 100) | 80 (60; 100) | 80 (60; 100) | 0.291 |
| Peak inspiratory pressure, median (Q1; Q3), cmH2O | 31 (28; 35) | 30 (28; 34) | 31 (28; 35) | 0.392 |
| End-inspiratory plateau pressure, median (Q1; Q3), cmH2O | 24 (21; 28) | 24 (21; 28) | 25 (21; 28) | 0.323 |
| Driving pressure, median (Q1; Q3), cmH2Ob | 12 (10; 15) | 12 (9; 15) | 12 (10; 15) | 0.972 |
| Compliance, median (Q1; Q3), mL/cmH2Oc | 35.7 (28; 46.2) | 35.2 (27.6; 43.3) | 35.7 (28.2; 47.2) | 0.443 |
| Ventilatory ratio, median (Q1; Q3)d | 1.69 (1.38; 2.12) | 1.67 (1.37; 2.03) | 1.7 (1.39; 2.15) | 0.416 |
| Position, n (%) | 0.044 | |||
| Supine | 630 (62) | 182 (87) | 448 (60) | 0.029 |
| Prone | 362 (36) | 83 (31) | 279 (37) | 0.053 |
| Lateral | 12 (1) | 4 (1) | 8 (1) | 0.529 |
| Other | 11 (1) | 0 (0) | 11 (1) | 0.071 |
| Septic shock at ICU admissione | 125 (9) | 6 (1) | 119 (15) | <0.001 |
Abbreviations: ICU indicates intensive care unit; Q1, first quartile; Q3, third quartile; BMI, body mass index; APACHE, acute physiology and chronic health evaluation; APS, acute physiology score; SOFA, sequential organ failure assessment; PaO2, partial pressure of arterial oxygen; FiO2, fraction of inspired oxygen; LDH, lactate dehydrogenase; MV, mechanical ventilation. Percentages calculated on non-missing data. p-values marked in bold indicate numbers that are statistically significant on the 95% confidence limit.
a
Patients who received non-invasive respiratory support but needed intubation were included in the invasive mechanical ventilation group.
b
Defined as plateau pressure – PEEP.
c
Defined as tidal volume/(plateau pressure – PEEP).
d
Defined as (minute ventilation × PaCO2) − (PBW × 100 × 37.5).
e
Criteria for the Sepsis-3 definition of septic shock include vasopressor treatment and a lactate concentration >2 mmol/L.