Background
Material and methods
Data collection
Diagnosis of SARS-CoV-2
Construction of the symptom diagnostic scale
Statistical analysis
Results
Baseline characteristics of patients with SARS-CoV-2 infection
Variable | Total (n = 2137) | Positive SARS CoV2 patients (n = 1148) | Negative SARS CoV2 patients (n = 989) | P Value |
---|---|---|---|---|
Age, mean ± SD | 45.93 ± 15.34 | 48.60 ± 15.6 | 42.82 ± 14.42 | < 0.001a |
Gender, n (%) | ||||
Female | 1034 (48.3) | 508 (44.2) | 526 (53.1) | < 0.001b |
Male | 1103 (51.6) | 640 (55.7) | 463 (46.8) | |
Vital sings | ||||
Temperature (C°), median (IQR) | 36.4 (36.2) | 36.4 (36.2–36.8) | 36.4 (36.2–36.7) | 0.01c |
Hear rate (bpm), median (IQR) | 90 (78–103) | 94 (82–108) | 87 (75–99) | < 0.001c |
Respiratory rate (bpm), median (IQR) | 22 (20–24) | 22 (20–24) | 22 (20–24) | < 0.001c |
SBP (mmHg), mean ± SD | 191.2 ± 19.1 | 131.3 ± 18.6 | 131.1 ± 19.7 | 0.78a |
DBP (mmHg), mean ± SD | 76.6 ± 20.0 | 76.7 ± 24.4 | 76.5 ± 13.2 | 0.82a |
Oxygen saturation (%), median (IQR) | 94 (90–95) | 93 (85–95) | 95 (93–96) | < 0.001c |
Weight (kg), median (IQR) | 74 (63–85) | 75 (64–86) | 72 (62–84) | < 0.001c |
Height (m), mean ± SD | 1.63 ± 0.09 | 1.62 ± 0.09 | 1.63 ± 0.09 | 0.42a |
BMI (kg/m2), median (IQR) | 27.8 (24.76–31.21) | 28.4 (25.28–31.74) | 27.3 (24.11–30.46) | < 0.001c |
Oxygen saturation < 93%, n (%) | 170 (7.96) | 127 (11.06) | 43 (4.35) | < 0.001 a |
General symptoms, n (%) | ||||
Fever | 891 (41.69) | 615 (53.57) | 276 (27.91) | < 0.001b |
Cough | 1284 (60.08) | 816 (71.08) | 468 (47.32) | < 0.001 b |
Odynophagia | 1058 (49.51) | 574 (50.00) | 484 (48.94) | 0.62 b |
Thoracic pain | 708 (33.13) | 445 (38.76) | 263 (26.59) | < 0.001 b |
Asthenia | 1354 (63.36) | 789 (68.73) | 565 (57.13) | < 0.001 b |
Myalgia | 1188 (55.59) | 705 (61.41) | 483 (48.84) | < 0.001 b |
Rhinorrhea | 652 (30.51) | 373 (32.49) | 279 (28.21) | 0.03 b |
Headache | 1287 (60.22) | 709 (61.76) | 578 (58.44) | 0.11 b |
Anosmia | 410 (19.19) | 309 (26.92) | 101 (10.21) | < 0.001 b |
Conjunctivitis | 304 (14.23) | 162 (14.11) | 142 (14.36) | 0.87 b |
Dyspnea | 788 (36.87) | 550 (47.91) | 238 (24.06) | < 0.001 b |
Comorbidities, n (%) | ||||
COPD | 29 (1.36) | 21 (1.83) | 8 (0.81) | 0.04 b |
Type 2 diabetes mellitus | 326 (15.26) | 218 (18.99) | 108 (10.92) | < 0.001 b |
Hypertension | 447 (20.92) | 285 (24.83) | 162 (16.38) | < 0.001 b |
Chronic Kidney disease | 84 (3.93) | 54 (4.78) | 30 (3.03) | 0.04 b |
Immunodeficiency | 65 (3.04) | 34 (2.96) | 31 (3.13) | 0.81 b |
Hepatopathy | 11 (0.51) | 8 (0.70) | 3 (0.30) | 0.20 b |
Obesity | 1148 (57.72) | 537 (60.47) | 611 (48.92) | < 0.001 b |
Symptoms associated with SARS-CoV-2 infection
Comorbidities in the SARS-CoV-2 positive patient group
Stratified and multivariate analysis of the symptomatology of SARS-CoV-2 positive patients
Stratified analysis | Multivariate analysisb | |||||
---|---|---|---|---|---|---|
Variable | OR | 95% CI | P valea | OR | 95% CI | P valea |
Fever | 2.98 | 2.47–3.58 | < 0.001 | 1.96 | 1.58–2.41 | < 0.001 |
Cough | 2.73 | 2.27–3.28 | < 0.001 | 1.95 | 1.58–2.41 | < 0.001 |
Odynophagia | 1.04 | 0.87–1.24 | 0.62 | |||
Thoracic pain | 1.74 | 1.44–2.11 | < 0.001 | |||
Asthenia | 1.64 | 1.37–1.97 | < 0.001 | |||
Myalgia | 1.66 | 1.39–1.98 | < 0.001 | 1.25 | 1.00–1.56 | 0.04 |
Headache | 1.14 | 0.96–1.37 | 0.11 | |||
Rhinorrhea | 1.22 | 1.01–1.48 | 0.03 | |||
Anosmia | 3.23 | 2.52–4.17 | < 0.001 | 2.96 | 2.27–3.87 | < 0.001 |
Conjunctivitis | 0.98 | 0.76–1.26 | 0.87 | |||
Dyspnea | 2.90 | 2.39–3.51 | < 0.001 | 1.48 | 1.17–1.87 | 0.001 |
O2S < 93 | 2.73 | 1.89–4.00 | < 0.001 | 1.56 | 1.17–1.87 | 0.001 |
Fever and anosmia | 4.30 | 3.05–6.07 | < 0.001 | |||
Cough and fever | 4.44 | 3.61–5.47 | < 0.001 | 2.79 | 2.12–3.69 | < 0.001 |
Cough and anosmia | 3.45 | 2.61–4.56 | < 0.001 | 2.48 | 1.65–3.74 | < 0.001 |
Fever and dyspnea | 3.72 | 2.96–4.67 | < 0.001 | |||
Anosmia and dyspnea | 3.43 | 2.42–4.86 | < 0.001 | |||
Fever, cough, anosmia, dyspnea, O2S < 93 | 12.19 | 1.60–92.92 | < 0.001 |
Diagnostic performance of the symptomatology, as a tool for SARS-CoV-2 identification
Symptoms | Sensitivity | Specificity | PPV % | NPV % | LR+ | LR- | Accuracy | Pa | AUC |
---|---|---|---|---|---|---|---|---|---|
Fever % (95% CI) | 53.57 [50.64–56.49] | 72.09 [69.18–74.87] | 69.02 [66.54–71.40] | 57.22 [55.42–59.01] | 1.92 [1.71–2.15] | 0.64 [0.60–0.69] | 62.14 [60.05–64.21] | < 0.001 | 0.62 0.60–0.64 |
Cough % (95% CI) | 71.08 [68.36–73.69] | 52.68 [49.51–55.83] | 63.55 [61.79–65.28] | 61.08 [58.48–63.62] | 1.50 [1.39–1.62] | 0.55 [0.49–0.61] | 62.56 [60.47–64.62] | < 0.001 | 0.61 0.59–0.63 |
Odynophagia % (95% CI) | 50.00 [47.07–52.93] | 51.06 [47.9–54.22] | 54.25 [52.11–56.38] | 46.80 [44.72–48.9] | 1.02 [0.94–1.11] | 0.98 [0.90–1.07] | 50.46 [48.35–52.63] | 0.62 | 0.5 0.48–0.52 |
Thoracic pain % (95% CI) | 38.76 [35.93–41.65] | 73.41 [70.54–76.14] | 62.85 [59.85–65.76] | 50.80 [49.32–52.29] | 1.46 [1.28–1.65] | 0.83 [0.79–0.89] | 54.8 [52.66–56.92] | < 0.001 | 0.56 0.54–0.58 |
Asthenia % (95% CI) | 68.73 [65.96–71.40] | 42.87 [39.76–46.02] | 58.27 [56.64–59.88] | 54.15 [51.36–56.91] | 1.20 [1.13–1.29] | 0.73 [0.65–0.82] | 56.76 [54.63–58.88] | < 0.001 | 0.55 0.53–0.57 |
Myalgia % (95% CI) | 61.41 [58.53–64.24] | 51.16 [48.00–54.32] | 59.34 [57.43–61.22] | 53.32 [50.95–55.68] | 1.26 [1.16–1.36] | 0.75 [0.69–0.83] | 56.67 [54.54–58.78] | < 0.001 | 0.56 0.54–0.58 |
Headache % (95% CI) | 61.76 [58.88–64.58] | 41.56 [38.46–44.70] | 55.09 [53.36–56.08] | 48.35 [45.76–50.96] | 1.06 [0.99–1.13] | 0.92 [0.83–1.02] | 52.41 [50.27–54.55] | 0.11 | 0.51 0.49–0.53 |
Rhinorrhea % (95% CI) | 32.49 [29.79–35.29] | 71.79 [68.87–74.58] | 57.21 [54.01–60.35] | 47.81 [46.42–49.21] | 1.15 [1.01–1.31] | 0.94 [0.89–0.99] | 50.68 [48.54–52.82] | 0.03 | 0.52 0.50–0.54 |
Anosmia % (95% CI) | 26.92 [24.37–29.58] | 89.79 [87.73–91.60] | 75.37 [71.31–79.02] | 51.42 [50.40–52.44] | 2.64 [2.14–3.24] | 0.81 [0.78–0.85] | 56.01 [53.88–58.13] | < 0.001 | 0.58 0.56–0.59 |
Conjunctivitis % (95% CI) | 14.11 [12.15–16.26] | 85.64 [83.3–87.77] | 53.29 [48.08–58.43] | 46.21 [45.35–47.07] | 0.98 [0.80–1.21] | 1.00 [0.97–1.04] | 47.22 [45.08–49.36] | 0.87 | 0.49 0.48–0.51 |
Dyspnea % (95% CI) | 47.91 [44.98–50.84] | 75.94 [73.15–78.57] | 69.80 [67.07–72.39] | 55.67 [54.05–57.28] | 1.99 [1.76–2.26] | 0.69 [0.64–0.73] | 60.88 [58.77–62.96] | < 0.001 | 0.61 0.59–0.63 |
O2S < 93% (95% CI) | 11.06 [9.31–13.02] | 95.65 [94.19–96.84] | 74.71 [67.87–80.51] | 48.09 [47.49–48.70] | 2.54 [1.82–3.56] | 0.93 [0.91–0.95] | 50.21 [48.07–52.35] | < 0.001 | 0.53 0.52–0.54 |
Combination of symptoms | |||||||||
Fever and anosmia % (95% CI) | 16.38 [14.28–18.65] | 95.65 [94.19–96.84] | 81.39 [76.04–85.76] | 49.63 [48.91–50.35] | 3.77 [2.73–5.19] | 0.87 [0.85–0.90] | 53.07 [50.92–55.20] | < 0.001 | 0.56 0.54–0.57 |
Cough and fever, % (95% CI) | 44.86 [41.96–47.79] | 84.53 [82.12–86.73] | 77.10 [74.16–79.78] | 56.91 [55.47–58.34] | 2.89 [2.47–3.40] | 0.65 [0.62–0.69] | 63.22 [61.13–65.27] | < 0.001 | 0.64 0.62–0.66 |
Cough and anosmia % (95% CI) | 21.34 [19.00–23.83] | 92.72 [90.92–94.26] | 77.29 [72.63–81.35] | 50.38 [48.51–51.26] | 2.93 [2.29–3.76] | 0.85 [0.82–0.88] | 54.38 [52.24–56.50] | < 0.001 | 0.57 0.55–0.58 |
Fever and dyspnea, % (95% CI) | 33.54 [30.81–33.35] | 88.07 [85.88–90.02] | 76.54 [73.00–79.75] | 53.30 [52.13–54.47] | 2.81 [2.33–3.39] | 0.75 [0.72–0.79] | 58.77 [56.65–60.87] | < 0.001 | 0.60 0.59–0.62 |
Anosmia and dyspnea, % (95% CI) | 13.50 [11.58–15.62] | 95.65 [94.19–96.84] | 78.28 [72.22–83.33] | 48.79 [48.13–49.45] | 3.11 [2.24–4.31] | 0.90 [0.88–0.93] | 51.52 [49.38–53.66] | < 0.001 | 0.54 0.53–0.55 |
Fever, cough, anosmia, dyspnea, O2S < 93, % (95% CI) | 1.22 [0.67–2.04] | 99.90 [94.44–100] | 93.33 [64.84–99.07] | 46.56 [46.39–46.73] | 12.06 [1.59–91.56] | 0.99 [0.98–1] | 46.89 [44.75–49.03] | 0.002 | 0.50 0.50–0.50 |
Performance of the symptoms scale as a diagnostic instrument for SARS-CoV-2
Numbers of symptoms | Sensitivity % | Specificity % | PPV % | NPV % | LR+ | LR- | Accuracy | Pa | AUC |
---|---|---|---|---|---|---|---|---|---|
≥ 2 symptoms [95% CI] | 83.45 [81.17–85.55] | 32.86 [29.94–35.89] | 59.06 [57.83–60.28] | 63.11 [59.37–66.69] | 1.24 [1.18–1.31] | 0.50 [0.43–0.59] | 60.04 [57.92–62.2] | < 0.001 | 0.58 [0.56–0.60] |
≥ 3 symptoms [95% CI] | 67.39 [64.59–70.10] | 58.24 [55.10–61.34] | 65.18 [63.25–67.06] | 60.63 [58.26–62.96] | 1.61 [1.48–1.76] | 0.56 [0.51–0.62] | 63.16 [61.07–65.21] | < 0.001 | 0.62 [0.60–0.64] |
≥ 4 symptoms [95% CI] | 49.69 [46.76–52.63] | 80.08 [77.45–82.53] | 76.32 [71.60–76.86] | 57.85 [56.25–59.44] | 2.49 [2.17–2.86] | 0.63 [0.59–0.67] | 63.76 [61.68–65.81] | < 0.001 | 0.64 [0.62–0.66] |
≥ 5 symptoms % (95% CI) | 27.99 [25.4–30.68] | 93.23 [91.48–94.71] | 82.73 [78.88–86.01] | 52.75 [51.75–53.74] | 4.13 [3.22–5.30] | 0.77 [0.74–0.80] | 58.19 [56.07–60.30] | < 0.001 | 0.60 [0.58–0.62] |
≥ 6 symptoms % (95% CI) | 11.16 [9.40–13.13] | 97.67 [96.53–98.52] | 84.77 [78.26–89.59] | 48.66 [48.10–49.23] | 4.8 [3.10–7.42] | 0.91 [0.89–0.93] | 51.22 [49.07–53.36] | < 0.001 | 0.54 [0.52–0.56] |
Stratified and multivariate analysis of the symptoms scale for the diagnosis of SARS-CoV-2 with positive patients
Stratified analysis | Multivariate analysisb | |||||
---|---|---|---|---|---|---|
Numbers of symptoms | OR | 95% CI | P a | OR | 95% CI | P a |
≥ 2 symptoms | 2.46 | 2.00–3.04 | < 0.001 | 1.28 | 0.98–1.67 | 0.06 |
≥ 3 symptoms | 2.88 | 2.40–3.45 | < 0.001 | 1.23 | 0.93–1.62 | 0.13 |
≥ 4 symptoms | 3.97 | 3.25–4.84 | < 0.001 | 2.01 | 1.15–2.69 | < 0.001 |
≥ 5 symptoms | 5.34 | 4.02–7.17 | < 0.001 | 2.16 | 1.45–3.20 | < 0.001 |
≥ 6 symptoms | 5.27 | 3.32–8.68 | < 0.001 | 1.22 | 0.70–2.14 | 0.46 |