Table 4

Predictors of radiographic pneumonia.

All patients (n = 364) n (%)Pneumonia (n = 48) n (%)Non-pneumonic LRTI (n = 316) n (%)P-valueSensitivitySpecificityPPVNPVCrude OR (95% CI)Adjusted OR (95% CI)
Vital signs
 Heart rate ≥100 BPM43 (12)12 (25)31 (10)0.0060.250.900.280.893.06 (1.45 to 6.49)1.93 (0.83 to 4.51)
 Respiratory rate ≥22 breaths/min89 (24)24 (50)65 (21)<0.0010.500.790.270.913.86 (2.06 to 7.24)1.93 (0.94 to 3.99)
 SATO2 ≤95%86/357 (20)25 (52)61/309 (20)<0.0010.520.800.290.924.42 (2.35 to 8.31)2.87 (1.42 to 5.80)
 Temperature ≥38°C47/354 (13)14/47 (30)33/307 (11)0.0020.300.890.300.893.52 (1.71 to 7.25)1.61 (0.70 to 3.72)
Biochemical markers of inflammation
 CRP ≥20 mg/l145/363 (40)35 (73)110/315 (35)<0.0010.730.650.240.945.02 (2.59 to 9.88)2.83 (1.33 to 6.04)
 Leukocyte count ≥10 million/ml86/362 (24)22 (46)64/314 (20)<0.0010.460.800.260.913.31 (1.76 to 6.21)1.33 (0.62 to 2.82)
GP's diagnosis
 Clinical pneumonia122/345 (35)28/47 (60)94/298 (32)<0.0010.600.680.230.913.20 (1.70 to 6.02)
 Clinical pneumonia & CRP ≥20 mg/l71/344 (21)23/47 (49)48/297 (16)<0.0010.490.840.320.914.97 (2.60 to 9.52)
 Clinical pneumonia & SATO2 ≤95%38/338 (11)15/47 (32)23/291 (8)<0.0010.320.920.390.895.46 (2.59 to 11.52)
 Clinical pneumonia or CRP ≥20 mg/l192/344 (56)39/47 (83)153/297 (52)<0.0010.830.480.200.954.59 (2.07 to 10.15)
 Clinical pneumonia or SATO2 ≤95%164/338 (49)37/47 (79)127/291 (44)<0.0010.790.560.230.944.78 (2.29 to 9.97)
  • PPV = positive predictive value. NPV = negative predictive value. CRP = C-reactive protein. OR = odds ratio.