Bacterial superinfection in upper respiratory tract infections estimated by increases in CRP values: A diagnostic follow-up in primary care

Figures & data

Figure 1.  Entire study population (first and second visit corresponding to CRP determinations). Hatched squares=: excluded patients.

Table I.  Distribution of CRP1 and CRP2 values above and below the limit at the first and second consultation.

	1st visit (n = 506)	2nd visit (n = 297)*
CRP2 < 30	370 (73.1%; CI 69.0–76.9)	273 (91.9%; CI 88.2–94.8)
CRP2 ≥ 30	136 (26.9%; CI 23.1–31.0)	24 (8.1%; CI 5.2–11.8)

Notes: *The distribution of CRP2 values from patients included with a CRP1 below 30 units. In 36 out of 333 patients CRP2 values were missing (see Figure 1).

Table II.  Mean CRP values and duration of illness referring to the three defined groups.

Group		Variable	n	Mean	CI for the mean
1	“Bacterial infection” CRP1 ≥ 30	CRP1 CRP2 duration (days)	129 119 116	62.95 18.53 7.17	56.09 14.38 6.46	69.81 22.68 7.88
2	“Viral infection” CRP1 < 30 + CRP2 < 30	CRP1 CRP2 duration (days)	333 273 257	8.40 5.84 6.40	7.44 5.02 5.99	9.37 6.67 6.82
3	“Superinfection” CRP1 < 30 + CRP2 ≥ 30	CRP1 CRP2 duration (days)	333 24 24	16.69 58.50 9.46	12.83 45.27 7.92	20.56 71.73 10.99