Table 1.
Significant differences between group 1 (proven), group 2 (false-positive) and group 3 (unknown) subjects
| Group 1 ‘proven cases’ (N = 466) | Group 2 ‘false-positive cases’ (N = 103) | Group 3 ‘unknown cases’ (N = 115) | ||
|---|---|---|---|---|
| Categorical variables* | n (%) | n (%) | n (%) | Significance tests |
| Age group |
Group 1 vs. 3
χ2 = 14·5, 5 d.f., P = 0·013 |
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| 0–5 months | 80 (17·2) | 18 (17·5) | 16 (13·9) | |
| 6–11 months | 70 (15·0) | 7 (6·8) | 9 (7·8) | |
| 1–2 years | 120 (25·8) | 27 (26·2) | 24 (20·9) |
Group 2 vs. 3
χ2 = 6·72, 5 d.f., P = 0·24 |
| 3–4 years | 61 (13·1) | 22 (21·4) | 17 (14·8) | |
| 5–6 years | 46 (9·9) | 9 (8·7) | 10 (8·7) | |
| ⩾7 years | 89 (19·1) | 20 (19·4) | 39 (33·9) | |
| Presenting hospital role† |
Group 1 vs. 3
χ2 = 5·33, 2 d.f., P = 0·070 |
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| Paediatric specialist | 221 (47·5) | 17 (16·5) | 54 (47·0) | |
| Major hospital | 140 (30·1) | 12 (11·7) | 25 (21·7) | |
| District/other | 104 (22·4) | 74 (71·8) | 36 (31·3) |
Group 2 vs. 3
χ2 = 36·43, 2 d.f., P < 0·0001 |
| Presenting symptoms |
Group 1 vs. 3
χ2 = 50·58, 2 d.f., P < 0·0001 |
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| No meningitis/sepsis | 41 (8·8) | 53 (51·5) | 39 (33·9) | |
| Meningitis only present | 176 (37·8) | 12 (11·7) | 25 (21·7) | |
| Sepsis present | 249 (53·4) | 38 (36·9) | 51 (44·4) |
Group 2 vs. 3
χ2 = 7·96, 2 d.f., P = 0·019 |
| Year of admission |
Group 1 vs. 3
χ2 = 4·77, 7 d.f., P = 0·69 |
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| 2000 | 54 (11·6) | 6 (5·8) | 19 (16·5) | |
| 2001 | 71 (15·3) | 8 (7·8) | 15 (13·0) | |
| 2002 | 91 (19·5) | 10 (9·7) | 20 (17·4) |
Group 2 vs. 3
χ2 = 20·96, 7 d.f., P = 0·0038 |
| 2003 | 67 (14·4) | 17 (16·5) | 12 (10·4) | |
| 2004 | 54 (11·6) | 10 (9·7) | 17 (14·8) | |
| 2005 | 47 (10·1) | 16 (15·5) | 14 (12·2) | |
| 2006 | 34 (7·3) | 20 (19·4) | 8 (7·0) | |
| 2007 | 48 (10·3) | 16 (15·5) | 10 (8·7) | |
| Continuous variable* | Mean (s.d.) | Mean (s.d.) | Mean (s.d.) | |
| Total length of stay | 8·3 days (11·8) | 3·1 days (3·5) | 5·1 days (5·7) |
Group 1 vs. 3
t = 4·25, P < 0·0001 |
|
Group 2 vs. 3
t = 3·17, P = 0·0018 |
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| Total time on mechanical ventilation | 7·7 h (29·8) | 1·3 h (7·6) | 2·1 h (13·1) |
Group 1 vs. 3
t = 3·0, P = 0·0027 |
|
Group 2 vs. 3
t = 0·56, P = 0·58 |
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Group 1 ‘proven’ cases: those notified as having meningococcal disease. May include subjects with single or multiple clinical records.
Group 2 ‘false-positive’ cases: non-notified subjects who had been discharged without a meningococcal diagnosis recorded on their final clinical record. Only includes subjects with multiple clinical records.
Group 3 ‘unknown’ cases: non-notified subjects who had been discharged with a meningococcal diagnosis on their final (or only) clinical record. May include subjects with either single or multiple clinical records.
Analysis of all categorical variables is based on the first hospital separation for the illness episode. Continuous variables are summed over all hospital separations in the illness episode.
One missing value in group 1.