Table 2.
Descriptive characteristics that influence the chances of matching initial cases, 1997–2011
| Matching from initial hospitalization dataset to initial notification dataset OR (95% CI) | Matching from initial notification dataset to initial hospitalization dataset OR (95% CI) | Matching from Auckland register† to overall notification dataset OR | Matching from Auckland register† to overall hospitalization dataset OR | Matching from Upper North Island registers‡ to overall notification dataset OR (95% CI) | Matching from Upper North Island registers‡ to overall hospitalization dataset OR (95% CI) | |
|---|---|---|---|---|---|---|
| Age (years) | ||||||
| <5 | 0·36 (0·18–0·70) | >100 (0-∞) | 1·7 | ∞ | 1·1 (0·3–3·7) | 2·94 (1·1–7·5) |
| 5–15* | – | – | 1 | 1 | 1 | 1 |
| 16–30 | 0·46 (0·36–0·60) | 0·30 (0·20–0·44) | – | – | 0·3 (0·3–0·5) | 0·6 (0·4–0·9) |
| ⩾31 | 0·08 (0·05–0·15) | 0·15 (0·07–0·35) | – | – | 0·2 (0·1–0·3) | 0·3 (0·1–0·9) |
| Sex | ||||||
| Male* | – | – | 1 | 1 | 1 | 1 |
| Female | 0·83 (0·70–1·0) | 0·65 (0·46–0·93) | 1·3 | 1·3 | 0·7 (0·6–1) | 0·8 (0·6–1·1) |
| Unknown | – | 0·55 (0·31–0·98) | – | – | 0·2 (0·1–0·4) | – |
| Ethnicity | ||||||
| Māori* | – | – | 1 | 1 | 1 | 1 |
| Pacific | 0·72 (0·59–0·87) | 0·93 (0·63–1·35) | 1 | 1 | 0·2 (0·1–0·2) | 0·2 (0·1–0·2) |
| European | 0·29 (0·20–0·41) | 0·56 (0·28–1·13) | 0·5 | ∞ | 1 (0·6–1·7) | 0·5 (0·3–0·8) |
| Other | 0·34 (0·21–0·55) | 0·32 (0·18–0·58) | 1·6 | 0·4 | 0·3 (0·1–0·7) | 0·3 (0·1–0·6) |
| Meet Jones criteria | ||||||
| Yes* | – | – | 1 | 1 | 1 | 1 |
| No | – | 0·27 (0·25–0·64) | – | – | – | 1·48 (0·9–2·5) |
| Unknown | – | – | – | – | – | 0·4 (0·3–0·6) |
OR, Odds ratio; CI, confidence interval.
Bold values are statistically significant.
*
Compared to reference groups: age 5–15 years; male; Māori ethnicity; meets the Jones criteria.
†
Auckland register data covers cases added to the register between 1998 and 2010.
‡
Upper North Island registers are Hawke's Bay and Waikato registers.