Table 1.
Cases admitted to hospital
|
All cases
|
||||||
---|---|---|---|---|---|---|---|
Time period | No of cases | No of deaths | Case fatality rate (95% CI) | No of cases | Incidence per 100 000 population (95% CI) | No of deaths† | Case fatality rate (95% CI) |
1963-8 | 41 | 5 | 12.2 (2.2 to 22.2) | 42 | 1.23 (0.86 to 1.60) | 6 | 14.3 (3.7 to 24.9) |
1969-73 | 72 | 6 | 8.3 (1.9 to 14.7) | 74 | 1.72 (1.33 to 2.11) | 8 | 10.8 (3.7 to 17.9) |
1974-8 | 108 | 12 | 11.1 (5.2 to 17.0) | 111 | 1.24 (1.01 to 1.47) | 15 | 13.5 (7.2 to 19.9) |
1979-83 | 113 | 11 | 9.7 (4.3 to 15.2) | 113 | 1.09 (0.89 to 1.29) | 11 | 9.7 (4.3 to 15.2) |
1984-8 | 147 | 16 | 10.9 (5.8 to 15.9) | 152 | 1.33 (1.12 to 1.54) | 21 | 13.8 (8.3 to 19.3) |
1989-93 | 303 | 25 | 8.3 (5.2 to 11.3) | 308 | 2.40 (2.13 to 2.67) | 30 | 9.7 (6.4 to 13.1) |
1994-8 | 464 | 41 | 8.8 (6.3 to 11.4) | 473 | 3.55 (3.23 to 3.87) | 50 | 10.6 (7.8 to 13.3) |
1963-98 | 1248 | 116 | 9.3 (7.7 to 10.9) | 1273 | 1.97 (1.86 to 2.07) | 141 | 11.1 (9.4 to 12.8) |
P value for trend‡ | 0.31 | <0.001 | 0.28 |
International Classification of Diseases, 9th revision, code 036 and 10th revision code A39.
Includes 25 people who died outside hospital or who had no record of hospital admission.
P values refer to the change in annual rates 1963-98 from logistic regression modelling. Visual inspection of the annual incidence and further modelling showed little change in incidence during 1963-88 (P=0.10) and a significant increase during 1989-98 (P<0.001).