Editor—Sheikh and Alves's paper ends with the introduction of ICD-10 (international classification of diseases, 10th revision) in figures for 1995-6; the authors rightly stated that the change in classification could affect results.1 ICD-10 subdivided anaphylaxis into four categories: reaction to food (T78.0), unspecified (T78.2), serum (T80.5), and medicinal (T88.6). With this change, the numbers dropped to 501 admissions in 1995-6. Such swings are not uncommon when new classification systems are introduced.
Hospital episode statistics are now available for 1998-9, and the coding discrepancy seems to have been resolved: the number of admissions for anaphylaxis increased to the level recorded in 1994-5 and now exceeds it (an admission being uniquely identified as the first episode in a spell). In 1998-9 there were 1202 admissions, or 11.05/100 000 admissions; this compares with 876 discharges (10.2/100 000 discharges) reported in 1994-5 (table).
Sheikh and Alves asked for more detailed reporting of vaccines causing an anaphylactic reaction, and there is better provision of this information in ICD-10; the latest data report the type of medicine involved. For example, in 1998-9 there were 76 acute anaphylactic shocks due to an adverse reaction to penicillin, 17 to hydroxyquinoline derivatives, and 16 to propionic acid derivatives. The additional information presented here further strengthens the need for more detailed research into the reasons underlying this escalating trend and on the longer term outcomes.
Table.
Admissions with primary diagnosis of anaphylactic shock among patients treated in England 1995-6 to 1998-9. Figures are numbers (percentages)*
| Year | Category under which reaction was classified
|
Overall No | |||
|---|---|---|---|---|---|
| Food | Unspecified | Serum | Medicinal substance | ||
| 1995-6 | 158 (31.5) | 229 (45.7) | 1 (0.2) | 113 (22.6) | 501 |
| 1996-7 | 312 (37.1) | 366 (43.6) | 9 (1.1) | 153 (18.2) | 840 |
| 1997-8 | 390 (35.6) | 513 (46.8) | 10 (0.9) | 183 (16.7) | 1096 |
| 1998-9 | 406 (33.8) | 558 (46.4) | 3 (0.2) | 235 (19.6) | 1202 |
Source: Hospital episode statistics.
Footnotes
I thank the Department of Health for access to the hospital episode statistics via the safe haven pilot.
References
- 1.Sheikh A, Alves B. Hospital admissions for acute anaphylaxis: time trend study. BMJ. 2000;320:1141. doi: 10.1136/bmj.320.7247.1441. . (27 May.) [DOI] [PMC free article] [PubMed] [Google Scholar]