Table 2.
Summary of diagnoses validated in the seven studies which reported the specific codes validated
| Study | Coding System | Diagnosis Validated | Specific Codes/Algorithms Representing the Diagnosis | Notes |
|---|---|---|---|---|
| Walker, 2018 | READ | Probable AD | Any of: Eu00.00, Eu00000, Eu00011, Eu00012, Eu00013, Eu00100, Eu00111, Eu00112, Eu00113, Eu00200, Eu00z00, Eu00z11, F110.00, F110000, F110100, Fyu3000 | Patients may also have codes on the “possible AD” list and codes representing a prescription for a drug used exclusively in the treatment of dementia, detailed in BNF section 4.11, excluding idebenone. |
| Possible AD | Any of: E00..00, E00..11, E00..12, E000.00, E001.00, E001000, E001100, E001200, E001300, E001z00, E002.00, E002000, E002100, E002z00, E003.00, E00z.00, Eu02z11, Eu02z12, Eu02z14, Eu02z15, Eu02z16, Eu05700, F11z.11 | Patients may also have codes on the “possible AD” list and codes representing a prescription for a drug used exclusively in the treatment of dementia, detailed in BNF section 4.11, excluding idebenone. | ||
| Non‐AD And mixed dementia | Any of: Eu02z13, Eu02z00, Eu02.00, Eu02y00, 6AB..00, E041.00, 9hD1.00, 9hD0.00, E00y.00, F112.00, 8BPa.00, E02y100, Eu01111, Eu02000, Eu02100, Eu02200, Eu02300, Eu02400, Eu02500, Eu04100, F111.00, F116.00, F11x200, E004.00, E004.11, E004000, E004100, E004200, E004300, E004z00, Eu01.00, Eu01.11, Eu01000, Eu01100, Eu01200, Eu01300, Eu01y00, Eu01z00 or any code representing a prescription for a drug used exclusively in the treatment of dementia, detailed in BNF section 4.11, excluding Idebenone | Patients may also have codes on the “probable AD” and “possible AD” lists, but due to the presence of a non‐AD specific code, they do not meet the criteria for these classifications. | ||
| Heath, 2015 | READ | Dementia | Any of: 66 h, 6AB.., E00.., E000., E001., E0010, E0011, E0012, E0013, E001z, E002., E0020, E0021, E002z, E003., E004., E0040, E0041, E0042, E0043, E004z, E00y., E00z., E041., Eu00., Eu000, Eu001, Eu002, Eu00z, Eu01., Eu010, Eu011, Eu012, Eu013, Eu01y, Eu01z, Eu02., Eu020, Eu021, Eu022, Eu023, Eu024, Eu025, Eu02y, Eu02z, F110., F1100, F1101, F111., F112., F116., Fyu30(in addition to codes representing a prescription for a drug used exclusively in the treatment of dementia, detailed in BNF section 4.11) | |
| Blak, 2011 | READ | Dementia | Any of: E11.%, F212., F21Z, F371a | |
| Sommerland, 2018 | ICD‐10 | Dementia | Any of: F00x‐F03x, G30x, G31.0, G31.8 | |
| Brown, 2016 | ICD‐10 | Dementia | Any of: E512, F00, F01, F02, F03, F10.6, F10.7, G30, or G31.0. | |
| Soo, 2014 | ICD‐10 | Dementia | Any of: F01, F00, F03, F02, F05.1, G30, G31.1 | |
| Ryan, 1994 | ICD‐9b | Dementia | 290 |
Abbreviations: AD, Alzheimer's disease; ICD‐9, International Classification of Disease (9th Edition); ICD‐10, International Classification of Disease (10th Edition).
a
The “%” symbol represents a wildcard for READ codes (ie, a search using E11.% would identify E11 and all codes nested under it).
b
Harmonisation between ICD‐8 and ICD‐9 occurred for the period 1968 to 1979.