Change in serum creatinine concentration from the baseline in all patients with and without the ICD-10 N17× code for AKI (referred to as code positive and code negative)
| Emergency department cohort | Hospitalised cohort | ||||||
|---|---|---|---|---|---|---|---|
| Absolute change (µmol/l) | Relative change (%)* | Absolute change (µmol/l) | Relative change (%)* | ||||
| Diagnostic coding algorithm | Code | N | Median (IQR) | N | Median (IQR) | ||
| All diagnoses | + | 426 | 133 (62 to 288) | 87 (43 to 204) | 2023 | 98 (43 to 200) | 69 (28 to 153) |
| − | 35623 | 2 (−8 to 14) | 2 (−9 to 15) | 36 543 | 6 (−4 to 20) | 7 (−5 to 22) | |
| Main diagnosis/most responsible diagnosis | + | 227 | 187 (89 to 383) | 128 (62 to 295) | 388 | 196 (93 to 396) | 121 (49 to 275) |
| − | 35822 | 2 (−8 to 14) | 2 (−9 to 16) | 38 178 | 7 (−4 to 22) | 7 (−4 to 24) | |
| Admission diagnosis | + | n/a | 1366 | 114 (39 to 187) | 75 (30 to 169) | ||
| − | 37 230 | 6 (−4 to 21) | 7 (−4 to 23) | ||||
Both absolute and relative changes in serum creatinine were significantly different between code positive and code negative patients in both types of hospital encounters (all p values <0.001) (means presented in box plot; online supplementary figures S2 and 3)
*((peak serum creatinine—baseline serum creatinine)/baseline serum creatinine)).
To convert serum creatinine from μmol/l to mg/dl divide by 88.4.
AKI, acute kidney injury; CKD, chronic kidney disease; ICD-10, International Classification of Diseases, tenth revision; N, number; +, code positive; −, code negative; n/a, not applicable.