Table 1.
Baseline characteristics of patients discharged home from the emergency department (ED) with AKI
| Characteristic | Patients Discharged Home from the ED with AKI, n (%)a | |||
|---|---|---|---|---|
| All Patients | AKI Stageb | |||
| 1 | 2 | 3 | ||
| Cohort size | 6346 | 6012 | 290 | 44 |
| Age, yr, mean (SD) | 69 (13) | 69 (13) | 68 (14) | 65 (13)ठ|
| 40 to <65 | 2326 (37) | 2189 (36) | 112 (39) | 25 (57)ठ|
| 65 to <80 | 2475 (39) | 2351 (39) | 114 (39) | 10 (23)ठ|
| ≥80 | 1545 (24) | 1472 (25) | 64 (22) | 9 (21) |
| Women | 2948 (47) | 2745 (46) | 177 (61)† | 26 (59)‡ |
| Year of cohort entry (index date) | ||||
| 2003–2005 | 1593 (25) | 1497 (25) | 87 (30)† | 9 (21)‡§ |
| 2006–2008 | 2903 (46) | 2769 (46) | 116 (40)† | 18 (41)‡ |
| 2009–2011 | 1850 (29) | 1746 (29) | 87 (30) | 17 (39)‡§ |
| Rural residence | 969 (15) | 912 (15) | 51 (18) | 6 (14)§ |
| Comorbid conditionsc | ||||
| Hypertension | 4783 (75) | 4525 (75) | 222 (77) | 36 (82)ठ|
| Diabetes | 2405 (38) | 2292 (38) | 100 (35) | 13 (30)ठ|
| Heart failure | Not reported | 1325 (22) | 48 (17)† | ≤5 (≤11)‡§ |
| Coronary artery diseased | 2160 (34) | 2069 (34) | 78 (27)† | 13 (30)‡ |
| Chronic liver disease | Not reported | 399 (7) | 24 (8) | ≤5 (≤11)§ |
| Nephrolithiasis | Not reported | 162 (3) | 11(4) | ≤5 (≤11)‡§ |
| Aggregated diagnosis group point scoree | ||||
| 0–5 | 1756 (28) | 1669 (28) | 79 (27) | 9 (21)‡§ |
| ≥6 | 4589 (72) | 4343 (72) | 211 (73) | 35 (80)‡§ |
| Medication utilizationf | ||||
| Ontario Drug Benefit eligible patients | 4605 (73) | 4367 (73) | 213 (73) | 25 (57)ठ|
| Medication classg | ||||
| Angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers | 2750/4605 (60) | 2614/4367 (60) | 122/213 (57) | 14/25 (56) |
| Antibiotics | 2041/4605 (44) | 1931/4367 (44) | 97/213 (46) | 13/25 (52)ठ|
| Antipsychotic medications | Not reported | 284/4367 (7) | 18/213 (9) | ≤5/25 (≤20) |
| Nonpotassium-sparing diuretics | 2609/4605 (57) | 2465/4367 (56) | 128/213 (60) | 16/25 (64)‡ |
| Potassium-sparing diuretics | Not reported | 511/4367 (12) | 34/213 (16)† | ≤5/25 (≤20)‡§ |
| Nonsteroidal anti-inflammatory drugsh | 892/4605 (19) | 849/4367 (19) | 34/213 (16) | 9/25 (36)ठ|
| No. of unique drug names, median (interquartile range) | 5 (0–10) | 5 (0–10) | 5 (0–10) | 0 (0–7) |
| Pre-ED baseline kidney functioni | ||||
| Baseline serum creatinine in mg/dl, mean (SD) | 1.1 (0.6) | 1.2 (0.6) | 0.9 (0.3)† | 1.1 (1.0)§ |
| No. of d taken before ED visit, mean (SD) | 133 (102) | 132 (102) | 140 (105) | 152 (116)ठ|
| No. with serum creatinine ≤0.6 mg/dl | Not reported | 215 (4) | 44 (15)† | ≤5 (≤11)‡§ |
| Baseline eGFR, ml/min per 1.73 m2 | ||||
| ≥60 | 3919 (62) | 3654 (61) | 230 (80)† | 35 (80)‡ |
| 45 to <60 | Not reported | 1029 (17) | 34 (12)† | ≤5 (≤11)‡§ |
| 30 to <45 | Not reported | 833 (14) | 19 (7)† | ≤5 (≤11)‡ |
| <30 | Not reported | 496 (8) | 7 (2)† | ≤5 (≤11)§ |
| Albumin-to-creatinine ratio, mg/g | 1689 (27) | 1602 (27) | 77 (27) | 10 (23) |
| <30 | Not reported | 959 (16) | 49 (17) | ≤5 (≤11)‡§ |
| 30 to <300 | Not reported | 262 (4) | 13 (5) | ≤5 (≤11) |
| ≥300 | Not reported | 381 (6) | 15 (5) | ≤5 (≤11) |
| ED visit laboratory values | ||||
| Serum potassium in mEq/L, mean (SD) | 4.2 (0.6) | 4.2 (0.6) | 4.1 (0.8)† | 4.2 (0.8)§ |
| Serum sodium in mEq/L, mean (SD) | 137 (5) | 137 (5) | 136 (5)† | 134 (5)‡§ |
| Serum creatinine in mg/dl | ||||
| Mean (SD) | 1.7 (0.8) | 1.6 (0.7) | 2.0 (0.8)† | 3.8 (2.1)‡§ |
| Median (interquartile range) | 1.5 (1.2–1.8) | 1.4 (1.2–1.8) | 1.8 (1.4–2.3) | 3.4 (2.3–4.8) |
| Absolute change in serum creatinine in mg/dl | ||||
| Mean (SD) | 0.5 (0.4) | 0.5 (0.2) | 1.1 (0.5)† | 2.7 (1.4)‡§ |
| Median (interquartile range) | 0.4 (0.4–0.6) | 0.4 (0.4–0.5) | 1.0 (0.8–1.3) | 2.5 (1.6–3.7) |
| Percent change in serum creatinine, % | ||||
| Mean (SD) | 52 (34) | 48 (18) | 129 (26)† | 294 (128)‡§ |
| Median (interquartile range) | 45 (35–60) | 44 (34–57) | 121 (108–144) | 265 (224–359) |
| Previous health care utilizationj | ||||
| ED visit in the previous 30 d | 1114 (18) | 1062 (18) | 45 (16) | 7 (16) |
| Hospitalization in the previous 30 d | 481 (8) | 451 (8) | 24 (8) | 6 (14)ठ|
| Family physician visit | 6251 (99) | 5924 (99) | 283 (98) | 44 (71)ठ|
| General internist visit | 1470 (23) | 1385 (23) | 76 (26) | 9 (21)§ |
| Nephrology visit | Not reported | 270 (5) | 14 (5) | ≤5 (≤11) |
| Urology visit | 1132 (18) | 1084 (18) | 40 (14)† | 8 (18)§ |
| Imaging and investigations | ||||
| Computed tomography with contrast | Not reported | 175 (3) | 7 (2) | ≤5 (≤11) |
| Coronary angiogram or revascularization | Not reported | 138 (2) | 6 (2) | ≤5 (≤11)‡§ |
| ED patient acuity and wait times | ||||
| Canadian triage acuity scalek | ||||
| 1 and 2 | 1321 (21) | 1271 (21) | 43 (15)† | 7 (16)‡ |
| 3 | 3797 (60) | 3579 (60) | 193 (67)† | 25 (57)§ |
| 4 and 5 | 1228 (19) | 1162 (19) | 54 (19) | 12 (27)ठ|
| Time (in hr) waiting for physician assessment, mean (SD) | ||||
| Canadian triage acuity scale 1 and 2 | 0.6 (0.8) | 0.6 (0.8) | 0.5 (0.6)† | 0.3 (0.5)‡§ |
| Canadian triage acuity scale 3 | 1.3 (1.3) | 1.3 (1.3) | 1.5 (1.3) | 1.6 (1.1)ठ|
| Canadian triage acuity scale 4 and 5 | 1.6 (1.4) | 1.6 (1.4) | 1.7 (1.4) | 1.4 (1.2)ठ|
A standardized difference of ≥10% was found between the following two AKI subgroup comparisons: †stage 1 versus stage 2; ‡stage 1 versus stage 3; and §stage 2 versus stage 3. To convert serum creatinine from traditional units (milligram per deciliter) to SI units (micromole), multiply by 88.42.
Reported as n (%) unless otherwise noted. To comply with privacy regulations for minimizing the chance of patient reidentification, numbers of patients were suppressed in five or fewer patients. The total number of patients was not reported if there were other calculations that could result in the reidentification of five or fewer patients.
Stage 1, evidence of a relative increase in serum creatinine value of ≥50% to <100% or ≥0.3 mg/dl from baseline; stage 2, evidence of a relative increase in serum creatinine value of ≥100% to <200% from baseline; and stage 3, evidence of a relative increase in serum creatinine value of >200% from baseline or an absolute increase in serum creatinine value to ≥4 mg/dl or the initiation of dialysis.
Look-back window for comorbidities was 5 years unless otherwise noted.
Does not include angina.
The Aggregated Diagnosis Groups point score, derived from the John Hopkins Adjusted Clinical Groups system, is a weighted measure of health care utilization as a proxy measure for comorbidity and accounts for the duration of condition, severity of condition, diagnostic certainty, etiology of the condition, and specialty care involvement. The higher Aggregated Diagnosis Groups score, the greater the comorbidity. Individuals with an Aggregated Diagnosis Groups score of 0–2 reflect low health care costs with no prior hospitalizations; 3–5 reflects high health care costs but no prior hospitalizations; and a score of ≥6 reflects high health care costs and at least one prior hospitalization.
Look-back window for medication utilization was 120 days.
Percentages reported are on the basis of the number of Ontario Drug Benefit eligible patients (those aged ≥65 years).
Does not include acetylsalicylic acid.
Pre-ED visit look-back window was 7–365 days.
Look-back window for health care utilization was 365 days unless otherwise noted.
Patients with a Canadian Triage Acuity Scale score of 1 or 2 need to be seen immediately 98% of the time or within 15 minutes 95% of the time, respectively. Patients with a Canadian Triage Acuity Scale score of 3 need to be seen within 30 minutes 90% of the time or 60 minutes 85% of the time, respectively. Patients with a Canadian Triage Acuity Scale score of 4 or 5 need to be seen within 120 minutes 80% of the time.