Cluster analysis and subgroup characterization among people who made frequent emergency department visits from Apr. 1, 2013, to Mar. 31, 2014 — Ontario
| Characteristic | Subgroup 1 (“Short duration”) | Subgroup 2 (“Older patients”) | Subgroup 3 (“Young mental health”) | Subgroup 4 (“Injury”) |
|---|---|---|---|---|
| Subgroup characteristics (clustering variables) | ||||
| No. of patients | 34116 | 74995 | 49167 | 292704 |
| Age, yr, median (IQR) | 49 (32–64) | 69 (54–80) | 45 (29–63) | 47 (30–65) |
| No. of visits to the emergency department, median (IQR) | 2 (1–3) | 3 (2–4) | 6 (4–8) | 2 (1–3) |
| Charlson Comorbidity Index, median (IQR) | 0 (0–0) | 1 (1–1) | 0 (0–0) | 0 (0–0) |
| No. of different discharge diagnosis chapters, median (IQR) | 2 (2–2) | 3 (2–4) | 5 (4–6) | 3 (2–3) |
| No. of months in the year that patients visited the emergency department, median (IQR) | 1 (1–2) | 3 (3–4) | 6 (5–7) | 3 (2–3) |
| Regularity index, median (IQR) | 1 (0.8–1) | 0.9 × 10−7 (0.6 × 10−7 to 6.8 × 10−5) | 1.3 × 10−7 (0.9 × 10−7 to 2.2 × 10−7) | 0.9 × 10−7 (0.5 × 10−7 to 1.2 × 10−4) |
| Patient characteristics (NACRS metadata) | ||||
| Gender, n (%) | ||||
| Female | 16875 (49.5) | 39575 (52.8) | 29136 (59.3) | 166034 (56.7) |
| Male | 17241 (50.5) | 35420 (47.2) | 20030 (40.7) | 126667 (43.3) |
| Other | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (0.0) |
| Undifferentiated | 0 (0.0) | 0 (0.0) | 1 (0.0) | 1 (0.0) |
| Not available | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (0.0) |
| Rural or urban, n (%) | ||||
| Rural | 7361 (21.6) | 15945 (21.3) | 10957 (22.3) | 58949 (20.1) |
| Urban | 26669 (78.2) | 58923 (78.6) | 37485 (76.2) | 232647 (79.5) |
| Emergency department visit characteristics (NACRS metadata) | ||||
| No. of emergency department visits | 113990 | 386011 | 563397 | 1187131 |
| Top 5 ICD-10 emergency department primary diagnoses, n (%) | ||||
| 1 | Drug therapies 13082 (11.5) | COPD 23782 (4.2) | Abdominal pain 23782 (4.2) | Abdominal pain 46055 (3.9) |
| 2 | Abdominal pain 3944 (3.5) | Asthma 15192 (2.7) | Drug therapies 15192 (2.7) | UTI 37335 (3.1) |
| 3 | Dressings 3151 (2.8) | Pneumonia 15025 (2.7) | UTI 15025 (2.7) | Chest pain 31801 (2.7) |
| 4 | Cellulitis of the lower limb 3107 (2.7) | Bronchitis 12552 (2.2) | Chest pain 12552 (2.2) | Drug therapies 26497 (2.2) |
| 5 | Cellulitis of the upper limb 2021 (1.8) | CHF 10268 (1.8) | Alcohol intoxication 10268 (1.8) | Cellulitis of the lower limb 16941 (1.4) |
| Visit disposition, n (%) | ||||
| Discharged | 92928 (81.5) | 266750 (69.1) | 455419 (80.8) | 1003316 (84.5) |
| Left against medical advice | 4525 (4.0) | 8323 (2.2) | 32546 (5.8) | 43506 (3.7) |
| Admitted | 9544 (8.4) | 101667 (26.3) | 64298 (11.4) | 121653 (10.2) |
| Transferred to another facility | 6952 (6.1) | 8706 (2.3) | 10989 (2.0) | 18268 (1.5) |
| Died | 41 (0.0) | 565 (0.1) | 145 (0.0) | 388 (0.0) |
| Hospitalization characteristics (DAD metadata) | ||||
| No. of patients with at least 1 admission (%) | 6825 (20.0) | 45430 (60.6) | 21745 (44.2) | 72084 (24.6) |
| No. of admissions | 8078 | 100924 | 57359 | 110157 |
| Top 5 ICD-10-CA primary diagnosis chapters, n (%) | ||||
| 1 | Digestive 1574 (19.5) | Circulatory 30001 (29.7) | Digestive 12229 (21.3) | Digestive 19370 (17.6) |
| 2 | Injury and poisoning 1351 (16.7) | Respiratory 20441 (20.3) | Abnormal clinical findings 6901 (12.0) | Injury and poisoning 14330 (13.0) |
| 3 | Circulatory 1286 (15.9) | Abnormal clinical findings 7836 (7.8) | Injury and poisoning 5604 (9.8) | Abnormal clinical findings 12961 (11.8) |
| 4 | Abnormal clinical findings 599 (7.4) | Neoplasms and blood 7459 (7.4) | Circulatory 4707 (8.2) | Circulatory 12934 (11.7) |
| 5 | Genitourinary 560 (6.9) | Digestive 6693 (6.6) | Genitourinary 4615 (8.0) | Genitourinary 9034 (8.2) |
| All alcohol-related diagnoses, n (%) | ||||
| No | 8027 (99.4) | 100643 (99.7) | 55351 (96.5) | 108918 (98.9) |
| Yes | 51 (0.6) | 281 (0.3) | 2008 (3.5) | 1239 (1.1) |
| Mental health hospitalization–related characteristics (HMHDB metadata) | ||||
| No. of patients with at least 1 admission (%) | 1103 (3.2) | 4955 (6.6) | 10048 (20.4) | 20031 (6.8) |
| No. of mental health–related admissions | 1926 | 8467 | 40 406 | 45 035 |
| Diagnosis category among mental health–related admissions, n (%) | ||||
| Mood disorder | 629 (32.7) | 1967 (23.2) | 10473 (25.9) | 14071 (31.2) |
| Schizophrenic and psychotic disorder | 524 (27.2) | 1291 (15.2) | 9852 (24.4) | 11582 (25.7) |
| Substance-related disorder | 337 (17.5) | 1150 (13.6) | 10686 (26.4) | 8766 (19.5) |
| Organic disorder | 177 (9.2) | 3097 (36.6) | 1379 (3.4) | 3606 (8.0) |
| Other mental health disorder | 137 (7.1) | 423 (5.0) | 3248 (8.0) | 3478 (7.7) |
| Anxiety disorder | 57 (3.0) | 344 (4.1) | 1582 (3.9) | 1772 (3.9) |
| Personality disorder | 51 (2.6) | 162 (1.9) | 2964 (7.3) | 1517 (3.4) |
| Non–mental health disorder | 11 (0.6) | 30 (0.4) | 177 (0.4) | 183 (0.4) |
| Unknown disorder | 3 (0.2) | 3 (0.0) | 45 (0.1) | 60 (0.1) |
Note: CHF = congestive heart failure, COPD = chronic obstructive pulmonary disease, DAD = Discharge Abstract Database, HMHDB = Hospital Mental Health Database, ICD-10-CA = International Statistical Classification of Diseases and Related Health Problems, 10th revision, Canadian version, IQR = Interquartile range, NACRS = National Ambulatory Care Reporting System, UTI = urinary tract infection.