Technical Note: Percentage of Patients With Repeat Hospitalizations for a Mental Illness

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2.3   Percentage of Patients With Repeat Hospitalizations for a Mental Illness

Unit of Analysis

The unit of analysis is an episode of care. An episode of care refers to all contiguous hospitalizations in general hospitalsxxx. To construct an episode of care, a transfer is assumed to have occurred if the following condition is met:

  • Admission to a general hospital/day surgery facility occurs on the same day as discharge from another general hospital.


Number of individuals with at least one episode of care for mental illness within a year. An episode of care for mental illness is identified as follows:
Inclusion criteria:

  1. A selected mental illness is coded as most responsible diagnosis (MRDx)
  2. Diagnosis codes for selected mental illness:
    1. Substance-related disorders—ICD-10-CA: F55, F10 to F19; DSM-IV: 291.x (0, 1, 2, 3, 5, 81, 89, 9), 292.0, 292.11, 292.12, 292.81, 292.82, 292.83, 292.84, 292.89, 292.9, 303.xx (00, 90), 304.xx (00, 10, 20, 30, 40, 50, 60, 80, 90), 305.xx (00, 10 to 90 excluding 80); Provisional diagnosisxxxi: (d) substance-related disorder; or
    2. Schizophrenia, delusional and non-organic psychotic disorders—ICD-10-CA: F20 (excluding F20.4), F22, F23, F24, F25, F28, F29, F53.1; DSM-IV: 295.xx (10, 20, 30, 40, 60, 70, 90), 297.1, 297.3, 298.8, 298.9; Provisional diagnosis3: (e) schizophrenia disorder; or
    3. Mood/affective disorders—ICD-10-CA: F30, F31, F32, F33, F34, F38, F39, F53.0; DSM-IV: 296.0x, 296.2x, 296.3x, 296.4x, 296.5x, 296.6x, 296.7, 296.80, 296.89, 296.90, 300.4, 301.13; Provisional diagnosis3: (f) mood disorders; or
    4. Anxiety disorders—ICD-10-CA: F40, F41, F42, F43, F48.8, F48.9, F93.8; DSM-IV: 300.xx (00, 01, 02, 21, 22, 23, 29), 300.3, 308.3, 309.x (0, 3, 4, 9), 309.24, 309.28, 309.81; Provisional diagnosis3: (g) anxiety disorders or (o) adjustment disorders; or
    5. Selected disorders of adult personality and behaviour—ICD-10-CA: F60, F61, F62, F68, F69, F21; DSM-IV: 301.0, 300.16, 300.19, 301.20, 301.22, 301.4, 301.50, 301.6, 301.7, 301.81, 301.82, 301.83, 301.9; Provisional diagnosis3: (p) personality disorders.
  3. Age at admission is 15 years or older
  4. Sex recorded as male or female
  5. Admission to a general hospital
  6. Canadian resident

Exclusion criteria:

  1. Records with an invalid health card number
  2. Records with an invalid date of birth
  3. Records with an invalid admission date
  4. Records with an invalid discharge date
  5. Discharged as a death


Number of individuals with three or more episodes of care for a mental illness within a year. After the first episode of care, all individuals have one year of follow-up; the second and other subsequent episodes of care are identified within a year of discharge of the first episode of care. Therefore, two fiscal years are necessary to obtain the numerator. An episode of care for a mental illness is identified using the same inclusion and exclusion criteria as for the denominator.


xxx. Excludes free-standing psychiatric facilities.

xxxi. Only for data extracted from the Ontario Mental Health Reporting System (OMHRS) with no DSM-IV code recorded.

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