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

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Technical Note

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 hospitals1. 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.

Denominator

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)
    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); 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; 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; 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; 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.
  2. Age at admission is 15 years or older
  3. Sex recorded as male or female
  4. Admission to a general hospital
  5. 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

Numerator

Number of individuals with three or more episodes of care for a mental illness within a year. An episode of care for a mental illness is identified using the same inclusion and exclusion criteria as for the denominator.

1 Excludes free-standing psychiatric facilities.