Technical Note - Asthma Readmission

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Technical Note

Asthma Readmission


Unit of Analysis:

The unit of analysis is an "Episode of care". An episode of care refers to all contiguous in-patient hospitalizations and same-day surgery visits. For episodes with transfers within or between facilities, transactions were linked regardless of diagnoses. To construct an episode of care a transfer is assumed to have occurred if either of the following conditions is met:

  • Acute care hospitalization or same day surgery visit occurs within 6 hours of discharge from previous acute care hospitalization or same day surgery visit regardless of whether the transfer is coded;
  • Acute care hospitalization or same day surgery visit occurs within 6-12 hours of discharge from previous acute care hospitalization or same day surgery visit and at least one of the hospitalization or visit has coded the transfer.

Denominator (Index Episode)

Inclusion Criteria:

    1. Asthma (ICD-9/ICD-9-CM: 493.0, 493.1, 493.8, 493.9 or ICD-10-CA: J45) is coded as MRDx, but not also as a diagnosis type (2); or
    2. Where another diagnosis is coded as the most responsible and also as a diagnosis type (2), and a diagnosis of asthma is coded as a type (1), or .
  1. Discharge between April 1 and March 3 of the following year (period of case selection ends March 3 to allow for 28 days of follow-up)
  2. Age at admission between 15 and 84 years
  3. Gender recorded as male or female
  4. Admission to an acute care institution
  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 or time
  4. Records with an invalid discharge date or time
  5. Discharged as a death or self sign-out
  6. Any one of the following diagnoses recorded in any position:
    1. Cancer (ICD-9/ICD-9-CM: 140-208, V58.1, V58.0 or ICD-10-CA: C00-C26, C30-C44, C45-C97, Z51.0, Z51.1)
    2. HIV (ICD-9: 042, 043, 044, 795.8 or ICD-9-CM: 042, 043, 044, 795.71, V08 or ICD-10-CA: B24, Z21, R75)
    3. Trauma (ICD-9/ICD-9-CM: E800-848, E880-886, E888, E890-899, E900-910, E913-926, E928, E950-958, E960-968, E970-976, E990-998 or ICD-10-CA: V01-V99, W00-W23, X00-X09, W92-W94, X17, X30, X31, X51, X53, X54, X57, X20-X29, W50-W60, X33-X38, W30, W31, W44, W45, W64-W77, W81-W84, W25-W27, W33-W40, W85-W99, X10-X19, X60-X84, X85-Y09, Y35.0-Y35.4, Y35.6, Y35.7, Y36)

Numerator:

Inclusion Criteria:

  1. Readmission within 28 days of discharge after the index episode of care
  2. Emergent or urgent (non-elective) readmission to an acute care hospital
  3. Readmission for any one of the following most responsible diagnoses:
    1. Pneumococcal pneumonia (ICD-9/ICD-9-CM: 481 or ICD-10-CA: J13, J18.1; excluding cases where ICD-9/ICD-9-CM: 496 or ICD-10-CA: J44 is also recorded in any diagnosis position)
    2. Other bacterial pneumonia (ICD-9/ICD-9-CM: 482 or ICD-10-CA: J14, J15.0-J15.6, J15.8, J15.9; excluding cases where ICD-9/ICD-9-CM: 496 or ICD-10-CA: J44 is also recorded in any diagnosis position)
    3. Bronchopneumonia, organism unspecified (ICD-9/ICD-9-CM: 485 or ICD-10-CA: J18.0; excluding cases where ICD-9/ICD-9-CM 496 or ICD-10-CA J44 is also recorded in any diagnosis position)
    4. Pneumonia, organism unspecified (ICD-9/ICD-9-CM: 486 or ICD-10-CA: J18.8, J18.9; excluding cases where ICD-9/ICD-9-CM: 496 or ICD-10-CA: J44 is also recorded in any diagnosis position)
    5. Asthma (ICD-9/ICD-9-CM: 493 or ICD-10-CA: J45)
    6. Empyema (ICD-9/ICD-9-CM: 510 or ICD-10-CA: J86)
    7. Pulmonary collapse (ICD-9/ICD-9-CM: 518.0 or ICD-10-CA: J98.1)
    8. Respiratory arrest (ICD-9/ICD-9-CM: 799.1 or ICD-10-CA: J96, R09.2)
    9. Respiratory complications resulting from a procedure (ICD-9: 997.3 or ICD-9-CM: 997.3, 512.1 or ICD-10-CA: J95.4, J95.8, J95.9)

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