Concept: Postal Codes and Coding Methods in Manitoba Health Claims Data

MHSIP Master Registry

The Manitoba Health Services Insurance Plan (MHSIP): http://www.gov.mb.ca/health/mhsip/ is financed from general revenues of the Province of Manitoba and with funds provided by the Government of Canada. All Manitoba residents who make their home and are physically present in Manitoba, at least six months of a calendar year may be registered. Each postal code is based on the current address and registration of the family head. The following procedures depend on whether a registration number (REGNO) / (REGNO_CODE) exists in the MHSIP database:


• Registration number is present: if the registry number is available, postal code and municipality code values are taken from the then-current family head entry in the Master Registration System at MHSIP. The municipal code must be in-province but the postal code can be out-of-province if the family head has moved out-of-province. It is important to note that the postal code is always taken from the Master Registry and never as entered at the physician's office.
  
  
• Registration number is not present: if registry number is not available, the municipal code will be coded as out-of-province. If a claim was filed using the manual system, the postal code will be missing. If a claim was electronically filed, the postal code will be as originally entered by the hospital (likely an address supplied by the patient). Also, medical claims on Non-Manitoban residents served in Manitoba do not have registration numbers so the postal code is as provided on the original claim.

Corrections Are Not Retroactive

Given a valid registration number, the residence information cannot change until the registration data has been updated. If a claim disagrees with the registry, the change will not be stored on the current claim. Claims processed after a correction has been recorded in the registration data will be revised (generally in two week intervals).

Postal Codes Vary Over Time

Due to changing postal service needs, postal codes are not fixed over time. Individuals may show changes in postal code while remaining at the same address. This is hard to detect unless someone wants to map each postal code to its predecessor. Formats and income tables are affected by changed or newly assigned postal codes and may become inconsistent over time.

Implications

• Inaccuracy of Residence Data
  
  Residential postal codes and/or municipal codes on claims are subject to inaccuracies entirely dependent on how up-to-date the fields are maintained within the master registration files. Discrepancies between coded values and registry are never corrected, although, the registry may be updated within the next two weeks to reflect information detected from past claims and confirmed elsewhere (contact with physician, phone books, reported by registrant, etc.).
  
  Residence information given on claims is more accurate and timely than that found in the Manitoba Health Insurance Registry / MCHP Research Registry data, simply because it was obtained near (not necessarily on) the date of the service using registry information presently available. This accuracy is not due to residence on claims being "declared" by the patient.
  
  This information, however, is not as accurate as it would be if it were per individual and date-specific (as seen at the physician's office or in hospital admitting). The loss of accuracy is more than made-up for by the existence of the registry database which gives us reasonably good information on people who do not have routine contact with health care providers.
  
  
• Interpretation of Residence data
  
  For Residents of Manitoba , postal and municipal code fields reflect the mailing address of the named family head, which may differ from their physical residence. A few cases show arbitrary postal codes, such as the public trustee's office in major centers - which is where the individual's mail is intended to go but which is not the registrant's actual area of residence. Family address may easily differ from that of a spouse or child (under 19) who no longer resides with the family head. MHSIP does not keep such information anywhere in the database.
  
  
• Inconsistent Definition of Residence Municipal Code Versus Postal code
  
  Municipal codes may be misleading since, in some cases, Manitoba retains the last known municipal code when persons leave Manitoba and remain covered for three months. The postal code shows non-residence, while municipal code implies residence in Manitoba. Postal code can also be misleading since Manitoba residents may actually receive their mail in another province (usually border areas of Saskatchewan or Ontario). Some residents are misrepresented because the family head lives out of province (e.g. students) but the dependents remain. Postal code does not reflect each dependent's true residence unless the individual is actually living with the named family head.
  
  
• Residence Definition for Non-Manitoban Residents
  
  Detection of postal codes beginning with the appropriate value is relatively simple and strongly implies that the patient is a resident of Manitoba. It is invalid to isolate other postal regions in Canada and infer that non-resident patients are coming from these specific areas. The information is not consistent across hospitals and is affected by current mailing addresses for both former and recent residents of Manitoba. Users are encouraged to explore the use of Province of residence codes and the 'Non-Resident Reject Reason' to determine patterns among reciprocal services between different Canadian provinces.

Hospital Claims: Year-End Files

• Hospitals in Manitoba which Manually Code
  
  Manually coded forms are sent to Manitoba Health for key-edit (data entry). Postal code is entered on the form and is likely to be correct for the individual at the date of admission. When MHSIP clerks enter the registration number, name, and other data fields, they apparently do not enter the postal code. When the computer system searches for eligibility and Personal Health Identification Number, the values for postal code and municipal code are taken from the then-current master registration system entry for the family head for the given registration number. Except for newborns or stillbirth, the Personal Health Identification Number recorded should be numeric and valid.
  
  If no registration number is provided, the computer program codes a missing postal code and a non-Manitoba resident municipal code by default. The original value for postal code is either not retained or was not actually coded. In these cases, the Personal Health Identification field should be missing. At MCHP, the Personal Health Identification values are alphanumeric (i.e.: H93000001) in installed SAS files.
  
  If the registration number is valid, but the family head is currently not residing in Manitoba (regardless of residence of other family members), the registry may contain an out-of-province postal code and the municipal code indicating where the family head last lived. These will be transferred to all claims for the members of the given family.
  
  Personal health identification numbers should be numeric and valid. This is true for all hospitals which do not use electronic submission of claims. These currently include the Health Sciences Centre and St. Boniface General Hospital.
  
  
• Hospitals in Manitoba Using Electronic Submissions
  
  Postal code is entered at the hospital and is carried through to the computerized validation stages. If the registration number is current, valid, and refers to the correct resident, Manitoba Health validation systems will replace the postal code on claims with the family's registered postal code and municipal code, as noted above. If the registration number is current and valid but does not refer to the resident, the claims validation systems will substitute the current registration values including out-of-province postal code and the most recent municipal code.
  
  For non-resident patients (registration number is missing) or ineligible Manitoba residents (registration number is inactive), the value coded by the hospital should survive the process and will be retained on the claim record.
  
  Personal Health Identification Numbers will most likely be present and valid since the electronic claims system apparently requires a PHIN assigned by MHSIP (for non-residents) for successful registry validation. This is true for the hospitals using electronic submission of claims, including many smaller Winnipeg area hospitals.
  
  
• Claims from Out-Of-Province Hospitals
  
  Postal Code appears to be captured by the data process for reciprocal claims and survives intact much like for hospitals with electronic submissions. Out-of-province claims are handled separately from in-province claims and do not become part of the "hospital file" until the final year-end statistical dataset is produced in June of each year.
  
  Again, if the registration number is eligible and valid, the postal code and municipal code are taken from the then-current family head. If the registration number is ineligible, the postal code would still be obtained from the family registration.
  
  Reciprocal claims (MB residents admitted out-of-province) should not exist without a valid MB Health Registration number.
  
  Personal Health Identification Numbers may be missing for newborns.

Medical Claims

• Fiscal Year and Fiscal Service Year: Statistical
  
  All records have valid registration number so all records have registry based postal code and municipal code. Municipal code should not be non-resident or missing. Postal Code can be non-Manitoba if family head has left this province (or receives mail out-of-province).
  
  
• Non-statistical (Non-Manitoban Resident Served in Manitoba)
  
  Records which have valid registration numbers include former residents who have left more than three months prior to date of service. It is not clear whether registration data for residence is substituted on these claims. Records which do not have a valid registration number are non-residents, and postal code should be as coded by the physician. Municipal code should be coded as non-resident.
  
  
• Reciprocal Claims (Manitoba Resident, Out-Of-Province)
  
  Registration number must be valid so postal code/municipal code (if available) will most likely be substituted using the registration system. It is likely that the residence data are not recorded here since these claims are not normally included in the Manitoba Health statistical reports.

Other Systems

Most Manitoba Health systems which contain postal codes retrieve the field from the registration for the family head as of the date the claim was first processed. Corrections are seldom made retroactively (probably never).

The possible sources for municipal codes in any system are either to link to registration/family head using registration number or by a look-up table search using Postal codes and the Post-Municipal Conversion files. This is a manual operation for MHSIP staff.

The Manitoba Immunization Monitoring System (MIMS) is an exception as the public health side of the program maintains current address records independently of the central family head/registration system. Changes made to MIMS are eventually passed to the Master Registration System but not always immediately.

Mental Health records are usually independent of the MHSIP master registration system as well. The Manitoba Mental Health Information System (MMHIS) has a separate client registration component.