Max Rady College of Medicine

Concept: Patient Characteristics

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Concept Description

Last Updated: 2002-10-16


    Patient characteristics are used to confirm the dynamics of the patient-physician link. Physician to patient contact patterns, which can be measured by unreferred ambulatory visits, are related to key patient characteristics including demography, neighborhood income level, and overall health status.

    This concept is based on the article by Roos, Carriere,and Friesen (1998) which documented a variety of practice styles for managing patients with hypertension. They investigated the validity of various explanations for the different styles and of the relative contribution of patient characteristics to the rates at which hypertensive patients contact physicians.

Unreferred Ambulatory Visits

    This key variable of interest is the total number of unreferred Ambulatory Visits - Physician each patient makes during the year, regardless of location (home, clinic, or office), physician, and diagnosis as documented by the claims file for physician payment. While unreferred ambulatory visits measure contact with physicians, particularly general practitioners, consultative ambulatory visits measure contact with specialists and indicate health status of a patient.


Neighborhood Income Level

    Mean household income, based on the patient's neighborhood of residence, is a socioeconomic characteristic which is strongly linked to health status. Household income may be determined by aggregating public census data at the geographic unit of the enumeration area. The areas are then ranked from poorest to wealthiest and grouped into equally sized population quintiles. Each patient may then be linked to an area by residential postal code and assigned an income quintile rank. Similar analyses may be done by neighborhood education level, as education is also a valuable socioeconomic characteristic.

Overall Health Status

    The overall health of a patient may be indicated by examining several contributing factors:

    • Number of referrals for consultation to another physician (0, 1, 2, or more).
    • Number of hospital admissions over a one year period.
    • Presence of coexisting conditions.
    • Presence of 3 serious medical problems. A serious medical problem is one that is found to be associated with 4 key dimensions of health (Cohen & MacWilliam, 1995). For a complete listing of specified conditions and suggested SAS coding see Defining A Serious Medical Problem - SAS Code below.
    • Patients with mental health problems are particularly frequent users of physician services, thus the number of visits per year is a valuable indicator.
    • Sequential nature of provider continuity of care

SAS code and formats 

Related concepts 

Related terms 


  • Cohen MM, MacWilliam L. Measuring the health of the population. Med Care 1995;33(12 Suppl):DS21-DS42. [Abstract] (View)
  • Roos NP, Carriere KC, Friesen D. Factors influencing the frequency of visits by hypertensive patients to primary care physicians in Winnipeg. CMAJ 1998;159(7):777-783. [Abstract] (View)

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Manitoba Centre for Health Policy
Community Health Sciences, Max Rady College of Medicine,
Rady Faculty of Health Sciences,
Room 408-727 McDermot Ave.
University of Manitoba
Winnipeg, MB R3E 3P5 Canada