Concept: Patient Characteristics

Introduction

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.

Demography

Patient age and gender may be identified from various sources. Many relevant databases, including the Manitoba Health Insurance Registry (see Manitoba Health Insurance Registry / MCHP Research Registry - Overview concept) provide demographic data including age, sex, marital status and location of residence.

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