Concept: Measuring Majority of Care
Last Updated: 2015-03-25
1 - Mustard et al. (1996)
Mustard et al. (1996) created a measure called "Regular Source of Care (RSOC)". Ambulatory visits were counted for each individual physician providing care for a child, and this count was expressed as a proportion of all ambulatory visits. The physician providing the greatest proportion of care in a specified time period was defined as the regular source of care. For more information, please read the Regular Source of Care (RSOC) concept.
2 - Menec et al. (2000)
Menec et al. (2000) developed a continuity measure called Majority of Care based on physician visits that determines if a patient has a regular source of care. In the majority of care approach, patients are assigned to a physician if more than 50% (or any chosen percentage between 50% and 100%) of their ambulatory physician visits are attributable to that physician. Note: patients can be assigned to an individual physician, a physician group or a clinic, depending on the purpose of the study.
In Menec et al., patients were assigned to physician groups, not to individual physicians, and only if they received the majority of their care from the same clinic. Physician groups were defined on the basis of existing utilization patterns and only included ambulatory visits to General Practitioners / Family Practitioners (GP/FP). Visits to specialists did not affect the assignment of patients to a practice population. The physician groups were narrowed down to include groups consisting of four physicians or more, resulting in 29 major groups within Manitoba at the time. Both the number of physicians working for the group and the number of "full-time equivalents" were used as selection criteria. The EUSLCD (site code) variable from the Medical Services (Physician Claims) Data of the MCHP Repository was used to identify physicians who worked together. For more information on how this was done, please read section 4. Identifying Physician Groups / Clinics in the Patient Allocation: Assigning Patients to Physicians, Physician Groups or Clinics concept.
Menec et al. investigated majority of care using six different percentage cut-off levels - 50%, 60%, 65%, 70%, 75% and 80% of physician visits. According to this definition, patients have to receive at least 50% (or another percentage) of their total ambulatory care from a specific clinic in order to be classified as having a regular source of care. Patients with more visits to a physician group than the cut-off percentage have continuity of care - that is, they have a regular "physician". On the other hand, those patients with less visits than the cut-off level are called "not rostered".
These regular patients constituted the assigned practice population of the clinic. It is important to distinguish between total and assigned practice populations.
- The total practice population is all of the patients who visited a group of physicians at least once during the study period.
- The assigned practice population is the patients who received the majority of their care from the same group.
Majority of care can be defined differently based on the percentage cut-off used. Changing the cut-off level had a substantial impact on the size of assigned practice populations. The impact was larger for urban groups than rural groups, due to the greater availability of physicians in urban areas. There was also great variability in the number of regular patients, especially in urban provider groups. Predictably, walk-in clinics had large numbers of patients per physician, but relatively small numbers of regular patients. The number of years of data analyzed also affected the size of assigned practice populations.
The assigned practice populations were compared using one, two, and three years of data. Using only two years of data, as compared to three years, did not change the number of regular patients (per FTE physician) very much. However, using only one year of data reduced the assigned practice populations (per FTE physician) quite substantially, especially for rural groups, indicating that the results are quite unstable when using less than two years of data. It was recommended in the report that two years of data be used to determine assigned practice populations.
Calculating Majority of Care
The _concare macro (see the _concare macro section in the concept titled MCHP SAS Macros for more information) provides the variable upc_r , which is a convenient way to determine if a patient has a regular "physician". The following code uses a 50% cut-off (e.g.: patients must receive at least half of their total ambulatory visits from a specific "physician"):
If upc_r >0.50 then cont_variable='1';
The majority of care definition is intuitive and easily interpreted, and the extent of continuity of care can be readily examined. The continuity variable (cont_variable) used above was validated against SCC, SECON, and COC (See 1 - Roos et al. (1998) of the Measuring Continuity of Care concept for more information on these measures). All four variables gave similar results and demonstrated similar trends.
To check for consistency at different levels, follow-up analyses used the 50% level. Patients were classified as having a regular source of care if they made more than 50% of their ambulatory visits to one physician or physician group over a two year period. The 50% level was compared to the 75% majority of care definition in all of the analyses.
For more detailed information about how this measure was used, see 3.0 Results and Discussion in Menec et al. (2000).
3. - Fransoo et al. (2005, 2009, 2013), Martens et al. (2008, 2010), Chartier et al. (2012) and Smith et al. (2013)
Fransoo et al. (2005, 2009 and 2013), Martens et al. (2008, 2010), Chartier et al. (2012), and Smith et al. (2013) use a measure that looks at the percentage of residents receiving greater than 50% of their ambulatory visits from the same physician, among those with at least three physician visits in a two year period. This research adjusted the definition of the measure for different age groups by including visits by different types of physician(s), as follows:
- for children aged 0 to 14 years, the measure used a GP/FP or a Pediatrician;
- for those aged 15 to 59 years, the measure used only GP/FPs; and
- for those aged 60+ years, the measure used a GP/FP or an Internal Medicine specialist.
NOTE: In Fransoo et al. (2005 and 2009), Martens et al. (2008,2010) and Chartier et al. (2012), this measure is referred to as "continuity of care". In Smith et al. (2013) and Fransoo et al. (2013), this measure is referred to as Majority of Care (Ambulatory). Both terms have the same definition.
Values are adjusted to reflect the total population of Manitoba (males and females combined). Residents with less than three ambulatory visits over the two year period are excluded from the analyses.
SAS Code: An example of the SAS code for calculating majority of care ("continuity") is available in the SAS Code and formats section below (internal access only).
- For more information on Majority of Care used in MCHP reports, including key findings, comparison to other findings and graphs by different geographical areas, please see:
- 6.6 Majority of Care in The 2013 RHA Indicators Atlas from Fransoo et al. (2013);
- Majority of Care in Social Housing in Manitoba. Part II: Social Housing and Health in Manitoba: A First Look from Smith et al. (2013);
NOTE: The following reports use the term Continuity of Care, but are referring to the measure of Majority of Care.
- 4.6 Continuity of Care in Sex Differences in Health Status, Health Care Use, and Quality of Care: A Population-Based Analysis for Manitoba's Regional Health Authorities from Fransoo et al. (2005);
- Continuity of Care in What Works? A First Look at Evaluating Manitoba's Regional Health Programs and Policies at the Population Level from Martens et al. (2008);
- 6.5 Continuity of Care in Manitoba RHA Indicators Atlas 2009 from Fransoo et al. (2009);
- 9.3 Continuity of Care Prevalence in Profile of Metis Health Status and Healthcare Utilization in Manitoba: A Population-Based Study from Martens et al. (2010);
- 9.4 Continuity of Care in Health and Healthcare Utilization of Francophones in Manitoba from Chartier et al. (2012);
4 - Additional MCHP Research Using the Majority of Care Measure
Other discussion and findings from MCHP research using the definition of Majority of Care (greater than 50% of visits) can be found in:
- 5.9 Continuity of Care in Manitoba Child Health Atlas Update from Brownell et al. (2008);
- Continuity of Care in Health Inequities in Manitoba: Is the Socioeconomic Gap in Health Widening or Narrowing Over Time? from Martens et al. (2010);
- Continuity of Care in Evaluation of the Healthy Baby Program from Brownell et al. (2010); and
- Continuity of Care in Manitoba Immunization Study from Hilderman et al. (2011).
- Practice Characteristics - Majority of Care in Evaluation of the Manitoba IMPRxOVE Program from Chateau et al. (2015).