Measurement of the Primary Care Roles Of Office-Based Physicians

Transcription

1 Measurement of the Primary Care Roles Of Office-Based Physicians JONATHAN P. WEINER, DRPH, AND BARBARA H. STARFIELD, MD Abstract: The Baltimore City Primary Care Study examined the role of the urban office-based physician in the delivery of primary care. During the course of the study, questionnaires were completed by over 90 per cent of licensed physicians in the city, and data were collected from a sample of 16,000 patients. The study developed and assessed three approaches for the measurement of primary care. An empirical method was based upon information regarding the following characteristics of each visit: first contact visit, referral visit, specialized care visit, or principal care visit. A normative method was based on an assessment of the degree to which the practice provided care that was comprehensive, longitudinal, accessible, and family-centered. The third method used physicians' judgments as to the proportion of patients for whom they maintained ongoing responsibility for general medical care. All three methods produced the same categorization of different specialties as providing either primary, intermediate, or specialty care. As a group, primary care physicians included general and family physicians, pediatricians, and general internists. General surgeons and obstetrician/gynecologists have characteristics of both primary care and specialist care. All other physician groups have characteristics of specialists. Any of these methods or a combination of methods can be used to assess the extent to which the practice of a particular physician or group of physicians provides primary care. (Am J Public Health 1982; 73: ) Introduction Primary care is a central yet elusive concept in health services. The first published reference to the concept appears in the Dawson Report of Britain in The term "Primary Health Centre" was used to denote the level at which patients first entered the health care system for each new problem. Some current definitions of primary care are based upon the same notion of first contact. In 1966, the Citizens Commission on Graduate Medical Education (chaired by J. Millis) issued a report2 which spoke of the need for "comprehensive continuing care... and for the physician who would accept primary responsibility for delivering it." Consequently, the provider of this type of care was dubbed the "primary physician." From the Johns Hopkins University, Health Services Research and Development Center, Department of Health Services Administration and Department of Pediatrics. Address reprint requests to Jonathan P. Weiner, DrPH, Senior Research Associate and Assistant Professor, Johns Hopkins University, Health Services Research and Development Center, 624 N. Broadway, Room 638, Baltimore, MD This paper, submitted to the Journal December 30, 1981, was revised and accepted for publication August 4, American Journal of Public Health 666 Since that time there have been two major approaches to measuring primary care: the empirical and the normative. The empirical approach measures primary care on the basis of characteristics of the encounter. These characteristics include presenting problems, diagnoses, treatments offered, and referral patterns.34 The normative approach measures primary care according to the achievement of certain attributes by the practice, such as accessibility, comprehensiveness, longitudinality, continuity, and family-centeredness.%7 In addition, subjective assessments by physicians of the amount of primary care they deliver have also been used.8 In this study the empirical, normative, and physician self-assessment approaches for the measurement of primary care were employed and compared. The study was a research effort initiated by the Baltimore City Medical Society. It was a cooperative venture involving state, regional, and city health planners, and a school of public health. The project had two broad objectives: to provide data for local health planning of the primary care delivery system; and to provide information that would complement national data on measurement of the extent of primary care in office-based settings. The survey's methods and backgrounds and a discussion of the project's findings as related to the availability and utilization of office-based services in a major urban area are presented in another report.9this paper concerns the mea- AJPH June 1983, Vol. 73, No. 6

2 PRIMARY CARE ROLES OF PHYSICIANS TABLE 1-The Primary Care Classification Algorithm Encounter Log Data Item First Last Check-up Last Cold/Flu Care Category* Referral Contact Here Care Here Principal Care no no yes yes First Encounter Care no yes no no Specialized Care no no no no Consultative Care yes yes or no yes or no yes or no *Ordering of categories is from "most" to "least" indicative of "Primary Care" Based on the above algorithm, the patients seen by each physician are placed into one of four categories. Using the formula below, an Empirical Primary Care Index (EPCI) is calculated: EPCI (PC x 1) + (FE x 0.67) + (SP x 0.33) + (CN x 0) (N) Where: EPCI = Empircal Primary Care Index (for each physician) PC = Number of patients in principal care category FE = Number of patients in first encounter care category SP = Number of patients in specialized care category CN = Number of patients in consultative care category N = Total number of patients seen surement of primary care and provides an assessment of the primary care role of different office-based specialists. Methods Data Collection A questionnaire containing 50 questions was sent to all physicians in the Baltimore metropolitan area who were licensed to practice medicine by the State of Maryland Board of Medical Examiners. Of the 2,505 medical doctors who practiced in the city of Baltimore, 90.1 per cent responded. Characteristics of practice of these physicians are contained in a prior report.9 The City's office-based physicians (n = 1,305) were stratified by both zip code and specialty (using a computerized random number generator) and a 40 per cent sub-sample was selected to maintain a patient encounter log for a one-week period. These logs were completed by the physician's office staff with data obtained directly from the patients. Of the original sample, 49.8 per cent of the offices responded (n = 286) with data from over 16,000 patients. This paper contains data from this sample. Analyses indicated that the specialty distribution, age, sex, race, and type of practice were similar among the physicians completing the logs and questionnaires, and those who did not do so. The number of physicians in each specialty who returned the log is presentqd as part of Table 2. The average completion rate of individ6ual items within the questionnaire and encounter log was high (>90 per cent). Index Development The Empirical Primary Care Index (EPCI) was designed to serve as a measure of primary care as expressed by certain characteristics of the relationship between practitioners and patients. This index was based in part on the University of Southern California care classification typology. 10 In contrast to the study conducted by those researchers (in which physicians, were asked to indicate how patients had reached them), all components of our EPCI were obtained from patients themselves. Data for the EPCI were obtained from the patient encounter logs. For each patient encounter, the log ascertained whether or not this visit was the first contact between the patient and this physician (first contact); whether or not the patient was referred by another physician for the problem seen during this visit (referral); whether or not the patient received his/her last complete medical check-up with this physician (an indicator of preventive care); and whether or not the patient received his/her last care for a bad cold or flu from this physician (an indicator of day-to-day acute care). These four items were used to classify each patient encounter into one of four categories as shown in Table 1. The characteristics of the four types of encounter classification categories are described as follows: Principal Care Encounter: The patient receives ongoing care for preventive and acute day-to-day problems and the encounter is neither referral nor first contact. First Contact Care Encounter: The patient is visiting the physician for the first time and the visit was not by referral (in this case the physician is acting as the entry point into the ambulatory care system). Specialized Care Encounter: The patient is receiving ongoing, nonreferral care for a particular problem or set of problems only and not for preventive or acute care needs. Consultative Care Encounter: The patient is receiving care for a particular problem on referral by another physician. A principal care encounter clearly is most indicative of primary care as patients respond that they have received both preventive and acute care from the physician. Consultative encounters are least indicative of primary care. The relative placement of first encounters and specialized care AJPH June 1983, Vol. 73, No

3 WEINER AND STARFIELD TABLE 2-Empirical Primary Care Measures by Specialty Specialty Internal Family General Medical Sub- Surgical Sub- Medicine Pediatrics Ob/GYN Practice Surgery Psychiatry Specialties Specialties Measure (n = 65) (n = 20) (n = 46) (n = 42) (n = 38) (n = 21) (n = 19) (n = 17) Principal Care First Encounter Care Specialized Care Consultative Care Empirical Primary Care Index (EPCI) Standard Deviation The figures in the top four rows represent the per oent of all specialty's encounters that can be classified into each category. The EPCI is a weighted index that combines the four encounter categories, where 100 is indicative of primary care. n represents the number of office-based physicians in each specialty who completed the encounter log. The results of 18 physicians, in specialties other than those listed, are not reported. encounters is less clear. Because the '"first contact" aspect has long been considered an important attribute of primary care, the first encounter category was ranked above the specialized care category in approximation to primary care. After each patient encounter was assigned into one of the four classification categories, the patient mix of each physician's practice was used to calculate a score (EPCI) ranging from 0 to 100 for each practitioner. In order to develop the EPCI, weights were assigned to each care category in accordance with its relative primary care rank. These weights were equidistant and ordinal, with the "highest" category (principal care) receiving a value of 1 and the lowest category (consultative care) a value of 0; the formula is presented as part of Table 1. Using this scheme, a score of 100 indicates that a physician is delivering only principal care (or "primary care"), and a score of 0 indicates that a physician is delivering entirely consultative care (or "specialty care"). The average EPCI score (and all other scores) for each specialty was calculated by averaging the individual scores of all applicable physicians in the sub-sample. The Normative Primary Care Index (NPCI) has four components, each measuring a separate primary care attribute. The attributes were: comprehensiveness, accessibility, longitudinality, and family-centeredness. Scores representing the attributes were calculated for each individual physician using data derived from both the physician questionnaire and the patient encounter log. The comprehensiveness score was obtained from information on the questionnaire which requested physicians to indicate which of the following services were provided in the practice: 1) Physical examinations; 2) Immunizations; 3) Pelvic examinations; 4) EKGs; 5) Blood hematocrit and hemoglobin determination; 6) Analyses requiring a microscope. Each of these items was equally weighted to develop a comprehensive score ranging from 0 to 100 for each practice. 668 The accessibility score was based on information in the questionnaire about practice characteristics that facilitate availability and accessibility, as follows: 1) Availability of emergency appointments; 2) Willingness to make outside office calls (i.e., to home or emergency room); 3) Use of an answering service; 4) Formal arrangements for after-hours coverage. These items were equally weighted to develop a score ranging from 0 to 100 for each practice. Longitudinal or continuous care was measured by the average duration of the patients' relationships with the physician as obtained from the patient encounter log. For these analyses, it was necessary to control for the age of the physician (by the use of partial correlation) as young physicians could not have developed long-term relationships with their patients. It was not possible to control for the age of the patient without introducing additional biases. This lack of control, however, places pediatricians with their younger patients at a disadvantage on this scale. For calculations of the NPCI, the score was converted to a scale by assigning a percentile to each physician based on the entire range of longitudinality results. Measurement of the amount of care that was familycentered (an important goal of the family medicine specialty) was based on the percentage of patients in a physician's practice who had at least one other immediate family member being seen by the same physician. Patients with no other family member residing in the area were excluded from the denominator. A family-centeredness score had a potential range of The above four scores were combined on an equally weighted basis and divided by four to obtain a single Normative Primary Care Index (NPCI) ranging from The Self-Assessed Primary Care Index (SAPCI) was based upon the physician's answer to the question: "What percentage of the visits at your main site would you estimate as being general medical care for patients for whom you maintain ongoing responsibility?; do not include care where AJPH June 1983, Vol. 73, No. 6

4 PRIMARY CARE ROLES OF PHYSICIANS FIGURE 1-Three Approaches for the Measurement of Primary Care you assume responsibility only for a selected or particular condition or type of condition." The SAPCI score for each specialty represents the average response of all physicians in that specialty. The potential range of the SAPCI score was Figure 1 summarizes the three approaches used by this study to measure the concept of "Primary Care." Results Each of the 16,033 patient visits in the 286 offices were classified into one of the four empirical care classification categories. The percentage of each specialty's patients assigned to each category is presented in Table 2. The largest range (1.5 per cent to 81.0 per cent) across the specialties was obtained for per cent of visits that were classified as principal care encounters. Internists, pediatricians, and family practitioners had the highest proportion of their visits in this category, followed by obstetricians and general surgeons. Medical subspecialists had the highest proportion of first encounter visits, psychiatrists the lowest proportion. The EPCI was highest for pediatricians, family physicians, and internists, intermediate for obstetricians, and lowest for others, especially the surgical subspecialists. Standard deviations for general surgeons and medical subspecialists were relatively high compared to the other specialties. This difference is noteworthy and indicates relatively less homogeneity within these specialties than was the case for other types of physicians. The NPCI and its components are presented in Table 3. For most of these, family practitioners, internists, and pediatricians rank at the top; general surgeons, ob/gyns, and the medical subspecialists in the middle; and the surgical subspecialists at the bottom. An exception to this general rule occurs for the accessibility score, where surgical subspecialists rank as high as internists and pediatricians. However, it should be noted that this score showed relatively little variation across specialties. Table 3 also presents the Self-Assessed Primary Care Index (SAPCI) for each specialty. Whereas most family practitioners, pediatricians, and internists assess themselves as providing primary care in the majority of instances, the remaining specialists consider primary care as representing a relatively small percentage of their case load. The rank order of the specialties for the three independent primary care measures are remarkably consistent. Figure 2 presents the relative ranking of the EPCI, NPCI, TABLE 3-Normative and Self-Assessed Primary Care Measures by Specialty Specialty Intemal Family General Medical Sub- Surgical Sub- Medicine Pediatrics Ob/GYN Practice Surgery Psychiatry Specialties Specialties Measure (n = 65) (n = 20) (n = 46) (n = 42) (n = 38) (n = 21) (n = 19) (n = 17) Comprehensiveness Score (S.D.) (23.4) (16.7) (15.3) (18.1) (24.1) (4.3) (28.6) (18.7) Accessibility Score (S.D.) (21.8) (34.7) (28.3) (23.2) (22.7) (26.6) (28.8) (23.4) Longitudinality Score (S.D.) (5.1) (2.6) (3.1) (5.6) (3.7) (3.2) (2.9) (1.1) Family Centeredness Score (S.D.) (24.0) (27.9) (27.3) (20.7) (31.9) (34.9) (31.1) (34.7) Normative Primary Care Index (NPCI)* (S.D.) (14.4) (16.5) (12.5) (1 1.9) (13.7) (12.4) (16.5) (22.0) Self-Assessed Primary Care Index (SAPCI) (S.D.) (25.2) (21.9) (25.4) (20.3) (30.8) (13.9) (27.4) (2.6) Top figure represents score, bottom figure represents the standard deviation. All scores are on a scale with the exception of longitudinality which is measured in years. *The NPCI is an equally weighted composite of the four preceding scores. AJPH June 1983, Vol. 73, No

5 WEINER AND STARFIELD RANK OF SPECIALTY I4IG#aSl I LOWEST I KUY EMWEICAL PRIMAR CARE INDX (I PC.1 NOMFAAIVE PRIMARY CARE W4DX (N PC I) SELF -ASSESSED PRIMAR CAMRE NDX (SAPC i) 4- S. 7. B. GIMIALOFAMLT PRACTICE iltuua MIDTICU MIOIATRICS cosstucs,m OVuscaOsv SCALm IWWRCIA&TIIS Gala" SRIRIRT EUIOCAL SUMSPRCIALTEIS PSTCHIAWFRY FIGURE 2-A Comparison of Three Independent Measures of Primary Care by Specialty and SAPCI for each of the eight specialty categories. For all three measures, family practitioners, pediatricians, and internists rank among the top three specialties; ob/gyns, medical subspecialists, and general surgeons rank in the middle; and surgical subspecialists and psychiatrists rank as the bottom two specialties. In order to assess the nature and magnitude of the relationship between the three indices and their components, correlational analyses were performed. The EPCI was associated (at the 0.05 probability level or less) with the comprehensiveness component of the NPCI for ob/gyns, general surgeons, and medical subspecialties. The more comprehensive their services, the more primary care delivered according to the EPCI. The EPCI was also associated with the longitudinality component of the NPCI for internists, general surgeons, surgical subspecialists, and medical subspecialists. For these specialties, the longer the relationship with patients, the more primary care delivered according to the EPCI. The EPCI was associated with the family-centeredness component of the NPCI for internists, pediatricians, famnily practitioners, and general surgeons. For these specialties, the greater the tendency of family units to receive care from a physician, the more primary care delivered according to the EPCI. In contrast, the EPCI and the accessibility component of the NPCI did not show any clearcut association, possibly because the accessibility score showed the least interspecialty variation of all measures. The Self-Assessed Primary Care Index (SAPCI) was associated with the EPCI for internists, pediatricians, family practitioners, general surgeons, and medical subspecialists. The remaining specialists, ob/gyns, surgical subspecialists, and psychiatrists did not accurately estimate the amount of primary care that they delivered as measured against the EPCI. Discussion The Baltimore City Primary Care Study has developed and applied methods that can be used to determine the primary care roles of office-based physicians. Although there is no reason to believe that the methods would not be applicable to other locations and settings, the findings describing the characteristics of the various specialties might not be generalizable. Replications of this study in other types of locales would be required before conclusions about the nature of primary care across the different specialties in the nation as a whole could be reached. The three measures used by the study each have advantages and limitations when used to determine the primary care availability within a given community or organization. The Empirical Primary Care Index (EPCI) is the most objective of the indices. Its main disadvantage is that it requires patient encounter data which may be available only where ongoing information systems exist or where special studies can be undertaken. The Normative Primary Care Inde'x (NPCI), which is based on physician's judgments about their practice, appears to provide a reasonable delineation between different types of physicians. The single component of the NPCI that appears to be most closely associated with primary care (as judged against the EPCI) is comprehensiveness of practice. While the NPCI and its components can be developed with easily obtainable data, the level of objectivity and precision ~~~~~~~~~~~~~~~~~~~~~~~AJPH June 1983, Vol. 73, No. 6

6 PRIMARY CARE ROLES OF PHYSICIANS they represent are more limited than those of the EPCI. In addition, for any individual physician (in contrast to all physicians in a specialty group), the correspondence between these idealized practice characteristics (NPCI) and the actual receipt of primary care by patients (EPCI) may not be high. The Self-Assessed Primary Care Index (SAPCI) appears to be associated with the delivery of primary care only for certain specialties (internal medicine, pediatrics, family practice, general surgery, and medical subspecialties). While this method requires only one element of data, it is a judgment that may be subject to considerable distortion, depending upon the circumstances under which it is elicited and used. Although it might appear that the greater "versatility" or age spread of family physicians would give them a mathematical advantage in calculation of the indices, there is no reason why they should have any advantage over other generalists in calculation of the EPCI. With regard to the NPCI, family physicians are at an inherent advantage only with regard to family centeredness, and, as Table 3 shows, they do score higher on this measure. However, when family centeredness is removed from the NPCI, the overall rank of the specialty does not change. Also with regard to the family centeredness measure, note the relatively high score for ob/gyns (45.7). This finding is difficult to interpret, but it might be due to the sharing of this type of physician between mothers and daughters. If no resources are available for determining the actual amount of primary care delivered by physicians within a site of interest, then the results of this study can be helpful in classifying physicians, either for planning or reimbursement purposes, into one of three primary care categories based only on specialty designation. General and family practitioners, internists, and pediatricians as a group can be considered primary care physicians; obstetricians/gynecologists, general surgeons, and medical subspecialists as intermediate care physicians; surgical subspecialists, psychiatrists, and other types of physicians as specialty care physicians. Accuracy of estimates of the supply of "primary care" in the United States rely heavily on the extent to which specialists provide such care. Aiken, et al, concluded that specialists serve as primary physicians for almost one of every five Americans.3 Their estimates of the per cent of patient encounters that are principal encounters are similar to ours for generalists, pediatricians, and internists. In contrast, their estimates of the proportion of principal encounters of medical subspecialists were considerably larger than ours across the entire range of subspecialties. No data were available for most surgical subspecialists or for psychiatrists, but the figure imputed for surgical subspecialists was much higher than was obtained in our study. Their paper did not provide the estimate used for psychiatrists. The data supporting the estimate of Aiken, et al, were derived, in part, from self-assessments of the extent to which physicians reported themselves as the majority source of care for patients who made visits to them. The reliability of these assessments has been questioned by an independent validation study."i As several of the objective measures used in our study correlated highly with our empirical measure, which is comparable in concept to that used by Aiken, et al, there is reason to believe that specialists overestimate the extent to which they provide a majority of care for their patients. Direct confirmation of this was provided by Dutton who recently showed that physicians in Washington, DC vastly overestimated the extent to which they were central in the patient's health care as compared with the actual proportion of visits that patients made to them.'2 The role of the specialist in the delivery of primary care should continue to be the subject of future investigations. In an era of ever increasing health care technology and subspecialization, the ability to discern primary care will become ever more important and ever more difficult. The methods developed during the course of this study can serve as the basis for practical applications such as communitybased planning or reimbursement programs. These methods can also provide useful research tools in an arena where very few presently exist. REFERENCES 1. Dawson L: Interim Report on the Future Provision of Medical and Allied Services. London: HMSO, Millis J: The Report of the Citizen's Commission on Graduate Medical Education. Chicago: American Medical Association, Aiken L, Lewis C, Craig J, et al: The contribution of specialists to the delivery of primary care. N Engl J Med 1979; 300: Thacker S, Salber B, Osborne C, et al: Primary care in Durham County: who gives care to whom. Med Care 1979; 17: Alpert J, Charney E: The Education of Physicians for Primary Care. Washington DC: DHEW Pub. No. (HRA) , Holmes C: Towards measurement of primary care. Milbank Mem Fund Q 1978; 56: Starfield B: Measuring the attainment of primary care. J Med Educ 1979; 54: Armondino N, Walker J: The Primary Care Physician: Issues in Distribution. Conn Health Services Research Series #7; Weiner J, Kassel L, Baker T, Lane B: The Baltimore City Primary Care Study: the role of the office-based physician. Maryland State Med J June 1982; Mendenhall R, Lewis C, DeFloria G, et al: A national study of medical and surgical specialties; III: empirical approach to the classification of patient care. JAMA 1979; 241: Perrin E, Harking E, Marihi M: Evaluation of the Reliability and Validity of Data Collected in the USC Medical Activities and Manpower Projects, Final Report. Seattle: Battelle Research Center, Dutton D: Children's Health Care: The Myth of Equal Access. In: Report of the Select Panel for Child Health, Vol IV, Washington, DC: DHEW, ACKNOWLEDGMENTS The Baltimore City Primary Care Study was supported in part by the Baltimore City Medical Society, the Morris Goldseker Foundation of Maryland, Inc., a W. K. Kellogg Fellowship awarded by the Hospital Research and Educational Trust, the Maryland State Health Planning and Development Agency, and the Central Maryland Health Systems Agency through a grant from the United States Department of Health and Human Services under provision of P.L An earlier version of this paper was presented at the 109th Annual Meeting of the American Public Health Association, November 1981, in Los Angeles. AJPH June 1983, Vol. 73, No