Procedures
Study protocols and materials, based on a similar practice-based research study conducted with pediatricians, were reviewed and approved by the Committee on Human Research of the Johns Hopkins School of Public Health and the Colorado Multi-Institutional Review Board.4,8,9 We conducted a pilot test in 5 practices; this test led to further refinements of methods and questionnaires.
Data collection occurred from September 1997 to February 1999, with 94% of physicians collecting data in 1998 only. Before beginning data collection, physicians completed a questionnaire concerning their practices and personal characteristics. Each practice selected a coordinator who communicated with research staff, learned study protocols, trained office staff and physicians, and monitored data quality. Coordinators completed a questionnaire about the organizational and financial components of their practice. They kept a log of all visits made during 15 consecutive business days and occurring during regularly scheduled office hours. A business day was defined as a half or full work day, provided that the physician held routine office hours. Each patient’s date of birth (5% missing), sex (2% missing), and principal diagnosis (5% missing) were recorded.
The coordinator kept another log of all referrals made by physicians, nurses, and other office staff. Referrals made during telephone conversations with patients were included. A referral was defined as a recommendation that a patient have a face-to-face encounter with another practitioner. We excluded referrals made to laboratories, radiologic facilities, emergency departments, hospitals for inpatient admission, and “curbside consultations” (ie, when the referring physician obtains advice from a specialist but does not send the patient for a visit).
A medical record abstractor assigned ICD-9-CM codes to diagnoses provided by office staff. We matched ICD codes to an expanded set of diagnosis clusters (EDCs). EDCs group ICD codes into clinically homogeneous categories using the methods developed by Schneeweiss.10 (For more information on EDCs, see http://acg.jhsph.edu.)
When physicians made a referral, they completed a questionnaire (response rate 93.9%) with items concerning the referral decision. Reasons for referral were based on our previously developed taxonomy used in a pediatric referral study4 and focus groups of family physicians convened during an annual ASPN convocation.
At the study’s conclusion, physicians received a report that compared their referral practice patterns with those of the entire sample. To defray office expenses associated with data collection, each practice was given a $100 stipend in addition to $5 for each physician referral.
Generalizability analysis
We compared referral rates of the study sample with the National Ambulatory Medical Care Survey (NAMCS), a nationally representative sample of office visits made to family physicians.11,12 We pooled surveys from 1989 to 1994, inclusive, when the majority of the items in the survey instruments remained unchanged.13 (The 1995–1999 surveys did not contain information on whether the visit led to referral.)
We selected visits made by patients enrolled in non-HMO health plans (NAMCS) and health plans that had neither capitated primary care physician payment nor gatekeeping arrangements (study sample). This was done because of the known effect of managed care in general, and of gatekeeping specifically, on increasing referral rates8,13 and the unequal distribution of managed care plans between the 2 samples. Unweighted visits yielded a sample size of 37,145; of these, 11,676 met the selection criteria.
The proportions of office visits referred were compared overall and by age, sex, and health condition. The 10 most frequently referred conditions in the study sample were used for the condition-specific referral rate assessments. Statistical significance was assessed by the chi-square statistic.
Results
Descriptive information on the 141 family physician sample is presented in Table 1. Physicians spent an average of 51.3 hours per week in their jobs. About 68% of their time was devoted to direct patient care. In most practices, a staff member coordinated administrative aspects of specialty referrals; 20% permitted patients to request a referral by leaving a voice mail message.
TABLE 1
FAMILY PHYSICIAN STUDY SAMPLE
| Personal Characteristics (N = 141 physicians) | Mean or Percentage |
|---|---|
| Age, mean (SD) | 45.3 (7.2) |
| Years in primary care practice, mean (SD) | 14.0 (7.9) |
| % female | 21.3 |
| Hours/week spent in: | |
| Direct patient care, mean (SD) | 34.7 (16.2) |
| Administration, mean (SD) | 6.5 (5.7) |
| Academic medicine, mean (SD) | 3.0 (5.3) |
| Research, mean (SD) | 1.2 (3.2) |
| Medical education, mean (SD) | 5.9 (8.8) |
| General Practice Characteristics (N = 87 practices) | |
| Practice arrangement, % | |
| Solo practice | 27.6 |
| 2- or 3-physician practice | 13.8 |
| Family practice group (more than 3 physicians) | 33.3 |
| Multispecialty group | 16.1 |
| Community health center | 5.8 |
| Hospital-based practice or clinic | 3.4 |
| Practice ownership, % | |
| Hospital | 46.5 |
| Insurer | 5.8 |
| Another medical group | 4.6 |
| Subgroup of physicians in practice | 5.8 |
| All physicians in practice | 30.2 |
| Publicly owned clinic | 7.0 |
| Number of physician FTEs per practice, mean (SD) | 4.6 (5.9) |
| Staff: physician FTE ratio per practice, mean (SD) | 3.7 (2.4) |
| Practice Characteristics Related to Referrals (N = 87 Practices) | |
| Practice has an administrative referral coordinator, % | 60.0 |
| Personnel permitted to refer a patient, % | |
| Nurses with physician input | 85.9 |
| Nurses without physician input | 14.5 |
| Administrative staff with physician input | 67.4 |
| Administrative staff without physician input | 7.1 |
| Referrals are made during telephone conversations with patients, % | 90.8 |
| Practice allows patients to request a referral by leaving a recorded message, % | 19.5 |
| FTE denotes full-time equivalents; SD, standard deviation. | |