METHODS: We performed a retrospective cohort study for the year 1996 using demographic, contact, diagnosis, and prescription data available in the December 1997 PPRNet database. We identified patients with new diagnoses of depression from the problem lists in the electronic medical record. Psychopharmacologic agents prescribed within 5 days of the diagnosis, follow-up contacts within 6 months of the diagnosis, and diagnoses of patients prescribed antidepressants without a new diagnosis of depression were also identified. We performed descriptive analyses for all practices and for individual practices.
RESULTS: During 1996, there were 149,327 active adult patients in the 39 participating practices. Of the 131,141 patients without a history of depression or antidepressant prescription, 2103 (1.6%) had a new diagnosis of depression in 1996. Incidence among the 39 practices ranged from 0.4% to 4.0%. Forty-nine percent of the newly diagnosed patients received an antidepressant prescription within 5 days of diagnosis; 81% of the prescriptions were for selective serotonin reuptake inhibitors. Ninety percent of the patients prescribed antidepressants had at least one contact in the 6 months after diagnosis (mean = 5.3 contacts). One third of the patients who had not begun antidepressants within 5 days of their diagnoses started taking one by the end of 1996. Among the 149,327 active patients, 6.3% received a prescription for an antidepressant in 1996. More than 40% of these patients had never been diagnosed with depression.
CONCLUSIONS: Our study highlights the high prevalence and wide interpractice variations of diagnosing depression and prescribing antidepressants in primary care. Follow-up of patients newly diagnosed with depression was common and consistent with published guidelines. Opportunities for increased detection and treatment of depression exist in approximately half of the study practices.
Primary care clinicians, who by most estimates provide the majority of mental health care in the United States, are often criticized for the underdiagnosis and undertreatment of patients with depression.1 However, most studies antedate the widely publicized 1993 Agency for Health Care Policy and Research (AHCPR) primary care practice guidelines.2,3 A recent survey of 1350 primary care physicians documented diagnostic and treatment patterns consistent with high-quality care,4 but more information about actual practice is needed. Studies that examine depression management in the context of primary care using tools that enable the assessment of episodes of care are needed.5
The purpose of our study was to examine the initial pharmacologic management and follow-up of patients with newly diagnosed depression in primary care practice. The use of antidepressants among patients not diagnosed with depression was also examined. Our study was done within the Practice Partner Research Network (PPRNet), a national practice-based network of primary care physicians who use a common electronic medical record (Practice Partner, PMSI, Seattle, Wash) and pool data for research.6
We used a retrospective cohort design with the calendar year 1996 as the primary period of observation. Each month participating practices run a computer program to extract patient-level data from their electronic medical records. The first time the program runs, all existing data are extracted; in subsequent months only new data are extracted. To protect patient confidentiality, the program assigns a unique anonymous numerical identifier to each patient. Extracted data include diagnoses, medications, vital signs, laboratory results, and other variables; the text from progress notes and reports are not extracted. The information is copied to diskettes and mailed to the PPRNet coordinating center. At the center, data are aggregated and undergo rigorous quality control and bridging of text strings of diagnoses and medications to standard data dictionaries. Original text strings of diagnoses are maintained in the database. Updated data tapes are sent quarterly to the PPRNet offices at the Medical University of South Carolina Center for Health Care Research, where they are converted to SAS data sets (Statistical Analysis System, Cary, NC) on a UNIX computer. PPRNet staff use microcomputers with standard database and statistical software to perform all subsequent analyses.7
Practice eligibility criteria for our study included family medicine or general internal medicine specialty, enrollment in PPRNet before July 1, 1995, and reliable recording of diagnoses and medications. Patients were eligible for the study if they had at least one entry in their electronic medical records during the years 1993-1995 and were at least 18 years old by December 31, 1996.