PRIMARY CARE PHYSICIAN DEPARTURE: EFFECTS ON HEALTH CARE QUALITY. A.G. Pereira 1 , S.D. Pearson 1 ; 1 Harvard Medical School/Harvard Pilgrim Health Care, Boston, MA PURPOSE: Discontinuity of care is an important health policy issue, but few data exist to assess its effects on health care quality or outcomes. This study evaluated measures of health care quality in patients whose primary care providers (PCPs) left their medical practice. METHODS: This study was performed in a large, multi-site multispecialty group practice associated with a single insurer. We used a controlled pre-post design to compare measures of health care quality received by patients whose PCPs left the practice (LEAVEmds) with the measures of health care quality in patients whose PCPs did not leave the practice (STAYmds). For all patients, we compared rates of preventive care, and in patients with hypertension, we compared blood pressure control. The practice had a standardized process for reassigning patients of departing PCPs. Patients were eligible for analysis if their insurance and care within the practice was uninterrupted over a four-year study period. LEAVEmds were matched to eligible STAYmds by age, sex and practice site. RESULTS: During the study period, nine PCPs, caring for 3,931 patients, voluntarily left the group practice. These LEAVEmds were matched to 16 STAYmds, caring for 8,009 patients. Mean age of LEAVEmd patients and STAYmd patients was the same: 46 (13); 76%of the LEAVEmd patients were women, as compared to 80%of the STAYmd patients (p < 0.01). During the two baseline years prior to LEAVEmd departures, there were no differences in quality of care measures between the two groups of patients. In the two years following PCP departure there was no difference in rates of Pap smears among women aged 25 ± 65 (88%vs. 88%, p = 0.85), or in mammography in women 50 ± 65 (90%vs. 93%, p = 0.09). Rates of fecal occult blood testing for colon cancer in all patients aged 50 ± 65 were lower among LEAVEmd patients (51%vs. 56%, p = 0.02). There was no difference in the proportion of patients with hypertension who experienced a rise of !10%in mean systolic and/or diastolic blood pressure (6.0%vs. 7.0%, p = 0.53). CONCLUSION: Overall, PCP departure from this group practice was not associated with substantial decreases in rates of several important preventive screening measures for their patients who continued to receive care within the practice. Among patients with hypertension, we found no difference in rates of blood pressure control. Further research is needed to address two questions: first, whether these findings are consistent with the experiences of patients in a variety of practice settings, and second, whether PCP discontinuity may adversely affect subgroups of patients with other chronic conditions. PURPOSE: Helical computed tomography (CT) is commonly used to diagnose pulmonary embolism (PE), although its operating characteristics have been insufficiently evaluated. Therefore, we aimed to assess the performance of helical CT. METHODS: Two-hundred and ninety-nine consecutive patients admitted to the emergency ward for clinically suspected PE, with a D-dimer level above 500 "g/L (ELISA assay) were included. The diagnosis of PE was established by a validated algorithm including clinical assessment, lower limb compression ultrasonography, lung scan and pulmonary angiography. The CT scans were read by radiologists blind to all clinical data 3 months after image acquisition. RESULTS: Pulmonary embolism was present in 118 patients (39 %) in the study population. In 12 patients (4%), the CT scan was inconclusive, of whom two had a PE. Among patients with a conclusive CT, sensitivity of CT was 70%(95%CI 62 to 78), specificity was 91%(95%CI 86 to 95), positive predictive value was 84%(95%CI 76 to 91) and negative predictive value was 82%(95%CI 76 to 87). Sensitivity of a strategy adding lower limb ultrasound to helical CT increased to 79%(95%CI 71 to 86), and associating a lung scan in patients with normal ultrasound, helical CT being performed in patients with a nondiagnostic lung scan, would have a sensitivity of 95%(95%CI 89 to 98) and a specificity of 93%(95%CI 88 to 96). Interobserver agreement was high (kappa coefficients 0.82 to 0.90). CONCLUSION: Helical CT should not be used as a single test in suspected PE, but it could replace angiography in combined strategies including ultrasound and lung scan. PURPOSE: Helical computed tomography (CT) is increasingly used in the diagnosis of suspected pulmonary embolism, alone or in combination with other diagnostic tests, such as lung scan, lower limb ultrasound (US) or plasma D-dimer measurement (DD). Therefore, we assessed the cost-effectiveness of including helical CT in the diagnosis of suspected pulmonary embolism. METHODS: We performed a formal cost-effectiveness analysis by a decision model. Probabilities for test characteristics and clinical outcomes were obtained from the literature. Cost estimates were derived from our hospital's database. We compared 1) CT as a single test, and 2) inclusion of CT in a sequential strategy resting on clinical assessment, DD, US, lung scan and pulmonary angiography, either as a substitute for angiography or for lung scan. These strategies were compared with a reference strategy in which all patients with a nondiagnostic lung scan underwent an angiogram. Outcome measures were costs per patient, 3-month quality-adjusted survival, and incremental costs per quality-adjusted life years (QALYs) gained. RESULTS: Helical CT as a single test is associated with a 1%higher mortality than the reference strategy, and higher costs ($3,439 per QALY compared to $3,202 per QALY for the reference strategy). Replacing angiography by CT in the sequential strategy, was the most costeffective strategy ($2,447 per QALY gained). Replacing lung scan by CT was also cost-effective ($2,700 per QALY gained) provided an angiogram was performed in patients with a high clinical probability and a negative CT. Omitting DD measurement from the strategies increased costs but did not change effectiveness. The results were stable over the entire range of values tested in sensitivity analysis. CONCLUSION: Helical CT as a single test in suspected pulmonary embolism is not costeffective. However, CT may be cost-effective when included in combined diagnostic strategies.