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Biomedical subjects

Andrew T McAfee

Publications and source records attributed to Andrew T McAfee.

7 recordsLinked to original sources
PubMed2006

The probability of pulmonary embolism is a function of the diagnoses considered most likely before testing.

OBJECTIVES: To determine the frequency of pulmonary embolism (PE) diagnosis when different alternative diagnoses were considered most likely before testing, because the relationship between specific alternative diagnoses and the diagnosis of PE has not been explored. METHODS: This study was a preplanned secondary analysis of a prospective study of the diagnosis of pulmonary embolism conducted in the emergency department (ED) of an urban university hospital. Physicians were queried as to their most likely pretest diagnosis when they ordered any of the following tests to evaluate possible PE: D-dimer, contrast-enhanced computed tomography of the chest, ventilation-perfusion lung scan, or pulmonary angiogram. To compare the frequency of PE diagnosis across alternative diagnoses, risk ratios, 95% confidence intervals (CI), and p-values using Fisher's exact test were calculated. RESULTS: Six hundred seven patients were enrolled, and 61 had PE. Physicians thought PE was the most likely pretest diagnosis in 162 (26.7%) patients, and 20.4% (95% CI = 14.4% to 27.4%) of these patients had PE. For four alternative diagnoses, PE was diagnosed less frequently than when PE was considered most likely: musculoskeletal pain (2.2%, 95% CI = 0.4% to 6.2%), anxiety (1.7%, 95% CI = 0.0 to 9.2%), asthma or chronic obstructive pulmonary disease (0, 95% CI = 0.0 to 10.9%), and viral syndrome (0, 95% CI = 0.0 to 14.3%). CONCLUSIONS: The frequency of PE is related to the most likely pretest alternative diagnosis. PE is diagnosed infrequently when anxiety, asthma or chronic obstructive pulmonary disease, musculoskeletal pain, or viral syndrome is the most likely alternative diagnosis.

Diagnosis, Differential↗
PubMed2006

Rosuvastatin safety: a comprehensive, international pharmacoepidemiology programme.

Results from clinical trials and clinical practice have shown statins to be generally well tolerated with a low frequency of clinically relevant side effects. Nevertheless, there are rare occasions when adverse events (AEs), sometimes serious, may occur. Rosuvastatin is the newest statin to be approved in the USA and many other countries. As part of the continued assessment of the benefit-risk profile of rosuvastatin, AstraZeneca has developed a progressive, comprehensive pharmacoepidemiology programme to complement safety data obtained from randomised clinical trials and spontaneous reporting systems, which have demonstrated that rosuvastatin has a safety profile in line with comparator statins. This programme comprises nine studies conducted in recognised centres of excellence assessing over 50,000 patients treated with rosuvastatin. It consists of three components: patient characteristics studies (four studies), safety evaluation studies (four studies); and review of data generated from the Prescription-Event Monitoring (PEM) study, designed and run by an independent third party. Patient characteristics studies are designed to describe the characteristics and drug utilisation patterns of new users of rosuvastatin compared with new users of other statins in automated databases. Safety evaluation studies will examine the rates of specific AEs in different cohorts of statin users and determine risk factors for these events using data recorded prospectively in automated databases with case adjudication via medical record review. The independent PEM study will monitor any significant events recorded by general practitioners since starting rosuvastatin treatment. This article is an overview of the rationale and methodology of the rosuvastatin pharmacoepidemiology programme.

Canada↗
PubMed2006

The comparative safety of rosuvastatin: a retrospective matched cohort study in over 48,000 initiators of statin therapy.

PURPOSE: The purpose of this study was to compare incidence rates of hospitalization associated with rhabdomyolysis, myopathy, renal, or hepatic dysfunction, and of in-hospital death, between initiators of rosuvastatin and other statins. METHODS: This was a matched cohort study of statin initiators from the administrative database of a large health insurer in the US, during the first 6 months of rosuvastatin availability with up to 18 months of follow-up. All outcome events were verified by medical record review. Incidence rates, risk ratios, and associated 95% confidence intervals were estimated. RESULTS: From an initial pool of 12,217, 11,249 eligible rosuvastatin initiators were matched to 37,282 initiators of other statins. The incidence rate (IR) per 1000 person-years for rhabdomyolysis was 0.10 [0.00, 0.55] for rosuvastatin initiators (n = 1) and 0.06 [0.01, 0.22] for other statin initiators (n = 2), for a hazard ratio (HR) of 1.98 [0.18, 21.90]. The IR for myopathy was 0.20 [0.02, 0.71] for rosuvastatin initiators (n = 2) and 0.00 [0.00, 0.09] for other statin initiators (n = 0). The IR for renal dysfunction was 1.18 [0.61, 2.06] for rosuvastatin initiators (n = 12) and 1.26 [0.91, 1.71] for other statin initiators (n = 42), for a HR of 0.90 [0.47, 1.73]. The IR for hepatic dysfunction was 0.20 (0.02, 0.71) for rosuvastatin initiators (n = 2) and 0.24 (0.10, 0.47) for other statin initiators (n = 8), for a HR of 0.87 (0.18, 4.14). CONCLUSIONS: This study found no difference between rosuvastatin and the other statins in the incidence of hospitalizations associated with renal or hepatic events, or death. The absolute incidence rates of rhabdomyolysis and myopathy were reassuringly low among all statin initiators but remain too small for firm conclusions to be drawn on any difference between the statins.

Adolescent↗
PubMed2005

The contribution of the subjective component of the Canadian Pulmonary Embolism Score to the overall score in emergency department patients.

BACKGROUND: Clinicians frequently use their experience to determine the pretest probability of pulmonary embolism (PE), although scoring systems are promoted as being more reliable. The Canadian Pulmonary Embolism Score (CPES) combines six objective questions and one subjective question. The CPES has been validated and appears to be useful for risk-stratifying patients. However, research suggests that subjective gestalt performs similarly to the CPES, and the influence of the subjective question on the predictive value of the CPES is not clear. OBJECTIVES: To determine the test characteristics of the CPES, its subjective question, and the degree to which the predictive value of the CPES is influenced by its individual questions. METHODS: The authors performed a prospective observational study on a cohort of emergency department patients suspected of having PE. The authors compared patients' CPES results with the diagnosis of PE, calculated the test characteristics of the CPES, and determined the contribution of individual CPES questions to the score's overall predictive value. RESULTS: Of 607 patients, 61 (10%) had PE. Of low-risk patients (CPES < or =4), 5.54% (n = 449; 95% confidence interval [95% CI] = 3.64% to 8.11%) had PE. The sensitivity (59.0%; 95% CI = 47.4% to 69.8%) and the negative predictive value (94.4%; 95% CI = 92.8% to 95.9%) of the CPES were similar to the sensitivity (53.2%; 95% CI = 40.2% to 65.8%) and negative predictive value (93.5%; 95% CI = 90.7% to 95.5%) of the subjective question alone. In multivariable analysis, nearly all of the predictive value of the CPES was derived from the subjective question. CONCLUSIONS: The predictive value of the CPES appears to be derived primarily from its subjective component.

Antifibrinolytic Agents↗
PubMed2003

Panic disorder and emergency services utilization.

OBJECTIVES: The characteristics of patients with panic disorder in emergency department (ED) patient populations are unknown. This study compares demographic information and emergency care use among patients identified as having a high likelihood of having panic disorder with that of patients who tested negative on the screening test for panic disorder. METHODS: Prospective cross-sectional study of a convenience sample of patients presenting to an urban ED. Patients were excluded if they were aged 18 years or younger, were unstable, or could not speak English or Spanish. Of 968 patients, 813 agreed to participate. Over a period of 23 days, patients were administered a Diagnostic and Statistical Manual (DSM)-IV screening questionnaire (PRIME-MD) for panic disorder along with a survey assessing their use of medical services during the prior year. RESULTS: One hundred patients (12.3%) met PRIME-MD criteria for having a high likelihood of panic disorder. Patients with Medicare were 2.84 times more likely to have a positive result on the screening test than those without insurance. Patients who had four to seven ED visits or eight or more ED visits in one year were 2.63 and 3.10 times more likely to screen positive on the PRIME-MD, respectively, compared with those who had one to three visits. Patients who activated 911 two to ten times or 11 or more times in one year were 2.02 and 4.99 times more likely to screen positive for panic disorder, respectively, compared with those who had never activated 911. CONCLUSIONS: Patients who screen positive for panic disorder use emergency medical services and ED services more frequently. In addition, the overall prevalence of screening positive for panic disorder in an ED is higher than previously reported.

Adult↗
PubMed2002

Assessment of stroke index using impedance cardiography: comparison with traditional vital signs for detection of moderate acute blood loss in healthy volunteers.

OBJECTIVES: Impedance cardiography has been used to detect early hemorrhagic shock, but, to the best of the authors' knowledge, no previous study has looked at the test characteristics of bioimpedance-derived hemodynamic parameters for the detection of a measured loss of blood volume. The authors set out to investigate the effect of controlled hemorrhage on stroke index (SI) using impedance cardiography, and to evaluate the performance of this test for moderate blood loss in comparison with the performance of traditional vital signs. METHODS: Supine and standing measurements of SI were made using a thoracic electrical bioimpedance monitor in 197 healthy, adult volunteers before and after donation of a standard unit (500 mL) of whole blood. Pre- and post-donation means for supine SI, heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP), and for the postural changes in each of these measurements ( triangle up SI, triangle up HR, triangle up SBP, triangle up DBP), were compared using a paired-sample, two-tailed t-test. For each term, receiver operating characteristic (ROC) curves were generated, treating pre- and post-donation populations as independent. Areas under the ROC curves were compared using a method for correlated test result data. RESULTS: Mean +/- SD pre- and post-donation values for SI were 47.0 +/- 6.9 mL/m(2) and 43.9 +/- 7.3 mL/m(2), respectively (p < 0.0001). Mean pre- and post-donation values for triangle up SI were -7.7 +/- 5.8 mL/m(2) and -9.0 +/- 8.2 mL/m(2), respectively (p = 0.02). For discriminating between pre- and post-donation status, the areas under the ROC curves for SI and triangle up SI were 0.62 and 0.58, respectively. In comparison, the areas under the ROC curves for HR, SBP, DBP, triangle up HR, triangle up SBP, and triangle up DBP were 0.49, 0.61, 0.56, 0.82, 0.53, and 0.50, respectively. The area under the ROC curve for triangle up HR was significantly greater than the area under any of the other curves (p < 0.0001). CONCLUSIONS: Moderate blood loss was associated with a decline in mean SI that was clearly detectable with impedance cardiography. However, as a test for moderate blood loss in this controlled setting, neither SI nor triangle up SI performed better than traditional vital signs.

Adult↗