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Pulmonary Embolism
appreciate how this would be a much greater problem in developing countries with a higher prevalence of TB and support Dr Dutt’s call for a consensus statement regarding the use of spirometry in TB-prevalent countries. Andrea S. Gershon, MD J. Charles Victor, MSc, PStat Jun Guan, MSc Teresa To, PhD Toronto, ON, Canada Shawn D. Aaron, MD Ottowa, ON, Canada Affiliations: fi From Sunnybrook y Health Sciences Centre (Dr Gershon); the Institute for Clinical Evaluative Sciences (Drs Gershon and To, Mr Victor, and Ms Guan); the Universityy of Toronto (Drs Gershon and To and Mr Victor); The Hospital p For Sick Children (Drs Gershon and To); and the Ottawa Hospital Research Institute (Dr Aaron), Universityy of Ottawa. Financial/nonfi financial disclosures: The authors have reported p to CHEST T that no p potential confl flicts of interest exist with anyy companies/organizations p g whose products or services may be discussed in this article. Correspondence p to: Andrea S. Gershon, MD, Sunnybrook y Health Sciences Centre, G1 06, 2075 Bayview y Ave, Toronto, ON, M4N 3M5, Canada; e-mail: [email protected] g © 2012 American College g of Chest Physicians. y Reproduction p of this article is prohibited p without written permission p from the American College g of Chest Physicians. y See online for more details. DOI: 10.1378/chest.12-1428
References 1. Gershon AS, Victor JC, Guan J, Aaron SD, To T. Pulmonary function testing in the diagnosis of asthma: a population study. Chest. 2012;141(5):1190-1196.
Pulmonary Embolism Weekend Effect or Monday Effect? To the Editor: The thought-provoking study by Nanchal et al1 in CHEST (September 2012) shows that patients admitted to the hospital with a principal diagnosis of pulmonary embolism (PE) during weekends have a signifi ficantly higher risk of in-hospital death than those admitted on weekdays (OR, 1.17; 95% CI, 1.11-1.22). The authors suggest that delayed access to inferior vena cava (IVC) filters during weekends might explain this finding. We believe that alternative interpretations merit consideration. As the authors rightly point out, weekend admissions represent only 21% of all admissions, instead of 28.5% (two out of seven). A simple and plausible interpretation for this finding is a selection bias: Some patients with the least severe clinical forms of PE delay the diagnostic workup (and eventual admission) up to the next working day, whereas patients with severe PEs cannot and do not. The signifi ficantly higher rate of severe PEs among weekend admissions (2.8% vs 2.3%, P , .05) supports this interpretation. Interestingly, if such a bias does exist, Mondays should be associated with the highest absolute number of admissions and the lowest death rate of the week, which could be called a “Monday effect.” Could the authors provide this information? The authors also suggest that delayed IVC filter fi placements could explain a higher death rate. However, it is far from established that filters, fi let alone the “timeliness” of filter placement, have an impact on mortality.2-5 Furthermore, as compared with European journal.publications.chestnet.org
studies, the overall filter fi placement rate in this study (13.6%) is disturbingly high. In the Computerized Registry of Patients With VTE (RIETE), a mainly European database, only 2% of patients with VTE received an IVC filter fi as part of their initial treatment.3 The only two recommended indications for filter fi placement in patients with PE (ie, contraindications to curative anticoagulation and PE despite adequate anticoagulation)4 are unlikely to be more frequent in the United States than in Europe. Therefore, in the study by Nanchal et al,1 if a substantial proportion of the indications for filter placement in the population were questionable (eg, IVC filters fi in addition to anticoagulants4), the prognostic impact of delayed placements would appear even more questionable. The increased mortality rate reported by Nanchal et al1 among weekend admissions for PE may represent real excess deaths. But more convincing arguments are needed to rule out a mere selection bias. And without precise information regarding the indications for filter placement and concurrent anticoagulant use, the timing of IVC filter insertions cannot be regarded as a reliable marker of the quality of care in patients with PE. Philippe Girard, MD, FCCP Guy Meyer, MD Paris, France Patrick Mismetti, MD, PhD Saint Etienne, France Affi filiations: From the Département p Thoracique q (Dr Girard), Institut Mutualiste Montsouris; the Service de Pneumologie g et Soins Intensifs (Dr Meyer), y Hôpital p Européen p Georges g Pompip dou; and the Unité de Pharmacologie Clinique (Dr Mismetti), CHU de Saint Etienne. Financial/nonfi financial disclosures: The authors have reported p to CHEST T that no potential p confl flicts of interest exist with anyy companies/organizations p g whose products or services may be discussed in this article. Correspondence p to: Philippe pp Girard, MD, FCCP, Département p Thoracique, q Institut Mutualiste Montsouris, 42 boulevard Jourdan, 75014, Paris, France; e-mail: p [email protected] pp g © 2012 American College g of Chest Physicians. y Reproduction p of this article is prohibited p without written permission p from the American College g of Chest Physicians. y See online for more details. DOI: 10.1378/chest.12-1262
References 1. Nanchal R, Kumar G, Taneja A, et al; from the Milwaukee Initiative in Critical Care Outcomes Research (MICCOR) Group of Investigators. Pulmonary embolism: the weekend effect. Chest. 2012;142(3):690-696. 2. Decousus H, Leizorovicz A, Parent F, et al. A clinical trial of vena caval filters fi in the prevention of pulmonary embolism in patients with proximal deep-vein thrombosis. Prévention du Risque d’Embolie Pulmonaire par Interruption Cave Study Group. N Engl J Med. 1998;338(7):409-415. 3. Monreal M, Falgá C, Valdés M, et al; RIETE Investigators. Fatal pulmonary embolism and fatal bleeding in cancer patients with venous thromboembolism: findings from the RIETE registry. J Thromb Haemost. 2006;4(9):1950-1956. 4. Kearon C, Akl EA, Comerota AJ, et al. Antithrombotic therapy for VTE disease: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2010; 141(2)(suppl):e419S-e494S. 5. Spencer FA, Bates SM, Goldberg RJ, et al. A populationbased study of inferior vena cava filters fi in patients with acute venous thromboembolism. Arch Intern Med. 2010;170(16): 1456-1462. CHEST / 142 / 4 / OCTOBER 2012
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References 1. Gershon AS, Victor JC, Guan J, Aaron SD, To T. Pulmonary function testing in the diagnosis of asthma: a population study. Chest. 2012;141(5):1190-1196.
Pulmonary Embolism Weekend Effect or Monday Effect? To the Editor: The thought-provoking study by Nanchal et al1 in CHEST (September 2012) shows that patients admitted to the hospital with a principal diagnosis of pulmonary embolism (PE) during weekends have a signifi ficantly higher risk of in-hospital death than those admitted on weekdays (OR, 1.17; 95% CI, 1.11-1.22). The authors suggest that delayed access to inferior vena cava (IVC) filters during weekends might explain this finding. We believe that alternative interpretations merit consideration. As the authors rightly point out, weekend admissions represent only 21% of all admissions, instead of 28.5% (two out of seven). A simple and plausible interpretation for this finding is a selection bias: Some patients with the least severe clinical forms of PE delay the diagnostic workup (and eventual admission) up to the next working day, whereas patients with severe PEs cannot and do not. The signifi ficantly higher rate of severe PEs among weekend admissions (2.8% vs 2.3%, P , .05) supports this interpretation. Interestingly, if such a bias does exist, Mondays should be associated with the highest absolute number of admissions and the lowest death rate of the week, which could be called a “Monday effect.” Could the authors provide this information? The authors also suggest that delayed IVC filter fi placements could explain a higher death rate. However, it is far from established that filters, fi let alone the “timeliness” of filter placement, have an impact on mortality.2-5 Furthermore, as compared with European journal.publications.chestnet.org
studies, the overall filter fi placement rate in this study (13.6%) is disturbingly high. In the Computerized Registry of Patients With VTE (RIETE), a mainly European database, only 2% of patients with VTE received an IVC filter fi as part of their initial treatment.3 The only two recommended indications for filter fi placement in patients with PE (ie, contraindications to curative anticoagulation and PE despite adequate anticoagulation)4 are unlikely to be more frequent in the United States than in Europe. Therefore, in the study by Nanchal et al,1 if a substantial proportion of the indications for filter placement in the population were questionable (eg, IVC filters fi in addition to anticoagulants4), the prognostic impact of delayed placements would appear even more questionable. The increased mortality rate reported by Nanchal et al1 among weekend admissions for PE may represent real excess deaths. But more convincing arguments are needed to rule out a mere selection bias. And without precise information regarding the indications for filter placement and concurrent anticoagulant use, the timing of IVC filter insertions cannot be regarded as a reliable marker of the quality of care in patients with PE. Philippe Girard, MD, FCCP Guy Meyer, MD Paris, France Patrick Mismetti, MD, PhD Saint Etienne, France Affi filiations: From the Département p Thoracique q (Dr Girard), Institut Mutualiste Montsouris; the Service de Pneumologie g et Soins Intensifs (Dr Meyer), y Hôpital p Européen p Georges g Pompip dou; and the Unité de Pharmacologie Clinique (Dr Mismetti), CHU de Saint Etienne. Financial/nonfi financial disclosures: The authors have reported p to CHEST T that no potential p confl flicts of interest exist with anyy companies/organizations p g whose products or services may be discussed in this article. Correspondence p to: Philippe pp Girard, MD, FCCP, Département p Thoracique, q Institut Mutualiste Montsouris, 42 boulevard Jourdan, 75014, Paris, France; e-mail: p [email protected] pp g © 2012 American College g of Chest Physicians. y Reproduction p of this article is prohibited p without written permission p from the American College g of Chest Physicians. y See online for more details. DOI: 10.1378/chest.12-1262
References 1. Nanchal R, Kumar G, Taneja A, et al; from the Milwaukee Initiative in Critical Care Outcomes Research (MICCOR) Group of Investigators. Pulmonary embolism: the weekend effect. Chest. 2012;142(3):690-696. 2. Decousus H, Leizorovicz A, Parent F, et al. A clinical trial of vena caval filters fi in the prevention of pulmonary embolism in patients with proximal deep-vein thrombosis. Prévention du Risque d’Embolie Pulmonaire par Interruption Cave Study Group. N Engl J Med. 1998;338(7):409-415. 3. Monreal M, Falgá C, Valdés M, et al; RIETE Investigators. Fatal pulmonary embolism and fatal bleeding in cancer patients with venous thromboembolism: findings from the RIETE registry. J Thromb Haemost. 2006;4(9):1950-1956. 4. Kearon C, Akl EA, Comerota AJ, et al. Antithrombotic therapy for VTE disease: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2010; 141(2)(suppl):e419S-e494S. 5. Spencer FA, Bates SM, Goldberg RJ, et al. A populationbased study of inferior vena cava filters fi in patients with acute venous thromboembolism. Arch Intern Med. 2010;170(16): 1456-1462. CHEST / 142 / 4 / OCTOBER 2012
1073