BMJ 2013;347:f7340 doi: 10.1136/bmj.f7340 (Published 9 December 2013)
Page 1 of 1
Letters
LETTERS ERYTHROCYTOSIS
Obstructive sleep apnoea does not lead to clinically significant erythrocytosis Andrew J King haematology registrar, Toby Eyre haematology registrar, Tim Littlewood consultant haematologist Department of Haematology, Oxford University Hospitals NHS Trust, Oxford, UK
Keohane and colleagues report that obstructive sleep apnoea should be considered in the differential diagnosis of a secondary erythrocytosis.1 Obstructive sleep apnoea is also mentioned as a cause of secondary erythrocytosis in the national guidelines on the diagnosis, investigation, and management of erythrocytosis.2 However, the evidence that this condition can cause clinically significant erythrocytosis is largely anecdotal or based on case reports.
Only two large studies have looked at this matter, and both concluded that although obstructive sleep apnoea may lead to minor increases in packed cell volume, it does not cause clinically significant erythrocytosis.3 4 This mild increase is almost certainly caused by a reduction in plasma volume (relative or apparent erythrocytosis) rather than hypoxia, because continuous positive airway pressure is sufficient to reduce the packed cell volume after only 24 hours of treatment.5 Obstructive sleep apnoea alone is therefore not sufficient to explain
secondary erythrocytosis and other causes should always be sought. Competing interests: None declared. 1 2 3 4 5
Keohane C, McMullin MF, Harrison C. The diagnosis and management of erythrocytosis. BMJ 2013;347:f6667. (18 November.) McMullin MF, Bareford D, Campbell P, Green AR, Harrison C, Hunt B, et al. Guidelines for the diagnosis, investigation and management of polycythaemia/erythrocytosis. Br J Haematol 2005;130:174-95. Hoffstein V, Herridge M, Mateika S, Redline S, Strohl KP. Hematocrit levels in sleep apnea. Chest 1994;106:787-91. Choi JB, Loredo JS, Norman D, Mills PJ, Ancoli-Israel S, Ziegler MG, et al. Does obstructive sleep apnea increase hematocrit? Sleep Breath 2006;10:155-6. Krieger J, Sforza E, Delanoe C, Petiau C. Decrease in hematocrit with continuous positive airway pressure treatment in obstructive sleep apnea patients. Eur Respir J 1992;5:228-233.
Cite this as: BMJ 2013;347:f7340 © BMJ Publishing Group Ltd 2013
[email protected] For personal use only: See rights and reprints http://www.bmj.com/permissions
Subscribe: http://www.bmj.com/subscribe
Page 1 of 1
Letters
LETTERS ERYTHROCYTOSIS
Obstructive sleep apnoea does not lead to clinically significant erythrocytosis Andrew J King haematology registrar, Toby Eyre haematology registrar, Tim Littlewood consultant haematologist Department of Haematology, Oxford University Hospitals NHS Trust, Oxford, UK
Keohane and colleagues report that obstructive sleep apnoea should be considered in the differential diagnosis of a secondary erythrocytosis.1 Obstructive sleep apnoea is also mentioned as a cause of secondary erythrocytosis in the national guidelines on the diagnosis, investigation, and management of erythrocytosis.2 However, the evidence that this condition can cause clinically significant erythrocytosis is largely anecdotal or based on case reports.
Only two large studies have looked at this matter, and both concluded that although obstructive sleep apnoea may lead to minor increases in packed cell volume, it does not cause clinically significant erythrocytosis.3 4 This mild increase is almost certainly caused by a reduction in plasma volume (relative or apparent erythrocytosis) rather than hypoxia, because continuous positive airway pressure is sufficient to reduce the packed cell volume after only 24 hours of treatment.5 Obstructive sleep apnoea alone is therefore not sufficient to explain
secondary erythrocytosis and other causes should always be sought. Competing interests: None declared. 1 2 3 4 5
Keohane C, McMullin MF, Harrison C. The diagnosis and management of erythrocytosis. BMJ 2013;347:f6667. (18 November.) McMullin MF, Bareford D, Campbell P, Green AR, Harrison C, Hunt B, et al. Guidelines for the diagnosis, investigation and management of polycythaemia/erythrocytosis. Br J Haematol 2005;130:174-95. Hoffstein V, Herridge M, Mateika S, Redline S, Strohl KP. Hematocrit levels in sleep apnea. Chest 1994;106:787-91. Choi JB, Loredo JS, Norman D, Mills PJ, Ancoli-Israel S, Ziegler MG, et al. Does obstructive sleep apnea increase hematocrit? Sleep Breath 2006;10:155-6. Krieger J, Sforza E, Delanoe C, Petiau C. Decrease in hematocrit with continuous positive airway pressure treatment in obstructive sleep apnea patients. Eur Respir J 1992;5:228-233.
Cite this as: BMJ 2013;347:f7340 © BMJ Publishing Group Ltd 2013
[email protected] For personal use only: See rights and reprints http://www.bmj.com/permissions
Subscribe: http://www.bmj.com/subscribe
