Erythropoietin levels with treatment of obstructive sleep apnea.

The effect of nasal continuous positive pressure (CPAP) treatment on erythropoietin (EPO) was examined by measuring diurnal serum EPO levels before and twice (over the 3rd day and over 1 day on recall after > or = 1 mo of therapy) after initiation of treatment in 12 obstructive sleep apnea syndrome patients with normal hemoglobin, hematocrit, creatinine, blood urea nitrogen, and albumin levels. Over each study day, oxygen saturation was measured by an ambulatory pulse oximetry system. Patients spent 27 +/- 9% (SE) of time below oxygen saturation of 88% vs. 2.1 +/- 0.6% after initiation of nasal CPAP treatment (P < 0.01). The number of desaturation events per hour of sleep before nasal CPAP treatment was 62 +/- 6 vs. 9 +/- 2 with nasal CPAP (P < 0.01). EPO levels measured by radioimmunoassay were drawn every hour before and at 3 days (n = 9) and before and at recall (n = 0) after initiation of CPAP therapy. The mean serum EPO level was higher before treatment (61 +/- 14 mU/ml) than that at 3 days (38 +/- 10 mU/ml, P < 0.01) or at recall (32 +/- 7 mU/ml, P < 0.01). We conclude that nasal CPAP treatment of sleep-disordered breathing will reduce diurnal levels of EPO.