Abhishek Goyal1, Abhijit Pakhare2, Ishan Raj Tiwari3, Alkesh Khurana4, Poonam Chaudhary5. 1. Pulmonary Medicine, AIIMS Bhopal, India. Electronic address: abhishek.pulmed@aiimsbhopal.edu.in. 2. Community and Family Medicine, AIIMS Bhopal, India. 3. AIIMS Bhopal, India. 4. Pulmonary Medicine, AIIMS Bhopal, India. 5. Department of Biochemistry, AIIMS Bhopal, India.
Abstract
BACKGROUND: Recently, new classification criteria for obesity hypoventilation syndrome (OHS) have been described. OHS prevalence according to new criteria has not been reported in obstructive sleep apnea (OSA). Prevalence of OHS has not been previously reported from India. METHODS: Retrospective study was carried out in OSA patients for whom both arterial blood gases (ABG) and end-tidal CO2 (etCO2) records were available. OHS was defined according to old and new criteria. Analysis was carried out among various groups: patients without OHS (Group A), patients with sleep hypoventilation but without daytime hypercapnia (Group B) and patients with daytime hypercapnia (Group C). RESULTS: Out of 367 patients with OSA (body mass index, BMI) 31.9 ± 12.27 kg/m2), finally 128 obese OSA patients were included for analysis. Of those, 15 (5.9%, 95% confidence interval (CI) 3.5-9.4) and 45 patients (17.8%, 95% CI 13.4-22.9) fulfilled prevalence of OHS according to old and new criteria, respectively. Continuous positive airway pressure (CPAP) titration failed in 9.6%, 53.3% and 66.7% in Groups A, B, and C, respectively. For all parameters of OSA severity (apnea-hypopnea index (AHI), Nadir O2, T90) and positive airway pressure (PAP) requirements, patients in Group B were in between those in Groups A and C. Statistically significant difference was seen between Group A and Group B, and between Groups A and C, but not between Groups B and C. CONCLUSION: One in six OSA patients and one in three obese OSA patients (BMI >30 kg/m2) have OHS according to new criteria. Since patients with isolated nocturnal hypoventilation were as sick as patients with daytime hypercapnia, screening for sleep hypoventilation should be carried out in all obese OSA patients.
BACKGROUND: Recently, new classification criteria for obesity hypoventilation syndrome (OHS) have been described. OHS prevalence according to new criteria has not been reported in obstructive sleep apnea (OSA). Prevalence of OHS has not been previously reported from India. METHODS: Retrospective study was carried out in OSApatients for whom both arterial blood gases (ABG) and end-tidal CO2 (etCO2) records were available. OHS was defined according to old and new criteria. Analysis was carried out among various groups: patients without OHS (Group A), patients with sleep hypoventilation but without daytime hypercapnia (Group B) and patients with daytime hypercapnia (Group C). RESULTS: Out of 367 patients with OSA (body mass index, BMI) 31.9 ± 12.27 kg/m2), finally 128 obeseOSApatients were included for analysis. Of those, 15 (5.9%, 95% confidence interval (CI) 3.5-9.4) and 45 patients (17.8%, 95% CI 13.4-22.9) fulfilled prevalence of OHS according to old and new criteria, respectively. Continuous positive airway pressure (CPAP) titration failed in 9.6%, 53.3% and 66.7% in Groups A, B, and C, respectively. For all parameters of OSA severity (apnea-hypopnea index (AHI), Nadir O2, T90) and positive airway pressure (PAP) requirements, patients in Group B were in between those in Groups A and C. Statistically significant difference was seen between Group A and Group B, and between Groups A and C, but not between Groups B and C. CONCLUSION: One in six OSApatients and one in three obeseOSApatients (BMI >30 kg/m2) have OHS according to new criteria. Since patients with isolated nocturnal hypoventilation were as sick as patients with daytime hypercapnia, screening for sleep hypoventilation should be carried out in all obeseOSApatients.