Nasal Expiratory Positive Airway Pressure Devices (Provent) for OSA: A Systematic Review and Meta-Analysis

Table 1

General characteristics of original studies.

Author, year, country	Study type, methods	Number of patients	Duration of treatment	Demographics (M/F)	Average/mean age (years), M/F	Average/mean BMI; M/F	OSA severity	Main findings/treatment duration effect
Colrain et al., 2008 [12]; USA	(i) Prospective; (ii) 30 subjects randomly divided into two groups (16 & 14) treated versus nontreated with n-EPAP; (iii) No placebo nasal device; (iv) Resistance of device: 60–90 cm H20 sec/Liter	30; 24 OSA and 6 primary snorers	1 night	20/10	50.1 ± 9.8/49.0 ± 12.9	28.2 ± 4.0/27.0 ± 5.34	Mild to severe; AHI (5.1–83.8)	AHI and ODI decreased, minimum SPO2 increased significantly
Patel et al., 2011 [13]; USA	(i) Prospective study; (ii) Two-night PSG, one with n-EPAP and another with CPAP to check for efficacy and identify predictors of response and possible mechanisms for n-EPAP; (iii) Resistance of device: 80 cm H20 sec/Liter	20 (19 included in final analysis)	2 nights	15/5	54.3 ± 12.0	33.5 ± 5.6	Mild to severe; AHI with 4% desaturation; (34 ± 30/h)	(i) RDI was reduced significantly; (ii) Demographics, lung volumes, , PSG measures are not good predictors of therapeutic success; (iii) Positional OSA is a better predictor
Rossi et al., 2013 [14]; UK, Switzerland	(i) Prospective; (ii) Randomized, dual-center, parallel, placebo-controlled clinical trial; (iii) Comparison between Placebo-Provent, Provent, and CPAP after 2-week therapy of each treatment modality	67	~2 weeks	53/14	CPAP: 64.4 ± 7.7; Provent: 63.2 ± 8.7; Placebo: 59.7 ± 12.5	CPAP: 35.1 ± 6.0; Provent: 33.4 ± 6.6; Placebo: 33.0 ± 6.2	Moderate to severe	@2 weeks: ODI went up to 35.8 ± 17.4, AHI to 27.6 ± 16.4 from 4.3 ± 5.1 & 2.4. ± 2.4 in Provent, respectively; @2 weeks: ODI went up to 28.2 ± 18.3, AHI to 24.2 ± 16.8 from 4.3 ± 5.1 & 2.4. ± 2.4 in Placebo-Provent, respectively
Friedman et al., 2015 [15]; USA	(i) Prospective; (ii) Two-arm pilot study; Arm 1: no nasal symptoms and <50% nasal obstruction; Arm 2: occasional nasal symptoms and 50%–80% nasal obstruction	38	1 mo.	54–76% males	Arm 1: 51.5 ± 11.8; Arm 2: 51.3 ± 11.6	Arm 1: 29.4 ± 5.0; Arm 2: 30.3 ± 3.7	Mild to moderate	Arm 1: 43.3% failure rate, overall 45.2% cured and 9.7% treatment success; Arm 2: failed treatment
Rosenthal et al., 2009 [16]; USA	(i) Prospective, multicenter trial; (ii) 4-night protocol, 1-night baseline PSG, 3 nights with device of varying expiratory resistance (50, 80, and 110 cm H20 sec/Liter); (iii) Final PSG after 30-day device use	28	1 mo.	22/6	49.8 ± 10.2	30.1 ± 5.9	Mild to moderate	@3 initial treatment nights: 59% response rate in reducing AHI to 50% (13.5 ± 18.7 versus control 24.5 ± 23.6) (); @1 month: 41%; (15.5 ± 18.9 versus control as above); ()
Walsh et al., 2011 [17]; USA	(i) Prospective study; (ii) Three-night protocol with PSG1 without n-EPAP, PSG2 with n-EPAP at 10 days following PSG1, and PSG3 with n-EPAP after 5-6 weeks of PSG2; (iii) Resistance of device: 50, 80 cm H20 sec/Liter	43	2 mo.	27/16	53.7 ± 10.9	34.9 ± 6.7	Moderate to severe; (43.3 ± 29.0/h)	(i) AHI at PSG1 31.9 ± 19.8, PSG2; 11.0 ± 7.9 & PSG3 16.4. ± 12.2; (ii) AHI at PSG2 & PSG3 was decreased; however AHI slightly increased at PSG3 compared to PSG2
Berry et al., 2011 [18]; USA	(i) Prospective, randomized, double-blinded, multicenter, parallel group, sham-controlled trial; (ii) Comparison of n-EPAP on & off versus sham device over 3 months; (iii) Resistance of device: 80 cm H20 sec/Liter	229	3 mo.	Device: 65.5% males; Sham: 71.4% males	Device: 47.7 ± 13.4 ITT; Sham: 46.8 ± 12.0 ITT; Device: 49 ± 13.1 mITT; Sham: 47.3 ± 12.3 mITT; (Age difference nonsignificant in both groups)	Device: 32.6 ± 7.0; Sham: 33.8 ± 6.5; Device: 32.8 ± 6.7 mITT; Sham: 34.6 ± 6.6 mITT; (BMI difference nonsignificant in both groups)	Mild to severe (mainly mild to moderate); Device: 5.3 ± 22.6; Sham: 4.8 ± 21.8	@1 week: median AHI change 52.7% (ITT) & 55.1% (mITT) (); @3 months: median AHI change 42.7% (ITT) & 42.8% (mITT) (); @1 week: median ODI change 43.2% (mITT) (); @3 months: median ODI change 35.2% (mITT) (); @3 months: ESS change 9.9 ± 4.7 to 7.2 ± 4.2 () in NEPAP versus sham 9.6 ± 4.9 to 8.3 ± 5.1 (). In mITT ESS decreased in both as well
Kryger et al., 2011 [19]; USA	(i) Prospective, multicenter, single arm, open labeled extension trial of 3-month n-EPAP versus sham study; (ii) Comparison of n-EPAP on & off versus sham device over 12 months; (iii) Resistance of device: 80 cm H20 sec/Liter	34	12 mo.	63.4% M	50.1 ± 13.6	32.5 ± 7.5	Mild to severe	@12 mo.: median AHI reduced to 4.7 versus baseline 15.7 (71.3% success rate); (i) ODI decreased to 7.6 versus baseline 12.6; (ii) ESS decreased to 6 versus baseline 11

No strict follow-up was aimed or short-term follow-up or no follow-up. Most studies in this category completed assessment within the above-mentioned time periods.
n-EPAP: nasal EPAP (Provent); CPAP: continuous positive airway pressure; PSG: polysomnogram; ESS: Epworth Sleepiness Scale; ITT: intention to treat; mITT: modified intention to treat.