TABLE IX.A.1.

Evidence for defining CPAP non-adherence

Study	Year	LOE	Study design	Study groups	Clinical end-points	Conclusion
Faccenda et al.1477	2001	1b	RCT crossover study	1. Control placebo pill (n = 70) 2. CPAP use group (n = 71)	Change in BP, ESS, FOSQ	Patients on CPAP with use >3.5 h/night had a drop in BP 1.5 mmHg.
Redline et al.1310	1999	1b	RCT	RDI < 30 and nonsleepy patients randomized 1. Control conservative therapy (n = 52) 2. CPAP users (n = 59)	Change in ESS, mood, MSLT, functional status, neuropsychologic testing	Average CPAP use 3.1 h/night, CPAP group had significant improvements in RDI, MSLT, O2 nadir, and ESS score. Improvement in O2 saturation and RDI was significantly grearter in CPAP than control group.
Barbé et al.38	2012	1b	RCT	Nonsleepy (ESS < 10) OSA patients with AHI > 20 1. No intervention (n = 366) 2. CPAP (n = 357)	Change in BP and cardiovascular events	No significant difference found between groups, but in those with CPAP use >4 h/night, there was a significant decrease in the incidence density ratio of hypertension or cardiovascular events.
Stradling et al.1474	2000	1b	RCT	1. Therapeutic CPAP 2. Subtherapeutic CPAP as control	1. CPAP adherence 2. Post-treatment neurocognitive and behavioral tests	Degree of improvement correlated significantly with amount of CPAP use in the therapeutic CPAP group, but did not in the subtherapeutic CPAP group.
Kribbs et al.1091	1993	3b	Cohort	CPAP users (n = 35)	CPAP adherence	Average use 4.88 h/night, and only 46% of the patients met criteria for regular use of >4 h/night. Very few patients, (2/35), used CPAP for >7 h/night.
Engleman et al.1472	1994	3b	Cohort	CPAP users (n = 54)	CPAP adherence	CPAP use <5 h/night, did not correlate with OSA severity.
Reeves-Hoche at al.1473	1994	3b	Cohort	CPAP users (n = 38)	CPAP adherence	Mean hours of CPAP use at effective pressure was for 4.3 h/night.
Weaver et al.1098	2007	3b	Cohort	Moderate to severe OSA	1. CPAP adherence 2. Post-treatment neurocognitive and behavioral tests	Increased CPAP usage is associated with increased objective and subjective sleepiness measures. In those with severe OSA, greatest propotion normalized ESS scores with 4 h/night of CPAP, analysis shows further improvement can be obtained with more hours of use.
Antic et al.1476	2011	3b	Cohort	Moderate to severe OSA	1. CPAP adherence 2. Post-treatment neurocognitive and behavioral tests	Increasing CPAP adherence improves behavioral and neurocognitive outcomes in a linear fashion, even highly compliant patients may not attain normal functional status.
Schwab et al.1196	2013	5	Expert opinion	None	None	There is insufficient evidence to support 4 h/night for 70% of nights in a consecutive 30-day period as the definition of adherence.
Campos-Rodriguez et al.1475	2005	3b	Case–control	1. Noncompliant CPAP use, <1 h/night 2. Mildly compliant, 1–6 h/night 3. Compliant, >6 h/night	Mortality rate	Patients who use CPAP >1 h/night have a significantly lower mortality than those who use it <1 h/night.
Zimmerman et al.1478	2006	3b	Case–control	1. CPAP poor users, <2 h/night (n = 14) 2. CPAP moderate users, 2–6 h/night (n = 25) 3. CPAP optimal users, >6 h/night (n = 19)	Memory performance measured by HVLT-R	Patients with OSA and memory impairment have improvement in memory scores if they used CPAP >6 h/night.
Aloia et al.1479	2010	3b	Cohort	CPAP users with neuropsychologic testing prior to starting treatment and 3–6 months after (n = 150)	Changes in neuropsychologic tests before and after CPAP treatment	Based on the reimbursement criteria for CPAP of 4 h/night for 70% of nights during consecutive 30-day period during the first 3 months of use, 37% of patients would be considered nonadherent. However, both adherent and nonadherent patients experienced similar improvements in neuropsychologic testing, and these improvements accumulated at the 6-month point.
Krakow et al.1480	2016	3b	Case–control	1. Noncompliant CPAP use, < 2h/night (n = 13) 2. Subcompliant CPAP use, 3–4 h/night (n = 21) 3. Compliant CPAP use, >4h/night (n = 59)	Changes in insomnia, sleepiness, and nocturia based on CPAP adherence	Both compliant and subcompliant CPAP users had improvements in insomnia, sleepiness, and nocturia. Patients exhibited a dose dependent response to CPAP use.
Sawyer et al.1107	2011	5	Expert opinion	None	None	The historical level of CPAP use of 4 h/night is not necessarily relevant given the evidence of a dose response relationship between CPAP use and benefits.
Brown et al.21	2010	5	Expert opinion	None	None	The CMS guidelines for reimbursement of CPAP, 4 h/night for >70% of nights during consecutive 30-day period during the first 3 months of use, is inappropriate considering the evidence of a dose response to CPAP use.
Ravesloot et al.1481	2011	5	Expert opinion	None	None	Using mean AHI instead of arbitrary compliance rates for CPAP use is a more effective way of measuring CPAP adherence, as worsened OSA severity requires higher CPAP usage to be deemed effective.