A Step Forward for Better Interpreting the Apnea-Hypopnea Index

Moderate obstructive sleep apnea and cardiovascular outcomes in older adults: a propensity score-matched multicenter study (CPAGE-MODE study)

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) has been associated with cardiovascular events (CVEs), although recent randomized controlled trials have not demonstrated that long-term continuous positive airway pressure (CPAP) prevents CVEs. Our objective was to determine the effect of CPAP on older adults with moderate OSA regarding CVE reduction.

METHODS

An observational and multicenter study of a cohort of older adults (> 70 years of age) diagnosed with moderate OSA (apnea-hypopnea index 15.0-29.9 events/h) was conducted. Two groups were formed: (1) CPAP treatment and (2) standard of care. The primary endpoint was CVE occurrence after OSA diagnosis. Association with CPAP treatment was assessed by propensity score matching and inverse weighting probability. Secondary endpoints were incidence of CVE separately and time to first CVE.

RESULTS

A total of 614 patients were included. After matching, 236 older adults (111 men, mean age 75.9 ± 4.7 years) with a follow-up of 47 months (interquartile range: 29.6-64.0 months) were considered for primary and secondary endpoint evaluations. Forty-one patients presented at least 1 CVE (17.4%): 20 were in the standard-of-care group (16.9%) and 21 were in the CPAP group (17.8%), with a relative risk of 1.05 (95% confidence interval [CI], 0.60-1.83; P = .43) for CPAP treatment. Inverse probability weighting of the initial 614 patients determined an adjusted relative risk of 1.24 (95% CI, 0.79-1.96; P = .35) for CPAP treatment. No statistical differences were found in secondary endpoint analyses.

CONCLUSIONS

CPAP should not be prescribed to reduce CVE probability in older adults with moderate OSA.

CITATION

López-Padilla D, Terán-Tinedo J, Cerezo-Lajas A, et al. Moderate obstructive sleep apnea and cardiovascular outcomes in older adults: a propensity score-matched multicenter study (CPAGE-MODE study). J Clin Sleep Med. 2022;18(2):553-561.

Impact of different hypopnea definitions on obstructive sleep apnea severity and cardiovascular mortality risk in women and elderly individuals

OBJECTIVE

To assess the impact of three hypopnea definitions on the severity classification of obstructive sleep apnea (OSA) and its association with cardiovascular mortality risk in women and elderly individuals.

METHODS

We analyzed two Spanish clinical cohorts (1116 women and 939 elderly individuals) who were studied for suspicion of OSA between 1998 and 2007. A calibration model was used to apply different definitions of hypopnea to our two cohorts. Hypopnea was defined as a 30-90% reduction in oronasal flow for ≥10 s followed by (1) ≥4% fall in oxyhemoglobin saturation-AHI_4%; (2) ≥3% fall in oxyhemoglobin saturation-AHI_3%; or (3) ≥3% fall in oxyhemoglobin saturation or an event-related arousal-AHI_3%a.

RESULTS

In both cohorts, the prevalence of an AHI ≥30 events/h increased by 14% with AHI_3%a, compared to AHI_4% criteria. The percentage of women with an AHI <5 events/h decreased from 13.9% with AHI_4% to 1.1% with the AHI_3%a definition. In fully adjusted multivariable analyses, AHI ≥30 events/h was associated with increased cardiovascular mortality risk in women, regardless of the hypopnea definition, and in elderly individuals diagnosed using the AHI_4% and AHI_3% but not the AHI_3%a definition.

CONCLUSIONS

Our findings suggest that hypopnea definitions substantially influence OSA prevalence and severity classification, and also affect the association with cardiovascular outcomes. With the currently recommended criterion (AHI_3%a), a threshold of 30 events/h is appropriate to identify women, but not elderly individuals with increased risk of cardiovascular death.