A polysomnography-derived mean nocturnal respiratory rate (RR) of ≥16 breaths per minute was an independent predictor of long-term cardiovascular and all-cause mortality among community-dwelling older men and women, according to study results published in the European Respiratory Journal.
Currently, RR predicts in-hospital and short-term mortality in patients with a variety of conditions, but its predictive value in the general population for long-term cardiovascular and all-cause mortality is unknown.
The current study was conducted to determine the prognostic value of RR for predicting long-term cardiovascular and all-cause mortality in 2 large independent cohorts of community-dwelling older men and women. Considering how much RR can vary across the day, investigators decided to measure rates during sleep to yield standardized measurement conditions. Data analyzed were derived from the overnight home polysomnograms of 406 older women participating in the Study of Osteoporotic Fractures (SOF) and 2686 older men participating in the Osteoporotic Fractures in Men Study (MrOS) sleep study.
A total of 46 women (11.2%) in the SOF cohort (mean 6.4±1.6 years of follow-up) and 166 men (6.1%) in the MrOS cohort (mean 8.9±2.6 years of follow-up) died from cardiovascular disease. All-cause mortality was 51.2% during 13.7±3.7 years of follow-up in the MrOS cohort and 26.1% during 6.4±1.6 years of follow-up in the SOF cohort. Multivariate Cox regression analysis adjusted for significant covariates showed that RR dichotomized at 16 breaths per minute was independently associated with cardiovascular mortality (MrOS: hazard ratio [HR], 1.57 [95% CI, 1.14-2.15]; P =.005 and SOF: HR, 2.58 [95% CI, 1.41-4.76]); P =.002) and all-cause mortality (MrOS: HR. 1.18 [95% CI, 1.04-1.32]; P =.007; SOF: HR, 1.50 [95% CI, 1.02-2.20]; P =.04).
Despite limitations such as using self-reported baseline exposures to various conditions, not considering the possible confounding effects of medications, and using observations based on predominately white participants with an older baseline age (76±6 years for men and 81±3 years for women) that may have introduced a survivor bias, the investigators concluded that “[i]n community-dwelling older men and women, nocturnal RR is an independent predictor of long-term [cardiovascular] and all-cause mortality. Whether RR could be used as a risk marker for mortality in the clinical setting warrants further prospective studies.”
Disclosures: Dr Linz reports having served on the advisory boards or receiving lecture or consulting fees from LivaNova and ResMed.
Baumert M, Linz D, Stone K, et al. Mean nocturnal respiratory rate predicts cardiovascular and all-cause mortality in community-dwelling older men and women [published online May 31, 2019]. Eur Respir J. doi:10.1183/13993003.02175-2018