Predicting the Blood Pressure Response to CPAP Treatment
Does a cardiovascular system-focused micro–ribonucleic acid (miRNA) biomarker profile reliably discriminate those patients with a favorable blood pressure (BP) response to continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea (OSA)?
This was an analysis of data from participants who were part of a larger multicenter, randomized, controlled trial conducted in 24 Spanish teaching hospitals to evaluate the effect of CPAP treatment on the BP levels of patients with resistant hypertension and OSA. Resistant hypertension was defined as BP above therapeutic goals despite concurrent use of at least three antihypertensive agents at doses that provide optimal benefit, with one of these drugs ideally being a diuretic. This analysis was restricted to patients who used CPAP for 4 or more hours per day. Patients with a reduction in mean BP greater than the observed median of 4.5 mm Hg were classified as responders to CPAP treatment. Cardiovascular system-focused circulating miRNA expression was evaluated in plasma samples using an 84-miRNA array among patients with resistant hypertension and OSA at baseline and after 3 months of adherent CPAP use.
Three miRNAs provided a discriminatory predictive model for a BP response to CPAP (area under curve: 0.92; p = 0.01). CPAP treatment significantly altered a total of 47 plasma miRNAs. Decreases in aldosterone-to-renin ratios were significantly greater in the responder group (p = 0.016) and were positively correlated with the change in mean BP values after adherent CPAP use (r = 0.46; p = 0.001).
In patients with resistant hypertension and OSA, a singular pre-CPAP treatment cluster of three plasma miRNAs predicts BP response to CPAP treatment in male patients.
This is a valuable study that demonstrates that a cluster of miRNAs related to cardiovascular function reliably discriminates those patients with favorable BP responses to CPAP. As the authors acknowledge, there are multiple limitations that temper the enthusiasm for these results. The authors examined only male patients; and, a goodness-of-fit test for the score derived from the multivariable logistic regression model revealed poor calibration and poor discrimination for female patients. Although the authors report that the “determination of miRNAs can be performed in tertiary university hospitals at a low cost ($35 to $50),” the viability of such testing in community and/or resource-limited settings is questionable. Further studies should help clarify the interplay of mechanisms among miRNAs, cardiovascular risk, and response to adherent CPAP use.
Clinical Topics: Diabetes and Cardiometabolic Disease, Dyslipidemia, Heart Failure and Cardiomyopathies, Prevention, Lipid Metabolism, Novel Agents, Heart Failure and Cardiac Biomarkers, Hypertension, Sleep Apnea
Keywords: Aldosterone, Antihypertensive Agents, Arterial Pressure, Biological Markers, Blood Pressure, Continuous Positive Airway Pressure, Diuretics, Hypertension, Metabolic Syndrome X, MicroRNAs, Renin, Risk Factors, Sleep Apnea, Obstructive
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