Should We be Screening Cardiac Patients for Disordered Sleep Breathing?
There's a constant drumbeat in the medical community to screen and test patients for sleep apnea despite new studies confirming that various sleep apnea treatment modalities don't reduce heart disease
The skeptical cardiologist has been trying very hard but with little success over the last decade to counter the widespread dogma that cardiologists should be searching for and treating sleep apnea in any patient with atrial fibrillation, hypertension, stroke or heart failure.
Despite the widespread belief that obstructive sleep apnea (OSA) causes cardiovascular events like strokes, atrial fibrillation and heart attacks, there is no good evidence that treating OSA lowers the risk of such cardiovascular outcomes.
While I quite agree that high-quality sleep is really important, the scientific data only show associations of reduced sleep duration and quality with the chronic diseases that plague us and have not proven causality.
Healthy User Bias is a major confounder of most CPAP and all observational studies, as noted at ClinicalCorrelations
Observational studies have demonstrated that among patients with OSA, CPAP is associated with a lower incidence of fatal and nonfatal cardiovascular events. A recent meta-analysis of observational studies corroborated these findings, noting a hazard ratio (HR) of 0.37 (95% CI, 0.16 to 0.54) for cardiovascular mortality in CPAP treated patients compared to untreated patients. However, these studies are marred by their lack of randomization.
Therefore, the patients compliant with CPAP may have enjoyed their cardiovascular benefit from any number of downstream effects of their general aptitude towards making healthy lifestyle choices (the healthy user bias) rather than from CPAP alone
Sleep Apnea Screening Lacks Specificity
Despite the absence of evidence, doctors and patients are constantly being reminded of the importance of screening for sleep apnea by elements of the industrial-academic sleep apnea cartel.
Screening for OSA is often done by questionnaires such as STOP-BANG or the Epworth Sleepiness Scale.
STOP-BANG asks questions about snoring, sleepiness, observed apnea or choking, and hypertension, plus 4 clinical attributes (hypertension, obesity, age, neck size, and gender), and classifies patients as low, intermediate, or high risk.
When I first wrote about STOP-BANG in 2019 I said that “It has a high sensitivity of 90% but a very low specificity of 36%. This means that 2/3 of individuals who take this screening who don’t have OSA when tested formally will be told they may have OSA.”
It now appears even worse. Comically worse.
But STOP-BANG is perfect for the sleep apnea industry because it identifies most people as high risk for OSA. And these people can be routed for home or in-lab sleep studies, starting a cascade of treatment that most of them don’t need.
