Despite the numerous medications and therapeutics that have accumulated in the physician’s armamentarium, developing treatments is only half the battle with treating patients. While many drugs or devices work well in theory, in practice, there remains the major hurdle of patient compliance. Interventions may be too frequent or uncomfortable, or they are simply forgotten or skipped by patients, leading to poor outcomes despite having received the right prescription.
For patients with obstructive sleep apnea (OSA), continuous positive airway pressure (CPAP) is a proven effective treatment. However, CPAP requires patients to wear a mask every night, which is notoriously uncomfortable for patients, resulting in poor compliance. Rather than forcing patients to adhere to a difficult regimen, new therapies that conform better to patients’ preferences could be an advance.
In this week’s issue of NEJM, Strollo et al. publish the results of a prospective, multicenter, single-group cohort study that tests the efficacy of upper airway stimulation in OSA patients with difficulty adhering to CPAP. Upper airway stimulation involves an operation in which a sensing lead is placed to detect ventilatory effort, and a stimulation electrode is placed on the hypoglossal nerve. Because OSA has been reported to be accompanied by decreased upper airway muscle function, stimulation of the hypoglossal nerve, which activates the genioglossus muscle, may help treat the symptoms of OSA.
The authors recruited 126 patients with moderate to severe OSA with difficulty complying to CPAP. They first recorded baseline characteristics so that each patient served as his/her own control. The upper airway stimulation device was surgically implanted in all patients, and the majority of the patients were discharged the following day. Primary outcome measures were taken 12 months after implantation and compared to baseline values for each patient. By both objective and subjective outcome measures of OSA severity, upper airway stimulation led to significant improvements, including a 68% reduction in the apnea hypopnea index and a 70% reduction in the 4% oxygen desaturation index. In addition, at the 12 month visit, the first 46 patients that responded to the upper airway stimulation intervention were randomized to either continue the stimulator therapy or to therapy withdrawal, in which the device was turned off for seven days. There was a statistically significant increase in the apnea hypopnea indices of patients who underwent one week of therapy withdrawal compared to those of patients who continued the therapy, confirming that the improvement in the apnea hypopnea index over the 12 month period was indeed due to the upper airway stimulation and not due to random variability in the apnea hypopnea index.
This trial suggests that upper airway stimulation may be a viable therapeutic option for patients with moderate to severe OSA who have trouble adhering to CPAP. While further trials are required to compare this intervention to CPAP, the current standard of care, this finding, which could potentially help improve the health of noncompliant patients while minimally affecting their lifestyles. Many patients struggle with compliance, and upper airway stimulation for OSA is an excellent example of how innovative technology can overcome stubborn problems in medicine.