A Randomized Controlled Trial of Positional Therapy and Oral Appliance Therapy in Patients With Position Dependent Sleep Apnea

Obstructive sleep apnea (OSA) is associated with considerable health risks. OSA causes fragmentation of sleep and consequently daytime sleepiness. Furthermore OSA is related to multiple (mostly cardiovascular) diseases. Due to the effect of gravity of the base of the tongue and the soft tissue of the upper airway, the majority of OSA patients have an increase of obstructions in supine position. Position-dependent OSA  (POSA) is defined as an apnea hypopnea index (AHI) that is at least double in supine position compared to non-supine positions. OSA treatment starts with lifestyle alterations (e.g. avoidance of smoking and alcohol). Part of conservative treatment in patients with POSA is reduction of the supine sleeping time by positional therapy (PT). The sleep position trainer (SPT) is a device that is worn on the chest and gives vibro-tactile feedback to a patient when sleeping in supine position. Alternative treatment options for POSA include oral appliance therapy (OAT), continuous positive airway pressure and surgical procedures.

This multicenter, prospective and randomized controlled study assessed the effectiveness of PT compared to OAT in mild and moderate POSA (AHI<30) patients after three months of therapy. Primary outcome measures were the AHI and oxygen desaturation index (ODI). Secondary outcomes were the Epworth Sleeping Scale (ESS), the Functional Outcome of Sleep Questionnaire (FOSQ). The compliance of both treatments was objectively evaluated.

To ensure a power of 80% to evaluate the primary outcome, it was estimated that 36 patients per group would need to be enrolled, with the exact two-sided t-test set at a significance level of 5%. All data were tested for normality. Normally distributed continuous data were tested with the independent samples Students t-test and in case of skewed data, with the independent samples Mann-Whitney U-test.

A total of 177 patients were screened of which 99 patients underwent randomization; 70.7% were men. The mean age was 48.3 ± 10.1.

The median AHI in the SPT-group decreased from 12.7 to 6.8 and in the OAT-group from 12.9 to 6.9. The ODI in both groups reduced in a similar manner. No difference was seen in the median AHI in supine position, yet the median AHI decrease in non-supine positions was different; the SPT-group increases from 3.4 to 4.3 and the OAT-group decreased from 3.2 to 1.9 (P>0.005). The median percentage of sleep-time in supine position decreased more in the SPT-group, 42.4 to 14.4, compared to the OAT-group, 39.9 to 38.9 (P>0.000).

Secondary outcome measures showed an ESS outcome for SPT-group from 8.5 to 8.1 and for the OAT-group from 8.2 to 6.1 (P=0.051). In both groups the FOSQ did not decreased significantly. The compliance was slightly in favor of the SPT, 89.3 ± 22.4 and OAT 81.3 ± 30.0 (percentage of use >4 hours, 5 nights a week).

The SPT showed a decrease in AHI equal to the OAT in patients with mild and moderate POSA after three months of therapy. A significant decrease in sleeping time in supine position is achieved using the SPT compared with the OAT, although the OAT is also effective in the AHI in non-supine positions. Excessive daytime sleepiness displayed in the ESS, is better treated with OAT than SPT, resp. -2.1 and -0.4.

1. van Maanen, J. Peter, and Nico de Vries. "Long-term effectiveness and compliance of positional therapy with the sleep position trainer in the treatment of positional obstructive sleep apnea syndrome." Sleep37.7 (2014): 1209-1215.

2. Hoekema, A., B. Stegenga, and L. G. M. De Bont. "Efficacy and co-morbidity of oral appliances in the treatment of obstructive sleep apnea-hypopnea: a systematic review." Critical Reviews in Oral Biology & Medicine 15.3 (2004): 137-155.

ClinicalTrials.gov number NCT02045576