Baseline circadian BP profile influences response to oral appliance therapy for OSA

Circadian blood pressure (BP) profile at baseline has a significant impact on BP response to oral appliance therapy, primarily due to higher baseline BP in the nondipper subgroup, a study has shown. Thus, the therapy fails to convert obstructive sleep apnoea (OSA) patients to a more favourable circadian BP profile.

“Oral appliance therapy for OSA reduces BP, but there is little information on relationship to circadian BP pattern (nocturnal BP dipping or nondipping),” according to the authors.

This study then sought to determine whether nocturnal dipping pattern influences BP changes following oral appliance therapy and establish the effect of such therapy on circadian BP pattern. The authors included 152 participants in two randomized trials of oral appliance therapy (1–2 months) with 24-h ambulatory BP monitoring (ABPM) data.

 Subsequently, nocturnal BP dippers (nocturnal/diurnal systolic BP ratio <0.9) and nondippers were compared for changes in BP after oral appliance therapy. The authors then evaluated the effect of the regimen on nocturnal BP dipping.

Majority of the participants (64.5 percent) were dippers. On average, dippers were younger and less likely to be hypertensive (42 percent vs 82.7 percent; p<0.001). On the other hand, nondippers displayed greater reduction in nocturnal BP measures, associated with higher BP measures at baseline.

No significant between-group difference was noted in the relationship between treatment effectiveness and BP changes. Furthermore, oral appliance therapy converted only 23 percent of baseline nondippers to a nocturnal dipping profile.

“Further work is required to understand the effect of oral appliance therapy on circadian BP profile and of the individuals who will receive cardiovascular benefit from oral appliance therapy,” the authors said.