An observational study in OSA - Obstructive Sleep Apnea, Dysphagia and Oral Frailty, sponsored by National Sun Yat-sen University. Recruiting at 1 site in Taiwan. Open to participants aged 20 Years and older. Per ClinicalTrials.gov, last updated 2026-10-19.
Sponsored by National Sun Yat-sen University · Observational
Dysphagia is a commonly reported complaint among patients with obstructive sleep apnea (OSA), particularly those who have undergone upper-airway (oropharyngeal) surgery. However, how surgical treatment for OSA affects swallowing function and oral function (oral frailty) remains unclear.
This prospective cohort study recruits adults with moderate-to-severe OSA from the sleep medicine clinic of Kaohsiung Armed Forces General Hospital, Taiwan. Participants choose their own treatment as part of routine care; the study does not assign or influence treatment. Participants who undergo OSA surgery form the surgery group, and those who receive non-surgical treatment (e.g., CPAP) or no treatment form the non-surgical group. Swallowing difficulty (EAT-10) and oral frailty (seven oral hypofunction indicators) are assessed before treatment and at 1, 3, and 6 months after treatment.
Background: Obstructive sleep apnea (OSA) is one of the most prevalent non-communicable diseases worldwide. Impaired swallowing reflex, pharyngeal sensory deficits and dysphagia have been reported in 16-78% of patients with OSA, and oropharyngeal surgery (e.g., uvulopalatopharyngoplasty) may further alter swallowing physiology. Oral frailty, a cluster of declines in oral function, is associated with dysphagia, physical frailty and mortality, yet it has not been examined in surgically treated OSA patients.
Design: Prospective observational cohort study. This registration covers Phase 2 of a two-phase project; Phase 1 is a separate retrospective analysis of Taiwan's National Health Insurance Research Database (2001-2020) comparing the incidence of dysphagia between OSA patients and matched non-OSA controls.
Participants: Adults aged 20 years or older with moderate-to-severe OSA (apnea-hypopnea index >= 15 events/hour) who intend to receive next-step treatment. The target sample size is 450 (surgery group 225; non-surgical/no-treatment group 225), estimated with G*Power (exact test; p1 = 0.16, p2 = 0.05, power = 0.95, allocation ratio 1:1).
Exposure: Surgical treatment chosen by the patient, such as radiofrequency reduction of the soft palate or tongue base, palatine tonsillectomy, uvulopalatopharyngoplasty (UPPP), CO2 laser-assisted uvulopalatoplasty (LAUP), transoral robotic surgery (TORS) and other upper-airway procedures. Treatment decisions are made by patients and their physicians; the study only records the treatment received.
Assessments (T0 before treatment; T1, T2 and T3 at 1, 3 and 6 months after treatment): Eating Assessment Tool-10 (EAT-10); oral frailty assessed by the seven oral hypofunction indicators (Minakuchi et al., 2018): tongue coating index, Saxon test, oral diadochokinesis (/pa/, /ta/, /ka/), number of natural teeth, tongue pressure (Iowa Oral Performance Instrument), self-reported masticatory ability, and the repetitive saliva swallowing test (RSST). Covariates include demographics, anthropometrics, blood pressure, comorbidities, smoking, alcohol use, exercise, prior oropharyngeal surgery, fatigue and OSA severity (AHI).
Analysis: Descriptive statistics will summarize treatment choices and baseline characteristics; between-group differences will be compared; repeated-measures analysis will compare changes in dysphagia and oral frailty between the surgery and non-surgical groups over 6 months.
2,263 studies on the registry are indexed under Sleep Apnea, Obstructive; 465 are open to participants now.
This study's planned enrollment of 450 is above the median of 105 across 666 observational studies indexed under Sleep Apnea, Obstructive.
Browse Sleep Apnea, Obstructive studies →National Sun Yat-sen University is the lead sponsor of 5 studies on the registry; 4 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Adults with moderate-to-severe obstructive sleep apnea attending the sleep medicine outpatient clinic of Kaohsiung Armed Forces General Hospital, Taiwan, who intend to receive next-step treatment (surgical or non-surgical).
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Adults with moderate-to-severe OSA who choose non-surgical treatment (e.g., CPAP) or no treatment as part of routine care. Treatment is not assigned by the study.
Other: Non-surgical management
Adults with moderate-to-severe OSA who elect upper-airway surgery as part of routine care (e.g., radiofrequency reduction of the palate or tongue base, tonsillectomy, UPPP, LAUP, TORS). Treatment is not assigned by the study.
Procedure: Upper airway surgery for OSA
Upper-airway surgical procedures chosen by the patient as part of routine care, including radiofrequency reduction of the soft palate or tongue base, palatine tonsillectomy, partial glossectomy, uvulopalatopharyngoplasty (UPPP), CO2 laser-assisted uvulopalatoplasty (LAUP), transoral robotic surgery (TORS) and related procedures. Not assigned by the study.
CPAP or other non-surgical management (e.g., oral appliance, weight control), or no treatment, as chosen by the patient as part of routine care. Not assigned by the study.
Change in swallowing difficulty measured by the Eating Assessment Tool-10 (EAT-10)
Chinese version of the EAT-10; 10 self-rated items scored 0 (no problem) to 4 (severe problem); total score 0-40, with higher scores indicating worse swallowing difficulty. A total score of 3 or more indicates swallowing problems.
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Change in oral frailty (number of oral hypofunction indicators)
Number of the seven oral hypofunction indicators met (Minakuchi et al., 2018): poor oral hygiene, oral dryness, reduced occlusal force, reduced tongue-lip motor function, reduced tongue pressure, decreased masticatory function and deteriorated swallowing function. Range 0-7; meeting 3 or more indicators defines oral frailty (oral hypofunction).
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Tongue pressure
Maximum tongue pressure (kPa) measured with the Iowa Oral Performance Instrument (IOPI); participants press the bulb against the palate for 7 seconds, three trials with 30-second rests, mean value used. Less than 30 kPa indicates low tongue pressure.
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Tongue coating index
Tongue coating index (TCI, %); 50% or higher indicates poor oral hygiene.
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Oral dryness (Saxon test)
Saliva production measured by the Saxon test (gauze placed under the tongue for 1 minute); less than 0.1 g/min indicates oral dryness.
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Oral diadochokinesis
Number of repetitions per second of the syllables /pa/, /ta/ and /ka/ over 5 seconds; fewer than 6 per second for any syllable indicates reduced tongue-lip motor function.
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Number of natural teeth
Number of remaining natural teeth; fewer than 20 indicates reduced occlusal force.
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Self-reported masticatory ability
Self-reported masticatory ability questionnaire; difficulty or inability to chew 4 or more listed foods indicates decreased masticatory function.
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Repetitive saliva swallowing test (RSST)
Number of voluntary saliva swallows in 30 seconds; 3 or more is considered normal.
Time frame: Baseline (before treatment), and 1, 3 and 6 months after treatment
Plan to share: No
No publications or documents are linked to this record.
Started Jun 2026 (actual). Primary completion is estimated for Dec 2028, 30 months after the start.
Of 259 non-industry observational studies under Sleep Apnea, Obstructive, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 17 and three quarters within 60. This study's planned 30 months is close to that.
Counting every sponsor, half of 294 studies reached it within 30 months; a quarter within 15 and three quarters within 60.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
National Sun Yat-sen University