Response to the letter entitled “Obstructive sleep apnea, excessive daytime sleepiness, and adherence to antihypertensive treatment: Questionnaire survey”

Dear Dr Tomoyuki,

Thank you for your letter regarding our manuscript entitled “Influence of High Risk of Obstructive Sleep Apnea on Adherence to Antihypertensive Treatment in Outpatients.”1 We have addressed each of your concerns as follows:

Response to first comment: We agree with your concerns about items 1 and 3 of the STOP‐Bang questionnaire. Both items cover contents that imply immanent difficulty in answering. We had 0 and 10 (2.4%) undetermined answers to questions 1 and 3, respectively. Despite the difficulty in answering the items, the prevalence of obstructive sleep apnea in 78% of our sample is in agreement with rates in two previous studies of our group (78%2 and 71%).3 Both studies measured the apnea‐hypopnea index by home sleep apnea testing and by the Berlin questionnaire at the same clinic involving a smaller sample of the same outpatient population. Perhaps because of the features of our clinical specialized center and repeated visits, having family members present contributed to low rates of undetermined responses to items 1 and 3 of the STOP‐BANG questionnaire. Approximately 84% of our sample reported living with someone and 55% reported living with a partner. Taken together, these characteristics could have influenced the low rate of undetermined responses. Although snoring and observed apnea symptoms are important, there is no reason to suppose that this potential bias on the evaluation of risk of obstructive sleep apnea by the STOP‐Bang questionnaire was distributed unequally among participants with adherence and nonadherence to the medical prescription.

Response to second comment: Thank you for your insightful comment, which suggests a mechanism of the influence of obstructive sleep apnea over adherence to blood pressure drugs. We agree with this interpretation and have demonstrated this possibility in another study of adherence in our clinic. In a study with patients under pharmaceutical care to improve adherence, we identified that cognitive deficit was an independent risk factor for nonadherence.4 Unfortunately, we did not investigate risk for obstructive sleep apnea in this study. The field is therefore open for further investigations.