Introduction: Polypharmacy is the administration of 5 or more drugs and is particularly prevalent in the elderly.

Objective: To identify the number and drug classes administered to OSA patients for registered comorbidities.

Methods: We record a 2279 OSA patient database (April 2019-December 2022), registering anthropometric parameters, spirometry, questionnaires, comorbidities and corresponding drug treatment. Drugs are registered at level 2 of the Anatomical Therapeutic Chemical (ATC) classification system. The first level is a letter that denotes the main anatomical group, and the second level has two digits to indicate the therapeutic level at which the medicine acts; a drug may have multiple ATCs, e.g., for acetylsalicylic acid, N02 indicates its analgesic effects, and B01 indicates its antithrombotic properties.

Results: 79.9% of patients take at least one drug. Of these, 33.5% receive ?5 drugs (N5D patient category). The average age in N5D is 62.1 years; all patients have at least two drugs for the cardiovascular system (C) in their therapies. The most prescribed drugs in N5D target cardiovascular diseases: renin-angiotensin system-acting drugs (C09)?86.2%, diuretics (C03)?81.1%, lipid modifying agents (C10)?74.4%, beta-blockers (C07)?73.4%. Also, 72.1% of N5D received treatment with an antithrombotic agent (B01) to prevent cardiovascular events. Other drug classes are antidiabetics (A10), thyroid therapy (H03), and for obstructive airway diseases (R03). 67% of N5D have severe OSA (AHI ? 30).

Conclusion: Our analysis reveals a patient category with multiple morbidities that require multiple drug classes.

This work is supported by the European Union's Horizon 2020 Research and Innovation Programme, Grant 965417.