Diagnostic value of melatonin in determination of excessive daytime sleepiness

Background and Objective: Excessive daytime sleepiness is often seen in patients with sleep apnea who doesn't recieve a treatment or doesn't have a compliance with treatment. Therefore, if these patiens drive a vehicle or work in a dangerous job that needs attention, it can be problem both for the patient and fort he people around them. Excessive daytime sleepiness can cause traffic or industrial accidents. İn practice, excessive daytime sleepiness is being evaluated by subjective tests which can cause illusions. For the purpose of evaluating excessive daytime sleepiness with more objective marker in these patients, we aimed to research diagnostic value of melatonin in determination of daytime sleepiness. Method: Our study was conducted at Karadeniz Technical University, Department of Chest Diseases between December 2017 and May 2019, prospectively. Among patients that consulted to our sleep disorders clinic with a possible sleep disorder diagnosis and patients that underwent polysomnography; patients who accepted attending to study, are included. Patiens' demographic features, symptoms and polysomnography datas are recorded. Patients are questioned about situations that can cause excessive daytime sleepiness. Drugs that may affect melatonin levels are excluded from study. Epworth Sleepiness Scale and Stanford Sleepiness Scale are used to evaluate daytime sleepiness. In the afternoon (between 02:00 pm and 04:00 pm) five milliliter venous blood sample is taken from patiens whose polysomnography tests resulted as "Normal", "Sleep Apnea Syndrome" or "Others" (Simple Snoring, Restless Legg Syndrome, Upper Airway Resistance Syndrome, Shift Working, Jet Lag etc.) to meajure serum melatonin levels. After then, the sample is processed in various phases and melatonin level is measured. Results: Among 171 patients, 77 patient using drugs that may affect melatonin levels are excluded from the study. From 94 patients included (7 Normal, 79 Obstructive Sleep Apnea and 8 Central Sleep Apnea) 77 of them were male (81.9 %), 17 of them were female (18.1%). Median age was 47.2±12.3 (Male:46.2±11.6, Female:34.8±8.7) and median body mass index was 33.4±6.0 (Male:33.1±5.3, Female:34.8±8.7). Out of symptoms that have been questioned, frequencies of excessive daytime sleepiness, observed apnea and snoring were 81.6% (n:71), 77.4% (n:65) and 96,9% (n:86). Among patients consulted with excessive daytime sleepiness, incidence of patients whose ESS was geater than or equal to 10 was 66.2% (47/71); Among patients who doesn't have excessive daytime sleepiness, incidence of patients whose ESS was geater than or equal to 10 was 6.3% (1/16), which were statistically significant. There wasn't any significant correlation between melatonin and demographical features (age, height, weight, body mass index and gender), disease parameters (apnea hypopnea index, desaturation index and minimum saturation) of patients. Also, there wasn't any significant correlation between melatonin and sleep parameters (Epworth and Stanford Sleepiness Scale). Conclusion: There was no significant correlation between serum melatonin levels and excessive daytime sleepiness. Likewise, there was no significant correlation between melatonin levels and apnea-hypopnea index and other polysomnography parameters that represent sleep apnea severity.