MedicalResearch.com Interview with:
Miklos Z Molnar, MD, PhD, FEBTM, FERA, FASN
Associate Professor of Medicine
Division of Nephrology, Department of Medicine
University of Tennessee Health Science Center
Memphis, TN, 38163
Medical Research: What is the background for this study? What are the main findings?
Response: Restless legs syndrome is a common sleep disorder, but there is a paucity of large cohort studies examining the association of restless legs syndrome with clinical outcomes, including all-cause mortality, incident coronary heart disease, stroke and chronic kidney disease.
From a nationally representative prospective cohort of over 3 million US veterans [93% male, median follow-up time of 8.1 years (interquartile range: 7.0–8.5years)] with baseline estimated glomerular filtration rate ≥60 mL/min/1.73 m2, a propensity-matched cohort of 7392 patients was created, and the association between incident restless legs syndrome and the following was examined:
- (1) all-cause mortality;
- (2) incident coronary heart disease;
- (3) incident strokes; and
- (4) incident chronic kidney disease defined as estimated glomerular filtration rate <60 mL/min/1.73 m2.
Compared with restless legs syndrome-negative patients, incident restless legs syndrome was associated with 88% higher mortality risk [hazard ratio and 95% confidence interval: 1.88 (1.70–2.08)], and almost four times higher risk of coronary heart disease and stroke [hazard ratio: 3.97 (3.26–4.84) and 3.89 (3.07–4.94), respectively]. The risk of incident chronic kidney disease was also significantly higher in incident restless legs syndrome patients [hazard ratio: 3.17 (2.74–3.66)] compared with restless legs syndrome-negative counterparts. These associations was independent from other confounders such as demographic data, comorbidities and other sleep disorders (sleep apnea and periodic limb movements in sleep).
MedicalResearch.com Interview with:
Marie Marklund, DDS senior lecturer
Department of Odontology, Faculty of Medicine
MedicalResearch: What is the background for this study? What are the main findings?
Response: Snoring and obstructive sleep apnea are common in the population and these disorders continuously increase because of the ongoing obesity epidemic in many countries. Today, 34% of men and 17% of women in the US suffer from obstructive sleep apnea of all severities. Symptoms include daytime sleepiness, poor sleep quality, headache, insomnia and restless legs. In the longer term, a more severe sleep apnea is associated with serious consequences, such as hypertension, stroke, cancer, traffic accidents and early death.
Continuous positive airway pressure is a highly effective treatment for sleep apnea patients. Adherence problems, for instance from nasal stuffiness and claustrophobia reduces its effectiveness. An oral appliance holds the lower jaw forwards during sleep in order to reduce snoring and sleep apneas. This therapy has primarily been suggested for snorers and patients with mild and moderate sleep apnea. No previous placebo-controlled study has, however, evaluated this specific group of patients. Results from more severe sleep apnea patients have shown a good effect on sleep apneas. The effect of oral appliances on daytime symptoms is unclear. Symptomatic improvement is an important outcome for milder sleep apnea patients.
The primary aims of the present study were to study the effects on daytime sleepiness and quality of life of a custom-made, adjustable oral appliance in patients with daytime sleepiness and snoring or mild to moderate sleep apnea, i.e. the primary target group for this type of therapy. Secondary aims included the effects on sleep apnea, snoring and various other symptoms of sleep disordered breathing such as headaches and restless legs. We found that oral appliance therapy was effective in reducing sleep apneas, snoring and symptoms of restless legs. The apnea-hypopnea index was normal (<5) in 49% of patients using the active appliance and in 11% using placebo, with a numbers needed to treat of three. Daytime sleepiness and quality of life did not differ during active treatment and the placebo intervention. The patients experienced reduced headaches with active treatment, but the results did not differ from placebo. It was concluded, that a custom-made, adjustable oral appliance reduces obstructive sleep apneas, snoring and possibly restless legs. The efficacy on daytime sleepiness and quality of life was weak and did not differ from placebo in this group of patients. Continue reading