Chronic Kidney Disease and Sleeping Disordered Breathing (SDB)

Correlation between nocturnal intermittent hypoxemia and mild cognitive impairment in the older adult and the role of BDNF Val66Met polymorphism: a hospital-based cross-sectional study

PURPOSE

To explore the prevalence of nocturnal intermittent hypoxemia (NIH) in a tertiary hospital geriatric department and the relationship between NIH and mild cognitive impairment (MCI) in older adults, and to examine the role of brain-derived neurotrophic factor (BDNF) Val66Met polymorphism.

METHODS

Older adults aged ≥ 60 were enrolled. NIH and cognitive assessments were conducted. BDNF concentrations and BDNF Val66Met polymorphism were detected for a preliminary exploration of the possible mechanism of the process.

RESULTS

Of 325 older adults enrolled, 157 (48%) had NIH and were further divided into mild, moderate, and severe NIH groups according to their oxygen desaturation of ≥ 4% per hour of sleep (ODI4). MCI detection rate in the four groups gradually increased, and the differences were statistically significant (chi-square = 4.457, P = 0.035). ODI4 was negatively correlated with MoCA score in all participants (r =  - 0.115, P = 0.039) and patients with NIH (r =  - 0.199, P = 0.012). After adjusting for sex, age, and cardiovascular risk factors, NIH and MCI remained independently associated (OR = 3.13, 95% CI 1.03-9.53, P = 0.045). BDNF levels were positively correlated with MoCA score (r = 0.169, P = 0.028) and negatively correlated with nocturnal average oxygen saturation in patients with NIH (r =  - 0.288, P = 0.008). Older adults with different BDNF Val66Met genotypes did not show significant differences in MCI rate and BDNF levels (P > 0.05).

CONCLUSION

The older adults with NIH have a higher MCI detection rate. BDNF levels may be a potential biomarker for cognitive dysfunction in patients with NIH.

Bidirectional relationships of comorbidity with obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is frequently associated with comorbidities that include metabolic, cardiovascular, renal, pulmonary and neuropsychiatric. There is considerable evidence that OSA is an independent risk factor for many of these comorbidities but, more recently, there is evidence that some of these comorbidities may predispose to the development of OSA. Thus, there is growing evidence of a bidirectional relationship between OSA and comorbidity, especially for heart failure, metabolic syndrome and stroke. Potential mechanisms of bidirectional relationships differ in individual comorbidities with fluid retention and redistribution being especially important in heart failure and end-stage renal disease, whereas neural mechanisms may be more important in diabetes mellitus and stroke. The evidence for other comorbidities, such as hypertension and atrial fibrillation, support these being more a consequence of OSA with limited evidence to support a bidirectional relationship. The present review explores the evidence for such bidirectional relationships with a particular perspective on comorbidities that may predispose to OSA. The impact of therapy in bidirectional relationships is also reviewed, which highlights the clinical importance of accurate diagnosis. This aspect is especially true of COPD, where the identification of co-existing OSA has important implications for optimum therapy.

Obstructive sleep apnoea (OSA) is an independent risk factor for comorbidity, especially cardiometabolic. However, some comorbidities may be risk factors for OSA, supporting a bidirectional relationship that may have important implications for treatment.https://bit.ly/3BbJy6V

Chronic kidney disease and concomitant sleep apnea are associated with increased overall mortality: a meta-analysis

PURPOSE

Sleep apnea (SA) is common in advanced chronic kidney disease (CKD) patients. However, the association between CKD with concomitant SA and overall mortality remains inconclusive.

METHODS

Ovid MEDLINE, EMBASE, and the Cochrane Library were searched for eligible publications, including non-transplant CKD patients aged > 18 years with co-existing SA. CKD is defined by estimated glomerular filtration rate of < 60 mL/min/1.73 m².

RESULTS

Seven observational studies (n = 186,686) were included in the meta-analyses. 94.2% had end-stage kidney disease (ESKD) requiring hemodialysis (HD), 5.0% had ESKD requiring peritoneal dialysis (PD), and 0.8% had non-dialysis CKD. The mean age was 76.8 ± 2.2 years. Most patients were male (53.4%) and white (76.8%). Up to 39.3% had diabetes. The mean body mass index was 26.0 ± 0.6 kg/m². Among patients with advanced CKD and SA, the pooled estimated odds ratios (OR) for overall mortality and cardiovascular events were 2.092 (95% CI, 1.594-2.744) and 1.020 (95% CI, 0.929-1.119), respectively, compared to patients with CKD alone. The OR was 2.145 (95% CI, 1.563-2.944) when studies with polysomnography-diagnosed SA were examined independently. No potential publication bias was detected. There were no significant differences in odds ratios for overall mortality, based on subgroup analyses.

CONCLUSION

Co-existence between advanced CKD and SA is associated with increased overall mortality, but not cardiovascular (CV) events when compared with CKD alone. The analysis of CV events requires additional studies to confirm our findings. Moreover, clinical interventions aiming to prevent the progression of SA and CKD are encouraged.

Trastornos del sueño en el paciente con enfermedad renal crónica avanzada

Objetivo: Conocer las alteraciones y/o trastornos del sueño en los pacientes con Enfermedad Renal Crónica Avanzada. Método: Se realizó una búsqueda en las bases de datos Google Académico, Scielo, Science Direct, PubMed y Scopus. Se incluyeron artículos científicos en español e inglés y texto completo disponible. Se analizaron aquellos artículos que trataban sobre alteraciones del sueño en los pacientes en prediálisis, y en tratamiento renal sustitutivo: Hemodiálisis, Diálisis Peritoneal y Trasplante Renal. Resultados: Se han incluido 30 artículos publicados entre los años 2013 y 2018. Los pacientes con Enfermedad Renal Crónica Avanzada presentan una alta prevalencia de alteraciones del sueño, llegando a alcanzar una prevalencia de casi el 90% en pacientes en hemodiálisis y diálisis peritoneal, y 62% en pacientes con trasplante renal; y entre el 44% y el 77% en la etapa prediálisis. Las alteraciones del sueño más frecuentes encontradas, fueron: insomnio, síndrome de piernas inquietas, apnea del sueño y somnolencia diurna excesiva. Como principales medidas y tratamientos utilizados para las alteraciones del sueño en estos pacientes se han encontrado terapias tanto farmacológicas, como no farmacológicas y la combinación de ambas. Conclusiones: Las alteraciones del sueño tienen una alta prevalencia en los pacientes con Enfermedad Renal Crónica Avanzada, tanto en prediálisis como en tratamiento renal sustitutivo; siendo las más frecuentes el insomnio, el síndrome de piernas inquietas, la apnea obstructiva del sueño y la somnolencia diurna excesiva. Entre los factores de riesgo más influyentes destacan: ansiedad y depresión, Diabetes Mellitus, hipertensión arterial, problemas respiratorios y tiempo en diálisis.

Fluid Redistribution in Sleep Apnea: Therapeutic Implications in Edematous States

Sleep apnea (SA), a condition associated with increased cardiovascular risk, has been traditionally associated with obesity and aging. However, in patients with fluid-retaining states, such as congestive heart failure and end-stage renal disease, both prevalence and severity of SA are increased. Recently, fluid shift has been recognized to play an important role in the pathophysiology of SA, since the fluid retained in the legs during the day shifts rostrally while recumbent, leading to edema of upper airways. Such simple physics, observed even in healthy individuals, has great impact in patients with fluid overload. Correction of the excess fluid volume has risen as a potential target therapy to improve SA, by attenuation of nocturnal fluid shift. Such strategy has gained special attention, since the standard treatment for SA, the positive airway pressure, has low compliance rates among its users and has failed to reduce cardiovascular outcomes. This review focuses on the pathophysiology of edema and fluid shift, and summarizes the most relevant findings of studies that investigated the impact of treating volume overload on SA. We aim to expand horizons in the treatment of SA by calling attention to a potentially reversible condition, which is commonly underestimated in clinical practice.