Chronic kidney disease
Your kidneys are a pair of organs that sit either side of your body below your ribcage, towards the lower back. Their main functions are to:
- Filter your blood and remove waste substances
- Remove excess water from your blood
- Eliminate these waste substances by producing urine
- Help to keep your blood pressure stable.
Chronic kidney disease is a life-long condition where your kidneys become damaged so they function less effectively. There are six stages to kidney disease, ranging from very mild to severe. Lifestyle changes and medication can halt the progression of kidney damage, so most people with the disease remain at the milder end of the scale.
Chronic kidney disease and sleep apnoea
Sleep apnoea is thought to accelerate kidney damage and worsen chronic kidney disease. There are four main reasons why sleep apnoea could have this effect:
- Repeated apnoeas cause fluctuations in oxygen during sleep – This stresses the kidney cells, causing them to become inflamed. The result is scarring and loss of healthy kidney cells.
- Sleep apnoea activates the ‘fight or flight’ response – Repeated activation of the ‘fight or flight’ response leads to reduced blood flow to the kidneys. This causes the release of certain hormones that can lead to high blood pressure and scarring of the kidneys.
- Sleep apnoea can make diabetes worse – Diabetes can cause your kidneys to leak protein into your urine. This can lead to scarring of your kidneys and loss of healthy kidney cells.
- Sleep apnoea causes high blood pressure – The tiny, vulnerable blood vessels of the kidney can stretch, scar and weaken when blood flows through them at high pressure. When they become damaged the kidney is less able to filter blood.
Can treating sleep apnoea help?
Although research suggests that sleep apnoea can make chronic kidney disease worse, there have been no large-scale studies to find out whether treating sleep apnoea helps to improve your kidney function.
If you do have Obstructive Sleep Apnoea, small studies suggest that using a CPAP machine can help to improve your kidney function in the short term. It is not known whether therapy provides any long-term benefits for chronic kidney disease.
