Can gout affect kidney function? (Urate crystals may deposit in the kidneys, leading to kidney stones or renal impairment)

Yes, absolutely, and the relationship is quite close.

You can understand it this way: the root cause of gout is too much uric acid in the body. This uric acid is like salt in water; too much of it will crystallize.

These tiny, sharp uric acid crystals (monosodium urate) don't just cause trouble and severe pain in your joints (like the big toe); they also travel to your kidneys via the bloodstream.

The kidneys are our body's "filters," responsible for removing waste products from the blood. When these uric acid crystals reach the kidneys, two things can happen:

Formation of kidney stones: These crystals accumulate and clump together in the kidneys, forming "gouty tophi" or uric acid kidney stones. If these block the urinary tract, it can be extremely painful and affect urination.
Chronic damage to kidney function: More troublingly, even without forming large stones, these tiny crystals can slowly deposit in the kidney tissues, much like scale clogging a filter. They continuously irritate the kidneys, causing chronic inflammation and damage. Over time, the kidney's filtering function will decline, leading to what is known as "gouty nephropathy." This process is often silent; there may be no noticeable symptoms in the early stages, but by the time it's discovered, the kidneys may already be severely damaged.

Therefore, controlling uric acid is absolutely not just about preventing joint pain; a more crucial goal is to protect your kidneys. By lowering uric acid, there will be less "scale" in your kidneys, allowing them to work well for you in the long run.