Metabolic dysfunction associated steatotic liver and kidney stones: what is going on?

Purpose of review Metabolic dysfunction associated steatotic liver disease (MASLD) is increasing throughout the world, affecting nearly one in three individuals. Kidney stone disease, which is also increasing, is associated with MASLD. Common risk factors for both, including obesity, diabetes, dyslipidemia, hypertension, and metabolic syndrome, are likely drivers of this association. We present here a review of the associations and possible interconnections between these two common disease processes. Recent findings Epidemiological studies are discordant regarding the impact of sex on this association and on the impact of MASLD on incident stone risk. The nature of kidney stones is rarely taken into account. A favorable milieu for uric acid kidney stone formation may be created by a lower urine pH resulting from defective ammonium production associated with insulin resistance, common in MASLD. Endogenous oxalate synthesis, a major risk factor for calcium oxalate kidney stones, may be increased in MASLD via decline in the activity of enzymes involved in the detoxification of glyoxylate, the immediate precursor of oxalate. Summary The nature of kidney stones associated with MASLD and factors driving this association remain to be elucidated. Potential mechanisms identified underlying this include an increase in the risk factors for both uric acid and calcium oxalate kidney stones.