Impact of Obesity on Hospitalization Burden of Urolithiasis in Spain Between 1997 and 2021

<b>Background/Objective</b>: The prevalence of kidney stones has increased, especially in industrialized countries. Obesity and metabolic syndrome have also risen significantly and are considered factors driving this trend. Our goal was to assess the hospitalization burden of kidney stones and identify epidemiological trends in Spain over the past 25 years. Additionally, this study analyzed the relationship between the data of kidney stone patients and obesity-coded diagnoses in hospital discharges. <b>Methods</b>: A retrospective observational study was conducted with the data from 1,070,192 patients hospitalized for urolithiasis between 1997 and 2021 using the Minimum Basic Data System. The hospitalization burden of lithiasis and its association with obesity was analyzed, alongside trend evaluations. The incidence of lithiasis in obese hospitalized patients versus all hospitalizations was compared. Mortality rates, length of stay, and the costs of lithiasis hospitalizations were evaluated to determine obesity's impact on lithiasis patients. <b>Results</b>: Kidney stone cases increased by 1.8% annually (CI 95%: 0.2-3.3), with a more pronounced 10.7% (CI 95%: 7.3-14.2) increase in obesity-related hospitalizations. Obesity increased the likelihood of lithiasis hospitalization by 15.6 times and was associated with higher hospitalization costs. However, obesity did not significantly affect hospital stay duration or mortality rates. <b>Conclusions</b>: The increasing burden of kidney stone hospitalizations in Spain is linked to rising obesity rates. Obesity contributes to higher hospitalization costs. Preventive strategies targeting obesity should be implemented to reduce the burden on healthcare systems.