Trends in percutaneous nephrolithotomy use and outcomes in the United States

Purpose: We investigated recent trends in the use and perioperative outcomes of percutaneous nephrolithotomy in the United States in a population based cohort.

Materials and methods: We obtained the records of patients treated with percutaneous nephrolithotomy between 1999 and 2009 from the Nationwide Inpatient Sample (NIS). A weighted sample was used to estimate national utilization rates. Trends in age, comorbidity, perioperative complications and in-hospital mortality were analyzed. Temporal trends were quantified by the estimated annual percent change. We evaluated the association between patient and hospital characteristics, including complications, prolonged length of stay and in-hospital mortality, using logistic regression models adjusted for clustering.

Results: During 1999 to 2009, percutaneous nephrolithotomy use increased in men and women from 3.0/100,000 and 2.99/100,000 to 3.63/100,000 and 4.07/100,000, respectively. Women showed the largest increases in percutaneous nephrolithotomy use with an estimated annual percent change of 4.49% (95% CI 2.7-6.3, p <0.001) vs 2.90% (95% CI 1.5-4.3, p = 0.003) in men. Baseline comorbidity in patients undergoing percutaneous nephrolithotomy increased with time. Overall complications increased from 12.2% to 15.6% (p <0.001), while mortality remained stable at 0.0% to 0.4%. The transfusion rate was 4.0%. Sepsis increased from 1.2% to 2.4% of cases (p <0.001). Patients were at risk for complications if they were older, more ill and treated in more recent years. Age was significantly associated with increased odds of mortality.

Conclusions: Percutaneous nephrolithotomy use in the United States has increased and females are now the majority gender. Although mortality remains low, rates of sepsis and overall complications have increased. Broad use of percutaneous nephrolithotomy, especially in older and more ill patients, may account for these changes.