Abstract: PD35-02
Sources of Funding: None

Introduction

We aim to investigate costs variations for percutaneous nephrolithotomy (PCNL) in the United States using a population-based cohort.

Methods

Using the Premier Healthcare Database (Premier Inc, Charlotte, NC), we identified all patients diagnosed with kidney/ureter calculus (ICD-9: 592) who underwent PCNL (ICD-9: 55.04 or 55.03 combined with 55.21) from 2003 to 2013. We evaluated 90-day direct hospital costs (2015 USD); high costs were those above the 90th percentile and low costs were those below the 10th. We constructed a multilevel hierarchical regression model and calculated the pseudo-R2 of each variable, which translates to a percentage representing the variability contributed by that variable on 90-day direct hospital costs.

Results

Our final cohort consisted of 73,392 patients who underwent PCNL during the 11-year study period. Mean costs overall were $14374 (95% CI: $14150 - $14596). Mean cost in the low-cost group was $5,787 (95% CI: $5716 - $5856) versus $38,590 (95% CI: $37,357 - $39,923) in the high-cost group. Figure 1 shows mean costs (a) per surgeon and (b) per hospital ranked in ascending order and plotted along with 95% CI. Patient, hospital and surgical characteristics had a modest contribution toward costs variations (4.83%, 2.43%, 0.16%). Significant predictors of high costs include poorer comorbidity status (Charlson score ≥2 vs. 0: OR 2.98, p<0.001), region of hospital (West vs. Midwest: OR 1.96, p<0.01, Northeast OR 1.77, p=0.02), and hospital bedsize (>600 vs. <400 beds: OR 1.95, p<0.01. Factors less likely to be associated with high costs include age (OR: 0.99, p=0.04) and private insurance (vs. Medicare, OR 0.54, p<0.001).

Conclusions

Our contemporary analysis showed that patient, hospital and surgical characteristics had only a modest effect on costs variations for PCNL. Poor comorbidity status contributes to high costs highlighting the importance of patient selection. Larger hospitals in the West and Northeast are associated with higher costs; this may due to referral of complex stone cases to these centers.

Funding

None