5-33) cases. Centers above the median were classified as high-vol- ume. Primary outcome measures were complication rate, LOS, trans- fusion rate, and in-hospital mortality rate. Urologic complications were excluded because urologic diagnoses are often miscoded as urologic complications in NIS datasets. A secondary analysis examined the relationship between the presence of a complication itself, LOS, and in-hospital mortality rate. Statistical tests were two-sided t-test, Chi- square test, Mann-Whitney U test, and multinomial logistic regression, where appropriate. RESULTS: We identified a weighted sample of 7,785 patients of which 3,592 (46%) had PCNL at a high-volume center. High-volume centers had lower in-hospital mortality than low-volume centers (0% vs 0.5%, p  0.001). Complication rate (16.2% vs 17.7%), transfusion rate (5.7% vs 6.1%), and median LOS (3 days) were equivalent between high- and low-volume centers, respectively, even when adjusting for differences in Charlson comorbidity index. When complications were broken down by type, cardiac (1.8% vs 3.4%, p 0.001), infectious (3.1% vs 4.1%, p = 0.03), and gastrointestinal (1.6% vs 2.2%, p = 0.03) complication rates were lower at high-volume centers. Patients who had a complication (n = 1305, 16.8%) had a higher in-hospital mortality rate (1.1% vs 0.1%, p 0.001) and a longer median LOS (7 vs 3 days, p 0.001) than those without a complication. CONCLUSIONS: Overall complication rates, transfusion rates, and LOS are equivalent between high- and low-volume centers for PCNL. In-hospital mortality is lower at high-volume centers. Patients who had a complication had significantly longer LOS as well as a higher death rate. Further studies using the NIS could examine if the above findings have changed over time. Source of Funding: None General & Epidemiological Trends & Socioeconomics: Evidence-Based Medicine & Outcomes (II) Moderated Poster Session 3 Saturday, May 4, 2013 3:30 PM-5:30 PM 65 BONE DENSITY RESULTS OF VITAMIN-D INADEQUATE PATIENTS PRESENTING WITH UROLITHIASIS TO A TERTIARY STONE CENTER Mohamed Elkoushy*, Terence Lee, Sero Andonian, Montreal, Canada INTRODUCTION AND OBJECTIVES: Vitamin-D Inadequacy (VDI) and its associated metabolic abnormalities are prevalent in pa- tients presenting with urolithiasis. Vitamin D plays a vital role in bone health and stone-formers are at risk of premature bone loss that may be exaggerated by VDI. Therefore, the aim of the present study was to assess abnormalities in bone density studies for patients with VDI presenting with urolithiasis to a tertiary stone clinic. METHODS: A retrospective review of prospectively collected data was performed for patients presenting to stone clinic from Novem- ber, 2009 to August, 2012. Demographic and clinical data were col- lected together with metabolic stone work-up and bone density studies. VDI was defined as VD levels  30 ng/ml. A Dual-energy X-ray Absorptiometry (DXA) scan was used to evaluate the Bone Mineral Density (BMD) at the femoral neck and lumbar spine. The World Health Organization (WHO) criteria were used to define patients with abnormal BMD; normal (within 1 SD), osteopenia (-1 to -2.5 SD), and osteoporosis (-2.5 SD). Patients with primary hyperparathyroidism or hypercalcemia were excluded. RESULTS: A total of 49 patients with VDI with DXA studies were included; 26 (53.1%) were males. Mean age (95%CI) was 51.5 (42.5-58.3) years, mean BMI (95%CI) was 27.9 (21.6- 31.2) kg/m2 and mean serum VD (95%CI) was 18.4 (16.4-26.2) ng/ml. Twenty-nine patients (59.2%) had abnormal DXA studies where 23 (46.9%) had osteopenia and 6(12.3%) had osteoporosis in the femoral neck and/or lumbar spine. Femoral neck was affected in 42.8% of patients (36.7% osteopenia and 6.1% osteoporosis) while lumbar spine was affected in 40.8% of patients (32.6% osteopenia and 8.2% osteoporosis; one patient had severe osteoporosis with history of osteoporotic fractures). Median serum VD (95%CI) was not significantly different between patients with normal and abnormal DXA scans [19.2 (8-29) vs. 17.2 (6-28) ng/ml, p=0.10). Similarly, median serum VD (95%CI) did not significantly differ between osteopenics and osteoporotics [17.6 (6-28) vs. 15.6 (6.8-23.6) ng/ml, p=0.64]. Of interest, 61.3% of those with abnormal DXA scans were males. CONCLUSIONS: A high prevalence of abnormal DXA scans was found in patients presenting with urolithiasis and vitamin D inade- quacy. These findings need to be taken into account during evaluation and replacement of vitamin D in this population. Source of Funding: This work was supported in part by the Canadian Urological Association Scholarship Foundation Award. 66 DIABETIC SEVERITY AND RISK OF KIDNEY STONE DISEASE Aviva Weinberg*, Chirag Patel, Glenn Chertow, John Leppert, Stanford, CA INTRODUCTION AND OBJECTIVES: Diabetes mellitus (DM), obesity, and metabolic syndrome are associated with kidney stone disease. We investigated the associations among the presence and severity of diabetes, glycemic control and insulin resistance with kidney stone disease in a nationally representative data sample. METHODS: We analyzed adult (age 20) participants in the 2007-2010 NHANES survey (N =12,153). A history of kidney stone disease was obtained by self-report. The presence of DM was defined by a self-reported history, DM related medication usage (insulin and oral hypoglycemic agents), and reported DM comorbidity (retinopathy). Insulin resistance was estimated using fasting plasma insulin (FPI) levels and the homeostasis model assessment of insulin resistance (HOMA-IR) definition. We classified glycemic control using HbA1c and fasting plasma glucose levels (FPG). Univariate logistic regression was used to calculate odds ratios (OR) for each measure of diabetic severity. We then constructed multivariate logistic regression models adjusting for patient age, gender, race/ethnicity, smoking history, and BMI (model A) as well additional laboratory values including serum uric acid, serum calcium, and serum creatinine (model B). All analyses accounted for the complex NHANES sample design. RESULTS: Univariate predictors of kidney stone disease in- cluded a self-reported history of diabetes (OR 2.44, CI 1.84-3.25) and history of insulin use (OR 3.31, CI 2.02-5.45). Patients with prediabetic range and diabetic range FPG had increased odds of kidney stone disease, OR 1.28 (CI 0.95-1.72) and OR 2.29 (CI 1.68-3.12), respec- tively. Patients with prediabetic and diabetic range HgbA1c values had ORs of 1.68 (CI=1.17-2.42) and 2.82 (1.98-4.02), respectively. In the multivariate model, a history of DM, the use of insulin, FPI levels and elevated HgbA1c levels remained significantly associated with kidney stone disease. These associations remained after further adjustment for serum uric acid, calcium and creatinine levels in Model B. (Table 1). CONCLUSIONS: The severity of diabetes, as estimated by measures of glycemic control (fasting plasma glucose levels, HbA1c), and insulin resistance (insulin use, fasting plasma insulin levels, and HOMA-IR) are associated with increased odds of kidney stone disease. Vol. 189, No. 4S, Supplement, Saturday, May 4, 2013 THE JOURNAL OF UROLOGY e27