Hospital Volume Does Not Influence in-Hospital Mortality of Autologous Hematopoietic Cell Transplant Among Multiple Myeloma Patients in the United States

Introduction:

Hospital volume and provider experience affects survival among patients with hematologic malignancies (Giri et al Blood 3359-60). Whether hospital volume affects outcomes of autologous hematopoietic cell transplant (autoSCT) among patients with multiple myeloma (MM) remains unclear.

Methods:

We utilized the Nationwide Inpatient Sample (NIS) database to identify all adults >18 years diagnosed with MM who underwent autoSCT in 2009-2011. NIS is the largest all-payer inpatient database in the US that captures about 20% of all US hospitalizations. Hospitals were divided into quartiles, based on the annual number of autoSCT performed, and classified into high volume (above 75th percentile) and low volume centers (below 25th percentile). In-hospital outcomes including inpatient mortality, infection, mechanical ventilation, and costs of hospitalization were compared between the two groups. All p-values were 2 sided, and the level of significance was chosen at 0.05. Statistical analysis was done using STATA 13.0 (StataCorp, College Station, TX).

Results:

A total of 2,750 autoSCTs were reported among patients with MM during the study period. The characteristics of study population included mean age of 58.7 ± 8.7 years, 56% males (n=1547) and 72% whites (n=1822). No significant difference existed in in-hospital mortality rate (0.86% vs. 1.59%; p=0.183) between high volume (≥178 autoSCTs per year) versus low volume centers (≤56 autoSCTs per year). The rate of fungal infection (5.32% vs. 4.94%; p=0.75), herpes simplex virus infection (1.58% vs. 1.59%; p=0.98), and the need for mechanical ventilation (1.87% vs. 1.27%) was similar between the high volume and low volume centers. Higher rates of stomatitis (57% vs. 46%; p<0.01), use of total parenteral nutrition (12.37% vs. 6.21%) and neutropenic fever (33.6% vs. 23.5%; p <0.01) were noted in high volume versus low volume centers. The cost of initial hospitalization was similar in the two groups (mean $ 161,085 vs. $ 154,161; p value 0.17).

Conclusion:

Our study demonstrates a low risk of inpatient mortality without center effect for autoSCT in MM in the recent years. The risks of fungal and herpes simplex virus infection were also similar between high volume and low volume centers. Higher rates of stomatitis, use of total parenteral nutrition and neutropenic fever were noted in high volume versus low volume centers. The reasons for these differences are not clear from our study but may relate to possible differences in patient characteristics or conditioning chemotherapy.