Bone Marrow Transplantation (2016) 51, 1004–1006 © 2016 Macmillan Publishers Limited All rights reserved 0268-3369/16 www.nature.com/bmt LETTER TO THE EDITOR Regionalization of stem cell transplant procedures into teaching hospitals in United States: are we ready? Bone Marrow Transplantation (2016) 51, 1004–1006; doi:10.1038/ in year 2007 to a high of 99.7% in year 2010. The characteristics of bmt.2016.33; published online 7 March 2016 patients who underwent SCTs by hospital teaching status are presented in Table 1. Mean age of patients who had SCTs in non-teaching hospitals was 47.7 years (44.1 years for those in Regionalization is a process wherein complex high-risk surgical teaching hospitals), and 78.3% of those who had SCTs in procedures are selectively referred to be performed in selectively non-teaching hospitals were Whites (73% of those in teaching high volume, specialized, teaching hospitals. In the recent past, there hospitals were Whites). Females comprised of 46.1% of patients has been increasing regionalization or concentration of a wide array treated in non-teaching hospitals (41.1% in teaching hospitals). of complex surgical procedures into high volume or teaching Northeastern region accounted for only 0.5% of all SCTs hospitals, the underlying empirical basis being that performing high- performed in non-teaching hospitals (23.2% of all SCTs in teaching risk complex surgical procedures in large hospitals will lead to better hospitals were performed in Northeastern region). outcomes.1–5 There is an increasing number of stem cell transplan- Results from the multivariable logistic regression model are tation (SCT) procedures performed in the United States.6,7 So far, summarized in Table 2. In the regression model, following there are no data on regionalization of SCTs into teaching hospitals. adjustment for multiple confounders, when compared to in year The specific aim of the present study is to examine if performance of 2004, SCT procedures were more likely to be performed in SCT procedures has been regionalized to teaching hospitals over a teaching hospitals in year 2010 (odd ratios (OR) = 8.01, 95% 7-year-period from 2004 to 2010. The present study tests the confidence interval (CI) = 1.22–52.84, P = 0.03) and in year 2008 hypothesis that during the latter years of the study period, more SCT (OR = 7.84, 95% CI = 1.19–51.46, P = 0.03). SCT procedures were procedures were performed in teaching hospitals as opposed to in also more likely to be performed in teaching hospitals in the non-teaching hospitals. A secondary aim is to examine if there is Northeastern region (OR = 54.91, 95% CI = 18.81–160.28, Po0.001) geographic variations in regionalization. compared to in Western regions. The Nationwide Inpatient Sample (NIS) for the years 2004–2010 Findings from our analysis indicate that a vast majority of SCTs was used. The NIS is the largest all-payer hospitalization database are performed in teaching hospitals. During the later years of the in the United States.8 NIS is sponsored by the Healthcare Cost study period, was increasing regionalization of SCTs into teaching and Utilization Project (HCUP) of the Agency for Healthcare hospitals. These findings are consistent with prior studies that Research and Quality (AHRQ). A data user agreement was have looked at the phenomenon of regionalization across multiple 1–5 completed with HCUP–AHRQ before obtaining the data. The complex surgical procedures. A further finding in our study is present study was granted Institutional Review Board Exempt that, there seems to be a geographic variation in regionalization. status as a large publicly available database was used. Regionalization appears to be significantly pronounced in the All patients who underwent a SCT procedure (see Table 1 for the Northeastern regions compared to other geographic areas. This ICD-9-CM procedure codes9 that were used to select cases) during has not been demonstrated in prior studies. the years 2004–2010 were selected for analysis. Performance of Before embarking on regionalization of SCTs into teaching SCT in a teaching hospital was the outcome and used as a binomial hospitals, we should assess the relative merits and trade-offs for variable. As per the NIS, a teaching hospital has an American regionalizing complex procedures (and associated medical care) Medical Association approved residency program, is a member of such as SCT. Although there is unequivocal support that the Council of Teaching Hospitals or has a ratio of full-time performing high-risk complex surgical procedures in high-volume equivalent interns and residents to beds of 0.25 or higher.8 The specialized hospitals or teaching hospitals will lead to better primary independent variables were: year of procedure and outcomes10,11 in terms of lower costs, lower mortality rates and geographic region (Northeast, Midwest, South or Western regions lower complications, these benefits need to be confirmed over of the United States) of hospital location. A multivariable logistic time and for SCT procedures in specific. A major concern regarding regression models was used to examine the association between regionalization is that indiscriminate concentration of procedures the outcome and independent variables. The confounding effects into select centers will overburden these centers. The underlying of age, sex, race, type of admission, type of SCT and comorbid framework that high-volume hospitals spread their fixed costs for burden were adjusted in the multivariable regression model. Year providing surgical care over a larger number of procedures and 2004 was used as the reference as this would enable us to examine thereby achieve economies of scale may not hold true in the long if regionalization occurred in the latter parts of the study period. term.12 Over time, these centers could be overburdened resulting The effect of clustering of outcomes within hospitals was adjusted. in long waiting times for patients to undergo SCTs. This may All statistical tests were two sided and a P-value of o0.05 was compromise the delivery of timely care to patients who will need deemed to be statistically significant. All statistical analyses were SCTs. Burdening the high-volume centers with large numbers of performed using SAS Version 9.3 software (SAS Inc., Cary, NC, USA) complex procedures could also precipitate a scenario wherein they and SAS callable SUDAAN Version 11.0.1 (Research Triangle are unable to provide low-risk procedures and health care services, Institute, Research Triangle Park, NC, USA). which could have lasting financial implications and threaten the During the study period, a total of 101 462 SCTs were very viability of these high-volume centers. A similar phenomenon performed. Of these, 97 301 were performed in teaching hospitals could also occur in low-volume non-teaching hospitals as they and 2954 in non-teaching hospitals. Status of hospital was withdraw from providing complex medical care/procedures. unknown for 1207 SCT procedures. Performance of SCTs in Specialist surgeons/providers may want to leave these hospitals teaching hospitals over the time period varied from a low of 91.5% as opportunities to provide highly specialized care dwindle. Letter to the Editor 1005 Table 1. Characteristics of patients having stem cell transplant procedures Characteristic Response Non-teaching Teaching hospitals: hospitals: N = 2954 N = 97 301 Type of SCT (ICD-9-CM procedure code)—Note: a Bone marrow transplant, not specified 0.6% 0.2% patient may have one more of the SCTs performed. (41.00) Consequently, the individual % values will not add up to 100% Autologous bone marrow transplant 7.8% 4.5% without purging (41.01) Allogeneic bone marrow transplant 1.8% 0.6% with purging (41.02) Allogeneic bone marrow transplant 6.8% 7.5% without purging (41.03) Autologous hematopoietic stem cell 50.6% 52.2% transplant without purging (41.04) Allogeneic hematopoietic stem cell 26.8% 28.8% transplant without purging (41.05) Cord blood stem cell transplant (41.06) 3.2% 3.7% Autologous hematopoietic stem cell 1.9% 1.7% transplant with purging (41.07) Allogeneic hematopoietic stem cell DS 1.3% transplant (41.08) Autologous bone marrow transplant DS 0.1% with purging (41.09) Sex Male 53.9% 58.9% Female 46.1% 41.1% Type of admission Emergency/urgent 19% 20.9% Elective 81% 79.1% Racea White 78.6% 73% Black 7.4% 8.8% Hispanic 9.8% 10.9% Asian/Pacific Islander 1.8% 3% Native American 0.6% 0.5% Other races 1.7% 3.7% Comorbid burdenb 0 22.9% 21.9% 1 33.8% 30.8% 2 21.5% 24.6% 3 11.9% 13.7% 4 6.6% 6% 5 2.2% 2.2% ⩾ 6 1.1% 0.8% Age in years Mean 47.7 years 44.1 years SE of mean 2.56 1.29 Median 51.5 years 49.7 years Hospital region Northeast 0.5% 23.2% Midwest 19.5% 23.8% South 13.4% 31% West 36.6% 21.9% Year of procedure 2004 9.2% 10.3% 2005 19.6% 13.6% 2006 12.2% 8.4% 2007 43.8% 14.3% 2008 2.3% 17.5% 2009 10.8% 17.4% 2010 2% 18.5% Abbreviation: SCT = stem cell transplantation. DS: discharge information is suppressed because individual cell count is ⩽10 (as per data user agreement with HCUP–AHRQ). aInformation on race was available for 2213 patients who had SCTs in non-teaching hospitals and 77 944 patients who had SCTs in teaching hospitals. bComorbid burden was computed by summing the presence of 29 different chronic comorbid conditions. The 29 comorbid conditions were: AIDS, alcohol abuse, deficiency anemias, rheumatoid arthritis/collagen vascular diseases, chronic blood loss anemia, congestive heart failure, chronic pulmonary disease, coagulopathy, depression, diabetes—uncomplicated, diabetes—with chronic complications, drug abuse, hypertension, hypothyroidism, liver disease, lymphoma, fluid and electrolyte disorders, metastatic cancer, neurological disorders, obesity, paralysis, peripheral vascular disorders, psychoses, pulmonary circulatory disorders, renal failure, solid tumor without metastasis, peptic ulcer disease, valvular disease, and weight loss.