An epidemic of cataract surgery in Korea: the effects of private health insurance on the National Health Insurance Service.

OBJECTIVES: In Korea, the National Health Insurance Service (NHIS) covers essential healthcare expenses, including cataract surgery. To address concerns that private health insurance (PHI) might have inflated the need for such procedures, we investigated the extent of the PHI-attributable increase in cataract surgery and its impact on NHIS-reimbursed expenses. METHODS: This retrospective, observational study uses nationwide claims data for cataract surgery from 2016 to 2020. We examined trends in utilization and cost, and we estimated the excess numbers of (1) cataract operations attributable to PHI and (2) types of intraocular lenses used for cataract surgery in 2020. RESULTS: Between 2016 and 2020, a 36.8% increase occurred in the number of cataract operations, with increases of 63.5% and 731.8% in the total healthcare costs reimbursed by NHIS and PHI, respectively. Over a 5-year period, the surgical rate per 100,000 people doubled for patients aged <65 years (from 328 in 2016 to 664 in 2020). Among the 619,771 cases in 2020 of cataract surgery reimbursed by the Korean diagnosis-related group system, more non-NHIS-covered intraocular lenses were used for patients aged <65 years than ≥65 years (68.1 vs. 14.2%). In 2020 alone, an estimated 129,311 excess operations occurred, accounting for an excess cost of US$115 million. CONCLUSIONS: A dramatic increase in the number and cost of cataract operations has occurred over the last 5 years. The PHI-related increase in operations resulted in increased costs to NHIS. Measures to curtail the non-indicated use of cataract surgery should be implemented regarding PHI.

Developing Core Elements and Checklist Items for Implementing Antimicrobial Stewardship Programs in Korean General Hospitals: A Modified Delphi Survey.

BACKGROUND: Antimicrobial stewardship programs (ASPs) aim to optimize antimicrobial use by minimizing the spread of antimicrobial resistance. The core elements for implementing ASPs in healthcare facilities have been developed by the World Health Organization, international research group and government agencies of various countries. However, to date, there is no documented core elements for implementation of ASP in Korea. This survey aimed to establish a national consensus on a set of core elements and their related checklist items for the implementation of ASPs in Korean general hospitals. MATERIALS AND METHODS: The survey was conducted from July 2022 to August 2022 by the Korean Society for Antimicrobial Therapy with support from the Korea Disease Control and Prevention Agency. A literature review was conducted by searching Medline and relevant websites to retrieve a list of core elements and checklist items. These core elements and checklist items were evaluated by a multidisciplinary panel of experts using a structured modified Delphi consensus procedure, using two-step survey included online in-depth questionnaires and in-person meeting. RESULTS: The literature review identified 6 core elements (Leadership commitment, Operating system, Action, Tracking, Reporting, and Education) and 37 related checklist items. Fifteen experts participated in the consensus procedures. Ultimately, all 6 core elements were retained, and 28 checklist items were proposed, all with ≥80% agreement; in addition 9 items were merged into 2 items, 2 items were deleted, and 15 items were rephrased. CONCLUSION: This Delphi survey provides useful indicators for the implementation of ASP in Korea and suggests national policy improvement about the barriers (e.g., shortage of staffing and financial support) existing in Korea for optimal implementation of ASPs.

Core Elements for Implementing Antimicrobial Stewardship Programs in Korean General Hospitals.

Currently, antimicrobial resistance (AMR) is a major threat to global public health. The antimicrobial stewardship program (ASP) has been proposed as an important approach to overcome this crisis. ASP supports the optimal use of antimicrobials, including appropriate dosing decisions, administration duration, and administration routes. In Korea, efforts are being made to overcome AMR using ASPs as a national policy. The current study aimed to develop core elements of ASP that could be introduced in domestic medical facilities. A Delphi survey was conducted twice to select the core elements through expert consensus. The core elements for implementing the ASP included (1) leadership commitment, (2) operating system, (3) action, (4) tracking, (5) reporting, and (6) education. To ensure these core elements are present at medical facilities, multiple departments must collaborate as teams for ASP operations. Establishing a reimbursement system and a workforce for ASPs are prerequisites for implementing ASPs. To ensure that ASP core elements are actively implemented in medical facilities, it is necessary to provide financial support for ASPs in medical facilities, nurture the healthcare workforce in performing ASPs, apply the core elements to healthcare accreditation, and provide incentives to medical facilities by quality evaluation criteria.

Preliminary Results of Teleconsultations Temporarily Allowed during the COVID-19 Pandemic.

PURPOSE: During the COVID-19 pandemic, Korea has temporarily expanded coverage of teleconsultation to ensure access to essential health services. As a preliminary study, we investigated service utilization patterns and the characteristics of doctors and patients involved in these temporary teleconsultation services. MATERIALS AND METHODS: Using national health insurance claims data from February 23, 2020 to June 30, 2020 from the Health Insurance Review and Assessment Service, 228269875 cases were identified. Among them, 567390 cases that received teleconsultation services were included in our study. We performed descriptive analyses according to the types of healthcare institutions. RESULTS: In total, 6193 healthcare institutions provided teleconsultation. Of these, 5466 (88.3%) were clinics. Physicians providing teleconsultations were most likely to be doctors of internal medicine (34.0%) or pediatricians (7.0%) and based in the Seoul Metropolitan area (30.4%). In terms of patients undergoing teleconsultation, the most common major disease categories treated were circulatory system diseases (I00-I99). In a detailed analysis, hypertensive diseases (I10-I15) were the most common diagnoses, with a total of 88726 cases (15.6%), followed by diabetes mellitus at 60298 cases (10.6%). The proportion of Medical Aid recipients receiving teleconsultations was higher (9.5%) than other socioeconomic groups. Among all participants, 356622 cases (84.6%) were from a return visit, and 108838 cases (19.2%) received teleconsultation services without being prescribed drugs. CONCLUSION: Temporarily allowed teleconsultation services were provided mostly to the following patients: 1) those scheduled for revisitation, 2) those with chronic diseases, and 3) those living in pandemic hotspots.

Nurse Staffing and Health Outcomes of Psychiatric Inpatients: A Secondary Analysis of National Health Insurance Claims Data.

PURPOSE: The present study investigated the association between nurse staffing and health outcomes among psychiatric inpatients in Korea by assessing National Health Insurance claims data. METHODS: The dataset included 70,136 patients aged 19 years who were inpatients in psychiatric wards for at least two days in 2016 and treated for mental and behavioral disorders due to use of alcohol; schizophrenia, schizotypal and delusional disorders; and mood disorders across 453 hospitals. Nurse staffing levels were measured in three ways: registered nurse-to-inpatient ratio, registered nurse-to-adjusted inpatient ratio, and nursing staff-to-adjusted inpatient ratio. Patient outcomes included length of stay, readmission within 30 days, psychiatric emergency treatment, use of injected psycholeptics for chemical restraint, and hypnotics use. Relationships between nurse staffing levels and patient outcomes were analyzed considering both patient and system characteristics using multilevel modeling. RESULTS: Multilevel analyses revealed that more inpatients per registered nurse, adjusted inpatients per registered nurse, and adjusted inpatients per nursing staff were associated with longer lengths of stay as well as a higher risk of readmission. More adjusted inpatients per registered nurse and adjusted inpatients per nursing staff were also associated with increased hypnotics use but a lower risk of psychiatric emergency treatment. Nurse staffing levels were not significantly associated with the use of injected psycholeptics for chemical restraint. CONCLUSION: Lower nurse staffing levels are associated with negative health outcomes of psychiatric inpatients. Policies for improving nurse staffing toward an optimal level should be enacted to facilitate better outcomes for psychiatric inpatients in Korea.

Association of Nurse Staffing With Nosocomial Infections of Very Low-Birth-Weight Infants.

Prior studies have reported inconsistent findings regarding the relationship between nurse staffing and nosocomial infections in very low-birth-weight (VLBW) infants. Little is known about whether similar associations occur in Korea. The purpose of this study was to identify the nurse staffing of neonatal intensive care units (NICUs) in Korea and to verify the association between nurse staffing and nosocomial infections among VLBW infants in NICUs. We selected 4654 VLBW infants admitted to 52 hospitals. Nosocomial infections were defined as incidence of bloodstream infection, urinary tract infection (UTI), or rotavirus infection. The average number of NICU patients per nurse was 4.51(minimum-maximum: 2.38-8.16). Hospitals with a higher number of patients per nurse exhibited a significant increased UTI rate (P = .005) and rotavirus infection rate (P = .025) in the univariate analysis. After adjusting for all patient and hospital characteristics, UTI significantly increased with increasing number of patients per nurse (odds ratio [OR] = 1.79; 95% confidence interval, 1.29-2.47), while bloodstream infection (OR = 0.93; 95% confidence interval, 0.79-1.09) and rotavirus infection (OR = 1.14; 95% confidence interval, 0.92-1.41) were not significant. These findings revealed that a nurse staffing in NICUs is an important factor for preventing UTI among VLBW infants.

Imbalance in Cardiovascular Surgery Medical Service Use Between Regions.

BACKGROUND: This study uses the relevance index to understand the condition of regional medical service use for cardiovascular surgery and to identify the medical service use imbalance between regions. METHODS: This study calculated the relevance index of 16 metropolitan cities and provinces using resident registration address data from the Ministry of Government Administration and Home Affairs and the 2010-2014 health insurance, medical care assistance, and medical benefits claims data from the Health Insurance Review and Assessment Service. We identified developments over the 5-year time period and analyzed the level of regional imbalance regarding cardiovascular surgery through the relative comparison of relevance indexes between cardiovascular and other types of surgery. RESULTS: The relevance index was high in large cities such as Seoul, Daegu, and Gwangju, but low in regions that were geographically far from the capital area, such as the Gangwon and Jeju areas. Relevance indexes also fell as the years passed. Cardiovascular surgery has a relatively low relevance index compared to key types of surgery of other fields, such as neurosurgery and colorectal surgery. CONCLUSION: This study identified medical service use imbalance between regions for cardiovascular surgery. Results of this study demonstrate the need for political intervention to enhance the accessibility of necessary special treatment, such as cardiovascular surgery.

The Association Between Treatment Frequency and Treatment Outcome for Cardiovascular Surgeries.

BACKGROUND: This study analyzed the association between the volume of heart surgeries and treatment outcomes for hospitals in the last five years. METHODS: Hospitals that perform heart surgeries were chosen throughout Korea as subjects using from the Health Insurance Review and Assessment Service. The treatment outcome of the heart surgeries was defined as the mortality within 30 postoperative days, while the annual volume of the surgeries was categorized. Logistic regression was used as the statistical analysis method, and the impacts of the variables on the heart surgery treatment outcomes were then analyzed. RESULTS: The chance of death of patients who received surgery in a hospital that performed 50 or more surgeries annually was noticeably lower than patients receiving operations from hospitals that performed fewer than 50 surgeries annually, indicating that the chance of death decreases as the annual volume of heart surgeries in the hospital increases. In particular, the mortality rate in hospitals that performed more than 200 surgeries annually was less than half of that in hospitals that performed 49 or fewer surgeries annually. CONCLUSION: These results indicate that accumulation of a certain level of heart surgery experience is critical in improving or maintaining the quality of heart surgeries. In order to improve the treatment outcomes of small hospitals, a support policy must be implemented that allows for cooperation with experienced professionals.

Development of Models for Regional Cardiac Surgery Centers.

BACKGROUND: This study aimed to develop the models for regional cardiac surgery centers, which take regional characteristics into consideration, as a policy measure that could alleviate the concentration of cardiac surgery in the metropolitan area and enhance the accessibility for patients who reside in the regions. METHODS: To develop the models and set standards for the necessary personnel and facilities for the initial management plan, we held workshops, debates, and conference meetings with various experts. RESULTS: After partitioning the plan into two parts (the operational autonomy and the functional comprehensiveness), three models were developed: the 'independent regional cardiac surgery center' model, the 'satellite cardiac surgery center within hospitals' model, and the 'extended cardiac surgery department within hospitals' model. Proposals on personnel and facility management for each of the models were also presented. A regional cardiac surgery center model that could be applied to each treatment area was proposed, which was developed based on the anticipated demand for cardiac surgery. The independent model or the satellite model was proposed for Chungcheong, Jeolla, North Gyeongsang, and South Gyeongsang area, where more than 500 cardiac surgeries are performed annually. The extended model was proposed as most effective for the Gangwon and Jeju area, where more than 200 cardiac surgeries are performed annually. CONCLUSION: The operation of regional cardiac surgery centers with high caliber professionals and quality resources such as optimal equipment and facility size, should enhance regional healthcare accessibility and the quality of cardiac surgery in South Korea.

Projections of Demand for Cardiovascular Surgery and Supply of Surgeons.

BACKGROUND: While demand for cardiovascular surgery is expected to increase gradually along with the rapid increase in cardiovascular diseases with respect to the aging population, the supply of thoracic and cardiovascular surgeons has been continuously decreasing over the past 10 years. Consequently, this study aims to achieve guidance in establishing health care policy by analyzing the supply and demand for cardiovascular surgeries in the medical service area of Korea. METHODS: After investigating the actual number of cardiovascular surgeries performed using the National Health Insurance claim data of the Health Insurance Review and Assessment Service, as well as drawing from national statistics concerning the elderly population aged 65 and over, this study estimated the number of future cardiovascular surgeries by using a cell-based model. To be able to analyze the supply and demand of surgeons, the recent status of new surgeons specializing in thoracic and cardiovascular surgeries and the ratio of their subspecialties in cardiovascular surgeries were investigated. Then, while taking three different scenarios into account, the number of cardiovascular surgeons expected be working in 5-year periods was projected. RESULTS: The number of cardiovascular surgeries, which was recorded at 10,581 cases in 2014, is predicted to increase consistently to reach a demand of 15,501 cases in 2040-an increase of 46.5%. There was a total of 245 cardiovascular surgeons at work in 2014. Looking at 5 year spans in the future, the number of surgeons expected to be supplied in 2040 is 184, to retire is 249, and expected to be working is 309-an increase of -24.9%, 1.6%, and 26.1%, respectively compared to those in 2014. This forecasts a demand-supply imbalance in every scenario. CONCLUSION: Cardiovascular surgeons are the most central resource in the medical service of highly specialized cardiovascular surgeries, and fostering the surgeons requires much time, effort, and resources; therefore, by analyzing the various factors affecting the supply of cardiovascular surgeons, an active intervention of policies can be prescribed for the areas that have failed to meet the appropriate market distributions.

Reoperation rate after surgery for lumbar spinal stenosis without spondylolisthesis: a nationwide cohort study.

BACKGROUND CONTEXT: Lumbar spinal stenosis is one of the most common degenerative spine diseases. Surgical options are largely divided into decompression only and decompression with arthrodesis. Recent randomized trials showed that surgery was more effective than nonoperative treatment for carefully selected patients with lumbar stenosis. However, some patients require reoperation because of complications, failure of bony fusion, persistent pain, or progressive degenerative changes, such as adjacent segment disease. In a previous population-based study, the 10-year reoperation rate was 17%, and fusion surgery was performed in 10% of patients. Recently, the lumbar fusion surgery rate has doubled, and a substantial portion of the reoperations are associated with a fusion procedure. With the change in surgical trends, the longitudinal surgical outcomes of these trends need to be reevaluated. PURPOSE: To provide the longitudinal reoperation rate after surgery for spinal stenosis and to compare the reoperation rates between decompression and fusion surgeries. STUDY DESIGN/SETTING: Retrospective cohort study using national health insurance data. PATIENT SAMPLE: A cohort of patients who underwent initial surgery for lumbar stenosis without spondylolisthesis in 2003. OUTCOME MEASURES: The primary end point was any type of second lumbar surgery. Cox proportional hazards regression modeling was used to compare the adjusted reoperation rates between decompression and fusion surgeries. METHODS: A national health insurance database was used to identify a cohort of patients who underwent an initial surgery for lumbar stenosis without spondylolisthesis in 2003; a total of 11,027 patients were selected. Individual patients were followed for at least 5 years through their encrypted unique resident registration number. After adjusting for confounding factors, the reoperation rates for decompression and fusion surgery were compared. RESULTS: Fusion surgery was performed in 20% of patients. The cumulative reoperation rate was 4.7% at 3 months, 7.2% at 1 year, 9.4% at 2 years, 11.2% at 3 years, 12.5% at 4 years, and 14.2% at 5 years. The adjusted reoperation rate was not different between decompression and fusion surgeries (p=.82). The calculated reoperation rate was expected to be 22.9% at 10 years. CONCLUSIONS: The reoperation rate was not different between decompression and fusion surgeries. With current surgical trends, the reoperation rate appeared to be higher than in the past, and consideration of this problem is required.

Reoperation rate after surgery for lumbar herniated intervertebral disc disease: nationwide cohort study.

STUDY DESIGN: Retrospective cohort study using national health insurance data. OBJECTIVE: To provide a longitudinal reoperation rate after surgery for lumbar herniated intervertebral disc (HIVD) disease, and to compare the reoperation rates of surgical methods. SUMMARY OF BACKGROUND DATA: Herniated intervertebral disc disease is the most common cause of lumbar spinal surgery. Despite improved surgical techniques and instrumentation, reoperation cannot be avoided. The reoperation rates were in the range of 6% to 24% in previous studies. A population-based study is less subject to bias; hence, a nationwide longitudinal analysis was warranted. METHODS: A national health insurance database was used to identify a cohort of patients who underwent first surgery for herniated intervertebral disc disease in 2003 and 18,590 patients were selected. Individual patients were followed for at least 5 years through their encrypted unique resident registration number. The primary endpoint was any type of second lumbar surgery. After adjusting for confounding factors, 5 surgical methods (fusion, laminectomy, open discectomy, endoscopic discectomy, and nucleolysis [including mechanical nucleus decompression]) were compared. Open discectomy was used as the reference method. RESULTS: Open discectomy was the most common procedure (68.9%) followed by endoscopic discectomy (16.1%), laminectomy (7.9%), fusion (3.9%), and nucleolysis (3.2%). The cumulative reoperation rate was 5.4% at 3 months, 7.4% at 1 year, 9% at 2 years, 10.5% at 3 years, 12.1% at 4 years, and 13.4% at 5 years. The reoperation rates were 18.6%, 14.7%, 13.8%, 12.4%, and 11.8% after laminectomy, nucleolysis, open discectomy, endoscopic discectomy, and fusion, respectively. Compared with open discectomy, the reoperation rate was higher after laminectomy at 3 months, whereas the other surgical methods had similar rates. CONCLUSION: The cumulative reoperation rate after 5 years was 13.4% and half of the reoperations occurred during the first postoperative year. With the exception of laminectomy, the reoperation rates of the other procedures were not different from that of open discectomy.

[Association between prophylactic antibiotic use and surgical site infection based on quality assessment data in Korea].

OBJECTIVES: To examine the prophylactic antibiotic use in reducing surgical site infection. METHODS: This was a retrospective study for patients aged 18 years and older who underwent gastrectomy, cholecystectomy, colectomy, cesarean section and hysterectomy. The data source was quality assessment data of the Health Insurance Review & Assessment Service gathered from medical records of 302 national hospitals. Prophylactic antibiotic use was defined as: timely antibiotic administration or inappropriate antibiotic selection. We performed hierarchical logistic regression to examine the association between prophylactic antibiotic use and surgical site infection with adjustment for covariates. RESULTS: The study population consisted of 16, 348 patients (1,588 gastrectomies, 2,327 cholecystectomies, 1,384 colectomies, 3,977 hysterectomies and 7,072 cesarean sections) and surgical site infection was identified in 351 (2.1%) patients. The rates of timely antibiotic administration and inappropriate antibiotic selection varied according to procedures. Cholecystectomy patients who received timely prophylactic antibiotic had a significantly reduced risk of surgical site infection compared with those who did not receive a timely prophylactic antibiotics (OR 0.64, 95% CI=0.50-0.83), but no significant reduction was observed for other procedures. When inappropriate prophylactic antibiotics were given, the risk of surgical site infection significantly increased: 8.26-fold (95% CI=4.34-15.7) for gastrectomy, 4.73-fold (95% CI=2.09-10.7) for colectomy, 2.34-fold (95% CI=1.14-4.80) for cesarean section, 4.03-fold (95% CI=1.93-8.42) for hysterectomy. CONCLUSIONS: This study examines the association among timely antibiotic administration, inappropriate antibiotic selection and surgical site infection. Patients who received timely and appropriate antibiotics had a decreased risk of surgical site infection. Efforts to improve the timing of antibiotic administration and use of appropriate antibiotic are needed to lower the risk of surgical site infection.

Effect of allergic rhinitis on the use and cost of health services by children with asthma.

PURPOSE: Allergic rhinitis (AR) is common among children with asthma and exacerbates asthma symptoms. To assess the incremental utilization and cost of asthma-related health services due to concomitant AR among asthmatic children. MATERIALS AND METHODS: Asthma-related claims were extracted from the Korean National Health Insurance (NHI) claims database, which covers 97% of the population. Per-capita utilization and costs of asthma-related services were determined from the societal perspective. RESULTS: Of 319,714 children (1-14 years old) with chronic asthma in 2003, 195,026 had concomitant AR (prevalence 610 per 1,000 asthmatic children). Children with AR had 1.14 times more outpatient visits, 1.30 times more emergency department (ED) visits, and 1.49 times more hospitalizations than children without AR. More children with AR used general hospitals (7.17%) than children without AR (3.23%). The ratios of unit pharmaceutical costs per outpatient visit, ED visit, and admission between children with and without AR were 1.27, 1.20, and 1.14. Total annual expenditure combining direct health care, transportation, and caregivers' costs, were $273 and $217 for children with and without AR, respectively. CONCLUSION: Health service utilization and costs for asthma were greater for asthmatic children with AR. More frequent ED visits and admissions among asthmatic children with AR suggest poorer control and more frequent exacerbations. Higher unit cost of pharmaceuticals during visits, tendency to receive asthma care from a higher-level facility, and greater risk of ED visit or admission all contributed to the additional economic burden of AR.

[Cost-of-illness study of asthma in Korea: estimated from the Korea National Health insurance claims database].

OBJECTIVES: We estimated the asthma-related health care utilization and costs in Korea from the insurer' s and societal perspective. METHODS: We extracted the insurance claims records from the Korea National Health Insurance claims database for determining the health care services provided to patients with asthma in 2003. Patients were defined as having asthma if they had > or =2 medical claims with diagnosis of asthma and they had been prescribed anti-asthma medicines. Annual claims records were aggeregated for each patient to produce patient-specific information on the total utilization and costs. The total asthma-related cost was the sum of the direct healthcare costs, the transportation costs for visits to healthcare providers and the patient's or caregivers' costs for the time spent on hospital or outpatient visits. RESULTS: A total of 699,603 people were identified as asthma patients, yielding an asthma prevalence of 1.47%. Each asthma patient had 7.56 outpatient visits, 0.01 ED visits and 0.02 admissions per year to treat asthma. The per-capita insurance-covered costs increased with age, from 128,276 Won for children aged 1 to 14 years to 270,729 Won for those aged 75 or older. The total cost in the nation varied from 121,865 million to 174,949 million Won depending on the perspectives. From a societal perspective, direct healthcare costs accounted for 84.9%, transportation costs for 15.1% and time costs for 9.2% of the total costs. CONCLUSIONS: Hospitalizations and ED visits represented only a small portion of the asthma-related costs. Most of the societal burden was attributed to direct medical expenditures, with outpatient visits and medications emerging as the single largest cost components.

Association of hospital procedure volume with post-transplant survival for allogeneic bone marrow transplantation.

OBJECTIVE: To examine the association between hospital procedure volume and treatment outcomes following allogeneic bone marrow transplantation (allo-BMT). METHODS: Out of 1, 050 patients who received allo-BMTs between 1998 and 2000 in 21 Korean hospitals, 752 with first allo-BMT and complete data were included in this study. Study subjects were divided into the following three groups according to cumulative hospital experience of all-BMTs during the study period: low (< 30 cases), medium (30-49) and high (> or =50 cases) volume. Patient outcome was defined as early survival at day 100 and one-year survival. Multiple logistic regression analyses were performed to examine the association between hospital experience and survival at day 100 and one year. RESULTS: When the low volume group was defined as the reference group, the adjusted relative risks (RR) of survival at day 100 for the high volume group were 2.46 (95% CI, 1.13-5.36) for all patients, 2.61 (1.04-6.57) for those with leukemia, and 2.20 (0.47-10.32) for those with aplastic anemia. For one-year survival, adjusted RR for the high volume group were 2.52 (1.40-4.51) for all patients, 1.99 (1.01-3.93) for leukemia, and 6.50 (1.57-26.80) for aplastic anemia. None of the RR for the medium volume group was statistically significant. Patient factors showing significant relationship with survival were donor-recipient relation, human leukocyte antigen matching status, time from diagnosis to transplant, and disease stage. CONCLUSIONS: The study results suggest that the cumulative experience of hospitals in providing allo-BMT is positively associated with patient survival.