Myelodysplastic Syndromes: Trends in Mortality, Costs of Hospitalizations, Length of Stay and Rate of Complications

Background: Myelodysplastic syndromes (MDS) most commonly occur in the elderly and are associated with bone marrow failure and potential transformation to acute myeloid leukemia. With the proportion of elderly population being on the rise in the US, conditions like MDS are likely to generate significant burden on the healthcare system. Our study is the first report aimed to analyze trends in mortality, costs of hospitalization, length of stay (LOS) and the rate of complications in patients with MDS over the past decade.

Methods: We queried the Nationwide Inpatient Sample (NIS) database to obtain data on patients hospitalized with MDS between 2005-2014. The ICD-9 codes 238.72, 238.73, 238.74 and 238.75 were applied in the primary diagnosis field. Patient characteristics including age, sex, insurance and hospital characteristics such as location, teaching status were recorded. Data regarding mortality, LOS and total hospitalization charges was examined and the trend was analyzed over the 10 year interval. We also determined the incidence of common in-hospital complications, and comparisons were made between academic and non-academic institutions.

Results: Over the 10-year interval, a total of 885,726 admissions were identified, out of which 803,341 admissions (90.6%) were in patients aged >65 years. The mean age of the population was 76.19 years and 47.6% patients were females. Majority of patients were treated at non-teaching hospitals (56%) and covered by Medicare (84%). Teaching hospitals admitted significantly greater number of patients belonging to the top income quartile and possessing private insurance (p=.000). In-hospital mortality has increased over the 10-year interval analyzed, with a mortality rate of 5.7% in 2005 and 6.1% in 2014. Comparison between teaching and non-teaching hospitals did not show a statistically significant difference in terms of mortality (p=.782). Mean length of stay (LOS) remained relatively constant over the 10-year interval (mean LOS=6.7 days; p=.382), however there was a substantial increase in the hospitalization charges. The overall hospital cost was $29795 in 2004 which increased by over 100% to $59656 in 2014. After adjusting for inflation by CPI healthcare index, the total cost was still higher by 49%. Teaching hospitals had significantly higher charges ($57,592 vs $37,674; p=.000) as well as length of stay (7.28 days vs 5.75 days; p=.000) than non-teaching hospitals.

The rates of hospital acquired pneumonia and bacteremia have decreased significantly over the study period (p=.001), whereas rate of Clostridium Difficile (C.Diff) infections increased from 0.42% to 0.67% and UTIs increased from 7.8% to 9.1%. The rate of ICU admissions has also increased from 0.67% in 2005 to 1.51% in 2014 (p=.001). The number of patients receiving in-hospital blood product transfusions has risen significantly from 30,564 in 2005 to 37,360 in 2014 (22.2% rise). Similarly, the number of admissions for major bleeding complications has increased by 34.6% from 1,378 in 2005 to 1,855 in 2014. In comparing the complication rates between the two hospital settings, rates of major bleeding (p =.0002) were lower at academic institutions whereas those of neutropenic fever (p=.0000) were lower at non-teaching hospitals. Differences in the occurrence of pneumonia, sepsis and rate of blood transfusions were not statistically significant between the two.

Conclusions: Our study suggests that the overall mortality from MDS has increased over the past decade. Early recognition and diagnosis of MDS can partly explain this finding. However, lack of standard treatment approach for symptomatic MDS patients (with the exception of lenalidomide in 5q deletion), likely contributes to the substantial rise in admissions for transfusions, bleeding complications as well as the death rate. The significant decline in pneumonia and bacteremia could be secondary to increased use of antibiotic prophylaxis whereas use of antibiotics at the same time has probably led to a rise in C.diff infections.

Our study also highlights a staggering increase in hospitalization costs. Since MDS is mostly a disease of the elderly, the rate of hospitalizations and the associated financial burden is only expected to rise as the population continues to age. This emphasizes the need for research into disease altering chemotherapy, better outpatient care and transfusion accessibility to prevent hospitalizations.