The Influence of High-Efficiency Particulate Air Filtration on Mortality Among Multiple Myeloma Patients Receiving Autologous Stem Cell Transplantation: A Nationwide Population-Based Study

Background

Multiple myeloma (MM) is a common hematologic neoplasm in Taiwan. Autologous stem cell transplantation (ASCT) is encouraged for transplant-eligible MM patients. A part of MM patients received ASCT in an isolation room with high-efficiency particulate air (HEPA) filtration. The effectiveness of the HEPA filtration on reducing treatment-related mortality or infection among ASCT patients is still controversial.

Methods

We enrolled patients with newly diagnosed MM in Taiwan between January 1, 2000 and December 31, 2017. The patients who were under 20 years, without ASCT, or receiving non-melphalan conditioning regimens were excluded. The primary endpoint of the study was treatment-related mortality, which was defined as death within 100 days after receiving ASCT. Only the first ASCT was analyzed. A Cox proportional hazards model was used to adjust for potential confounding factors in the multivariate analysis. The factors with p < 0.1 in the univariate analysis were included in the multivariate analysis.

Results

A total of 961 MM patients received ASCT during the 18-year study period. The median age of the patients was 57 years (range 28–76 years) and 54.9% were men. Of them, 480 patients (49.9%) received ASCT in an isolation room with HEPA filtration (HEPA group). The median overall survival from ASCT was 7.52 years (95% CI 6.00–8.73) for the HEPA group while it was 5.88 years (95% CI 4.99–8.46) for the remaining patients (non-HEPA group). The 100-day mortality rate was 1.5% and 1.0% for the HEPA and non-HEPA groups, respectively. The crude hazard ratio (HR) for the 100-day mortality HEPA group was 1.39 (95% confidence interval [CI] 0.44–4.37, p = 0.576) compared to the non-HEPA group. In the univariate analysis, only coronary artery disease (HR 5.80) and end-stage renal disease (HR 5.46) were associated with 100-day mortality. After adjusting for the variables found in univariate analysis, the 100-day mortality still had no difference between the HEPA and non-HEPA groups (adjusted HR 1.65, 95% CI 0.52–5.23, p = 0.399).

Conclusion

Although about 50% of MM patients in Taiwan received ASCT in an isolation room with HEPA filtration, we found that it didn’t affect 100-day mortality. This study may help clinicians allocate the limited resource of the HSCT facilities. Further validation of our findings in other cohorts is warranted.