Several guidelines classify autologous stem cell transplantation (ASCT) as a low to intermediate risk group for infection. In a nationwide population-based study, using the Korean Health Insurance Review and Assessment Service database, patients with lymphoma and multiple myeloma (MM) who underwent ASCT from 2002 to 2016 were retrospectively analyzed. Cumulative incidence rates (CIRs) and risk factors of opportunistic infections were investigated. CIRs of fungal, Varicella zoster virus (VZV), cytomegalovirus (CMV), and Pneumocystis jirovecii infections in lymphoma were 7.9%, 16.0%, 7.4%, and 5.1%, respectively, and CIRs in MM were 6.3%, 19.1%, 4.2%, and 5.6%, respectively. Fungal infection was significantly higher in patients with previous infection (Hazard ratio (HR) 2.003, p = 0.005) in lymphoma. Incidence of CMV infection was significantly higher in patients with prior CMV infection: HR 4.920, p < 0.001 (lymphoma); HR 3.022, p = 0.030 (MM). VZV infection was significantly lower in patients receiving prophylaxis: HR 0.082, p < 0.001 (lymphoma); HR 0.096, p < 0.001 (MM). For P. jirovecii infection, busulfex and melphalan conditioning (HR 1.875, p = 0.032) and previous P. jirovecii infection (HR 4.810, p < 0.001) had a higher incidence in MM. Patients who underwent ASCT should receive VZV prophylaxis and prophylaxis for fungal and P. jirovecii may be considered in patients with previous same infection.
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Autologous hematopoietic stem cell transplantation (ASCT) is a well-established treatment option for hematologic malignancies, especially malignant lymphoma and multiple myeloma (MM). With the advances in medicine, the success rate of ASCT has improved; however, infection is still an important complication related to the prognosis of ASCT and can affect the quality of life and long-term survival in the early and late phases of transplantation[
According to the National Comprehensive Cancer Network (NCCN) guideline (version 1. 2021), ASCT is in the intermediate-risk group for overall infections. Based on this risk, for fungal infections, when mucositis is present, prophylaxis with fluconazole or echinocandin is recommended until recovery from neutropenia (category 1, for which there is a high level of evidence), and prophylaxis is not recommended without mucositis (category 2 B, where there is a lower level of evidence but no uniform consensus)[
Even the two guidelines recommend differently for same infection, there are few reports on the incidence rate of opportunistic infections after ASCT in the literature[
In this study, we investigated the incidence and risk factors of fungal and viral infections after ASCT in patients with lymphoma and MM using big data especially in post-engraftment period. Based on these data, we would like to consider the effectiveness of prophylactic antifungal and antiviral agents in clinical practice.
We used the nationwide and population-based Health Insurance Review and Assessment Service database, which is based on data from the universal health insurance system run by the Korean government. Since the National Health Insurance is the only public medical insurance system in Korea, the program covers the entire Korean population. The database includes patient demographics, principal diagnoses, and comorbidities based on the International Classification of Diseases, 10th Revision, prescription codes, and special procedures such as transplantation for both outpatients and inpatients. The National Health Insurance Service provide these extensive data for use in research after the approval process. The independent Institutional Review Board of Kosin University Gospel Hospital approved this study and granted a waiver of informed consent from the study participants because anonymity of personal information was maintained (KUGH 2017-11-026). The data acquisition number for the National Health Insurance Sharing Service was REQ0000016684. All methods were carried out in accordance with relevant guidelines and regulations along with the approval.
From January 2002 to December 2016, of the patients registered with malignant lymphoma and MM who were over 18 years of age, those who underwent ASCT were enrolled. Patients who underwent allogeneic hematopoietic stem cell transplantation after ASCT were excluded.
Infections were limited to cases that occurred at least 30 days after ASCT. Fungal infections were defined as invasive candidiasis and aspergillosis, or cases in which antifungal agents such as intravenous (IV) amphotericin B, IV liposomal amphotericin B, IV caspofungin, IV itraconazole, IV voriconazole, and IV fluconazole were prescribed for more than 7 days. Patients with oral candidiasis were excluded from this study. Viral infection was defined as VZV reactivation, CMV viremia or disease, and was defined as IV acyclovir, per oral (po) famciclovir for more than 5 days, and IV ganciclovir and valganciclovir for more than 7 days. Herpes simplex virus and Epstein–Barr virus infections were excluded. P. jiroveciii infection was limited to cases in which IV trimethoprim/sulfamethoxazole was administered for more than 7 days and when P. jiroveciii infection or pneumonia was diagnosed.
Prophylactic drugs were defined as drugs used in clinical practice, based on the National Comprehensive Cancer Network guidelines. The antifungal prophylactic agents were po fluconazole, and anti-P. jirovecii prophylaxis was detected by po trimethoprim/sulfamethoxazole. In the case of antiviral therapy, VZV prophylaxis included po acyclovir and po valaciclovir. However, prophylaxis for CMV infection was not analyzed because there was no meaningful prophylactic therapy available at the time of analysis. Prophylaxis included cases in which each prophylactic agent was administered for ≥ 30 days.
We evaluated the cumulative incidence and risk factors of opportunistic infections after ASCT in patients with lymphoma and MM in Korea from 2002 to 2016. Because lymphoma and MM are different diseases and the intensity of conditioning is different, the incidence and risk factors of both diseases were analyzed. Incidence was calculated using the number of individuals with opportunistic infections as the numerator, and the patients who underwent ASCT as the denominator. The cumulative incidence rate (CIR) was reported at a specific time after transplantation (6 months, 12 months, and 5 years) using a landmark approach. The cumulative incidence was estimated using the Kaplan–Meier method. The strength of the association between the variables and opportunistic infections was assessed using Cox proportional hazards regression analysis. We used maximally selected log-rank statistics in the maxstat function of R software (version 3.4.4) to identify the optimal threshold to assess the cumulative incidence for age. We selected optimal age cutoffs of 45 years for lymphoma and 55 years for MM. Logistic regression analysis was used for multivariate analysis. Statistical analyses were performed using the R statistical software (version 3.4.4; R Foundation for Statistical Computing) and SAS statistical analysis software (version 9.4; SAS Institute Inc., Cary, NC, USA). Statistical significance was set at P < 0.05.
The characteristics of the 6516 patients who underwent ASCT for lymphoma (n = 3236) and MM (n = 3280) are described in Table 1. The median age was 48 years (range 18–70) for lymphoma and 56 years (range 18–68) for myeloma at the time of transplantation, and 62.5% (n = 2022) and 55.9% (n = 1834) of the patients were men with lymphoma and myeloma, respectively.
Table 1 Patient characteristics.
Value (%) Lymphoma (n = 3236) (%) Multiple myeloma (n = 3280) (%) Median (range) 48 (18–70) 56 (18–68) Male 2022 (62.5) 1834 (55.9) Female 1214 (37.5) 1446 (44.1) DLBCL/Burkitt lymphoma 1672 (51.7) Indolent B cell lymphoma 479 (14.8) T cell lymphoma 671 (20.7) Others (Hodgkin's disease, etc.) 414 (12.8) 2002–2006 520 (16.1) 468 (14.3) 2007–2011 1100 (34.0) 1059 (32.3) 2012–2016 1616 (49.9) 1753 (53.4) BuCyE 1084 (33.5) Melphalan only 2880 (87.8) BuMelE 849 (26.2) BuMel 237 (7.2) Others 1303 (40.3) Others 163 (5.0) < 2 2898 (89.6) 2701 (82.3) ≥ 2 338 (10.4) 579 (17.7) Fungal 141 (4.4) 78 (2.4) VZV 445 (13.8) 691 (21.1) CMV 35 (1.1) 40 (1.2) 60 (1.9) 31 (0.9) Fungal 208 (6.4) 205 (6.3) VZV 375 (11.6) 540 (16.5) 187 (5.8) 406 (12.4) Fungal 221 (6.8) 161 (4.9) VZV 461 (14.2) 531 (16.2) CMV 211 (6.5) 117 (3.6) 143 (4.4) 143 (4.4)
DLBCL Diffuse large B cell lymphoma, BuCyE Busulfan and Cyclophosphamide and Etoposide, BuMelE Busulfan and melphalan and Etoposide, P. jiroveciiiPneumocystitis jiroveciii, VZV Varicella zoster virus, CMV cytomegalovirus.
Of the patients with lymphoma, 51.7% of were diagnosed with diffuse large B-cell lymphoma or Burkitt lymphoma. There were 141 (4.4%), 445 (13.8%), 35 (1.1%), and 60 (1.9%) patients with fungal, VZV, CMV, and P. jirovecii infection prior to transplantation, respectively. The number of patients who received preventive treatment for fungal, VZV, and P. jirovecii infections was 208 (6.4%), 375 (11.6%), and 187 (5.8%), respectively.
For MM, 78 (2.4%), 691 (21.1%), 40 (1.2%), and 31 (0.9%) patients had a history of fungal, VZV, CMV, and P. jirovecii infections, respectively, prior to transplantation. A total of 205 (6.3%), 540 (16.5%), and 406 (12.4%) patients received prophylaxis against fungal, VZV, and P. jirovecii infections, respectively.
Compared to 2002–2006, the number of transplantations increased from 520 to 1616 for lymphoma and from 468 to 1753 for MM, in 2012–2016.
For lymphoma, 221 (6.8%), 461 (14.2%), 211 (6.5%), and 143 (4.4%) patients were infected with the fungi, VZV, CMV, and P. jirovecii pneumonia (PJP), respectively, and 161 (4.9%), 531 (16.2%), 117 (3.6%), and 143 (4.4%) patients with MM, respectively, after transplantation. (Table 1) The CIRs at 6 months of fungal, VZV, CMV, and P. jiroveciii infection in lymphoma were 3.4%, 7.8%, 3.3% and 1.9%, respectively, and the CIRs in MM were 1.1%, 7.2%, 1.6% and 0.8%, respectively. The CIRs at 12 months for fungal, VZV, CMV, and P. jirovecii infection in lymphoma were 4.9%, 11.3%, 4.7%, and 2.9%, respectively, and the CIRs in MM were 2.0%, 10.6%, 2.2%, and 1.7%, respectively. The CIRs at 5 years for fungal, VZV, CMV, and P. jirovecii infection in lymphoma were 7.9%, 16.0%, 7.4%, and 5.1%, respectively, and the CIRs in MM were 6.3%, 19.1%, 4.2%, and 5.6%, respectively (Fig. 1).
Graph: Figure 1 Cumulative incidence rates (CIRs) of opportunistic infections. (A) Lymphoma. (B) Multiple myeloma. (A) The CIRs at 6 months of fungal, Varicella zoster virus (VZV), Cytomegalovirus (CMV), and Pneumocystis jirovecii (P. jiroveciii) infection was 3.4%, 7.8%, 3.3% and 1.9%, respectively. The CIRs at 12 months was 4.9%, 11.3%, 4.7% and 2.9%. (B) The CIRs at 6 months of fungal, VZV, CMV, and P. jiroveciii infection was 1.1%, 7.2%, 1.6% and 0.8%, respectively. The CIRs at 12 months was 2.0%, 10.6%, 2.2% and 1.7%.
The results of the univariate and multivariate analyses of the associations with opportunistic infections in lymphoma and MM are shown in Tables 2 and 3. Multivariate analysis showed that the factors affecting fungal infection were the year of transplantation (hazard ratio (HR) = 2.330 [95% confidence interval (95% CI) 1.485–3.658]; p < 0.001 in lymphoma patients, HR = 2.650 [95% CI 1.519–4.623]; p = 0.001 in MM patients) and previous fungal infection history (HR = 2.003 [95% CI 1.236–3.244]; p = 0.005 in lymphoma patients only). For patients with CMV infection, in the multivariate analysis, the following factors showed a significantly higher incidence of infection: year of transplantation (HR = 2.752 [95% CI 1.689–4.484]; p < 0.001 in lymphoma patients only) and previous CMV infection history (HR = 4.920 [95% CI 2.552–9.600]; p < 0.001 in lymphoma patients and HR = 3.022 [95% CI 1.115–8.191]; p = 0.030 in MM patients). Multivariate analysis showed that other conditioning regimens (HR = 1.349 [95% CI 1.081–1.682]; p = 0.008 in lymphoma patients only) and prophylaxis (HR = 0.082 [95% CI 0.034–0.197]; p < 0.001 in lymphoma and HR = 0.096 [95% CI 0.053–0.175]; p < 0.001 in MM) were independent predictive factors for VZV reactivation. Based on multivariate analysis for P. jirovecii infection, the year of transplantation (HR = 2.552 [95% CI 1.439–4.526]; p = 0.001 in lymphoma and HR = 3.800 [95% CI 1.801–8.021]; p < 0.001 in MM) had a higher incidence. For MM patients, busulfan and melphalan conditioning (HR = 1.875 [95% CI 1.055–3.333]; p = 0.032), previous P. jirovecii infection (HR = 4.810 [95% CI 2.120–10.913]; p < 0.001) and prophylaxis (HR = 1.564 [95% CI 1.040–2.352]; p = 0.032) had a higher incidence.
Table 2 Univariate and multivariate Cox analysis for atypical infection in lymphoma.
Value Fungal CMV VZV Univariate HR (95% CI) p value Multivariate HR (95% CI) p value Univariate HR (95% CI) p value Multivariate HR (95% CI) p value Univariate HR (95% CI) p value Multivariate HR (95% CI) p value Univariate HR (95% CI) p value Multivariate HR (95% CI) p value ≤ 45 > 45 1.017 (0.779–1.328) 0.901 0.956 (0.729–1.255) 0.747 1.147 (0.952–1.383) 0.149 0.804 (0.579–1.116) 0.192 Male Female 0.906 (0.688–1.194) 0.485 0.999 (0.756–1.320) 0.992 0.970 (0.803–1.172) 0.751 0.709 (0.496–1.014) 0.060 Indolent B cell lymphoma DLBCL / Burkitt lymphoma 1.176 (0.770–1.796) 0.453 1.223 (0.802–1.864) 0.350 1.079 (0.820–1.421) 0.586 1.063 (0.638–1.771) 0.815 T cell lymphoma 1.649 (1.044–2.604) 0.032 1.361 (1.008–1.837) 0.044 1.557 (0.982–2.467) 0.060 1.275 (0.937–1.734) 0.122 1.716 (0.998–2.951) 0.051 Others (HD, etc.) 1.403 (0.841–2.341) 0.195 0.912 (0.515–1.612) 0.750 0.991 (0.692–1.419) 0.959 0.995 (0.512–1.934) 0.988 2002 ~ 2006 2007 ~ 2011 1.669 (1.050–2.653) 0.030 1.653 (1.040–2.629) 0.034 1.844 (1.113–3.055) 0.017 1.812 (1.093–3.002) 0.021 0.892 (0.695–1.144) 0.368 1.744 (0.966–3.151) 0.065 1.744 (0.966–3.151) 0.065 2012 ~ 2016 2.342 (1.492–3.676) < 0.001 2.330 (1.485–3.658) < 0.001 2.815 (1.728–4.585) < 0.001 2.752 (1.689–4.484) < 0.001 0.778 (0.606–0.998) 0.048 2.552 (1.439–4.526) 0.001 2.552 (1.439–4.526) 0.001 BuCyE BuMelE 1.177 (0.853–1.624) 0.321 1.292 (0.923–1.809) 0.136 1.225 (0.953–1.575) 0.113 1.194 (0.929–1.536) 0.166 1.571 (1.039–2.375) 0.032 1.295 (0.902–1.859) 0.160 Others 0.732 (0.531–1.008) 0.056 0.878 (0.632–1.219) 0.438 1.443 (1.157–1.799) 0.001 1.349 (1.081–1.682) 0.008 1.004 (0.667–1.512) 0.984 ≥ 2 comorbidity 0.949 (0.616–1.461) 0.811 0.761 (0.469–1.233) 0.267 0.870 (0.637–1.187) 0.378 0.544 (0.277–1.068) 0.077 Previous infection history 2.042 (1.261–3.307) 0.003 2.003 (1.236–3.244) 0.005 5.288 (2.712–10.314) < 0.001 4.920 (2.552–9.600) < 0.001 0.837 (0.629–1.114) 0.222 1.267 (0.404–3.977) 0.685 Prophylaxis 0.743 (0.405–1.362) 0.336 0.079 (0.033–0.191) < 0.001 0.082 (0.034–0.197) < 0.001 0.678 (0.299–1.535) 0.351
CMV Cytomegalo virus, VZV Varicella zoster virus, HR hazard ratio, CI confidence interval, DLBCL diffuse large B cell lymphoma, HD Hodgkin's disease, BuCyE Busulfan and Cyclophosphamide and Etoposide, BuMelE Busulfan and Melphalan and Etoposide;
Table 3 Univariate and multivariate Cox analysis for atypical infection in multiple myeloma.
Value Fungal CMV VZV Univariate HR (95% CI) p value Multivariate HR (95% CI) p value Univariate HR (95% CI) p value Multivariate HR (95% CI) p value Univariate HR (95% CI) p value Multivariate HR (95% CI) p value Univariate HR (95% CI) p value Multivariate HR (95% CI) p value ≤ 55 > 55 0.816 (0.598–1.115) 0.202 0.695 (0.480–1.006) 0.054 0.861 (0.726–1.022) 0.087 1.024 (0.738–1.422) 0.887 Male Female 0.817 (0.596–1.120) 0.209 0.813 (0.561–1.178) 0.275 0.956 (0.805–1.136) 0.611 0.751 (0.536–1.054) 0.098 2002–2006 2007–2011 1.877 (1.069–3.297) 0.028 1.877 (1.069–3.297) 0.028 1.227 (0.704–2.136) 0.470 0.905 (0.713–1.149) 0.413 3.740 (1.795–7.789) < 0.001 3.560 (1.706–7.430) 0.001 2012–2016 2.650 (1.519–4.623) 0.001 2.650 (1.519–4.623) 0.001 1.163 (0.670–2.018) 0.591 0.793 (0.625–1.006) 0.056 4.210 (2.013–8.803) < 0.001 3.800 (1.801–8.021) < 0.001 Melphalan only BuMel 1.659 (0.938–2.933) 0.082 0.872 (0.383–1.988) 0.745 0.897 (0.613–1.314) 0.578 2.142 (1.230–3.732) 0.007 1.875 (1.055–3.333) 0.032 Others 0.493 (0.157–1.547) 0.225 0.859 (0.316–2.331) 0.765 0.961 (0.607–1.519) 0.863 0.789 (0.291–2.135) 0.640 1.011 (0.372–2.743) 0.984 ≥ 2 comorbidity 0.835 (0.552–1.263) 0.393 0.837 (0.512–1.368) 0.477 0.902 (0.720–1.129) 0.369 1.354 (0.925–1.983) 0.119 Previous infection history 1.495 (0.661–3.379) 0.334 3.017 (1.113–8.177) 0.030 3.022 (1.115–8.191) 0.030 1.043 (0.850–1.281) 0.686 4.883 (2.156–11.060) < 0.001 4.810 (2.120–10.913) < 0.001 Prophylaxis 1.459 (0.858–2.483) 0.163 0.096 (0.053–0.175) < 0.001 0.096 (0.053–0.175) < 0.001 1.616 (1.075–2.429) 0.021 1.564 (1.040–2.352) 0.032
CMV Cytomegalo virus, VZV Varicella zoster virus, HR hazard ratio, CI confidence interval, BuMel Busulfan and Melphalan;
ASCT is the standard treatment for malignant lymphoma and MM. Depending on the diagnosis, this procedure is indicated as frontline treatment and in other cases as salvage therapy[
This is because reconstitution of bone marrow (BM) includes functional recovery of cellular interaction as well as simple numerical recovery of BM cellular elements[
However, few studies have evaluated the incidence of opportunistic infections and the impact of prophylaxis on infections in ASCT, focusing on a large population, especially in the post-engraftment period. We conducted a nationwide population-based study to provide information regarding the incidence and risk factors of opportunistic infections in patients with lymphoma and MM after ASCT in the Korean population. In particular, we analyzed whether prophylactic therapy is effective and investigated infections after engraftment for a long-term period of up to 5 years.
Among ASCT recipients, VZV reactivation occurred in 20–43% of the patients and extended through the first year[
In large studies involving more than 1000 patients with ASCT, the incidence of invasive fungal infection was 1.2–1.5%[
For CMV infection, the infection rate differs according to the diagnostic strategy. The incidence of CMV infection ranged from 17 to 33%, when prospectively monitored by antigenemia and/or viremia by PCR[
A large series in the 1990s reported an incidence rate for PJP of 1.4% in ASCT recipients[
In our study, fungal, CMV, and P. jiroveciii infections showed an increased risk in 2012–2016 compared to 2002–2006, which is thought to be because the number of transplants increased and more high-risk patients were transplanted. In fact, the median age of patients increases with the transplantation period. Compared to 2002–2006, in 2012–2016, it increased from 44 (range 18–65) to 50 (range 18–70) in lymphoma patients and from 54 (range 25–65) to 56 (range 18–68) in MM. In MM, the induction regimen including bortezomib has been available since October 2015, it is thought that bortezomib increased VZV infection in patients who underwent ASCT after 2016. Prior to transplantation, the same type of infection was a risk factor for all infections except VZV (Table 3). Therefore, we suggests that prophylaxis needs to be considered in patients with prior infection.
This study has several limitations. First, similar to other studies using big data, the results are based on physicians' diagnoses without additional microbiological confirmation, possibly resulting in overestimation of the incidence. In particular, since the administration of a therapeutic agent is defined as infection, there is a possibility that empirical treatment will be included. However, in order to exclude empirical treatment as much as possible, the minimum duration of medication was defined, and considering Korean insurance system, it is thought that clinically unlikely cases were not included. In addition, because we used data from the Health Insurance Review and Assessment Service's reimbursement system, we were unable to analyze drugs that were not reimbursed, such as VZV vaccine, voriconazole, atovaquone, pentamidine, and dapsone. The lack of detailed clinical information such as disease status (e.g., complete remission, partial remission or relapse etc.), laboratory data (WBC, lymphocyte count, etc.), previous or post-transplantation chemotherapy (maintenance or salvage chemotherapy) limits the analysis of various risk factors. Despite these limitations, it is a large-scale study covering the entire national population over 14 years in Korea and meaningful in that it evaluated the incidence of various opportunistic infections and the effectiveness of prophylactic therapy in the same disease group.
In conclusion, ASCT has a relatively low risk of infection compared to allogeneic hematopoietic stem cell transplantation because it does not accompany graft-versus-host disease and does not take immunosuppressants. However, since immune reconstitution is a process that occurs in both autologous and allogeneic stem cell transplantation, it is thought to be related to opportunistic infections in ASCT after engraftment. Based on the incidence and effectiveness of prophylaxis, patients undergoing ASCT should receive prophylaxis for VZV. In addition, prophylaxis for fungal infections and PJP needs to be considered in patients who have previously had an infection with the same organism. Further studies are required to determine the appropriate duration and dose of prophylaxis.
This study was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea Government (MSIT) (No. 2019R1G1A1010388 (D.J.K)).
D.J., H.S., S.R., and S.G. designed the study; S.J. contributed to data extraction and analyzed the data; S.R., S.G., S.N., S.Y., Y.R., W.S., M.H., S.H., S.H., S.H., and M.K. contributed to the conception of the study and reviewed the manuscript; D.J. and H.S. wrote the manuscript, and all authors approved the manuscript.
All data generated or analyzed during this study are included in this published article (Tables and Figures) and available from the corresponding author on reasonable request. The additional raw data are available on request to the National Health Insurance Service, Korea.
The authors declare no competing interests.
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By Da Jung Kim; Seri Jeong; Seom Gim Kong; Sangjin Lee; Sung-Nam Lim; Sung Yong Oh; Young Rok Do; Won Sik Lee; Mark Hong Lee; Sung Hwa Bae; Se Hyung Kim; Min Kyoung Kim and Ho Sup Lee
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