Characteristics of the study population
The detailed characteristics of the 109 patients who underwent allo-HCT between 2012 and 2021, including 68 patients with CDI diagnosed after 2016, are presented in Table 1.
Table 1. Characteristics of the study group.
Parameter
|
All patients
|
Patients diagnosed 2012-2016
|
Patients diagnosed 2017-2021
|
Demographic characteristics
|
Group size, n (%)
|
109 (100)
|
41 (37.6)
|
68 (62.3)
|
Sex distribution: female / male, n (%)
|
54 (49.5) / 55 (50.5)
|
19 (46.3) / 22 (53.7)
|
35 (51.5) / 33 (48.5)
|
Age at allo-HCT, y, median (range)
|
49 (18–72)
|
45 (20–65)
|
51 (18–72)
|
Diagnosis, n (%)
|
AML
|
51 (46.7)
|
20 (48.7)
|
31 (45.6)
|
ALL
|
26 (23.9)
|
9 (22.0)
|
17 (25.0)
|
MPN/MDS
|
20 (18.3)
|
9 (22.0)
|
11 (16.2)
|
MM/HL/NHL/CLL
|
12 (11.0)
|
3 (7.3)
|
9 (13.2)
|
HCT-CI (n=106), n (%)
|
0
|
45 (42.4)
|
21 (51.2)
|
24 (36.9)
|
1-2
|
34 (32.1)
|
16 (39.0)
|
18 (27.7)
|
3-5
|
27 (25.5)
|
4 (9.8)
|
23 (35.4)
|
Transplant characteristics
|
Donor type, n (%)
|
Matched sibling donor
|
32 (29.4)
|
16 (39.0)
|
16 (23.5)
|
Unrelated donor (matched, mismatched)
|
65 (59.6)
|
22 (53.7)
|
43 (63.2)
|
Haploidentical
|
12 (11.0)
|
3 (7.3)
|
9 (13.2)
|
Graft source: peripheral blood / bone marrow, n (%)
|
106 (97.2) / 3 (2.8)
|
40 (97.6) / 1 (2.4)
|
66 (97.0) / 2 (3.0)
|
Conditioning regimen:
MAC or RTC / RIC, n (%)
|
72 (66) / 37 (34)
|
32 (78) / 9 (22)
|
40 (58.8) / 28 (41.2)
|
Day of neutrophil engraftment ANC >0.5 G/l (if achieved), median (range)
|
17 (6–43)
|
19 (10–43)
|
17 (6–43)
|
Engraftment not achieved, n (%)
|
4 (3.7)
|
1 (2.4)
|
3 (4.4)
|
aGVHD / cGVHD prior to CDI diagnosis
|
24 / 5
|
10 / 1
|
14 / 4
|
aGVHD / aGVHD grade II-IV after CDI
|
40 / 36
|
18 / 16
|
22 / 19
|
cGVHD / moderate or severe cGVHD after CDI
|
9 / 8
|
3 / 2
|
6 / 6
|
GI-GVHD before CDI / after CDI
|
18 / 35
|
7 / 17
|
11 / 18
|
Abbreviations: aGVHD, acute graft-versus-host disease, ALL, acute lymphoblastic leukemia, AML, acute myeloid leukemia, ANC, absolute neutrophil count, CDI, Clostridioides difficile infection, cGVHD, chronic GVHD, CLL, chronic lymphocytic leukemia, GI-GVHD, gastrointestinal GVHD, HCT, hematopoietic cell transplantation, HCT-CI, HCT comorbidity index, HL, Hodgkin lymphoma, MAC, myeloablative conditioning, MDS, myelodysplastic neoplasm, MM, multiple myeloma, MPN, myeloproliferative neoplasm, NHL, non-Hodgkin lymphoma, RIC, reduced-intensity conditioning, RTC, reduced-toxicity conditioning
Diagnosis of Clostridioides difficile infection and outcomes of first-line and second-line treatment
Infections with CDI were diagnosed a median of 11 days after allo-HCT (range, -13 to 740 days). Twenty-four cases (18.3%) were diagnosed in the peritransplant period (just before or during the conditioning regimen up to day 0 of graft infusion). In most of the remaining cases (n = 64, 58.7%), CDI developed before day 100 after allo-HCT. The diagnosis of CDI was established based on recommended clinical criteria and laboratory confirmation of the presence of toxin A (n = 6, 5.5%), toxin B (n = 12, 11%), both toxins A and B (n = 58, 53.2%), or glutamate dehydrogenase confirmed by the positive nucleic acid amplification test or positive culture (n = 32, 29.3%).
In the study group, 34 patients (31.2%) were treated with metronidazole as first-line treatment, and 64 patients (58.7%) were treated with vancomycin. One patient (0.9%) was given fidaxomicin, and 10 patients (9.2%) received combination therapy (metronidazole plus vancomycin) due to severe CDI manifestation. Failure of the first-line treatment was more common with metronidazole than with vancomycin (n = 13 [38.2%] and n = 4 [6.2%], respectively, P <0.001). In the combination group, treatment failure was reported for 3 patients (30%) (Figure 1). Monotherapy with vancomycin was the most common second-line treatment (n = 12, 75%). The remaining options included monotherapy with fidaxomicin (n = 1, 6.3%) and combination therapy with fidaxomicin plus metronidazole (n = 2, 12.6%) or fidaxomicin plus vancomycin (n = 1, 6.3%). In 2 patients, the second-line treatment with vancomycin and fidaxomicin plus metronidazole failed. In the long-term follow-up, at least 14 patients experienced recurrent CDI. Four of these patients were treated successfully with fecal microbiota transplantation.
Colonization with multidrug-resistant bacteria and use of broad-spectrum antibiotics in patients with Clostridioides difficile infection
Colonization with multidrug-resistant bacteria prior to CDI was diagnosed in 71 patients (65.1%). The most common pathogens were vancomycin-resistant Enterococci and bacteria producing extended-spectrum B-lactamases: they were detected in 47 patients (43.1%) and 38 patients (34.9%), respectively. In 17 patients (15.6%), both types of pathogens were detected. Colonization with multidrug-resistant bacteria had no significant impact on the occurrence of GI-GVHD.
In 82 patients (75.2%), broad-spectrum antibiotics were administered directly before the onset of CDI. Of the 26 patients who were exposed only to a single antibacterial agent, 12 (46.1%) received meropenem and 7 (26.9%) received fluoroquinolone (levofloxacin or ciprofloxacin). The remaining 56 patients were exposed to at least 2 antibacterial agents, with many cases of sequential therapies which included meropenem or imipenem in 44 patients (78.6%), cefepime in 14 patients (25%), and piperacillin with tazobactam in 14 patients (25%).
Associations between Clostridioides difficile infection and graft-versus-host disease
Before CDI, aGVHD and cGVHD were diagnosed in 24 and 5 patients, respectively, including 18 patients with gastrointestinal involvement. Exacerbation of GVHD or de novo GVHD after the diagnosis of CDI was reported in 49 patients, including 40 cases of aGVHD (36 patients with grade 2-4) and 9 cases of cGVHD (moderate or severe in 8 patients). In 35 of the 49 patients (71.4%), gastrointestinal involvement was noted (Figure 2).
Patients receiving combination therapy had a higher rate of GVHD and GI-GVHD than those receiving metronidazole alone (P = 0.01 and P = 0.007, respectively) and vancomycin alone (P = 0.003 and P <0.001, respectively). Moreover, the incidence of GI-GVHD was higher in patients treated with metronidazole as monotherapy or as a component of combination therapy than in the remaining patients (P = 0.03). No differences were noted between monotherapy with metronidazole and vancomycin. However, the second-line treatment for CDI, which was administered more frequently in the metronidazole group, was associated with a higher rate of GI-GVHD (P <0.001).
Clostridioides difficile infection: treatment outcomes
The follow-up period was 2 years. Overall survival at 6 months, 1 year, and 2 years after allo-HCT in the study group was 75%, 62%, and 51%, respectively. In patients treated with vancomycin, metronidazole, and combination therapy, OS at 6 months was 81%, 70%, and 56%, respectively and at 1 year – 65%, 57%, and 47%, respectively. At 2 years, OS in patients treated with vancomycin and metronidazole was 59% and 45%, respectively. In the group treated with combination therapy, none of the patients survived at 2-year follow-up (Figure 3A).
Failure of the first-line treatment and a need to switch to the second- line treatment led to lower OS (P <0.05, Figure 4). The presence of GVHD before CDI (P <0.005) or the development or exacerbation of GVHD after CDI (P <0.05) was associated with increased mortality.
The non-relapse mortality (NRM) rate at 6 months, 1 year, and 2 years was 18%, 25%, and 27%, respectively. The rate differed between patients treated with vancomycin vs combination therapy (P <0.05, Figure 3b). Five patients died with active CDI within 30 days after allo-HCT, including 2 patients treated with metronidazole, 2 with vancomycin, and 1 with combination therapy. The need to switch to second-line CDI treatment was associated with higher mortality due to GVHD (P = 0.001) at 6-month follow-up.
In the multivariate analysis, the occurrence of aGVHD before CDI and the need to switch to the second-line treatment of CDI were predictors of death (HR, 3.19, 95% CI, 1.65–6.16, P = 0.009 and HR, 4.83, 95% CI, 2.46–9.47, P <0.001, respectively).
Clinical practice and treatment outcomes before and after the introduction of noninterventional Clostridioides difficile infection protocol
The comparison of patients treated before (retrospective data) and after (prospective data) the introduction of the noninterventional CDI protocol revealed that metronidazole was prescribed in 18 patients (43.9%) versus 16 patients (23.5%), and vancomycin, in 15 patients (22%) versus 49 patients (72%) (P = 0.001). The need for second-line treatment was less frequent in patients treated after the introduction of the protocol versus those treated before (P <0.05). However, there were no differences in OS and the rates of GI-GVHD between these groups.