Table 3.
Multivariate analysis
| Time | Risk factor | RR | p-value |
|---|---|---|---|
|
First six months period day 0–182 since first R dose |
Nadir ≥0.13 ×109 /L |
1.00 |
|
| Nadir <0.13 ×109 /L |
1.89 (1.00-3.60) |
0.051 |
|
| HIV neg. |
1.00 |
|
|
| HIV pos. |
2.92 (1.11-7.65) |
0.030 |
|
| no GVHD |
1.00 |
|
|
| GVHD |
1.49 (0.52-4.27) |
0.453 |
|
| Indolent lymphoma |
1.00 |
|
|
| Aggressive lymphoma |
2.76 (1.34-5.670 |
0.006 |
|
| Non-CD20 malignancy |
1.56 (0.56-4.33) |
0.394 |
|
|
Second six months period day 183–364 since first R dose |
Nadir ≥0.13 ×109 /L |
1.00 |
|
| Nadir <0.13 ×109 /L |
2.68 (1.19-6.04) |
0.017 |
|
| HIV neg. |
1.00 |
|
|
| HIV pos. |
1.21 (0.27-5.38) |
0.798 |
|
| no GVHD |
1.00 |
|
|
| GVHD |
7.22 (2.38-21.92) |
<0.001 |
|
| Indolent lymphoma |
1.00 |
|
|
| Aggressive lymphoma |
1.21 (0.48-3.02) |
0.687 |
|
| Non-CD20 malignancy |
1.57 (0.49-4.98) |
0.447 |
|
| Third six months period day 364–546 since first R dose | Nadir ≥0.13 ×109 /L |
1.00 |
|
| Nadir <0.13 ×109 /L |
2.54 (1.07-6.02) |
0.034 |
|
| HIV neg. |
1.00 |
|
|
| HIV pos. |
1.49 (0.33-6.67) |
0.601 |
|
| no GVHD |
1.00 |
|
|
| GVHD |
3.65 (1.11-12.04) |
0.034 |
|
| Indolent lymphoma |
1.00 |
|
|
| Aggressive lymphoma |
1.53 (0.60-3.91) |
0.371 |
|
| Non-CD20 malignancy | 0.93 (0.25-3.42) | 0.908 |
The model allows interaction with time since first Rituximab administration and each risk factor. The analysis provides moderate to strong evidence that all the 4 risk factors were associated with the infections in a time dependent manner; i.e.: HIV and type of diagnosis were associated with increased risk of infection in first six months only, GVHD in the second and third time periods while counts of lymphocytes at nadir was associated with increased risk for all the 3 time periods.
HSCT hematopoietic stem cell transplant, HIV antibody against human immunodeficiency virus, GVHD graft versus host disease, R Rituximab, CHT chemotherapy, IQR inter-quartile range, RR rate ratio, 95%CI 95% confidence interval.