In patients with chronic lymphocytic leukemia (CLL), risk for early mortality following diagnosis of a first serious inpatient bacterial infection was higher than for those with no infection; however, incidence of infection among patients with CLL has decreased. These findings of an observational study were published in European Journal of Haematology.
In this case-control study covering the period from 1982 to 2013, each of 13,009 adult patients with CLL included in the Swedish Cancer Registry were matched according to age, sex, year of birth, and area of residence with 4 population-based controls (49,380 people) without a history of hematologic cancer.
Also performed was a nested, case-control study in which adult patients with CLL and a first serious inpatient bacterial infection included in the Swedish Cancer Registry were matched with 2 other patients with CLL of the same sex, age, and year of diagnosis who had not yet experienced a serious inpatient bacterial infection as of the time point of reference.
Key findings included a significantly higher risk of serious inpatient bacterial infection in patients with CLL compared with population-based controls (hazard ratio [HR], 5.32; 95% CI, 5.11-5.53). Elevated risks of septicemia (HR, 6.91; 95% CI, 6.46-7.39), pneumonia and other lung infections (HR, 5.92; 95% CI, 5.64-6.18), and meningitis and intracranial abscess (HR, 4.91; 95% CI, 3.31-7.26) were particularly notable in the former compared with the latter group.
However, when the risk of CLL-related serious inpatient bacterial infections during the periods 1993 to 2002 and 2003 to 2013 were compared with that of 1982 to 1992, the respective HRs were 0.87 (95% CI, 0.81-0.94) and 0.76 (95% CI, 0.70-0.82).
In contrast, the risk of serious inpatient bacterial infections was shown to significantly increase over time in the population-based control group during the same periods, with HRs of 1.13 (95% CI, 1.07-1.19) and 1.12 (95% CI, 1.05-1.20), respectively, compared with the risk for the period from 1982 to 1992.
The study authors noted that their findings “of decreasing serious inpatient bacterial infections are in line with an earlier study that showed decreasing rate of positive bacterial blood cultures.” These results reinforce its conclusion that more effective treatments for CLL probably leads to decreased incidence of infection in these patients over the long term.
Furthermore, the hazard ratio for death in patients with CLL during the first 12 months following diagnosis of a first serious inpatient bacterial infection was 5.48 (95% CI 5.11-5.90) compared with patients with CLL and no serious inpatient bacterial infection.
“Changes in CLL treatment and supportive therapy have not resulted in increased risk of serious bacterial infections, and different risk of infections by sites can guide antibiotic prophylaxis and empiric treatment,” the study authors noted.
They further added that these findings “underline the importance of thorough and evidence-based guidelines on risk assessment, prophylaxis, and early treatment of infections.”
Steingrímsson V, Gíslason GK, Aspelund T, et al. A population-based study on serious inpatient bacterial infections in patients with chronic lymphocytic leukemia and their impact on survival. Eur J Haematol. Published online June 23, 2020. doi:10.1111/ejh.13477