Higher CD4 cell count reduces risk of death from non-Hodgkin lymphoma for patients with HIV

Mortality rates are still higher amongst HIV-positive patients with non-Hodgkin lymphoma than in HIV-negative individuals with the cancer, US investigators report in the on-line edition of AIDS.

However, a higher CD4 cell count and the absence of previous AIDS-defining illnesses reduced the risk of death from the cancer for patients with HIV, a finding which the investigators believe argues for an “aggressive HIV disease management strategy for patients infected with HIV and potentially earlier start of combination antiretroviral therapy.”

Non-Hodgkin lymphoma is an AIDS-defining malignancy. The number of cases of the cancer seen in patients with HIV has fallen since the advent of effective HIV treatment. The prognosis of patients who are diagnosed with non-Hodgkin lymphoma has also improved, but the exact extent is uncertain.

Therefore investigators from Kaiser Permanente California conducted a population-based study, comparing all-cause and non-Hodgkin lymphoma-related mortality between HIV-positive and HIV-negative individuals diagnosed with the cancer. The period of analysis, 1996-2005, encompassed the era of combination antiretroviral therapy. The investigators also analysed the factors associated with an increased risk of death for those with HIV.

“Our study, spanning a 10-year period since 1996, represents one of the largest to include HIV-infected and HIV-uninfected non-Hodgkin lymphoma patients”, comment the investigators.

A total of 259 cases of the cancer in patients with HIV were identified, and these were compared to 8230 cases in HIV-negative individuals.

The HIV-positive patients were younger, were more likely to be male (86% vs. 53%, p

In addition, patients with HIV had more advanced disease at the time of diagnosis, and were more likely to have central nervous system involvement (7% vs. 2%, p

First the investigators looked at all cause mortality. Two years after diagnosis, almost twice as many HIV-positive patients had died than HIV-negative individuals (59% vs. 30%). Statistical analysis showed that HIV infection was independently associated with a doubling in the risk of death (relative risk = 2.0; 95% CI, 1.7-2.3).

Stratification of the results by CD4 cell count, race, severity of disease, and type of lymphoma, did not affect this finding.

The investigators then looked at the risk of non-Hodgkin lymphoma specific mortality. They found that the risk was increased by 40% for patients with HIV (p = 0.001).

However, patients with a CD4 cell count above 200 cells/mm³ and no history of AIDS-defining illnesses had a comparable lymphoma-related mortality risk to HIV-negative individuals.

Analysis was then restricted to the patients with HIV to see which factors were associated with an increased risk of death for this group of patients.

There included Burkitt’s lymphoma (RR = 1.3; 95% CI, 1.0-1.7), a prior AIDS-defining illness (RR = 1.4; 95% CI, 1.1-1.9), non-white race (RR = 1.2; 95% CI, 1.0-1.5), and a CD4 cell count below 200 cells/mm³ (RR = 1.2; 95% CI, 1.0-1.6).

Moreover, the investigators found that mortality rates amongst patients with HIV remained essentially unaltered in the ten year period of the study.

“HIV-infected non-Hodgkin lymphoma patients continued to have a significantly elevated all-cause and lymphoma-specific mortality rate compared with non-Hodgkin lymphoma patients in the general public”, write the investigators.

However, they note that “HIV-infected patients with higher CD4 cell counts and no prior AIDS-defining illness had a similar risk of lymphoma-specific death as compared with non-Hodgkin lymphoma in the general public.”

They conclude that this finding emphasises “the importance in preserving the immune function during the course of HIV disease management, and further evaluating optimal treatment options for HIV-infected non-Hodgkin lymphoma patients with severely suppressed immunity, which account for 50% of the HIV-related non-Hodgkin lymphoma in the combination antiretroviral therapy era.”