By day 14, posttreatment, mean Hb compared with day 0 had decreased both in HIV-1-uninfected (−4.2 g/L; 95% CI: −5.8 to −2.5; paired t test: P < 0.0001) and HIV-1-infected patients (−5.0 g/L; 95% CI: −7.2 to −2.8; paired t test: P < 0.0001), though the Hb decrease between the 2 groups of patients was not statistically significant (HIV-1 positive vs HIV-1 negative: P = 0.23). However, mean Hb at day 14 was significantly lower in HIV-1-infected than HIV-1-uninfected patients (116.9 g/L; 95% CI: 114.2 to 119.7 vs 132.4 g/L; 95% CI: 130.6 to 134.2; P < 0.0001) (Fig. 2A). Similarly, the prevalence of anemia between days 0 and 14 increased both in HIV-1-negative (31.6%, 95% CI: 27.0 to 36.4; P = 0.06) and HIV-1-infected patients (64.1%, 95% CI: 56.9 to 70.8; P < 0.0001) (Fig. 2B). A larger Hb decrease at day 14 was associated with HIV-1 infection, higher parasite load, higher Hb values at enrollment, and SP treatment (all P < 0.001) (Table 2). In HIV-1-infected patients, CD4 cell count at enrollment was not associated with Hb changes at day 14 (P = 0.78).
Between days 14 and 45, Hb increased in both HIV-1-uninfected (+7.8 g/L; 95% CI: 5.7 to 10.0; paired t test: P = 0.0001) and HIV-1-infected patients (+4.2 g/L; 95% CI: 1.2 to 7.0; paired t test: P = 0.005) (Fig. 2A). Such increment was lower in HIV-1-infected than in HIV-1-uninfected patients (P = 0.04). Anemia prevalence decreased to 16.2% (95% CI: 12.8 to 20.1) in HIV-1-uninfected patients (P < 0.001) and to 45.7% (95% CI: 38.8 to 52.7) in HIV-1-infected ones (P < 0.0001) (Fig. 2B). A lower Hb increase between days 14 and 45 was not only associated with HIV-1 infection but also with a lower parasite load (P < 0.001), higher Hb values at enrollment (P = 0.001), female gender (P = 0.002), and older age (P = 0.03) (Table 2). The magnitude of hematological recovery was not influenced by impaired cellular immunity as measured by CD4 count (P = 0.46).
When considering the whole 45-day follow-up period, Hb significantly increased, compared with day 0, in HIV-1-uninfected patients (+3.54 g/L; 95% CI: 1.37 to 5.70; paired t test: P = 0.001) but not in HIV-1-infected patients (−0.72 g/L; 95% CI: −3.85 to 2.40; paired t test, P = 0.64). The difference in mean Hb between HIV-1-infected (122.5 g/L; 95% CI: 119.3 to 125.7) and HIV-1-uninfected patients (139.2 g/L; 95% CI: 137.0 to 141.4) became more pronounced by day 45 (P < 0.0001) (Fig. 2A). Compared with enrollment, prevalence of anemia at day 45 was significantly lower in HIV-1-uninfected patients (P = 0.0006) but not in HIV-1-infected ones (P = 0.88) (Fig. 2B). Older age (P < 0.002), female gender (P < 0.001), higher Hb values at enrollment (P < 0.001), and HIV-1 infection (P < 0.001) were all risk factors for a smaller Hb increment at day 45 (all P < 0.001; Table 2, last column).
Patients With Treatment Failure at Day 45
Fifty-two patients (30 HIV-1-negative and 22 HIV-1-infected patients) had a recurrent parasitemia at day 45. In these patients, mean Hb at enrollment (132.3 g/L in HIV-1-negative patients and 124.5 g/L in HIV-1-infected patients) was similar than in those without recurrent parasitemia. The mean difference of Hb between days 0 and 45 was negative in both HIV-1-negative (−7.8 g/L; paired t test P = 0.09) and HIV-1-positive patients (−8.8 g/L; paired t test P = 0.06) and almost reached statistical significance despite the very low statistical power.
In our study, as expected, at enrollment, Hb was lower in HIV-1-infected than in HIV-1-uninfected malaria patients, and after successful malaria treatment, both groups showed a fall and rise in Hb within the follow-up period. After multivariate analysis, HIV infection was a risk factor for a more important Hb decline and a slower hematological recovery. Therefore, 45 days after successful malaria treatment, the mean Hb in HIV-infected patients was similar to that during the malaria attack, whereas HIV-negative patients were already recovering.
In this selected cohort, compared with HIV-negative malaria patients, the HIV-1-positive malaria patients were older, had a slightly lower Hb level, and women were more represented. These findings are consistent with the epidemiology of HIV-1 in Zambia and with the overall trial findings.10,8
Patients with an underlying disease such as those with symptomatic AIDS or severe malaria, including hyperparasitemia and severe anemia (Hb < 70 g/L), were excluded. Therefore, our study patients represent a selected group with an Hb higher than that found in the whole population of HIV-1-infected individuals with clinical malaria.
At day 14, a larger Hb decline was associated with higher parasitemia, higher Hb at enrollment, and SP treatment. This confirms that the risk factors responsible for a lower Hb during a malaria episode remain active at least 14 days after successful treatment. Furthermore, compared with an efficacious and rapidly acting drug such as AL, the slower acting SP was a risk factor for a greater Hb decline observed at day 14. After adjustment, HIV-1 infection was retained as an independent risk factor for a greater Hb decline. As the degree of immune suppression did not influence the Hb decline, the mechanisms behind these greater decline in HIV infected are unclear. In this phase, the major contributor to the hemolytic anemia is the accelerated destruction of uninfected RBC,15 probably linked to immune mechanisms.1,16 Considering that there is a chronic activation of the immune system by the HIV infection, this may explain the probable accelerated destruction of uninfected RBC in this group of patients.
From 14 days onward, when the malaria-related factors contributing to hemolytic anemia have presumably abated, HIV-1 infection remained, next to higher Hb, lower parasitemia at day 0, and female gender and age, an independent risk factor for a slower hematological recovery. The slow hematological recovery was also not associated with the degree of immune suppression and could be explained by the impairment of the erythropoiesis and of the iron mobilization.17 It is unclear if the myelosuppressive effect of HIV-1 on the host erythropoietic system was enhanced due to a synergistic interaction between HIV-1 and malaria. The drug regimen did not have any influence on the hematological recovery, obviously because patients with recurrent parasitemia were excluded. The administration of the longer acting SP has been associated with lower rates of new infections, and this effect could provide an additional protection against anemia (compared with AL). However, this may be true when SP resistance is low. In this study, there was no difference in the occurrence of new infections between the 2 study arms, whereas recrudescences were much more frequent in the SP arm (reported in18). Such a little or no prophylactic effect related to SP indicates that resistance to this treatment was high with recurrent infections further decreasing Hb.
A faster Hb decline at day 14 and a better recovery afterward were both related to higher parasitemia levels. The faster decline was expected, but the physiopathological mechanisms behind the faster recovery are unclear.
Our data add to the evidence that HIV-1-infected patients represent, next to children and pregnant women, an additional vulnerable group for malaria.19,20 Female gender and age are well-known risk factors for both a slower Hb recovery and for HIV-1 infection. Furthermore, HIV-1 immune suppressed individuals have a higher risk of malaria infection and disease, a higher parasite load during a clinical malaria episode, and more likely to fail the treatment.8,19 This could rapidly lead to a vicious circle in which frequent malaria infections, even if successfully treated, may prevent a full hematological recovery and further worsen the anemia in a modest but stepwise manner. This is well illustrated in our patients with recurrent parasitemia at day 45, who had a lower Hb level at day 45 than at enrollment. This is worrying for all HIV-malaria-coinfected patients as there was no correlation with the degree of immune suppression. Furthermore, in immune suppressed patients, anemia is an independent prognostic marker of HIV disease progression.21 Therefore, HIV treatment guidelines recommend to start antiretroviral treatment for any “persistent unexplained anemia,” operationally defined as anemia that does not have any other apparent cause and fails to respond to the combination of anthelmintics, hematinics, and antimalarials after 1 month.12 Considering that in successfully treated patients Hb had not increased after 45 days, the diagnosis of persistent unexplained anemia should be done only after a longer period, possibly 2 or 3 months, from the clinical attack. Furthermore, as reported before, the absolute CD4 count, the chosen marker to monitor the progression of HIV-1 infection, is also altered during or just after a clinical malaria episode.22 Finally, patients with a low CD4 count or clinical stage 4, and eventually stage 3 or stage 4, should be given antiretroviral treatment or co-trimoxazole prophylaxis, both of them influencing the hematological status and possibly causing anemia.23 Therefore, this subgroup should be carefully evaluated.
Recent estimates show almost half of the world's malaria is in holoendemic areas.24 Clinicians and program managers working in areas where both diseases are prevalent should be aware that malaria and HIV-1 infection have specific and different but synergistic hematological effects. Prompt diagnosis and effective treatment is the backbone of malaria control, but in this highly vulnerable group of HIV infected, malaria prevention should be prioritized. Co-trimoxazole, an antifolate with antimalarial activities, is currently recommended as preventive therapy in immune suppressed HIV-1-infected patients.25 Furthermore, the combination of co-trimoxazole, insecticide-treated bed nets substantially reduced the frequency of malaria in adults with HIV.26 These policies, if widely implemented with other preventive measures, might decrease the malaria burden in HIV-1-infected individuals, including the anemia burden associated with repeated malaria episodes.27
We would like to thank all the patients and their families who contributed to this study. Sincere thanks also to the nursing and laboratory staff of the Tropical Disease Research Center and the health centers where the study was carried out. We are also grateful to Dr Emmanuel Kafwembe, the Director Tropical Disease Research Center for his support and to the Director of Ndola District Health Management Team for offering his clinic facilities to the study. The WHO provided good manufacturing practices approved artemether-lumefantrine. The Belgian Development cooperation was not involved in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the article. J.P.V. contributed to the analysis plan, data interpretation, produced the final dataset, did the analysis, and wrote the article and takes responsibility for the integrity of the data and the accuracy of the data analysis. M.M. organized the collection of data, supervised the trial, and contributed to the data interpretation and writing the article, V.C. and M.N. supervised the trial and contributed to the data interpretation, D.M. contributed to the organization of the trial and training, F.M. contributed to the study design and training, U.A. contributed to the study design, data interpretation, and the writing of the article, R.C. contributed to the data interpretation and the writing of the article.
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Keywords:© 2009 Lippincott Williams & Wilkins, Inc.
Africa; anemia; HIV-1; malaria; treatment