Haematological factors and anaemia in acute malaria: A prospective hospital-based cross-sectional observational study

Abstract

This prospective, observational, cross-sectional study was undertaken to estimate the burden of anaemia in malaria and to evaluate the contribution of haematogenic factors and haemolysis in its pathogenesis. Haematogenic factors (vitamin B12, folic acid, lactate dehydrogenase, ferritin, total iron binding capacity, direct Coombs test) were estimated in patients with malaria at the time of admission. They were categorized as anaemics or non-anaemics and their complications and outcomes were recorded. P. vivax (97/112) and P. falciparum (13/112) mono-infections dominated; anaemia was seen in 63.3%. Patients with and without anaemia were comparable in terms of haemolysis and the haematogenic factors evaluated. Bleeding events, acute kidney injury and acute liver injury were comparable; however, the need for mechanical ventilation and transfusion of blood products was significantly higher amongst the anaemics. We concluded that haemolysis and presumably transient bone marrow suppression contribute to anaemia in malaria. Pre-existing nutritional deficiencies do not, however, predispose to severe malaria.

Keywords

Malaria anaemia iron deficiency vitamin B12 deficiency haemolysis

Introduction

Malaria affects 3 billion people in 106 countries globally and kills approximately 2000 people every day.¹ In 2017, approximately 219 million malaria cases occurred worldwide.² In South East Asia, nearly 1.2 billion people living in 11 countries are at the risk of suffering from malaria and most of those people live in India.³ Manifestations of malaria can range from asymptomatic infection to multiorgan involvement and even death. The manifestations are determined by the host factors and factors related to the parasite.⁴ Besides organ dysfunction, acute malaria is complicated by haematological abnormalities, namely thrombocytopenia and anaemia.

The exact pathogenesis of the latter in malarial infection is still elusive; it is presumably multi-factorial and compounded by inter-current infections with P. falciparum and helminths, nutritional deficiencies and haemoglobinopathies.⁵ In India, anaemia is a major public health problem and is independently responsible for significant morbidity and mortality. The prevalence of anaemia in vivax malaria has been reported to vary between 1.4% and 32%.⁶ The burden is greater in younger children⁷ and during pregnancy.⁸

Although anaemia and malaria are seen in isolation in the community, the relative contribution of nutritional deficiencies and haemoglobinopathies on the occurrence of anaemia in acute malaria has not yet been delineated. We undertook this study to estimate the burden of anaemia in malaria and compare various haematological and biochemical parameters, the haematogenic factors, and complications and outcomes of those with and without anaemia.

Materials & Methods

This cross-sectional observational study was carried out at a tertiary referral centre of Uttarakhand over a period of one year after obtaining institutional ethical clearance. Patients aged 18 years or more, diagnosed with acute malaria (by positive peripheral blood smear) were included in the study after obtaining written informed consent. Details in clinical history, physical examination, demographic parameters, laboratory parameters, complications and outcomes of individual patients were compiled.

Hyperbilirubinaemia (bilirubin > 51 μmol/L), acute renal insufficiency (defined as urine output < 400 ml/24 h and serum creatinine > 265 μmol/L with no improvement with rehydration), respiratory distress (tachypnoea >20/min and oxygen saturation <90%) and ARDS (defined as PaO2/FiO2 < 200 mmHg together with radiological appearances of bilateral non-homogenous opacities) were the main outcomes studied.⁹

All included subjects were subjected to a battery of laboratory investigations including full blood count, serum ferritin, total iron binding capacity, vitamin B₁₂, folate, lactate dehydrogenase (LDH) levels and direct Coombs tests, besides the usual biochemical and radiological tests. They were categorized into two groups – with and without anaemia based on the haemoglobin levels (<120 g/L in women and <130 g/L in men) at the time of admission.¹⁰

Iron deficiency was defined as low serum ferritin (< 49 nmol/L) and/or high total iron binding capacity (>73 μmol/L). Vitamin B12 levels of <107 pmol/L while serum folic acid levels < 8.8 nmol/L were considered as deficient. Serum LDH > 3.6 μkat/L and/or positive direct Coombs test were taken as evidence of haemolysis.

Statistical analysis was performed using the SPSS software 22. Mean and median were the measures of central tendency and standard deviation was the measure of dispersion for descriptive statistics. Pearson's Chi-square test was used for assessing association for categorical data. Unpaired student T-test was used for assessing differences in the means of continuous variables. P-values of <0.05 were taken as significant.

Results

A total of 112 patients with acute malaria (60% males) were included in our study period; 48% were aged between 18 and 30 years. Mono-infection with P. vivax (n = 97; 86.6%) or P. falciparum (n = 13; 11.6%) predominated; only two patients were co-infected with both species. Prominent features included fever (97.3%), nausea and vomiting (36.6%), abdominal pain (20.5%), anorexia (19.6%), headache (16.1%), myalgia (13.4%) and jaundice (9.8%). Other features included shortness of breath, loose stools, conjunctival suffusion, decreased urine output, burning micturition, cough, arthralgias, altered sensorium and seizures.

While only ten patients presented with significant bleeding events (melaena (5), haematuria (4) and haematemesis (1)), 71 (63.3%) had anaemia, which was mild (Hb 100–120 g/L; 36.6%), moderate (Hb 50–100 g/L; 61.9%) or severe (Hb <50 g/L; 1.4%). Some 44.4% of males and 88.9% of females were anaemic. The mean age of presentation was 39.4 ± 18.0 years and 40.5 ± 16.1 years for anaemics and non-anaemics, respectively. Anaemia was observed in 62.8% and 62.2% patients infected with P. vivax and P. falciparum, respectively. Very few patients reported pre-existing morbidity.

Table 1 compares parameters and morbidity.

Table 1.

Comparison of haematological and biochemical characteristics in malaria, with and without anaemia.

Parameter	Anaemics (n = 71)	Non-anaemics (n = 41)	P-value
Haemoglobin (g/L)	91 ± 19 (71)	136 ± 13 (41)	0.000
Total leukocyte count (×10³/cu.mm)	8.9 ± 8.0 (71)	5.8 ± 2.4 (41)	0.020
Platelet count (×10³/cu.mm)	91.1 ± 129.2 (71)	75.9 ± 71.2 (41)	0.494
Neutrophil (%)	64.4 ± 19.0 (71)	71.16 ± 11.6 (41)	0.046
Lymphocyte (%)	28.1 ± 17.0 (71)	19.8 ± 9.4 (41)	0.006
Monocyte (%)	5.9 ± 3.9 (71)	6.8 ± 3.0 (41)	0.211
Eosinophils (%)	1.3 ± 3.2 (71)	1.0 ± 2.5 (41)	0.627
Basophils (%)	0.1 ± 0.7 (71)	0.4 ± 2.5 (41)	0.287
MCV (fL)	86.3 ± 13.1 (71)	87.3 ± 8.7 (41)	0.668
MCH (pg)	28.7 ± 4.5 (71)	29.6 ± 2.6 (41)	0.282
MCHC (g/dL)	32.9 ± 3.6 (71)	33.5 ± 0.8 (41)	0.285
S. creatinine (μmol/L)	167.9 ± 203.2 (71)	97.2 ± 35.3 (41)	0.040
Sodium (mmol/L)	134.8 ± 4.0 (71)	135.1 ± 3.8 (41)	0.740
Potassium (mmol/L)	4.1 ± 0.8 (71)	3.8 ± 0.6 (41)	0.036
BUN (mmol/L)	11.9 ± 12.1 (71)	6.8 ± 5.3 (41)	0.024
Total bilirubin (μmol/L)	64.9 ± 92.3 (71)	32.4 ± 30.7 (41)	0.048
Direct bilirubin (μmol/L)	35.9 ± 63.2 (71)	13.68 ± 17.1 (41)	0.063
Indirect bilirubin (μmol/L)	29.0 ± 32.4 (71)	17.1 ± 13.6 (41)	0.048
ALT (μkat/L)	0.9 ± 0.9 (71)	1.4 ± 2.8 (41)	0.139
AST (μkat/L)	1.2 ± 1.2 (71)	1.9 ± 2.7 (41)	0.095
S. albumin (μmol/L)	376.1 ± 75.2 (71)	451.3 ± 45.1 (41)	0.000
Prothrombin time (s)	15.0 ± 2.8 (27)	13.5 ± 1.2 (10)	0.128
INR	1.2 ± 0.3 (27)	1.05 ± 0.1 (10)	0.152
Ferritin (nmol/L)	1.5 ± 0.9 (55)	1.8 ± 0.8 (26)	0.199
Vitamin B12 (pmol/L)	554.3 ± 437.0 (55)	393.6 ± 374.9 (26)	0.097
Folate (nmol/L)	27.2 ± 16.3 (55)	22.0 ± 15.4 (26)	0.177
LDH (μkat/L)	10.6 ± 10.0 (55)	7.2 ± 5.4 (26)	0.094
TIBC (μmol/L)	52.1 ± 15.0 (55)	53.7 ± 12.4 (26)	0.624

Continuous data is expressed as mean ± SD; categorical variables as percentage of total of columns; NS: not significant. Figures in the parenthesis represent the number of cases where the data was available.

Laboratory data were not complete and are tabulated in Table 2.

Table 2.

Comparison of various haematological factors presumably implicated in the pathogenesis of anaemia in malaria.

	Anaemics (n = 55)	Non-anaemics (n = 26)	P-value (Chi-square/Fisher exact)
Haemolysis (n = 68)	46 (83.6)	22 (84.6)	0.153
Vitamin B12 deficiency (n = 21)	12 (21.8)	9 (34.6)	0.801
Bleeding events (n = 10)	9 (16.3)	1(3.8)	0.154
Iron deficiency (n = 9)	8 (14.5)	1 (3.8)	0.154
Folate deficiency (n = 8)	3 (5.4)	5 (19.2)	0.453

Discussion

Deficiencies of haematogenic factors seemed equally distributed amongst anaemics and non-anaemics.^11,12 Its severity varies in the existing literature.^13–16 Higher number of anaemics had hepatosplenomegaly than non-anaemics as expected with the presence of splenomegaly and long duration of fever.

Table 3.

Comparison of complications and outcomes in malaria with and without anaemia.

	Anaemics (n = 71)	Non-anaemics (n = 41)	P-value (Chi-square/Fisher exact test)
Complications
Acute liver injury (n = 47)	32 (45.0)	15 (36.5)	0.800
Acute kidney injury (n = 38)	28 (39.4)	10 (24.3)	0.265
Bleeding events (n = 10)	9 (12.6)	1 (2.4)	0.154
ARDS (n = 8)	8 (11.2)	0 (0)	0.049
Outcomes
Prolonged hospitalization (>5 days) (n = 38)	27 (38.0)	11 (26.8)	0.611
Ventilation (n = 33)	27 (38.0)	6 (14.6)	0.012
Platelet transfusion (n = 33)	25 (35.2)	8 (19.5)	0.102
RBC transfusion (n = 16)	16 (22.5)	0 (0)	0.001
Haemodialysis (n = 8)	8 (11.2)	0 (0)	0.164
Mortality (n = 6)	5 (7.0)	1 (2.4)	0.418
FFP transfusion (n = 2)	2 (2.8)	0 (0)	0.537

Mostly, however, the blood picture was normocytic normochromic.^17,18 High ferritin levels were observed in malaria possibly due to acute phase reactivity; however, conflicting data with low^19,20 and high²¹ ferritin levels in malaria exist.

Although pre-existing deficiencies of vitamin B₁₂, iron and folic acid were documented in a few patients in our study, haemolysis was observed in nearly three-quarters. However, no statistically significant association existed. By default, the cause of anaemia in malaria seems to be a combination of haemolysis and bone marrow suppression as evident from the bi- or pan-cytopenia almost universally found, as well as low erythropoietin levels where renal failure ensues; the pre-existing deficiency states seem to play no significant role in increasing its severity.

A limitation of our study is its small sample size and non-assessment of bone marrow. Nevertheless, we can emphasize that the relative contribution of haemolysis and transient bone marrow suppression is greater than pre-existing deficiencies in haematogenic factors in the genesis of anaemia in malaria, and that the latter do not predispose to the development of severe anaemia in malaria. We advocate investigating haematogenic factors only if the recovery of haemoglobin levels does not follow on short-term follow up of malaria patients, as this is a rational approach to ensure optimal utilization of resources.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Sohaib Ahmad

References

Editors. In: Kasper

Fauci

Hauser

Longo

Jameson

Loscalzo

(eds) Harrison's principles of internal medicine, 19e. New York: McGraw Hill, 2014, pp.1575.

World Health Organisation. World malaria report 2018. 1–146 p. Available from: www.who.int/malaria

Kondrashin

. Malaria in the WHO Southeast Asia region. Indian J Malariol 1992; 29: 129.

Silamut

White

. Relation of the stage of parasite development in the peripheral blood to prognosis in severe falciparum malaria. Trans R Soc Trop Med Hyg 1993; 87: 436–443.

Calis

Phiri

Faragher

, et al. Research article (New England Journal of Medicine) Severe anemia in Malawian children. Malawi Med J 2016; 28: 99–107.

Rodríguez-Morales

Sanchez

Vargas

, et al. Anemia and thrombocytopenia in children with Plasmodium vivax malaria. J Trop Pediatr 2006; 52: 49–51.

Nurleila

Syafruddin

Elyazar

, et al. Serious and fatal illness associated with falciparum and vivax malaria among patients admitted to hospital at West Sumba in eastern Indonesia. Am J Trop Med Hyg 2012; 87: 41–49.

Rodriguez-Morales

Sanchez

Vargas

, et al. Pregnancy outcomes associated with Plasmodium vivax malaria in northeastern Venezuela. Am J Trop Med Hyg 2006; 74: 755–757.

WHO Guidelines for malaria, 3 June 2022. Geneva: World Health Organization; 2022 (WHO/UCN/GMP/2022.01 Rev.2).

10.

Cappellini

Motta

. Anemia in clinical practice-definition and classification: does hemoglobin change with aging? Semin Hematol 2015; 52: 261–269.

11.

Kashinkunti

Alevoor

. Clinical, hematological and coagulation profile in malaria. Sch J Appl Med Sci 2014; 2: 584–588.

12.

Douglas

Anstey

Buffet

, et al. The anaemia of Plasmodium vivax malaria. Malar J 2012; 11: 135.

13.

Buffet

Safeukui

Milon

, et al. Retention of erythrocytes in the spleen: a double-edged process in human malaria. Curr Opin Hematol 2009; 16: 157–164.

14.

Abro

Ustadi

Younis

, et al. Malaria and hematological changes. Pak J Med Sci 2008; 24: 287.

15.

Bashawri

Mandil

Bahnassy

, et al. Malaria: hematological aspects. Ann Saudi Med 2002; 22: 372–376.

16.

Karrar

. Estimation of Serum Ferritin Level among Malaria Patients in Khartoum. Doctoral dissertation, Sudan University of Science & Technology 2019:1–43.

17.

Sharma

Dutta

Khan

, et al. Serum ferritin and hematological feature among malaria patients in Assam. Ann Trop Med Public Health 2014; 7: 14–18.

18.

Odunukwe

Salako

Okany

, et al. Serum ferritin and other haematological measurements in apparently healthy adults with malaria parasitaemia in Lagos, Nigeria. Trop Med Int Health 2000; 5: 582–586.

19.

Sumbele

Sama

Kimbi

, et al. Malaria, moderate to severe anaemia, and malarial anaemia in children at presentation to hospital in the Mount Cameroon area: a cross-sectional study. Anemia 2016; 2016: 1–12.

20.

Kochar

Das

Kochar

, et al. Severe Plasmodium vivax malaria: a report on serial cases from Bikaner in northwestern India. Am J Trop Med Hyg 2009; 80: 194–198.

21.

Tjitra

Anstey

Sugiarto

, et al. Multidrug-resistant Plasmodium vivax associated with severe and fatal malaria: a prospective study in Papua, Indonesia. PLoS Med 2008; 5: 28.