Table 2.
Comparison of indicators of severity and parasite biomass in uncomplicated and severe malaria.*
| Clinical manifestationa | n (%) | Age (years) GM (95%CI) | Hemoglobin (g/dL) GM (95%CI) | Platelets (×109/L)b GM (95%CI) | Lactate (mmol/L) GM (95%CI) | Parasitaemia (%) GM (95%CI) | Parasite density (×105 /μL) GM (95%CI) | Plasma PfHRP2 (ng/mL) GM (95%CI) | Circulating parasite biomass (×1010/kg) GM (95%CI) | Total parasite biomass (×1010/kg) GM (95%CI) | Sequestered biomass (×1010/kg)c median (95%CI) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Uncomplicated | 169 (57.1) | 6.47 (5.88–7.12) | 11.20 (10.90–11.51) | 109.6 (98.7–121.7) | 2.10 (1.97–2.24) | 3.00 (2.52–3.58) | 1.29 (1.08–1.53) | 101.5 (84.43–122.1) | 1.04 (0.87–1.24) | 1.13 (0.93–1.37) | 0.099 (−0.10 to 0.37) |
| All severe | 127 (42.9) | 4.25 (3.89–4.64) P < 0.001 |
9.11 (8.69–9.55) P < 0.001 |
61.2 (52.7–71.2) P < 0.001 |
4.69 (4.14–5.32) P < 0.001 |
7.90 (6.49–9.61) P < 0.001 |
2.79 (2.30–3.38) P < 0.001 |
247.6 (202.1–303.3) P < 0.001 |
2.38 (1.97–2.89) P < 0.001 |
3.14 (2.54–3.89) P < 0.001 |
0.12 (−0.27 to 0.84) P = 0.89 |
| Severe | |||||||||||
| SP | 56 (18.9) | 4.23 (3.71–4.82) P < 0.001 |
9.66 (9.09–10.25) P < 0.001 |
62.2 (50.8–76.2) P < 0.001 |
2.88 (2.37–3.50) P < 0.001 |
5.97 (4.34–8.21) P < 0.001 |
2.25 (1.64–3.09) P = 0.002 |
191.3 (146.6–249.7) P < 0.001 |
1.94 (1.41–2.66) P < 0.001 |
2.39 (1.80–3.16) P < 0.001 |
−0.29 (−0.71 to 0.57) P = 0.30 |
| SNP | 71 (24.0) | 4.27 (3.77–4.83) P < 0.001 |
8.70 (8.11–9.34) P < 0.001 |
60.5 (48.5–75.6) P < 0.001 |
6.90 (6.27–7.60) P < 0.001 |
9.85 (7.70–12.6) P < 0.001 |
3.31 (2.60–4.20) P < 0.001 |
303.4 (225.2–408.8) P < 0.001 |
2.81 (2.21–3.58) P < 0.001 |
3.90 (2.85–5.33) P < 0.001 |
0.57 (−0.04 to 1.44) P = 0.20 |
| Inclusive category | |||||||||||
| CM | 16 (5.4) | 3.99 (3.16–5.05) P = 0.003 |
8.60 (7.38–10.02) P < 0.001 |
39.9 (20.5–77.9) P < 0.001 |
7.31 (5.48–9.75) P < 0.001 |
11.38 (7.44–17.4) P < 0.001 |
3.60 (2.45–5.31) P < 0.001 |
417.4 (211.8–822.7) P < 0.001 |
3.10 (2.11–4.55) P = 0.001 |
5.52 (2.74–11.1) P < 0.001 |
1.69 (−0.49 to 8.45) P = 0.16 |
| LA | 64 (21.6) | 4.38 (3.83–5.00) P < 0.001 |
8.89 (8.30–9.52) P < 0.001 |
58.1 (45.8–73.8) P < 0.001 |
7.52 (6.95–8.13) P < 0.001 |
10.33 (7.94–13.4) P < 0.001 |
3.55 (2.75–4.59) P < 0.001 |
312.4 (226.0–431.9) P < 0.001 |
3.01 (2.32–3.91) P < 0.001 |
3.98 (2.83–5.60) P < 0.001 |
0.36 (−0.19 to 1.30) P = 0.49 |
| SA | 6 (2.0) | 2.75 (1.46–5.17) P = 0.001 |
4.54 (4.20–4.91) P < 0.001 |
79.7 (43.5–146.1) P = 0.27 |
5.31 (2.25–12.49) P < 0.001 |
10.17 (5.38–19.2) P = 0.01 |
1.87 (0.98–3.59) P = 0.43 |
484.8 (169.6–1386) P = 0.002 |
1.69 (0.92–3.12) P = 0.31 |
7.84 (2.82–21.8) P < 0.001 |
4.64 (2.08–25.2) P < 0.001 |
| Exclusive category | |||||||||||
| CM | 4 (1.4) | 3.76 (2.15–6.57) P = 0.09 |
10.06 (7.19–14.09) P = 0.24 |
81.7 (21.9–304.6) P = 0.41 |
3.52 (2.33–5.31) P = 0.02 |
4.29 (1.01–18.3) P = 0.54 |
1.62 (0.46–5.69) P = 0.69 |
203.4 (38.0–1118) P = 0.26 |
1.39 (0.41–4.70) P = 0.62 |
2.53 (0.43–15.1) P = 0.21 |
1.69 (−2.66 to 8.48) |
| LA | 50 (16.9) | 4.62 (3.99–5.35) P < 0.001 |
9.32 (8.72–9.96) P < 0.001 |
66.3 (52.6–83.6) P < 0.001 |
7.12 (6.56–7.74) P < 0.001 |
9.46 (6.83–13.1) P < 0.001 |
3.43 (2.50–4.69) P < 0.001 |
271.2 (187.2–392.7) P < 0.001 |
2.88 (2.09–3.97) P < 0.001 |
3.37 (2.28–4.97) P < 0.001 |
0.07 (−0.35 to 1.12) P = 0.99 |
| SA | 3 (1.0) | 2.89 (1.41–5.89) P = 0.03 |
4.55 (3.61–5.74) P < 0.001 |
96.3 (16.7–554.6) P = 0.75 |
2.76 (1.04–7.34) P = 0.26 |
10.73 (4.23–27.2) P = 0.06 |
1.85 (0.54–6.35) P = 0.59 |
277.1 (61.8–1242) P = 0.16 |
1.63 (0.49–5.37) P = 0.51 |
4.38 (1.03–18.6) P = 0.05 |
2.71 (1.44–5.23) |
| CMLA | 11 (3.7) | 3.94 (2.84–5.46) P = 0.01 |
8.63 (7.37–10.11) P < 0.001 |
30.9 (12.3–77.7) P < 0.001 |
8.82 (7.21–10.81) P < 0.001 |
15.72 (11.7–21.2) P < 0.001 |
4.96 (3.59–6.85) P < 0.001 |
453.1 (199.8–1027) P < 0.001 |
4.28 (3.13–5.87) P < 0.001 |
6.06 (2.65–13.8) P < 0.001 |
0.33 (−0.55 to 11.5) P = 0.48 |
| LASA | 2 (0.7) | 1.73 | 4.59 | 87.0 | 7.82 | 7.48 | 1.62 | 450.6 | 1.58 | 7.85 | 5.81 |
| CMLASA | 1 (0.3) | 6.0 | 4.40 | 38.0 | 17.3 | 16.0 | 2.62 | 3005 | 2.18 | 45.0 | 42.9 |
| Non-survivors | 5 (1.7) | 6.26 (3.40–11.54) P = 0.91 |
9.31 (6.79–12.76) P = 0.03 |
26.0 (18.3–36.9) P < 0.001 |
9.31 (5.90–14.69) P < 0.001 |
14.42 (5.19–40.0) P = 0.003 |
5.12 (2.25–11.6) P = 0.009 |
763.4 (162.6–3584) P < 0.001 |
4.14 (1.82–9.34) P = 0.009 |
9.15 (1.66–50.3) P < 0.001 |
11.5 (−2.00 to 39.1) |
GM, geometric mean; 95% CI, 95% confidence interval
*P value for comparison with the uncomplicated malaria group using the unpaired t-test on log10-transformed data, when n ≥ 3, unless specified otherwise. Only tests with P ≤ 0.029 have a false discovery rate of 5% or less using the Benjamini and Hochberg method to control for multiple comparisons and are considered significant (P value in bold type).
Severe malaria cases were grouped as SP, severe prostrated, or SNP, severe non-prostrated (within which syndromes were grouped inclusively (CM, cerebral malaria; LA, hyperlactataemia; SA, severe anaemia) or exclusively (CM, cerebral malaria; LA, hyperlactataemia; SA, severe anaemia; CMLA, cerebral malaria plus hyperlactataemia; CMSA, cerebral malaria plus severe anaemia; LASA, hyperlactataemia plus severe anaemia; CMLASA, cerebral malaria plus hyperlactataemia plus severe anaemia)).
Platelet count was not available for four subjects with prostration.
P values for comparison with the uncomplicated malaria group using the likelihood-ratio test when n > 5.