Comparison of statistical models to estimate parasite growth rate in the induced blood stage malaria model

Malaria Journal

Table 2 Average parasite growth rate estimates for models fitted by individual (models 1–6)

Model used	Parameter estimated	Sanderson et al.		Duncan et al.		Payne et al.		SD across studies fixed/non-fixed intercept model
Model used	Parameter estimated	Fixed intercept (n = 5)	Non-fixed intercept (n = 5)	Fixed intercept (n = 8)^a	Non-fixed intercept (n = 8)^b	Fixed intercept (n = 27)^c	Non-fixed intercept (n = 27)^c	SD across studies fixed/non-fixed intercept model
Log-linear	m (SD) [95% CI]	0.64 (0.064) [0.58–0.69]	0.72 (0.131) [0.61–0.84]	0.52 (0.039) [0.49–0.55]	0.71 (0.128) [0.62–0.80]	0.50 (0.049) [0.48–0.52]	0.68 (0.097) [0.65–0.72]	0.073/0.021
Sine-wave (fixed period)	m (SD) [95% CI]	0.63 (0.065) [0.58–0.69]	0.69 (0.197) [0.52–0.86]	0.52 (0.041) [0.49–0.54]	0.73 (0.104) [0.65–0.81]	0.50 (0.047) [0.48–0.52]	0.70 (0.135) [0.65–0.75]	0.073/0.021
Sine-wave (non-fixed period)	m (SD) [95% CI]	0.62 (0.059) [0.57–0.67]	0.74 (0.122) [0.64–0.85]	0.52 (0.045) [0.49–0.55]	0.76 (0.055) [0.71–0.80]	0.50 (0.044) [0.48–0.51]	0.72 (0.112) [0.68–0.76]	0.067/0.019

Fixed intercept models had the intercept fixed to the inoculum size, whereas non-fixed intercept models estimated the intercept as part of model fitting. Sine-wave models were fitted either with the period fixed to 48 h (fixed period), or with the period not fixed (non-fixed period). The parasite growth rate estimate (m) is given as average across individuals in a study. The values highlighted in italic correspond with the models used to fit the data in the original reports
m parasite growth rate estimate, SD standard deviation, CI confidence interval
^aExcept for sine-wave (non-fixed period) model, n = 7
^bExcept for sine-wave (fixed period) model, n = 7; sine-wave (non-fixed period) model, n = 6
^cExcept for sine-wave (non-fixed period) model, n = 26

ISSN: 1475-2875