Evaluating the effectiveness of IPTi on malaria using routine health information from sentinel health centres in southern Tanzania

Table 2 Incidence of first or only and all episodes of malaria, and incidence in all time at risk after IPTi dose, and within 28 days of IPTi dose one

	Intervention Area			Comparison Area			Effect
Intention to treat *	Events	PYAR	Rate	Events	PYAR	Rate	RR (95% CI)	p value	PE (95% CI)
Malaria incidence (first or only)
Crude	315	2048.3	0.154	448	1882.7	0.238	0.65 (0.56-0.75)	< 0.001	35% (25%,44%)
adjusted ^‡							0.75 (0.24-2.31)	0.584	25% (-131%,76%)
Malaria incidence (all episodes)
Crude	329	2105.9	0.156	507	1946.0	0.261	0.60 (0.52-0.69)	< 0.001	40% (31%,48%)
adjusted ^† ^‡							0.82 (0.29-2.29)	0.663	18% (-129%,71%)
	IPTi Intervention Area			Corresponding EPI vaccine Comparison Area			Effect
Per protocol **	Events	PYAR	Rate	Events	PYAR	Rate	RR (95% CI)	p value	PE (95% CI)
Malaria incidence (all episodes) in ATAR since IPTi dose
IPTi dose 1
crude	79	623.2	0.127	125	513.1	0.244	0.52 (0.39-0.69)	< 0.001	48% (31%,61%)
adjusted ^{† ‡}							0.68 (0.21-2.22)	0.498	32% (-122%,79%)
Malaria incidence within 28 days of IPTi dose
IPTi dose 1
crude	7	95.1	0.070	13	81.0	0.160	0.46 (0.18-1.15)	0.088	54% (-15%,82%)
adjusted ^‡							0.48 (0.11-2.13)	0.341	52% (-113%,89%)

* Intention to treat analyses comparing IPTi intervention and comparison areas
** Per protocol analyses comparing children who received IPTi in intervention areas to those that received corresponding EPI vaccines in comparison areas
EPI = expanded programme on immunization, PAYR = person years at risk, ATAR = all time at risk, RR = rate ratio, CI = confidence interval, PE = protective efficacy
^† Results adjusted for clustering within children for multiple episodes of malaria using Poisson random effects modeling
^‡ Using intervention and comparison area mean rate, unpaired t test p value and approximate 95% CI that adjust for clustering by health centre

ISSN: 1475-2875