Costs and cost-effectiveness of HIV counselling and testing modalities in Southern Mozambique

Table 1 Base-case inputs of parameters (probabilities and costs) for the model, their candidate distributions, and alpha–beta values characterizing those distributions (Manhiça District, Mozambique)

Model inputs	PICT	HBT	VCT	Distribution^a	Alpha-Beta^b	Source
Probabilities^c
Individual reached	–	0.752	–	β	8192–2705 (HBT)	[12]
Not known HIV-positive/not pregnant	–	0.822	–	β	6736–1456 (HBT)	[12]
Gave consent^d	–	0.760	–	β	5116–1620 (HBT)	[12]
HIV test positive	0.312	0.072	0.119	β	1046–2305 (PICT); 369–4747 (HBT); 909–6718 (VCT)	[12]
Enrolled in study	0.404	–	0.363	β	423–623 (PICT); 330–579 (VCT)
Enrolled in care	0.908	0.355	0.985	β	384–39 (PICT); 131–238 (HBT); 325–5 (VCT)	[12]
Attended 1st consultation	0.799	0.901	0.911	β	307–77 (PICT); 118–13 (HBT); 296–29 (VCT)	[12]
Linked to care	0.642	0.746	0.693	β	197–110 (PICT); 88–30 (HBT); 205–91 (VCT)	[12]
Costs^e
Average cost per test (SD), US$	7.14 (1.30)	11.07 (3.82)	7.79 (1.30)	γ	30.3–0.235 (PICT); 8.39–1.32 (HBT); 36.1–0.216 (VCT)	Table 2

^aCandidate distribution were determined based on expert opinion and other similer studies
^bAlpha-Beta values were dependent on the type of candidate distribution. For β distribution, alpha = number of people reaching that step while beta = total number of people who completed previous step – alpha. For γ distribution, alpha = $\frac{{\mu^{2} }}{{s^{2} }}$ while beta = $\frac{{s^{2} }}{\mu \prime }$ where μ is the mean and s² is the variance
^cThese were conditional probabilities derived directly from proportions of individuals reaching each step over the number of individuals completing the previous step, as described in the cohort study
^dThe probability of giving consent to be tested is a proxy to HBT uptake. Moreover, step downstream are conditional on successfully obtaining consent
^eAverage costs per person tested determined for each strategy from the micro-costing analysis were fed into the model. These were assumed to be equivalent to the average cost per test
PICT provider-initiated counselling and testing, HBT home-based testing, VCT voluntary counselling and testing, SD standard deviation