Modeling the cost of influenza: the impact of missing costs of unreported complications and sick leave

BMC Public Health

Table 1 Factors for estimating direct costs of seasonal influenza in the 2005/06 season

Direct cost		Mean	Distribution	Parameters
Pharmaceutical cost	Attack rate (%)	7.50	Beta ^b	α = 31.91	β = 393.5
	Cost per pack (USD)	7.4
	Number of packs	1.00	Gamma ^c	k = 6.83	Θ = 0.15
	Population (2005/06)	4 640 219
Outpatient cost^a	Adjusted influenza+pneumonia cost	3 415 900	Gamma ^c	k = 25.00	Θ = 13.66e3
	Percentage in private clinics	20.00	Beta ^b	α = 12.60	β = 50.40
Inpatient cost	Number of influenza hospitalization	446	Gamma ^c	k = 43.02	Θ = 10.37
	Number of pneumonia hospitalization	1 382	Gamma ^c	k = 35.48	Θ = 38.95
	Number of other hospitalization	890	Gamma ^c	k = 148.6	Θ = 5.99
	DRG points for influenza hospitalization	0.59	Gamma ^c	k = 25.00	Θ = 0.02
	DRG points for pneumonia hospitalization	1.47	Gamma ^c	k = 25.00	Θ = 0.06
	DRG points for other hospitalization	1.00	Gamma ^c	k = 25.00	Θ = 0.04
Indirect cost
Sick leave	Recovery period for influenza (days)	5.00	Normal	σ = 0.50
	Recovery period for other airway disease (days)	7.00	Normal	σ = 0.50
	Percentage with IA employers	50.0	Normal	σ = 1.67
	Percentage with non-IA employers	40.0	Normal	σ = 2.36
	Percentage self-employed	10.0	Normal	σ = 1.67
	Days prior to sick leave for non-IA employees	2.50	Uniform	range [2.00: 3.00]
	Days prior to sick leave for IA employees	4.00	Normal	σ = 0.50

^a Outpatient cost includes costs from GP visits, emergency room services and medical specialist visits.
^b $f (x; α, β) = \frac{1}{B (α, β)} x^{α - 1} {(1 - x)}^{β - 1}$ , where B is the Beta function.
^c $f (x; k, θ) = x^{k - 1} \frac{e^{- x / θ}}{θ^{k} Γ (k)}$ , where Γ is the Gamma function.

ISSN: 1471-2458