Cost-effectiveness analysis of valsartan versus losartan and the effect of switching

Figures & data

Figure 1.  Hypertension and switching treatment Markov state diagram.

Table 1.  Moderate hypertension model input values.

CVD event	Event cost	Utility decrement	Source
CHD events
Non-fatal MI	$41,813	−0.0409	11–16, 22
Fatal MI	$41,813	−0.0409	11–16, 22
Other CHD	$10,403	−0.0412	11–16, 22
CeVD event
Non-fatal stroke	$19,075	−0.0524	11–16, 22
Fatal stroke	$19,075	−0.0524	11–16, 22
Transient ischemic attack	$10,852	−0.0880	11–16, 21
Medical follow-up (per cycle)
Event-free follow-up	$104	−0.000 (baseline values age adjusted)*	11–16, 22
Post-event follow-up	$1,836	−0.0489	11–16, 22 weighted average
Treatment inputs	Valsartan	Losartan
	160 mg/day	100 mg QD
Branded drug cost (per day)	$2.95	$3.42	19
Time to generic price	2.75 years	0.33 years	Assumption
Generic price ratio	18%	18%	Assumption
Mean SBP reduction	−15.26	−12.00	1
Adherence	76%	76%	8
Discontinuation post-switching	–	8%	2

*Age-related utility values from Sullivan et al.22; range between 0.901–0.736 for 30–80 age groups.

Table 2.  Costs and outcomes of valsartan vs losartan and switching to losartan in moderate hypertension over 20 years.

	Valsartan 160 mg/day	Losartan 100 mg QD	Switching (valsartan to losartan)
Outcomes*
Event frequency (% of patients)
MI (fatal and non-fatal)	20.24%	20.64%	20.64%
Other CHD	16.88%	17.21%	17.21%
Stroke (fatal and non-fatal)	11.81%	12.25%	12.25%
TIA	2.25%	2.34%	2.34%
Survival in years
Overall survival	10.65	10.62	10.62
Quality Adjusted Survival	8.02	8.00	8.00
Cost outcomes
CHD and CeVD events	$9,603	$9,835	$9,835
Follow-up costs	$4,021	$4,103	$4,224
ARB drug costs	$3,182	$2,154	$2,079
		Valsartan vs losartan	Continuous valsartan vs switching
Incremental outcomes*
Incremental cost		$714	$667
Incremental QALYs		0.022	0.022
ICER–Cost per QALY		$32,313	$30,170
Incremental Life Years		0.026	0.026
ICER–Cost per LYG		$27,268	$25,460
Incremental CVD events		0.012	0.012
Cost per event avoided		$57,457	$53,646

*Future costs and outcomes discounted 3%.

Table 3.  Incremental scenario analyses of valsartan vs losartan and vs switching in moderate hypertension patients.

	Incremental cost*	Incremental QALY*	ICER-QALY
Valsartan (160 mg/day) vs Losartan (100 mg QD)
Base case	$714	0.022	$32,313
10 year time horizon	$872	0.007	$119,926
Adherence 80%	$787	0.022	$35,584
Adherence 60%	$425	0.022	$19,228
Valsartan (160 mg/day) vs Switching to Losartan (100 mg QD)
Base case	$667	0.022	$30,170
10 year time horizon	$811	0.007	$111,509
Discontinuation post-switch–1st year (10% higher)	$678	0.022	$30,659
Discontinuation post-switch–subsequent years 10% higher	$555	0.022	$25,089
Discontinuation post-switch–subsequent years 10% lower	$778	0.022	$35,171
SBP impact with lowered adherence or discontinuation–5% less efficacy (0.76 mmHg less decrease in SBP)	$650	0.023	$27,834
SBP impact with lowered adherence or discontinuation–10% less efficacy (1.53 mmHg less decrease in SBP)	$633	0.025	$25,731

*Future costs and outcomes discounted 3%.

Figure 2.  Tornado chart of incremental cost per QALY gained: Valsartan vs switching to losartan.

Sullivan PW, Ghushchyan V. Preference-Based EQ-5D index scores for chronic conditions in the United States. Med Decis Making 2006;26:410-20

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