The cost-effectiveness of celecoxib vs diclofenac in the treatment of osteoarthritis in the UK; an update to the NICE model using data from the CONDOR trial

Figures & data

Table 1.  Numbers of adverse events observed in CONDOR.

Adverse event	Number of observed events (dose adjusted number of events)
	CLASS		CONDOR		CONDOR–adjusted
	Celecoxib (n = 3987)	Diclofenac^a (n = 1996)	Celecoxib (n = 2238)	Diclofenac plus PPI (n = 2246)	Celecoxib (n = 2238)	Diclofenac without PPI^b (n = 2246)
GI symptoms leading to withdrawal from study	1990 (1645)	1369 (1230)	114 (236)	167 (240)	114 (236)	388 (424)
Symptomatic Ulcer	26 (18)	16 (14)	5 (5)	11 (10)	5 (5)	30 (25)
Complicated GI event	20 (14)	11 (9)	5 (4)	4 (8)	5 (4)	9 (8)
MI	19 (16)	5 (5)	2 (3)	4 (3)	2 (3)	2 (3)
Stroke	8 (7)	10 (9)	3 (3)	3 (3)	3 (3)	3 (3)
Heart Failure	9 (6)	2 (2)	0 (0)	0 (0)	0 (0)	0 (0)

^aThe comparator arms in CLASS consisted of diclofenac and ibuprofen and, thus, the diclofenac patient numbers (n) are approximately half those in the celecoxib arm.

^bThe diclofenac without PPI event rates have been calculated using the relative risks to remove the PPI efficacy from the diclofenac with PPI event rates.

Table 2.  Relative risks of adverse events based on estimated dose adjusted treatment effects.^a

Adverse event		Celecoxib vs Diclofenac relative risk
		CLASS	CONDOR– adjusted	Pooled (95% CI)
GI symptoms		0.67	0.56	0.66 (0.64, 0.70)
Symptomatic Ulcer		0.64	0.20	0.43 (0.24,0.76)
Complicated GI event		0.78	0.50	0.68 (0.34, 1.34)
MI		1.60	1.00	1.40 (0.60, 3.28)
Stroke		0.38	1.00	0.51 (0.22, 1.17)
Heart Failure		1.57	1.00^b	1.42 (0.32, 6.23)

^aEvent rates based on celecoxib 400 mg daily dose adjusted to ADQ dose of 200 mg and diclofenac 150 mg daily dose adjusted to ADQ dose of 150 mg.

^bBased on 0 events for both celecoxib and diclofenac.

Table 3.  Estimated costs for the management of adverse events.^a

	New costs		Original costs
Management of dyspepsia^b	£70		£40
Management of symptomatic ulcer^b,c	£796		£640
Management of complicated GI event^b,c,d	£2909		£2862
Management of CV events^e:	First cycle	Subsequent cycles	First cycle	Subsequent cycles
MI	£1437	£134	£1437	£134
Stroke	£2268	£435	£2268	£435
heart failure	£1770	£134	£1770	£134

^aAll costs based on original NICE analysis and include GP and primary care nurse visits (costed from PSSRU 201116).

^bIncludes GI outpatient visit (NHS Reference cost 2010–1114, specialty code 301M, face-to-face medical outpatient appointment, follow-up appointment).

^cIncludes Diagnostic Endoscopy (NHS Reference costs 2010–1114, Non-elective GI bleed diagnostic endoscopic costs).

^dIncludes Surgical procedure (NHS Reference cost 2010–1114, Very Major GI bleed procedure).

^eCosts based on NICE Hypertension guidelines17, and inflated to 2011 costs using PSSRU 2011 HCHS PPI16.

Table 4.  Costs, QALYs and ICERs for the trial data.

Treatment	Results per patient
	Discounted costs	Discounted QALYs	Marginal costs	Marginal QALYs	ICER
Pooled CLASS and CONDOR data – CONDOR adjusted to obtain event rate for diclofenac without PPI
Celecoxib plus PPI	£75	0.010	–	–	–
Diclofenac plus PPI	£18	0.004	£56	0.006	£9377
Pooled CLASS and CONDOR data – CLASS adjusted to obtain event rate for diclofenac with PPI
Celecoxib plus PPI	£80	0.010	–	–	–
Diclofenac plus PPI	£20	0.002	£61	0.007	£8507
CONDOR data
Celecoxib plus PPI	£77	0.006	–	–	–
Diclofenac plus PPI	£29	−0.004	£49	0.010	£4773
CLASS data
Celecoxib plus PPI	£77	0.010	–	–	–
Diclofenac plus PPI	£18	0.004	£59	0.006	£9538
CONDOR data – unadjusted for dose
Celecoxib plus PPI	£77	0.01	–	–	–
Diclofenac plus PPI	£34	−0.01	£44	0.013	£3340
CONDOR data – unadjusted for dose
Celecoxib	£82	0.00	–	–	–
Diclofenac plus PPI	£34	−0.01	£48	0.004	£12,736

Table 5.   Results of sensitivity analyses.

Sensitivity analysis			ICER of Celecoxib plus PPI vs Diclofenac plus PPI
Scenario	Treatment period	Age
Base case	3 months	55	£9377
		65	£5856
	24 months	55	£9606
		65	£6258
Equal cardiovascular risks	3 months	55	£14,083
		65	£9008
	24 months	55	£14,215
		65	£9440

Figure 1.  Scatter plot results from the probabilistic sensitivity analysis (pooled analysis).

Figure 2.  Cost-effectiveness acceptability curve (pooled analysis).

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