A cost-effectiveness analysis of celecoxib compared with diclofenac in the treatment of pain in osteoarthritis (OA) within the Swedish health system using an adaptation of the NICE OA model

Figures & data

Table 1. Relative risks for adverse events.

Adverse event	Celecoxib vs Diclofenac – relative risk	NSAID + PPI vs NSAID alone – relative risk	COX-2 + PPI vs COX-2 alone – relative risk
GI symptoms	0.67	0.43	0.25
Symptomatic ulcer	0.67	0.46	0.25
Complicated GI event	0.72	0.37	0.25
MI	1.70	1.00	1.00
Stroke	0.38	1.00	1.00
HF	1.74	1.00	1.00

GI, Gastrointestinal; HF, Heart Failure; MI, Myocardial Infarction; NSAID, non-steroidal anti-inflammatory drug; PPI, proton pump inhibitor.

Table 2. Swedish costs applied in the updated model.

	Daily cost
Drug
Diclofenac	1.52 kr	$0.22
Celecoxib	8.10 kr	$1.19
Omeprazole (PPI)	0.75 kr	$0.11
Health Service	Cost
Primary care nurse	1,300 kr	$192
GPA use (per day)	0 kr	$0
GI outpatient visit	1 kr	$0
Diagnostic endoscopy	3,193 kr	$471
Therapeutic endoscopy	2,376 kr	$350
H pylori test	6,057 kr	$893
Surgical procedure	0 kr	$0
Primary care nurse	31,613 kr	$4,663
Adverse Event	Cost of management
Dyspepsia	2,242 kr	$331
Symptomatic ulcer	8,192 kr	$55,535
Complicated GI event	19,738 kr	$133,806
MI (acute cycle cost)	32,746 kr	$221,989
MI (subsequent cycle cost)	2,398 kr	$16,256
Stroke (acute cycle cost)	30,841 kr	$209,075
Stroke (subsequent cycle cost)	5,013 kr	$33,984
HF (acute cycle cost)	35,507 kr	$240,706
HF (subsequent cycle cost)	2,194 kr	$14,873

GI, Gastrointestinal; HF, Heart Failure; MI, Myocardial Infarction; PPI, proton pump inhibitor.

Table 3. Swedish base case results without PPI.

Treatment	Results per patient
	Discounted costs	Discounted QALYs	Marginal costs	Marginal QALYs	ICER
Celecoxib	43,583 kr	11.92	–	–	–
Diclofenac	43,120 kr	11.92	463 kr	0.008	59,769 kr
No treatment	42,561 kr	11.92	1022 kr	0.003	299,564 kr

Costs and QALYs discounted annually at 3%.

ICER, incremental cost-effectiveness ratio; PPI, proton pump inhibitor; QALY, quality-adjusted life year.

Table 4. Addition of PPI to celecobxib—results.

Treatment	Results per patient
	Discounted costs	Discounted QALYs	Marginal costs	Marginal QALYs	ICER
Celecoxib + PPI	43,432 kr	11.93
Celecoxib	43,583 kr	11.92	−151 kr	0.01	Dominant

Costs and QALYs discounted annually at 3%.

ICER, incremental cost-effectiveness ratio; PPI, proton pump inhibitor; QALY, quality-adjusted life year.

Table 5. Addition of PPI to diclofenac—results.

Treatment	Results per patient
	Discounted costs	Discounted QALYs	Marginal costs	Marginal QALYs	ICER
Diclofenac + PPI	42,903 kr	11.92
Diclofenac	43,120 kr	11.92	−216 kr	0.01	Dominant

Costs and QALYs discounted annually at 3%.

ICER, incremental cost-effectiveness ratio; PPI, proton pump inhibitor; QALY, quality-adjusted life year.

Table 6. Swedish base case results with PPI.

Treatment	Results per patient
	Discounted costs	Discounted QALYs	Marginal costs	Marginal QALYs	ICER
Celecoxib + PPI	43,432 kr	11.93	–	–	–
Diclofenac + PPI	42,903 kr	11.92	529 kr	0.006	82,313 kr
No treatment	42,561 kr	11.92	871 kr	0.010	86,615 kr

Costs and QALYs discounted annually at 3%.

ICER, incremental cost-effectiveness ratio; QALY, quality-adjusted life year; PPI, proton pump inhibitor.

Figure 1. Scatterplot of Monte Carlo simulations QALYs, Quality-Adjusted Life Years.

Figure 2. Cost-effectiveness acceptability curve of Monte Carlo simulations.

Table 7. Sensitivity analysis results.

Sensitivity analysis			ICER of celecoxib plus PPI vs diclofenac plus PPI
Scenario	Treatment period (months)	Age (years)
Swedish base case	3	55	82,313 kr
		65	58,110 kr
	24	55	84,339 kr
		65	61,815 kr
Equal CV risks	3	55	112,021 kr

CV, Cardiovascular; PPI, proton pump inhibitor.

Figure 3. Sensitivity analysis varying the relative risk of GI events GI, Gastrointestinal; ICER, Incremental Cost-Effectiveness Ratio.

Figure 4. Sensitivity analysis varying the cost of treating each adverse event GI, Gastrointestinal; ICER, Incremental Cost-Effectiveness Ratio; MI, Myocardial Infarction.