Table 1.
Model Inputs
| Cohort Characteristics | ||||||||
| Demographics | ||||||||
| Parameter | Mean (SD) | Data Source | ||||||
| Mean Age (years) | 65 (5) | Assumption | ||||||
| Percent Female | 59% | US Census Bureau 201245 | ||||||
| WOMAC* Pain - High Pain Cohort |
50(15) | NHIS 201225 | ||||||
| WOMAC* Pain- Moderate Pain Cohort |
30(15) | NHIS 201225 | ||||||
| BMI (kg/m2) | 31(7) | NHANES 09–1046 | ||||||
| Quality of Life Weights by Age, Obesity, and WOMAC Pain (rate on a scale of 01) | ||||||||
| WOMAC Pain | Non-obese | Data Source | ||||||
| 45–54 | 55–64 | 65–74 | 75+ | Derived applying regression model proposed by Brazier et al 200424 to OAI26 data |
||||
| 1–16 | 0.82 | 0.82 | 0.85 | 0.83 | ||||
| 16–40 | 0.78 | 0.79 | 0.81 | 0.79 | ||||
| 41–70 | 0.71 | 0.72 | 0.74 | 0.73 | ||||
| 71–100 | 0.66 | 0.66 | 0.69 | 0.67 | ||||
| WOMAC Pain | Obese | |||||||
| 45–54 | 55–64 | 65–74 | 75+ | |||||
| 1–16 | 0.81 | 0.81 | 0.84 | 0.82 | ||||
| 16–40 | 0.77 | 0.78 | 0.8 | 0.78 | ||||
| 41–70 | 0.70 | 0.71 | 0.73 | 0.72 | ||||
| 71–100 | 0.64 | 0.65 | 0.67 | 0.66 | ||||
| Underlying Medical Costs (by Age Group) | ||||||||
| Age Group | Data Source | |||||||
| 50–54 | 55–59 | 60–64 | 65–69 | 70–74 | 75–79 | 80+ | Pope et al., 200447 MCBS 200948 NHANES 2009–201046 Red Book Online21 CPI35 |
|
| $2,813 | $3,685 | $4,490 | $4,826 | $5,621 | $6,571 | $8,636 | ||
| Treatment Characteristics | ||||||||
| Annual Regimen Cost | ||||||||
|
With or Without PPIs** |
Naproxen OTC | Naproxen Rx | Celecoxib | Data Source | ||||
| Without PPIs | $130 | $360 | $880 | Red Book Online® (February 2016)21 |
||||
| With OTC PPIs | $370 | $600 | $1,120 | |||||
| With Rx PPIs | - | $1,130 | $1,650 | |||||
| Discontinuation in the First 3 Months | ||||||||
| Naproxen OTC | Naproxen Rx | Celecoxib | Data Source | |||||
| 13.3% | 15.1% | 4.1% | Essex et al 201229 | |||||
| WOMAC Pam Decrement in First Year of Treatment (Stratified by Current Pain) | ||||||||
| Current WOMAC Pain | Mean WOMAC Pain Decrement (SD) | Data Source | ||||||
| Naproxen OTC | Naproxen Rx | Celecoxib | Smith et al 201628 | |||||
| 16–40 | 5.6 (17.6) | 6.3 (17.6) | 7.2(17.6) | |||||
| 41–70 | 13.4 (19.0) | 15.2 (19.0) | 17.2 (19.0) | |||||
| 71–100 | 20.9 (19.2) | 23.7 (19.2) | 26.8(19.2) | |||||
| Adverse Events | ||||||||
| Adverse Event Type | Naproxen OTC | Naproxen Rx | Celecoxib | Data Source | ||||
| Minor Toxicity | 55.4% | 63.0% | 63.0% | Bhala et al 201314 | ||||
| Major Toxicity | 0.53% | 0.60% | 0.40% | |||||
|
Gastrointestinal (year 1) |
0.53% | 0.60% | 0.20% | |||||
|
Cardiovascular (year 1) |
0.00% | 0.00% | 0.20% | |||||
|
RR of Gl event on Rx PPIs |
0.35 | Rostom et al 200249 | ||||||
|
RR of Gl event on OTC PPIs |
0.40 | |||||||
| Sensitivity Analyses† | ||||||||
| Variable | Values‡ | |||||||
| Annual Cost of generic celecoxib |
$1,320 | $880 | $600 | $360 | $190 | |||
| Discontinuation Rate (first 3 months) |
4% | 8% | 12% | 15% | ||||
| Gl Toxicity Rate (first year) |
0.2% | 0.3% | 0.4% | 0.5% | 0.6% | |||
| CV Toxicity Rate (first year) |
0.2% | 0.1% | 0.05% | 0% | ||||
WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index, an osteoarthritis pain scale used in the OAPol model
PPI: proton-pump-inhibitor
Values for sensitivity analyses were chosen to assist with the comparison between naproxen and celecoxib. For cost, the highest value reflects the cost of a 300 mg daily dose of celecoxib (200 mg in base case) and the lowest cost was the price of the cheapest generic celecoxib formulation available per Red Book. Finally, $360 was selected as that is the current cost of naproxen and $600 was chosen as an arbitrary value in between our base case and the cost of naproxen. Values for discontinuation rate and toxicity rates were varied between our base case scenario and the values for naproxen with at least two intermediate values selected to aid comparison.
Underlined values are the base case celecoxib values and bold values are equivalent to prescription naproxen