. Author manuscript; available in PMC: 2014 May 1.

Published in final edited form as: Osteoarthritis Cartilage. 2013 Feb 4;21(5):655–667. doi: 10.1016/j.joca.2013.01.016

Table 1.

Select OAPol Model inputs

Age at treatment initialization (mean ± standard deviation)			53.54 ± 14.39				Losina 2012³⁶

OSTEOARTHRITIS PROGRESSION (annual likelihood, %)

			K-L 2 to K-L 3		K-L 3 to K-L 4
	Obesity Group		Male	Female	Male	Female	Holt 2011¹⁹
	Non-Obese		5.58	4.00	1.29	1.95
	Obese		12.26	8.95	2.94	4.27

QUALITY OF LIFE UTILITIES

	Utility for subjects with severe OA (K-L 3 or 4)				0.690		Losina 2009⁴³

			Non-Obese		Obese
	Number of Comorbidities	Age Group	OA Pain	No OA Pain	OA Pain	No OA Pain
	0 – 1	25–44	0.814	0.955	0.781	0.921

		45–64	0.806	0.952	0.773	0.918

		65+	0.884	0.943	0.850	0.909

	2 –3	25–44	0.721	0.903	0.688	0.870	NHANES 2005–8^22,23

		45–64	0.713	0.901	0.679	0.867

		65+	0.791	0.891	0.757	0.858

	> 3		0.662	0.662	0.662	0.662

ANNUAL DIRECT MEDICAL COSTS (USD 2010)

	Number of Comorbidities		Age Group	OA Pain	No OA Pain
	0–1		25–34	$1,506	$1,302

			35–44	$2,018	$1,814

			45–49	$2.635	$2,431

			50–54	$2,636	$2,432

			55–59	$3,443	$3,239

			60–64	$4,144	$3,940

			65–69	$4,401	$4,198

			70–74	$5,092	$4,888

			75–79	$5,916	$5,712

			80+	$7,709	$7,505

	2–3		25–34	$6,856	$6,652		Pope 2004³⁷ NHANES 2005–8^22,23 CPI 2010³⁸ MCBS 2006³⁹ Red Book 2010³⁰

			35–44	$7,368	$7,165

			45–49	$7,958	$7,755

			50–54	$7,959	$7,755

			55–59	$8,436	$8,232

			60–64	$9,136	$8,933

			65–69	$9,060	$8,856

			70–74	$9,750	$9,547

			75–79	$10,575	$10,371

			80+	$12,367	$12,163

	>3		25–34	$12,710	$12,506

			35–44	$13,223	$13,019

			45–49	$11,954	$11,751

			50–54	$11,955	$11,751

			55–59	$13,105	$12,902

			60–64	$13,806	$13,602

			65–69	$15,570	$15,366

			70–74	$16,260	$16,056

			75–79	$17,084	$16,881

			80+	$18,877	$18,673

STANDARD OF CARE TREATMENTS

			First Year		Subsequent Year Failure

Regimen 1: NSAIDs, Acetaminophen, Physical Therapy, Assistive Devices	Pain Relief (annual, %)^††		64.00		24.00	Scott 2000³⁴

			First Year		Subsequent Years
	Major Toxicity (annual, %)		0.38		0.38	Solomon 2005¹¹, Goldstein 1999³³

	Minor Toxicity (annual, %)		2.95		2.24	Bensen 1999³⁵, Scott 2000³⁴, Silverstein 1995⁵⁵

	Cost (USD 2010)		$643		$483	Medicare 2010^56–58, Redbook 2010³⁰, MCBS 2006³⁹, Van Der Esch 2003⁵⁹, Grindrod 2010⁶⁰

			First Year		Subsequent Year Failure

Regimen 2: Intra-articular Injections	Pain Relief (annual, %)^††		64.00		19.00	Raynauld, 2003⁶¹

			First Year		Subsequent Years
	Major Toxicity (annual, %)		0.00		0.00	Ayral, 2001⁶²

	Minor Toxicity (annual, %)		24.00		24.00	Ayral, 2001⁶²

	Cost^†† (USD 2010)		$437		$437	Medicare 2010^56–58, MCBS 2006³⁹

			First Year		Subsequent Year Failure

Regimen 3: Primary TKR	Pain Relief (annual, %)^†††		86.20		4.00	Katz 2007⁶³

			First Year		Subsequent Years
	Major Toxicity (annual, %)		1.33		0.00	Paxton 2010⁶⁴, Katz 2004⁶⁵

	Minor Toxicity (annual, %)		2.94		0.00	Katz 2004⁶⁵

	Cost^†† (USD 2010)		$19,065		$90	Medicare 2010^56–58, HCUP 2009⁵¹, Buntin 2005⁶⁶, CPI 2010³⁸, Teeny 2003⁶⁷

			First Year		Subsequent Year Failure

Regimen 4: Revision TKR	Pain Relief (annual, %)^†††		74.30		5.60	Katz 2007⁶³

			First Year		Subsequent Years
	Major Toxicity (annual, %)		0.96		0.00	Paxton 2010⁶⁴, Katz 2004⁶⁵

	Minor Toxicity (%)		3.64		0.00	Katz 2004⁶⁵

	Cost^†† (USD 2010)		$24,631		$90	Medicare 2010^56–58, HCUP 2009⁵¹, Buntin 2005⁶⁶, CPI 2010³⁸, Teeny 2003⁶⁷

DMOADS^‡

		1st Year			Subsequent Years
Annual Costs (Base Case) (USD 2010)
Overall			$1,000 – $7,000 ($1,000)
Office Visits		$132			$93	2010 Medicare Data^56–58

Efficacy (Base Case) %, Annual		1st Year			Subsequent Year Failure
Halted Progression (K-L 2 – 3) ^‡‡		20 – 100 (50)			1 – 10 (10)
Pain Relief^* (K-L 2 – 3) ^‡‡		10 – 100 (30)			1 – 10 (1)

Toxicity (Base Case) %, Annual		1st Year			Subsequent Years
Major		0.5 – 2.0 (0.5)
Minor		9.50			7.27	Scott 2000³⁴, Bensen 1999³⁵

Toxicity Outcomes
Major	Cardiovascular	Likelihood	32.3			Solomon 2005¹¹

		Mortality	6.02			HCUP 2008⁶⁸

		Utility^**	0.778			Sullivan 2006⁶⁹, NHANES 05–08^22,23

		Cost^**	$18,478			HCUP 2008⁶⁸, CPI 2010³⁸

	Gastrointestinal	Likelihood	67.7			Goldstein 2000³³

		Mortality	2.93			HCUP 2008⁶⁸

		Utility	0.859			Jansen 2007⁷⁰, NHANES 05–08^22,23

		Cost	$9,408			HCUP 2008⁶⁸, CPI 2010³⁸

Minor	General Minor Events	Likelihood	100

		Mortality	0

		Utility	0.923			Jansen 2007⁷⁰, NHANES 05–08^22,23

		Cost	$47			Kamath 2003⁷¹, CPI 2010³⁸

^†

The lowest utility associated with the subject’s health state was used by the model; for example, a 45 year-old subject with severe OA and one comorbidity would have a utility of 0.690, whereas, the same subject with 3 comorbidities would have a utility of 0.662.

^††

Efficacy for Regimens 1 and 2 applies only to individuals who are at K-L grade 2.

^†††

Only pain relief efficacy associated with TKR is shown. TKR technical efficacy (e.g. stability of the implant) was greater than 98% for primary and revision TKR.

^‡

Sensitivity analysis ranges for each parameter have been presented; base case values appear in bold within parentheses.

^‡‡

Pain relief and suspended progression were 0% for subjects who have progressed to K-L grade 4. (K-L 4 represents the most severe level of knee OA, thus patients cannot progress beyond it.)

Pain relief only occurred if there was also suspended progression.

^**

Toxicity utilities and costs (USD 2010) were applied only in the year that the event occurred.

Abbreviations: OA, osteoarthritis; K-L, Kellgren-Lawrence grade; NHANES, National Health and Nutrition Examination Survey; CPI, consumer price inflation calculator; MCBS, Medicare Current Beneficiary Survey; HCUP, Healthcare Cost and Utilization Project; DMOADs, disease-modifying osteoarthritis drugs