Cost and utilization of healthcare services for hip and knee replacement

Figures & data

Table 1. Patient characteristics for the Thomson Reuters sample.

Parameter	Hip replacement	Knee replacement
n	22 618	50 686
Age in years, Mean (SD)	65.9 (10.8)	66.5 (9.7)
Gender
Male, n (%)	10 350 (45.8)	19 324 (38.1)
Female, n (%)	12 268 (54.2)	31 362 (61.9)
Health Plan Type, n (%)
Medicare	11 279 (49.9)	26 756 (52.9)
Preferred provider  organization (PPO)	6502 (28.7)	13 556 (26.7)
Health maintenance  organization (HMO)	2037 (9.0)	3836 (7.6)
Point of service, non-capitated	1296 (5.7)	2968 (5.9)
Comprehensive	995 (4.4)	2598 (5.1)
Consumer-driven health  plan (CDHP)	207 (0.9)	376 (0.7)
Missing/unknown	132 (0.6)	263 (0.5)
Point of service with capitation	98 (0.4)	174 (0.3)
Exclusive provider  organization (EPO)	72 (0.3)	159 (0.3)

Table 2. Patient characteristics for the Premier hospital inpatient sample.

Parameter	Hip replacement	Knee replacement
n	81 635	158 990
Age in years, Mean (SD)	66.5 (10.9)	66.9 (9.8)
Gender
Male, n (%)	35 121 (43.0)	56 586 (35.6)
Female, n (%)	46 514 (57.0)	102 404 (64.4)
Health Plan Type, n (%)
Medicare – traditional	37 578 (46.0)	77 779 (49.0)
Managed care – non-capitated	26 167 (32.1)	46 184 (29.0)
Commercial – indemnity	5 573 (6.8)	10 391 (6.5)
Medicare – managed care,  non-capitated	5 349 (6.6)	10 220 (6.4)
Medicare – managed care,  capitated	1731 (2.1)	3487 (2.2)
Medicaid – traditional	950 (1.2)	1846 (1.2)
Direct employer contract	901 (1.1)	1608 (1.0)
Managed care – capitated	697 (0.9)	1322 (0.8)
Other government payers	598 (0.7)	1379 (0.9)
Other	595 (0.7)	1089 (0.7)
Self-Pay	486 (0.6)	514 (0.3)
Medicaid – managed care,  non-capitated	442 (0.5)	800 (0.5)
Workers compensation	416 (0.5)	2188 (1.4)
Charity	73 (0.1)	58 (0.0)
Medicaid – managed care,  capitated	45 (0.1)	81 (0.1)
Indigent	34 (0.0)	44 (0.0)

Table 3. Length of stay and discharge status based on Premier data.

Variable	Hip replacement (n = 81,635)	Knee replacement (n = 158,990)
Mean Patient Length of Stay, M (SD)	4.4 (1.1)	4.3 (0.8)
Premier Patient Length of Stay, %
2 days	2.2	1.6
3 days	11.9	10.5
4 days	50.8	56.1
5 days	22.8	24.7
6 days	7.0	7.1
7 days	3.4	NA*
8 days	1.9	NA*
Premier Patient Discharge Status, %
To home with home healthcare	40.7	42.2
To a nursing facility	23.7	21.9
To home	21.7	21.9
To rehabilitation facility	11.6	11.8
To other locations	2.3	2.2

*Inclusion criteria limited THR hospitalizations to ≥2 days and ≤8 days and TKR hospitalizations to ≥2 days and ≤6 days.

Table 4. Inpatient cost and charges (USD) per patient based on Premier data.

Variable	Hip replacement		Knee replacement
	n	Mean (SD)	n	Mean (SD)
Premier Financial Results Per Patient*
Hospital charges	81 635	$47 694 ($48 779)	158 990	$44 364 ($23 492)
Hospital (total) cost of treating the patient	81 635	$17 588 ($10 216)	158 990	$16 267 ($9 591)
Hospital indirect cost	81 635	$7223 ($7222)	158 990	$6444 ($4827)
Hospital direct cost	81 635	$10 365 ($5922)	158 990	$9822 ($5922)
Top 3 Premier Hospital Departmental Costs*
Supply – total cost	81 621	$9276 ($7866)	158 964	$8298 ($6733)
Supply – direct cost	81 621	$6226 ($4456)	158 964	$5856 ($4363)
Operating room – total cost	81 598	$3447 ($2733)	158 893	$3423 ($2950)
Operating room – direct cost	81 598	$1686 ($1597)	158 893	$1668 ($1741)
Room and board – total cost	81 582	$2661 ($1778)	158 824	$2476 ($1387)
Room and board – direct cost	81 582	$1272 ($1033)	158 824	$1177 ($802)

*Cost and charge data are adjusted to December 2009 using the Medical Services component of the Consumer Price Index12.

Table 5. Payments (insurer perspective in USD) for hospital services based on Thomson Reuters data.

Variable	Hip replacement (n = 22 618),	Knee replacement (n = 50 686),
	Mean (SD)	Mean (SD)
Thomson Reuters Hospital Payments*†
Total hospital payment (payer + patient)	$22 967 ($15 875)	$21 583 ($14 777)
Medicare payment	$18 925 ($16 575)	$18 131 ($15 483)
Non-Medicare payment	$26 988 ($14 037)	$25 443 ($12 893)

*Financial data are adjusted to December 2009 using the Medical Services component of the Consumer Price Index12.

†The difference between total hospital payment and total insurer payment for THR ($333) and TKR ($307) represents copayments, deductibles, and adjustments.

Table 6. Percentage of patients with at least one claim and mean payment per patient (USD) for selected CPT procedures 90 days before and after hospitalization.

CPT procedure groups*	Hip replacement (n = 22 618)				Knee replacement (n = 50 686)
	90 days pre		90 days post		90 days pre		90 days post
	%	mean $ (SD)	%	mean $ (SD)	%	mean $ (SD)	%	mean $ (SD)
Physical medicine and rehabilitation	11.6	369.74 (759.52)	35.8	1054.22 (1030.10)	11.3	355.11 (543.94)	56.0	1517.37 (1314.25)
Durable medical equipment	7.3	254.72 (494.68)	24.6	211.07 (413.63)	6.9	296.45 (535.47)	32.1	340.62 (562.71)
Nursing facility services	0.1	168.76 (202.86)	15.0	280.21 (272.51)	0.9	124.42 (102.33)	12.8	263.18 (247.76)
Temporary procedures†	8.3	119.54 (557.65)	20.1	430.83 (673.33)	9.1	99.41 (186.92)	25.3	390.22 (674.65)
Temporary national procedures^†	0.9	84.95 (175.69)	9.4	847.15 (1002.11)	1.2	102.32 (396.61)	8.1	882.13 (887.90)

Means are the average payments for patients using a service at least once.

*Physical medicine and rehabilitation (97001–97799), durable medical equipment (E0000–E9999), nursing facility services (99301–99318), temporary procedures (G0000–G9999), and temporary national procedures (S0000–S9999).

†These CPT4 Category III codes are for ‘emerging technology, services, and procedures’, and are to be used, when available, instead of a Category I unlisted code. The most recent listing of these codes is available at www.ama-assn.org/go/cpt.

Figure 1. Average amount paid by insurer (USD) per patient in 30-day increments over the 360-day post-surgery period for hip and knee replacement. Hip n = 22,617; Knee n = 50,686. Cost data are adjusted to December 2009 using the Medical Services component of the Consumer Price Index12.

Table A1. Number of patients with inpatient hip replacement hospitalizations meeting study criteria.

Criteria	Removed	Remaining
Number of patients in the Thomson Reuters database with valid enrollment information during the years 2006–2008, which are the entry dates for this study.	NA	5 073 378
Keep patients with inpatient hospitalization claims with a first occurring primary ICD-9-CM procedure code for any hip replacement surgery (81.51, 81.52) between 1/1/2006 and 12/31/2008.	4 993 690	79 688
Keep patients with continuous eligibility 12 months before and after index date.	32 115	47 573
Omit patients younger than 45.	1904	45 669
Omit patients with multiple hospital summary records on their index date.	9	45 660
Omit patients with negative amounts in (net pay) on claims.	2322	43 338
Omit patients not having pharmacy coverage for the entire study period (RX = 0).	3663	39 675
Omit patients with non-hip procedure codes on their index hospitalization.	8369	31 306
Omit patients with a length of stay that was more than 8 days or less than 2 days on their index hospitalization.	2817	28 489
Omit patients with any inpatient hospitalization in pre-index period.	4148	24 341
Omit patients with a second hip surgery during the 360 days post-index.	1723	22 618

Table A2. Number of patients with inpatient knee replacement hospitalizations meeting study criteria.

Criteria	Removed	Remaining
Number of patients in the Thomson Reuters database with valid enrollment information during the years 2006–2008, which are the entry dates for this study.	NA	51 780 736
Keep patients with inpatient hospitalization claims with a first occurring ICD-9-CM procedure code for knee replacement surgery (81.54) between 1/1/2006 and 12/31/2008.	51 638 169	142 567
Keep patients with continuous eligibility 12 months before and after index date.	53 285	89 282
Omit patients younger than 45.	1097	88 185
Omit patients with multiple hospital summary records on their index date.	7	88 178
Omit patients with negative amounts in (net pay) on claims.	4860	83 318
Omit patients not having pharmacy coverage for the entire study period (RX = 0).	7923	75 395
Omit patients with complicating secondary procedure codes on their index hospitalization.	4631	70 764
Omit patients with a length of stay that was more than 6 days or less than 2 days on their index hospitalization.	5676	65 088
Omit patients with any inpatient hospitalization in pre-index period.	8031	57 057
Omit patients with a second knee surgery during the 360 days post-index.	6371	50 686

HCUP Databases. Healthcare Cost and Utilization Project (HCUP). 2006-2009. Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/databases.jsp. Accessed May 7, 2012

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