Rheumatoid Arthritis vs Osteoarthritis: Comparison of Demographics and Trends of Joint Replacement Data from the Nationwide Inpatient Sample

July 2, 2018 | Surgery

Alexander J. Kurdi, MD ; Benjamin A. Voss, MD ; Tony H. Tzeng, BS ; Steve L. Scaife, MS ; Mouhanad M. El-Othmani, MD ; Khaled J. Saleh, MD, MSc, MHCM, FRCS (C)

TAKE-HOME POINTS

Patients undergoing THA for OA, when compared to those with RA undergoing THA, had lower risk for postoperative cardiovascular, pulmonary, wound dehiscence, infections, and systemic complications.
Patients with OA undergoing THA had statistically significant higher risk of cerebrovascular complication compared to RA patients undergoing the same procedure.
In TKA, OA patients had significantly higher risk for cardiovascular and cerebrovascular complications, and a significant lower risk for mechanical wounds, infection, and systemic complications.
RA patients are at higher risk for postoperative infection, wound dehiscence, and systemic complications after TKA and THA compared to OA patients.
These findings highlight the importance of preoperative medical clearance and management to optimize RA patients and improve the postoperative outcomes.

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease that causes joint deterioration, leading to pain, disability, systemic complications, short lifespan, and decline in quality of life.^1-3 The deterioration primarily affects the synovial membranes of joints, causing arthritis and resulting in extra-articular sequelae such as cardiovascular disease,⁴ pulmonary disease,⁵ and increased infection rates.^3,6 RA is the most prevalent inflammatory arthritis worldwide and affects up to 50 cases per 100,000 in both the US and northern Europe.^2,7-9 Although the gold standard of care for these patients is medical management with immunosuppressant drugs such as disease-modifying anti-rheumatic drugs (DMARDs), total joint arthroplasty (TJA) remains an important tool in the management of joint deterioration in such patients.

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are common procedures utilized to treat disorders that cause joint pain and hindered joint mobility, including osteoarthritis (OA) and RA. Given the aging population, the amount of TKAs and THAs performed in the US has consistently increased each year, with the vast majority of this increase composed of patients with OA.¹⁰ As a result, previous studies investigated the trends and outcomes of these procedures in patients with OA, but relatively less is known about the outcomes and trends of patients with RA undergoing the same surgeries.

Given that RA is a fundamentally different condition with its own pathological characteristics, an understanding of how these differences may impact postoperative outcomes in patients with RA is important. This study aims to present a comparative analysis of the trends and postoperative outcomes between patients with RA and OA undergoing TKA and THA (Figure 1, Tables 1 and 2).

Table 1. Demographics of Total Knee Arthroplasty Patients Based on Primary Diagnosis of Osteoarthritis

	OA		RA		Total		P Value
	No.	Percent	No.	Percent	No.	Percent	(RA vs OA)
Age group							<.0001
<64 years	295,637	42.42	11,325	48.90	306,962	42.63
65 to 79 years	329,034	47.22	10,055	43.42	339,089	47.09
≥80 years	72,197	10.36	1780	7.69	73,977	10.27
Gender							<.0001
Male	259,192	37.19	4887	21.12	264,079	36.68
Female	435,855	62.54	18,248	78.88	454,103	63.07
Race							<.0001
White	468,632	67.25	14,532	77.18	483,164	67.10
Black	39,691	5.7	2119	11.25	41,810	5.81
Hispanic	28,573	4.1	1395	7.41	29,968	4.16
Other	21,306	3.06	783	4.16	22,089	3.07
Region of hospital							<.0001
Northeast	112,031	16.08	3417	14.75	115,448	16.03
Midwest	192,595	27.64	5975	25.80	198,570	27.58
South	257,855	37	9422	40.68	267,277	37.12
West	134,387	19.28	4346	18.77	138,733	19.27
Location/teaching status of hospital							<.0001
Rural	86,321	12.39	2709	11.79	89,030	12.36
Urban non-teaching	333,043	47.79	10,905	47.46	343,948	47.77
Urban teaching	273,326	39.22	9363	40.75	282,689	39.26
Hospital location							.0024
Rural	86,321	12.39	2709	11.79	89,030	12.36
Urban	606,369	87.01	20,268	88.21	626,637	87.03
Hospital teaching status							<.0001
Teaching	409,465	58.76	13,275	57.78	422,740	58.71
Non-teaching	283,225	40.64	9702	42.22	292,927	40.68
Comorbidities
Obstructive sleep apnea	65,342	9.38	1946	8.40	67,288	9.35	<.0001
Diabetes	147,292	21.14	4289	18.52	151,581	21.05	<.0001
Obesity	129,277	18.55	3730	16.11	133,007	18.47	<.0001

Abbreviations: OA, osteoarthritis; RA, rheumatoid arthritis.

Table 2. Demographics of Total Hip Arthroplasty Patients Based on Primary Diagnosis of Osteoarthritis or Rheumatoid Arthritis

	OA		RA		Total		P Value
	No.	Percent	No.	Percent	No.	Percent	(RA vs OA)
Age group							<.0001
<64 years	133,645	45.18	4679	48.02	138,324	45.27
65 to 79 years	123,628	41.8	3992	40.97	127,620	41.77
≥80 years	38,513	13.02	1073	11.01	39,586	12.96
Gender							<.0001
Male	129,708	43.85	2457	25.24	132,165	43.26
Female	165,010	55.79	7278	74.76	172,288	56.39
Race							<.0001
White	207,005	69.98	6322	80.08	213,327	69.82
Black	15,505	5.24	771	9.77	16,276	5.33
Hispanic	6784	2.29	522	6.61	7306	2.39
Other	7209	2.44	280	3.55	7489	2.45
Region of hospital							<.0001
Northeast	58,525	19.79	1683	17.27	60,208	19.71
Midwest	79,040	26.72	2446	25.10	81,486	26.67
South	95,337	32.23	3716	38.14	99,053	32.42
West	62,884	21.26	1899	19.49	64,783	21.20
Location/teaching status of hospital							.0065
Rural	30,954	10.46	993	10.26	31,947	10.46
Urban non-teaching	133,061	44.99	4245	43.87	137,306	44.94
Urban teaching	130,150	44	4439	45.87	134,589	44.05
Hospital location							.4098
Rural	30,954	10.46	993	10.26	31,947	10.46
Urban	263,211	88.99	8684	89.74	271,895	88.99
Hospital teaching status							.0077
Teaching	159,313	53.86	5108	52.78	164,421	53.82
Non-teaching	134,852	45.59	4569	47.22	139,421	45.63
Comorbidities
Obstructive sleep apnea	19,760	6.68	573	5.88	20,333	6.65	.0028
Diabetes	41,929	14.18	1325	13.60	43,254	14.16	.1077
Obesity	38,808	13.12	1100	11.29	39,908	13.06	<.0001

Abbreviations: OA, osteoarthritis; RA, rheumatoid arthritis

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