Declining Post-Arthroplasty Mortality after Total Knee Arthroplasty in the U.S.: A Time-Trends Study

Jasvinder A. Singh and Rekha Ramachandaran, University of Alabama at Birmingham, Birmingham, AL

Meeting: 2015 ACR/ARHP Annual Meeting

Date of first publication: September 29, 2015

Keywords: Arthroplasty, Knee, morbidity and mortality and outcomes

Session Information

Date: Tuesday, November 10, 2015

Title: Epidemiology and Public Health Poster III (ACR): Gout and Non-Inflammatory Musculoskeletal Conditions

Session Type: ACR Poster Session C

Session Time: 9:00AM-11:00AM

Background/Purpose:

Total Knee Arthroplasty (TKA) is mostly an elective procedure that is effective in improving pain, function and quality of life in patients with end-stage arthritis. Our objective was to compare mortality after Total Knee Arthroplasty (TKA) over time in a nationally representative sample of patients. We also sought to compare the mortality in patients residing in urban and rural locations to see if the mortality differed by location and over time.

Methods:

We used the U.S. Nationwide Inpatient Sample from 1998-2010 to compare outcomes after total knee arthroplasty (TKA). In-hospital post-arthroplasty mortality related to the index admission was assessed as an outcome. Overall time trends in in-hospital post-TKA mortality were compared using the Cochrane-Armitage test. Rural versus urban residence was determined based on patient’s residence at the time of surgery (available 2003-2010). Unadjusted and adjusted logistic regression analyses were performed comparing mortality by rural-urban location between 2003-06 to 2007-10, adjusting for age, race, gender, Charlson score and hospital TKA volume.

Results:

In-hospital post-TKA mortality decreased over time, from 197/100,000 TKA surgeries in 1998 to 97/100,000 TKA surgeries in 2010, a significant 50% reduction over time (p<0.0001; Table 1). The reduction was persistent over time. Similar significant time-trends in reduction in in-hospital post-TKA mortality were noted in both patients residing in rural and urban locations (p<0.0001 for both; Table 2). No significant rural-urban differences were noted in In-hospital post-TKA mortality in 2003-06 or 2007-10 (Table 3).

Table 1. Time-trend in in-hospital mortality after primary TKA
Year	Total Mortality	#TKA from NIS	Rate per 100,000
1998	497	252266	197
1999	491	263548	186
2000	485	282350	172
2001	501	314402	159
2002	459	351018	131
2003	653	380774	172
2004	582	432379	135
2005	564	498169	113
2006	525	497001	106
2007	455	551259	83
2008	561	616617	91
2009	446	621029	72
2010	481	658340	73

Table 2. Post-TKA in-hospital mortality over time by patient residence, rural vs. urban
Year	Location	Total Mortality	#TKA from NIS	Rate per 100,000
2003	Rural	149	86040	173
2004	Rural	127	99091	129
2005	Rural	166	113396	147
2006	Rural	122	110621	110
2007	Rural	98	121670	80
2008	Rural	96	127085	76
2009	Rural	113	134738	84
2010	Rural	102	152462	67
2003	Urban	501	293772	170
2004	Urban	455	332575	137
2005	Urban	398	384084	103
2006	Urban	399	385777	103
2007	Urban	342	410969	83
2008	Urban	459	473501	97
2009	Urban	323	466017	69
2010	Urban	373	480538	78
Rural-urban residence variable was available only from 2003 onwards; Cochran Armitage test of trend comparing the in hospital mortality rates: Rural: p<0.0001; Urban: p<0.0001

Table 3. Rural-urban differences in post-TKA in-patient mortality and time-trends
	All combined	Rural		Urban
	2003-2010	2003-2006	2007-2010	2003-2006	2007-2010	Unadjusted p-value	Adjusted p-value*
In-hospital Mortality, n (%)	874 (0.1)	112 (0.14)	85 (0.08)	366 (0.13)	303 (0.08)	0.45 0.67 0.41	0.82 0.42 0.24
*Adjusted for age, race, gender, Charlson score, hospital TKA volume For p-values: first p-value denotes rural/urban disparity in 2003 -2006; second the rural/urban disparity in 2007 -2010 and the third denotes the change in the disparity magnitude between 2003 – 2006 and 2007 – 2010.

Conclusion:

Significant decrease in in-hospital post-TKA mortality has occurred from 1998 to 2010 in the U.S. The magnitude of reduction is impressive. Rural and urban residing patients had similar mortality rates and reductions over time.

Disclosure: J. A. Singh, Takeda, Savient, 2,Takeda, Savient, merz, Regeneron, Allergan, Crealta, Bioiberica, 5; R. Ramachandaran, None.

To cite this abstract in AMA style:

Singh JA, Ramachandaran R. Declining Post-Arthroplasty Mortality after Total Knee Arthroplasty in the U.S.: A Time-Trends Study [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/declining-post-arthroplasty-mortality-after-total-knee-arthroplasty-in-the-u-s-a-time-trends-study/. Accessed .

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