Racial and ethnic disparities in short-stay primary total shoulder arthroplasty

Abstract

Background

There is a paucity of literature evaluating the utilization of short-stay total shoulder arthroplasty (TSA) in different racial groups. The purpose of this study is to compare short-stay TSA utilization and postoperative outcomes across racial groups.

Methods

The National Surgical Quality Improvement Program (NSQIP) database was queried from 2010 to 2018 to identify patients who underwent primary short-stay TSA, defined as a length of stay of less than 2 midnights. Annual proportions of short-stay TSA, demographic variables, preoperative comorbidities, and postoperative complications were compared across groups.

Results

All racial groups showed increases in the proportion of short-stay TSA cases over time, but this increase was most evident in Whites. Hispanics had increased rates of pneumonia (0.8% vs. 0.2%; p = 0.002) and transfusion (2.0% vs 1.0%; p = 0.015) compared to Whites, but no other differences in outcomes were observed between groups.

Discussion

Postoperative outcomes were similar across groups despite differing comorbidity profiles, suggesting that short-stay TSA is being implemented appropriately based on perceived preoperative risk. However, differences in utilization across groups suggest that underlying disparities may exist. Given the continued increase in short-stay TSA procedures, opportunities to resolve racial disparities are essential in mitigating the effects of social determinants of health in minority patient groups.

Introduction

Total shoulder arthroplasty (TSA), both anatomic and reverse, is an increasingly utilized procedure that is estimated to account for up to 70,000 surgeries performed in the United States each year.^1–4 Numerous studies have found that various racial/ethnic disparities exist in TSA regarding utilization rates, postoperative outcomes, and comorbidities.^5–9 Notably, Black and Hispanic populations have demonstrated decreased utilization rates, increased hospital stays, increased preoperative comorbidities, and a higher cost when compared to White patients undergoing TSA.^7,8,10

Short-stay surgery is a concept first described in the 1990’s, and its use in the surgical literature has increased in the last 2 decades. ¹¹ The main objective of this protocol is to optimize perioperative expenditure and resource allocation through a decreased hospital length of stay (LOS). ¹¹ In carefully selected patients, short-stay TSA protocols have been associated with decreased complications. ¹² Short-stay surgery is characterized by a short LOS and is defined in our study as a postoperative hospital stay of 2 or less nights.

The successful implementation of decreased LOS was followed by a trend of performing traditionally inpatient orthopaedic procedures as outpatient procedures in select groups of patients to further reduce healthcare costs.^13–15 Reports of outpatient TSA first appeared in 2005 and its prevalence has continued to increase.^14,16 Outpatient TSA has been established as a cost-effective alternative with comparable outcomes in carefully selected patients.^17–20

There is a paucity of literature evaluating the utilization of short-stay TSA in different racial and ethnic groups and disparities may exist. The purpose of this study is to analyze short-stay TSA utilization across racial and ethnic groups and determine whether rates of short-term postoperative outcomes for short-stay TSA differ in Blacks and Hispanics compared to Whites. We hypothesized that Whites would have decreased rates of postoperative complications and higher short-stay TSA utilization rates when compared to Blacks and Hispanics.

Methods

This was a retrospective cohort study using data from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. The NSQIP database was queried from 2010 to 2018 to identify all patients who underwent elective primary TSA using current procedural terminology (CPT) code 23472. Patients who underwent revision TSA, removal of a TSA component, and shoulder hemiarthroplasty were excluded from the initial patient selection. Additionally, patients who underwent any prior procedure within 30 days of the index primary TSA were excluded. In accordance with the methodology of prior studies and the Centers for Medicare & Medicaid Services’ definition of outpatient total joint arthroplasty, we defined short-stay status as a hospital LOS of less than two midnights. ²¹ Due to the use of existing de-identified patient data, this study was exempt from Institutional Review Board approval and informed consent was not sought.

Patients were classified into a Black, White, or Hispanic group based on race/ethnicity. In accordance with US Census Bureau reporting, patients with Hispanic ethnicity were categorized as Hispanic, regardless of the patient's race. Patients missing a race/ethnicity classification were excluded. Utilization of short-stay TSA as a proportion of total TSA was calculated. Patient demographics, preoperative comorbidities, and postoperative complications including 30-day rates of readmission, reoperation, and mortality were compared across Black, White, and Hispanic groups that underwent short-stay TSA.

Patient demographics included age, sex, body mass index (BMI), and smoking status within one year of surgery. Preoperative comorbidities included diabetes, congestive heart failure, hypertension requiring medication, anemias, bleeding disorders, chronic obstructive pulmonary disease (COPD), functional status, and American Society of Anesthesiologists (ASA) score. Functional status is a trichotomous variable in the NSQIP database that represents a patient's ability to perform activities of daily life and includes the designations “independent”, “partially dependent”, and “totally dependent”. ASA score is a numeric index used to represent a given patient's ability to tolerate surgery. Operative time was also compared between groups.

Postoperative complications included superficial surgical site infection, deep surgical site infection, wound dehiscence, pneumonia, unplanned intubation, pulmonary embolism, ventilation for greater than 48 h, progressive renal insufficiency, urinary tract infection, cerebrovascular accident, cardiac arrest, myocardial infarction, complications requiring transfusion, deep vein thrombosis, sepsis, and septic shock.

Data analysis was conducted using SPSS Statistics software, version 28 (IBM, Armonk, NY, USA). Overall volume and proportion of short-stay TSA was computed for each race and ethnicity group. These proportions were computed by dividing the number of short-stay TSA cases by the total number of TSA cases for each comparison group. Continuous variables were compared using independent samples t-tests and one-way analysis of variance for binomial and multinomial groups respectively. Categorical variables were compared using chi-square tests. For each comparison, Black and Hispanic groups were compared to the White group. For all statistical comparisons, an alpha value of 0.05 defined significance.

Results

Over the nine-year study period a total of 21,466 cases of elective primary TSA were performed in White, Black, and Hispanic patients, of which 17,452 (81%) were performed as short-stay procedures. Short-stay TSA procedures consisted of 15,884 (91.6%) White, 862 (4.9%) Black and 706 (4.0%) Hispanic patients. All racial groups showed increases in the proportion of short-stay TSA cases over time, but this increase was most evident in Whites compared to Blacks and Hispanics (Table 1).

Table 1.

Annual surgical volume utilization of short-stay TSA as a percentage of total TSA stratified by race and ethnicity.

	White		Black		Hispanic		p-value
Year	n	%	n	%	n	%
2010	423	73%	18	78%	18	78%	*0.001
2011	494	72%	19	56%	13	72%	*0.047
2012	724	72%	24	65%	27	69%	*0.005
2013	972	74%	43	63%	31	76%	*0.029
2014	1552	77%	78	70%	67	78%	*0.006
2015	2088	79%	113	76%	103	77%	*0.002
2016	2715	83%	165	78%	120	75%	*0.025
2017	3262	86%	204	81%	148	80%	*0.025
2018	3654	88%	198	86%	179	86%	*0.003

*Indicates statistical significance.

Regarding demographic characteristics and comorbidity data, Black patients were younger (64 vs. 69 years; p < 0.001), more likely to be female (61% vs. 52%; p < 0.001) and had a higher mean BMI (33 vs. 31; p < 0.001) in comparison to White patients (Table 2). Black patients were also more likely to be active smokers within one year of surgery (23% vs. 10%; p < 0.001) and have diabetes (25% vs. 15%; p < 0.001) and hypertension (78% vs. 65%; p < 0.001). Black patients were also more likely to have an ASA classification of three or greater (64% vs. 52%; p < 0.001) compared to White patients. In comparison to White patients, Hispanic patients were more likely to have diabetes (27% vs. 15%; p < 0.001), less likely to have COPD (4.1% vs. 5.9%; p = 0.045) and more likely to have an ASA classification of one (3.4% vs. 1.6%; p = 0.003). When comparing surgical time between groups, Black (118 vs. 107 min; p < 0.001) and Hispanic (114 vs. 107 min; p < 0.001) patients were found to have a longer mean operative time than White patients. However, these differences are likely not clinically relevant.

Table 2.

Demographic and comorbidity data for short-stay TSA patients stratified by race and ethnicity.

Variable	White (n = 15,884) n (%)	Black (n = 862) n (%)	p-value	Hispanic (n = 706) n (%)	p-value
Age (avg. years ± SD)	69 ± 9.2	64 ± 10	* < 0.001	68 ± 11	*0.049
Sex (female)	8201 (52)	529 (61)	* < 0.001	390 (55)	0.060
BMI (avg. ± SD)	31 ± 6.6	33 ± 8.0	* < 0.001	31 ± 6.2	0.898
Active smoker	1626 (10)	196 (23)	* < 0.001	64 (9.1)	0.314
Diabetes	2424 (15)	211 (25)	* < 0.001	190 (27)	* < 0.001
CHF	57 (0.4)	5 (0.6)	0.298	2 (0.3)	0.741
Hypertension	10,364 (65)	676 (78)	* < 0.001	476 (67)	0.235
Bleeding disorder	355 (2.2)	17 (2.0)	0.610	12 (1.7)	0.344
COPD	939 (5.9)	52 (6.0)	0.884	29 (4.1)	*0.045
Functional status			0.113		*0.002
Independent	15,653 (99)	843 (98)		685 (97)
Partially dependent	221 (1.4)	19 (2.2)		21 (3)
Totally dependent	10 (0.1)	0 (0)		0 (0)
ASA Classification			* < 0.001		*0.003
1	253 (1.6)	6 (0.7)		24 (3.4)
2	7363 (46)	307 (36)		305 (43.2)
3 or greater	8268 (52)	549 (64)		377 (53.4)
Surgical time (avg. min ± SD)	107 ± 42	118 ± 47	* < 0.001	114 ± 46	* < 0.001

Short-stay, length of stay ≤ 2 midnights; SD, standard deviation; BMI, body mass index; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; ASA, American Society of Anesthesiologists.

*Indicates statistical significance.

Looking at complications and 30-day outcomes, Hispanic patients had higher rates of pneumonia (0.8% vs. 0.2%; p = 0.002) and anemia requiring transfusion (2.0% vs 1.0%; p = 0.015) compared to White patients (Table 3). However, no additional differences in rates of perioperative complications were noted between groups Additionally, there were no differences in rates of readmission, reoperation, and mortality in the Black and Hispanic groups compared to the White patient group.

Table 3.

Rates of medical complications and outcomes for short-stay TSA patients stratified by race and ethnicity.

Outcome	White (n = 15,884) n (%)	Black (n = 862) n (%)	p-value	Hispanic (n = 706) n (%)	p-value
Superficial SSI	23 (0.1)	3 (0.3)	0.140	2 (0.3)	0.353
Deep SSI	15 (0.1)	2 (0.2)	0.217	0 (0.0)	0.414
Wound dehiscence	9 (0.1)	0 (0.0)	0.485	1 (0.1)	0.368
Pneumonia	38 (0.2)	1 (0.1)	0.465	6 (0.8)	*0.002
Unplanned intubation	9 (0.1)	1 (0.1)	0.487	1 (0.1)	0.368
PE	39 (0.2)	2 (0.2)	0.938	1 (0.1)	0.582
Ventilation for >48 h	4 (0.0)	0 (0.0)	0.641	1 (0.1)	0.081
Progressive renal insufficiency	10 (0.1)	0 (0.0)	0.461	1 (0.1)	0.427
UTI	73 (0.5)	4 (0.5)	0.985	3 (0.4)	0.894
CVA	8 (0.1)	0 (0.0)	0.510	0 (0.0)	0.551
Cardiac arrest	4 (0.0)	0 (0.0)	0.641	0 (0.0)	0.673
MI	21 (0.1)	1 (0.1)	0.898	2 (0.3)	0.291
Transfusion necessary	162 (1)	11 (1.3)	0.469	14 (2.0)	*0.015
DVT	52 (0.3)	3 (0.3)	0.918	1 (0.1)	0.392
Sepsis	21 (0.1)	1 (0.1)	0.898	1 (0.1)	0.946
Septic shock	2 (0.0)	0 (0.0)	0.742	0 (0.0)	0.766
Readmission within 30 days	347 (2.2)	27 (3.1)	0.067	21 (3.0)	0.163
Reoperation within 30 days	161 (1)	12 (1.4)	0.284	8 (1.1)	0.757
Death within 30 days	12 (0.1)	1 (0.1)	0.678	1 (0.1)	0.539

Short-stay, length of stay ≤ 2 midnights; SSI, surgical site infection; PE, pulmonary embolism; UTI, urinary tract infection; CVA, cerebrovascular accident; MI, myocardial infarction; DVT, deep vein thrombosis

*Indicates statistical significance.

Discussion

This study showed that Black patients had the lowest utilization rates of short-stay TSA. Additionally, they had an increased surgical time and a higher comorbidity burden in comparison to White patients, consistent with our hypothesis. Hispanic patients had a higher incidence of diabetes than White patients but had a similar comorbidity burden, which contradicted our hypothesis. There were no differences in rates of readmission, reoperation, and mortality in the Black and Hispanic groups compared to the White patient group. Regarding postoperative outcomes, the only differences found were that Hispanic patients had higher rates of pneumonia and anemia requiring transfusion when compared with White patients.

The lack of racial differences in postoperative outcomes was an unexpected finding in this study, as other studies have shown that Black race is associated with worse outcomes following TSA.^6,8,9 Despite having an increased comorbidity burden, Blacks in this study experienced no significant differences in postoperative outcomes compared to Whites. A recent study by Rudisill et al. examining racial differences in outcomes in outpatient TSA showed similar findings. ²² One possible explanation for these findings is strict patient selection and optimization criteria for short-stay TSA, but further research is needed to clarify what role these protocols have on postoperative outcomes.

As the prevalence of short-stay TSA increases, it is important that these protocols are optimized to minimize the exclusion of minority groups, as strict eligibility requirements have been shown to disproportionately preclude minority groups from undergoing TSA. ²³ Patient autonomy and risk reward discussions should be considered, while still emphasizing patient safety. This study found increased preoperative comorbidities including smoking status, diabetes, and hypertension in Black patients compared to White patients. The underlying causes that lead to increased comorbidities in minorities are multifactorial, but social determinants of health are consistently associated with racial healthcare disparities.^24,25 Insurance status, household income, and level of education are social determinants that have been shown to influence TSA outcomes.^26–29 Ultimately, any long term reduction in comorbidity disparities will require ameliorating the racial gap that persists in many social determinants of health.

White patients had the highest utilization rates of short-stay TSA with all racial groups displaying increases over time for total short-stay TSA procedures. Contrary to our hypothesis, Hispanic patients had a similar comorbidity burden to White patients. However, this did not correlate with a proportional rate of utilization, as Hispanic short-stay utilization rates remained below Whites for 5 out of the 9 years included in this study. The reasons for this are multifactorial, but the presence of language barriers is a potential contributing factor. Multiple studies have elucidated areas for improvement in language concordance within the field of orthopaedics.^30,31 In TSA, language barriers have been associated with increased LOS and discharge to a facility. ³²

This study is among the first of its kind to examine racial disparities in short-stay TSA and was done utilizing NSQIP, a nationwide validated database that provided a large sample size. It provides valuable information regarding short-stay TSA that can be used to guide institutional policy and help mitigate disparities amidst a growing trend towards shorter LOS following TSA. However, NSQIP does have some inherent limitations including a lack of socioeconomic and long-term outcome data, as well as the potential for human error when inputting data. NSQIP also has a limited follow-up time of 30 days, and we were unable to account for outcomes that occurred after this timeframe. Additionally, the Black and Hispanic cohorts were relatively small compared to the White cohort.

Conclusion

Postoperative outcomes were similar between racial and ethnic groups despite differing comorbidity profiles, suggesting that short-stay TSA is being implemented appropriately based on perceived preoperative risk. However, differences in utilization across racial groups suggest that underlying disparities may exist. Given the continued increase in short-stay TSA procedures, opportunities to resolve racial and ethnic disparities are essential in mitigating the effects of social determinants of health in minority patient groups.