Impact of Chronic Obstructive Pulmonary Disease on Outcomes After Total Joint Arthroplasty: A Meta-analysis and Systematic Review

Abstract

Background

Comorbid chronic obstructive pulmonary disease (COPD) is increasingly common and may have an adverse impact on outcomes in patients undergoing total joint arthroplasty (TJA) of lower extremity. The purpose of this meta-analysis is to compare the postoperative complications between COPD and non-COPD patients undergoing primary TJA including total hip and knee arthroplasty.

Methods

PubMed, EMBASE, and Cochrane Library were systematically searched for relevant studies published before December 2021. Postoperative outcomes were compared between patients with COPD versus those without COPD as controls. The outcomes were mortality, re-admission, pulmonary, cardiac, renal, thromboembolic complications, surgical site infection (SSI), periprosthetic joint infection (PJI), and sepsis.

Results

A total of 1,002,779 patients from nine studies were finally included in this meta-analysis. Patients with COPD had an increased risk of mortality (OR [odds ratio] = 1.69, 95% confidence interval [CI] 1.42–2.02), re-admission (OR = 1.54, 95% CI 1.38–1.71), pulmonary complications (OR = 2.73, 95% CI 2.26–3.30), cardiac complications (OR = 1.40, 95% CI 1.15–1.69), thromboembolic complications (OR = 1.21, 95% CI 1.15–1.28), renal complications (OR = 1.50, 95% CI 1.14–1.26), SSI (OR = 1.23, 95% CI 1.18–1.30), PJI (OR = 1.26, 95% CI 1.15–1.38), and sepsis (OR = 1.36, 95% CI 1.22–1.52).

Conclusion

Patients with comorbid COPD showed an increased risk of mortality and postoperative complications following TJA compared with patients without COPD. Therefore, orthopedic surgeons can use the study to adequately educate these potential complications when obtaining informed consent. Furthermore, preoperative evaluation and medical optimization are crucial to minimizing postoperative complications from arising in this difficult-to-treat population.

Level of evidence

Level III.

Registration

None.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-022-00794-2.

Introduction

Primary total joint arthroplasty (TJA) of the lower extremity, including total hip and knee arthroplasty (THA and TKA), is one of the most successful orthopedic operations to reduce joint pain and improve quality of life [1]. However, patients undergoing TJA tend to have more comorbidities than the general population [2, 3]. Furthermore, comorbidities in patients undergoing TJA impact its (TJA) safety with increased rates of medical complications, re-admission rates, and mortality [4–7].

Chronic obstructive pulmonary disease (COPD) is characterized by a progressive airflow limitation and tissue destruction caused by chronic inflammation and structural lung changes [8]. COPD is a major contributor to morbidity and mortality and is the third leading cause of death worldwide [9, 10]. With the rising life expectancy, the number of patients with COPD is increasing in the aging population of patients undergoing TJA.

Additionally, several previous studies have investigated the impact of COPD on the postoperative prognosis for patients undergoing TKA and THA, and the risk was markedly higher for pulmonary, cardiac, thromboembolic complications, infection, and mortality in patients with COPD than in those without COPD [11–15]. However, the impact of COPD on postoperative outcomes after primary TJA of the lower extremity is still not well established. Although the literature increasingly focused on the influence of COPD and various outcomes, there is no comprehensive systematic review and meta-analysis to the best of our knowledge.

Therefore, this meta-analysis compared the postoperative complications between COPD and non-COPD patients who underwent primary TJA. Furthermore, the results of this study should be beneficial for orthopedic surgeons to optimize treatment strategies and improve outcomes for patients with COPD undergoing primary TJA.

Methods

This study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines [16]. This study is registered with the ResearchRegistry and the unique identifying number is: reviewregistry1448. Additionally, the study’s design did not require patient consent or ethical review. Data were extracted, cross-checked, and reviewed separately by two independent authors. Disagreements were, however, resolved through discussion with a third independent author. Using the kappa statistic (κ), inter-reviewer reliability was evaluated for study screening and selection, quality evaluation, data extraction, and result pooling. With a value ranging from 0.92 to 1.00, the inter-reviewer reliability was satisfactory for the screening and selection of studies, quality evaluation, data extraction, and result pooling.

Search Strategy

For studies addressing comorbidities and postoperative complications in patients receiving elective primary TKA or THA, with or without COPD, major literature databases were searched, including MEDLINE/PubMed, Cochrane Central Register of Controlled Trials, EMBASE, and Scopus (Supplementary file 1). The search was done for publications that were released before December 2021. The [Title/Abstract] field of the search engines was searched using the terms “hip,” “knee,” “arthroplasty,” “replacement,” “pulmonary disease, chronic obstructive,” and “chronic obstructive airway disease,” as well as their corresponding Medical Subject Headings terms. There were no other limitations, not even linguistic ones. To find the relevant articles that were omitted during the database search, relevant eligible references in the selected articles were examined.

Eligibility Criteria and Study Selection

Two independent authors screened all the titles and abstracts. The initial selected studies were further reviewed for inclusion according to the following uniform criteria. The inclusion criteria were as follows: (1) prospective or retrospective studies comparing outcomes after TJA between patients with underlying COPD as case group versus non-COPD as control group, (2) patients undergoing TJA of lower extremities, including THA or TKA, (3) at least one postoperative outcome of interest reported, (4) accessible full-text articles, and (5) studies reporting sufficient information to extract and calculate risk estimate and corresponding 95% confidence intervals. The exclusion criteria were as follows: (1) case reports, review articles, and conference abstract, (2) studies without a control group, (3) data unable to be extracted. The list of excluded manuscripts from the full-text review was provided (Supplementary file 2).

Data Extraction and Outcomes of Interest

From all selected studies, two independent authors extracted the data. With the help of a third author, disagreements were settled through discussion and consensus. According to the following descriptive information, the data were extracted: (1) study characteristics, such as the first author’s name, the year the study was published, the data source, the study’s design, and its location; (2) patient demographics, including the number of patients, sex, and age; (3) the type of TJA, such as TKA and THA; (4) follow-up period; and (5) outcomes of interest.

Outcomes of Interest

For this meta-analysis, the outcomes of interest included the following: (1) all-cause mortality (at the end of follow-up), length of stay (LOS), revision surgery, re-admission, unplanned return to the operating room, pulmonary complications (including pneumonia, re-intubation, and prolonged use of ventilator > 48 h), cardiac complications (including acute myocardial infarction [AMI], and cardiac arrest), thromboembolic complications (including cerebrovascular accident [CVA], deep vein thrombosis [DVT], and pulmonary embolism [PE]), renal complications (including progressive renal insufficiency [PRI], acute kidney injury [AKI], and urinary tract infection [UTI]), surgical site infection (SSI) (including superficial, deep and organ/space SSI, and periprosthetic joint infection [PJI]), perioperative transfusion rate, and sepsis (including systemic sepsis and septic shock). Revision surgery was defined as removing or replacing the implant during postoperative 1 year. Surgical wound infection was defined as superficial or deep SSI, whereas the organ/space SSI was categorized into PJI.

Quality Assessment

All included studies were evaluated for quality by two independent authors, and any discrepancies were settled through discussion and agreement with a third author. Any included study’s bias was evaluated using the Quality in Prognosis Studies tool, as previously mentioned [17]. This test assesses bias across six domains, including study participants, study attrition, prognostic factor measurement, outcome measurement, study confounding, and statistical analysis and reporting.

Certainty of Evidence

Using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, two independent authors assessed the degree of certainty of the evidence. Certainty of evidence could be high, moderate, low, or very low [18, 19].

Statistical Analysis

The odds ratio (OR) was extracted with 95% confidence interval (CI) for dichotomous outcomes. Adjusted data were maximally used when available. For continuous outcomes, the standardized mean difference (SMD), defined as the intergroup difference in mean outcomes divided by the standard deviation of the difference in the outcome, was calculated at 95% CI. Meta-analyses were conducted to pool the effects and associated 95% CIs. A χ²-based test of homogeneity was performed, and the inconsistency index (I²) and Q statistics were determined. If I² statistics were < 50%, the fixed-effected model (Mantel–Haenszel method) was used because of the low heterogeneity. I2 ≥ 50% was considered a significant heterogeneity. A “leave-one-out” sensitivity analysis was performed by sequentially deleting one study to determine the heterogeneity source. After excluding each study, an analysis was performed to determine whether heterogeneity existed; if so, the random-effects model (DerSimonian–Laird method) was used [20]. Subgroup analyses based on the type of TJA including TKA and THA were performed to investigate the risk of postoperative complications in each subgroup. Publication bias was examined using Egger’s regression symmetry test [21]. All statistical analyses were performed using Rstudio v.1.0.143 (RStudio Inc., Boston, MA) and the significance level was set at p < 0.05.

Results

Search Results

Figure 1 summarizes the details of the study identification and selection process. Six hundred and forty-three articles were yielded after the initial search. Then, two hundred and fifty-nine duplicates were eliminated, and three hundred and forty-nine articles were removed based on their titles and abstracts. Next, among 35 articles that underwent full-text review, 26 without access to the inclusion criteria were excluded. Finally, nine articles were included in the meta-analysis [11–15, 22–25].

Fig. 1.

PRISMA flow diagram

Study Characteristics and Quality Assessment

The characteristics of included studies are described in Table 1. Seven studies [11–13, 15, 23–25] are retrospective cohort studies, whereas two studies [14, 22] are retrospective case–control studies. In total, 1,002,779 cases of lower extremity TJA, including 187,241 patients with COPD and 815,538 patients without COPD, were reported. The nine identified articles described patients who underwent primary THA or TKA. Specifically, three studies [13, 24, 25] investigated primary THA, five studies [11, 12, 14, 15, 23] investigated primary TKA, and one study [22] investigated primary TKA and THA. The quality assessment results for the included studies are shown in Fig. 2. All the included studies were considered low-risk in terms of overall risk of bias. Two studies [12, 13] had a moderate risk of bias in study confounding, while one [22] had a moderate risk of bias in outcome measurement.

Table 1.

Characteristics of included studies

First author (year)	Data source	Design	Sample size (n)	Type of TJA	Anesthesia mode (%) (general/regional) (COPD vs. non-COPD)	Number of patients (COPD/non-COPD)	Mean age (y) (COPD/non-COPD)	Male (%) (COPD/non-COPD)	Length of follow-up (months)	DM (%) (COPD/Non-COPD)	CAD/MI/CHF (%) (COPD/Non-COPD)	CKD (%) (COPD/Non-COPD)
Liao et al. (2016) [12]	NHIRD of Taiwan	Retrospective cohort study	2426	THA	NA	335/2091	75.88/68.92	53.4/41.9	1 month	27.8/24.8	CAD; 17.9/7.7	13.7/9.6
Liao et al. (2016) [13]	NHIRD of Taiwan	Retrospective cohort study	3431	TKA	NA	358/3073	72.56/69.78	38.0/24.0	3 months	25.7/26.2	CAD; 17.9/6.9	11.7/7.5
Gu et al. (2018)	ACS NSQIP	Retrospective cohort study	6159	Bilateral TKA	60.7/32.1 vs. 59.1/32.1	140/6019	NA	39.3/57.0	1 month	25.7/15.1	CHF; 0.7/0.1	0/0
Klasan et al. (2018) [22]	Institutional database	Retrospective case–control study	448	TKA and THA	Regional; 62.9/63.6	224/224	70.6/69.5	36.6/40.4	In-hospital	21.8/15.2	CHF; 36.1/19.3	25.4/18
Yakubek et al. (2018) [15]	ACS NSQIP	Retrospective cohort study	64,796	THA	General; 55/55	2426/62,370	70/65.2	39.9/44.2	1 month	16.0/11.3	CHF; 1.8/0.2	NA
Yakubek et al. (2018) [24]	ACS NSQIP	Retrospective cohort study	111,168	TKA	General; 56/53	3975/107,193	68.7/66.8	38.7/37.1	1 month	25.1/17.6	CHF; 1.2/0.2	NA
Vakharia et al. (2020) [14]	PearlDiver Patient Records Database	Retrospective case–control study	211,378	TKA	NA	35,230/176,148	NA	34.2/34.2	3 months	58.3/58.3	CAD; 66.4/66.4	NA
Lemme et al. (2021) [23]	PearlDiver Patient Records Database	Retrospective cohort study	166,946	TKA	NA	46,769/120,177	NA	32.6/43.0	3 months	64.2/53.5	CHF; 28.3/15.1	0.3/0.2
Yang et al. (2021) [25]	PearlDiver Patient Records Database	Retrospective cohort study	436,027	THA	NA	97,784/338,243	NA	38.2/45.0	1 month	48.1/36.8	CHF; 19.3/9.3	22.5/16.1

TJA total joint arthroplasty, COPD chronic obstructive pulmonary disease, DM diabetes mellitus, CAD coronary artery disease, MI myocardial infarction, CHD chronic heart disease, CKD chronic kidney disease, NHIRD National Health Insurance Research Database, THA total hip replacement; Registry, ACS NSQIP American College of Surgeons National Surgical Quality Improvement Program, NIS National Inpatient Sample

Fig. 2.

A, B Quality assessment

Meta-Analysis Results

Complications

Meta-analysis results for postoperative complications between patients with or without COPD are summarized in Table 2. The pooled results demonstrated that patients with COPD were associated with increased risk of mortality (OR = 1.69, 95% CI 1.42–2.02, I² = 38%), re-admission (OR = 1.54, 95% CI 1.38–1.71, I² = 96%), unplanned return to operating room (OR = 1.36, 95% CI 1.14–1.62, I² = 0%), revision surgery (OR = 1.21, 95% CI 1.01–1.46, I² = 92%), and a prolonged LOS (SMD = 0.16, 95% CI 0.11–0.21, I² = 60%). For pulmonary complications, the pooled results showed that patients with COPD were associated with increased risk of overall pulmonary complications (OR = 2.73, 95% CI 2.26–3.30, I² = 64%), pneumonia (OR = 2.70, 95% CI 2.13–3.43, I² = 75%), re-intubation (OR = 3.07, 95% CI 2.18–4.31, I² = 31%), and ventilator use > 48 h (OR = 3.47, 95% CI 2.16–5.56, I² = 8%). Furthermore, the heterogeneity could not be ignored for the summary analysis of re-admission, revision surgery, LOS, pulmonary complications, and pneumonia.

Table 2.

Summary of prognostic evidence of complications after total joint arthroplasty in patients with chronic obstructive pulmonary disease

	OR or SMD	LL 95% CI	UL 95% CI	P value	Heterogeneity (%)	Analysis model	Egger’s test (P value)	Grading of recommendation assessment, development, and evaluation
								No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other consideration	Certainty of evidence with explanations for downgrading of evidence
Mortality	1.69	1.42	2.02	< 0.01	38	Fixed	0.07	5	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Length of stay	0.16	0.11	0.21	< 0.01	60	Random	0.99	4	Observational studies	Not serious	Seriousa	Not serious	Not serious	None	Low aStatistical heterogeneity and inconsistency in direction of effect
Re-admission	1.54	1.38	1.71	< 0.01	96	Random	0.23	7	Observational studies	Not serious	Seriousb	Not serious	Not serious	None	Low aStatistical heterogeneity and inconsistency in direction of effect
Return to operating room	1.36	1.14	1.62	< 0.01	0	Fixed	0.34	3	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Perioperative transfusion	1.00	0.93	1.09	0.95	11	Fixed	0.05	3	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Revision	1.21	1.01	1.46	0.04	92	Random	NA	2	Observational studies	Not serious	Seriousc	Not serious	Seriousd	None	Very low cStatistical heterogeneity and inconsistency in direction of effect dTwo studies with small sample size and wide confidence interval
Overall pulmonary complication	2.73	2.26	3.30	< 0.01	64	Random	0.01	7	Observational studies	Not serious	Seriouse	Not serious	Not serious	None	Low eStatistical heterogeneity and inconsistency in direction of effect
Pneumonia	2.70	2.13	3.43	< 0.01	75	Random	0.01	7	Observational studies	Not serious	Seriousf	Not serious	Not serious	None	Low fStatistical heterogeneity and inconsistency in direction of effect
Re-intubation	3.07	2.18	4.31	< 0.01	31	Fixed	NA	2	Observational studies	Not serious	Not serious	Not serious	Seriousg	None	Low gTwo studies with small sample size and wide confidence interval
Prolonged use of ventilator > 48 h	3.47	2.16	5.56	< 0.01	8	Fixed	0.79	3	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Overall cardiac complication	1.40	1.15	1.69	< 0.01	37	Fixed	0.09	4	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Acute myocardial infarction	1.41	0.95	2.10	0.09	49	Fixed	0.20	3	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Cardiac arrest	2.61	1.55	4.39	< 0.01	0	Fixed	0.36	3	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Overall thromboembolic complication	1.21	1.15	1.28	< 0.01	13	Fixed	0.02	6	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Cerebrovascular accident	1.67	1.14	2.46	< 0.01	0	Fixed	0.18	4	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Deep vein thrombosis	1.20	1.14	1.26	< 0.01	0	Fixed	0.88	4	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Pulmonary embolism	2.73	2.31	3.23	< 0.01	0	Fixed	0.81	3	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Overall renal complication	1.50	1.14	1.26	0.02	35	Fixed	0.01	3	Observational studies	Not serious	Serioush	Not serious	Not serious	None	Low hStatistical heterogeneity and inconsistency in direction of effect
Acute kidney injury	2.23	1.11	4.50	0.02	0	Random	NA	2	Observational studies	Not serious	Not serious	Not serious	Seriousi	None	Low iTwo studies with small sample size and wide confidence interval
Progressive renal insufficiency	4.17	0.92	18.92	0.06	79	Random	NA	2	Observational studies	Not serious	Not serious	Not serious	Seriousj	None	Low jTwo studies with small sample size and wide confidence interval
Urinary tract infection	1.35	1.10	1.65	< 0.01	0	Fixed	0.93	3	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Surgical site infection	1.24	1.18	1.31	< 0.01	29	Fixed	0.11	8	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Wound infection (superficial and deep)	1.22	1.15	1.30	< 0.01	24	Fixed	0.35	5	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Periprosthetic joint infection	1.26	1.15	1.38	< 0.01	0	Fixed	0.53	5	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Sepsis	1.36	1.22	1.52	< 0.01	0	Fixed	0.16	4	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate
Septic shock	2.23	1.27	3.93	< 0.01	0	Fixed	0.02	3	Observational studies	Not serious	Not serious	Not serious	Not serious	None	Moderate

OR odds ratio, SMD standardized mean difference, LL lower limit, CI confidence interval, UL upper limit

For cardiac complications, the pooled results demonstrated that patients with COPD were associated with increased risk of overall cardiac complications (OR = 1.40, 95% CI 1.15–1.69, I² = 37%) and cardiac arrest (OR = 2.61, 95% CI 1.55–4.39, I² = 0%). For thromboembolic complications, the pooled results demonstrated that patients with COPD were associated with increased risk of overall thromboembolic complications (OR = 1.21, 95% CI 1.15–1.28, I² = 13%), CVA (OR = 1.67, 95% CI 1.14–2.46, I² = 0%), DVT (OR = 1.20, 95% CI 1.14–1.26, I² = 0%), and PE (OR = 2.73, 95% CI 2.31–3.23, I² = 0%). Additionally, for renal complications, the pooled results demonstrated that patients with COPD were associated with increased risk of overall renal complications (OR = 1.50, 95% CI 1.14–1.26, I² = 35%), AKI (OR = 2.23, 95% CI 1.11–4.50, I² = 0%), and UTI (OR = 1.35, 95% CI 1.10–1.65, I² = 0%). Furthermore, the pooled results demonstrated that patients with COPD were associated with increased risk of overall SSI (OR = 1.23, 95% CI 1.18–1.30, I² = 34%), surgical wound infection (OR = 1.22, 95% CI 1.15–1.30, I² = 24%), and PJI (OR = 1.26, 95% CI 1.15–1.38, I² = 0%). The pooled results showed that patients with COPD were associated with increased risk of sepsis (OR = 1.36, 95% CI 1.22–1.52, I² = 0%) and septic shock (OR = 2.23, 95% CI 1.27–3.93, I² = 0%). Our GRADE certainty of evidence judgements is included in Table 2. The most common reasons for downgrading certainty of evidence were inconsistency and imprecision.

Subgroup Analyses

The results of the subgroup analyses are summarized in Supplementary table 1. Subgroup analyses found significant statistical differences in risk of various postoperative complications. The results demonstrated that patients with THA were associated with higher risk of mortality, overall pulmonary complications, re-intubation, prolonged use of ventilator, UTI, PJI, and sepsis, while the patients with TKA showed higher risk of return to operating room, cardiac arrest, CVA, DVT, PE, overall renal complications, surgical wound infection, and septic shock. However, these findings should be interpreted with caution because only one study was included to estimate the risk of return to operating room, re-intubation, prolonged use of ventilator, cardiac arrest, DVT, PE, UTI, surgical wound infection, and septic shock (Supplementary table 1).

Sensitivity Analyses and Publication Bias

Sensitivity analyses were performed using the leave-one-out approach to assess whether individual studies would affect the overall results of each meta-analysis. The meta-analysis was reliable and no single study had a significant impact on the results, as shown by the fact that the direction of combined estimates did not change significantly when the studies were eliminated. However, two studies by Vahkaria et al. [14] and Yakubek et al. [24] strongly affected the pooled results of overall thromboembolic complications and surgical wound infection, respectively, and they were discarded from each meta-analysis (Supplementary Figs. 1 and 2).

Discussion

This review and meta-analysis investigated whether COPD adversely impacted the postoperative outcomes of TJA with data of over one million patients. The most important findings are that patients with COPD had a significantly increased mortality risk compared with those without COPD. In addition, patients with COPD showed longer LOS and had an increased risk of re-admission, unplanned return to the operating room, and 1-year revision surgery. Furthermore, COPD was significantly associated with an increased risk of developing postoperative complications, including pulmonary, cardiac, thromboembolic, renal complications, SSI, PJI, and sepsis in patients undergoing TJA.

Patients with COPD are in a state of chronic systemic/vascular inflammation and hypercoagulation with an upregulated C-reactive protein, increased production of inflammatory cytokines and tissue factors, higher fibrinogen levels [26, 27]. COPD also shares several risk factors or comorbidities with cardiac or thromboembolic complications including older age, cigarette smoking, and ischemic heart disease [28–30]. Studies included in the present review also reported higher incidence of diabetes mellitus and cardiovascular disorders (Table 1). This exaggerated inflammatory response and comorbidities associated with COPD may predispose patients to venous thromboembolic complications, CVA, and cardiovascular complications. Previous studies suggested that patients with COPD had an increased risk of postoperative cardiac complications following cardiac and non-cardiac surgeries [28, 31]. COPD patients also have high prevalence of venous thromboembolism including DVT and PE [32, 33]. Similarly, the pooled results of this study demonstrated that COPD was independently associated with postoperative cardiac and thromboembolic complications including cardiac arrest, DVT, PE, and CVA. However, the results from the present study does not qualify as a statistical significant risk factor for myocardial infarction. This apparent discrepancy in the results could be explained by the fact that the increased risk of myocardial infarction in previous studies [34, 35] was restricted to within 1–5 days, whereas the current analysis encompassed 30 days of postoperative data.

Additionally, impaired gas exchange and mucociliary clearance of aspirated bacteria can predispose COPD patients to postoperative pulmonary complications [8, 36]. The present study demonstrated that COPD was significantly associated with overall pulmonary complications, pneumonia, and respiratory failure, including re-intubation or failure to wean from the ventilator within 48 h. However, our findings concerning overall pulmonary complications and pneumonia should be interpreted with caution because of their high heterogeneity. For example, anesthesia mode is a crucial factor associated with postoperative pulmonary complications [37, 38]. However, only four studies reported that anesthesia mode and regional anesthesia rates vary, contributing to heterogeneity [11, 15, 22, 24].

For renal complications, the pooled analyses of this study determined COPD to be a risk factor after TJA, consistent with previous studies regarding cardiac or non-cardiac surgeries [28, 39]. Rodrigues et al. [39] found COPD to be a risk factor for AKI after cardiac surgery; Gupta et al. [28] found the association between COPD and postoperative renal insufficiency and AKI requiring dialysis in patients undergoing non-cardiac surgery. The components of smoke, including nicotine and several heavy metals, are risk factors for kidney disease, and various comorbidities, including diabetes mellitus, CKD, and cardiovascular disease, are highly prevalent in patients with COPD [28–30, 40–42] (Table 1). Therefore, these may be contributing factors to postoperative renal complications.

Additionally, our study showed that patients with COPD have an increased risk of UTI, SSI, PJI, and sepsis. A potential explanation for these complications is related to immune system derangements secondary to the chronic inflammatory state observed in patients with COPD, leading to bacterial retention, biofilm formation, increased risk of various infectious complications, and sepsis [26, 27, 43, 44]. Chronic hypoxia resulting from obstructed ventilation also results in poor wound healing, increased risk of SSI by poor tissue oxygenation, and increased reactive oxygen species [45, 46]. Furthermore, using corticosteroids to manage COPD may increase the risk of infection [47]. The reported incidence of sepsis following TJA was 0.34%, and sepsis is associated with a high-risk mortality [48]. The most common sources of sepsis were UTI, SSI, and pneumonia, which are postoperative complications with increased risk in patients with COPD [48]. Therefore, these results further explain the importance of immaculate sterile technique, safely tapering systemic steroids preoperatively, and good respiratory management in the postoperative recovery period.

In this study, patients with COPD had a significantly increased mortality compared with those without, which agrees with findings in the literature from other surgical subspecialties [28, 49, 50]. Although studies included did not report the specific causes of mortality, patients experiencing postoperative adverse events have a high postoperative mortality rate [28, 51, 52]. The increased risk of postoperative complications, such as cardiac arrest, pulmonary embolism, CVA, and sepsis, may contribute to the increased mortality in the present study.

Re-admission, LOS, return to the operating room, and revision surgeries are related to the increased costs of care. Of all medical comorbidities, performing a TKA on a patient with COPD has the highest cost, averaging $26,299 per patient [53]. Consistent with previous studies regarding cardiac and non-cardiac surgeries, this study found that patients with COPD had an increased risk of LOS, re-admission, and return to the operating room following TJA [28, 50, 54]. No included studies except one by Vakharia et al. [14] reported the exact causes of increased LOS, re-admission, or return to the operating room. Vakharia et al. [14] reported that the leading causes of re-admission in descending order were SSI, pulmonary, and cardiac causes. However, our results on LOS and re-admission should be interpreted with caution because of their moderate to high heterogeneity.

The causes of revision surgery include infection, dislocation, osteolysis, or loosening of the component. Furthermore, dislocation and mechanical loosening are the main causes after THA, and a systematic review reported that risk factors for THA included younger age, more comorbidities, and avascular necrosis [55]. For TKA, infection and mechanical loosening were reportedly the primary etiology for revision, associated mainly with demographic and surgical factors, such as uncemented procedure, implant malalignment, and longer operative times [56]. This study found that patients with COPD had an increased risk of 1-year revision surgery. However, data from only two studies, including each THA and TKA cohort, were pooled, and both studies have not adjusted for the aforementioned confounding risk factors [23, 25]. Therefore, these results should be interpreted with caution, and future studies are needed to determine the risk and causes of revision surgery accounting for various risk factors in patients with comorbidities, including COPD.

According to this study’s results, comorbid COPD significantly adversely impacted the safety of TJA. Therefore, recognizing COPD and its associated comorbidities is crucial to optimizing these high-risk patients for surgery perioperatively [57, 58]. This study has strengths and limitations. The first study on concomitant COPD and outcomes following elective TJA was conducted, and that study is this review and meta-analysis. Additionally, the analysis was reinforced by using data from 1,002,779 patients throughout the nine trials that were included. Furthermore, the findings in this meta-analysis were centered on the most current research; as all of the clinical reports it included had only been published during the previous five years.

Nevertheless, the following limitations of this review should be noted. First, only retrospective studies with a low level of evidence were included. However, most of the included studies used national claims or registry databases to provide reliable postoperative outcomes [59]. Second, the studies were heterogeneous regarding the baseline characteristics of the cohorts, comorbidities, and outcome measurements. COPD was commonly associated with various comorbidities including diabetes mellitus, CKD, and cardiovascular diseases that impact postoperative outcomes after lower extremity arthroplasty. Therefore, the potential influence of these confounding factors can be a source of heterogeneity of the results and have exaggerated our results. Third, subgroup analyses were performed based on the type of TJA because these patients may have various indications for surgery, different comorbidities, and levels of mobility, as well as be exposed to different surgical burdens and postoperative protocols. However, there is serious concern about the certainty of estimates because most of the results were based on one included study. Fourth, the definition of COPD varied among studies because of the inherent limitations of the national claims or registry database in which the diagnoses are based on disease codes. Furthermore, it was unable to assess the severity of COPD and its impact on the dependent variables measured. Two studies by Yakubek et al. only included patients with COPD and the following criteria: a functional disability due to COPD, chronic bronchodilator therapy, an exacerbation requiring hospitalization, or a forced expiratory volume in 1 s less than 75% of the expected [15, 24]. Therefore, it could not explain the sources of substantial heterogeneity in several outcomes, such as pulmonary complications, pneumonia, LOS, and re-admission. Future prospective studies are highly warranted to more accurately investigate COPD’s impact on TJA and address the prognostic roles of different severities of COPD.

Conclusively, patients with comorbid COPD showed an increased risk of mortality and postoperative complications following TJA compared with patients without COPD. Therefore, orthopedic surgeons can use the study to adequately educate these potential complications when obtaining informed consent. Furthermore, preoperative evaluation and medical optimization are crucial to minimizing postoperative complications from arising in this difficult-to-treat population.

Supplementary Information

Below is the link to the electronic supplementary material.

Abbreviations

TJA

Total joint arthroplasty

THA

Total hip arthroplasty

TKA

Total knee arthroplasty

COPD

Chronic obstructive pulmonary disease

PRISMA

Preferred reporting items for systematic reviews and meta-analyses

LOS

Length of stay

AMI

Acute myocardial infarction

CVA

Cerebrovascular accident

DVT

Deep vein thrombosis

PE

Pulmonary embolism

PRI

Progressive renal insufficiency

AKI

Acute kidney injury

UTI

Urinary tract infection

SSI

Surgical site infection

PJI

Periprosthetic joint infection

SMD

Standardized mean difference

OR

Odds ratio

CI

Confidence interval

Author contributions

KHS was the project leader and participated in all aspects of the study, including planning, design, literature searches, data screening and extraction, quality appraisal, and management of all aspects of manuscript preparation and submission. JUK, ITJ, SBH, and SBK contributed to literature searches, data screening and extraction, quality appraisal, and manuscript editing. All authors read and approved the final manuscript.

Funding

No funding source was applicable to any part of this study.

Data availability

All data generated or analyzed during this study are included in this published article and its supplementary information files.

Declarations

Conflict of interest

The authors declare that they have no conflicts of interest.

Ethical approval and consent to participate

Not applicable.

Consent for publication

Not applicable.