A Retrospective Comparison of 90-day Outcomes, Length of Stay, &amp; Readmissions Between Robotic-Assisted &amp; Laparoscopic Colectomy

doi:10.21203/rs.3.rs-2577669/v1

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A Retrospective Comparison of 90-day Outcomes, Length of Stay, & Readmissions Between Robotic-Assisted & Laparoscopic Colectomy

https://doi.org/10.21203/rs.3.rs-2577669/v1

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published 05 Jun, 2023

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Purpose: Investigations generally assess 30-day perioperative outcomes with robotic-assisted and laparoscopic colectomy. Outcomes beyond 30-days serve as a quality metric of surgical services and an assessment of 90-day outcomes may have greater clinical utility. The purpose of this study was to assess 90-day outcomes, length of stay (LOS), and readmissions among patients who underwent a robotic-assisted versus laparoscopic colectomy using a national database.

Methods: Patients undergoing either robotic-assisted or laparoscopic colectomy were identified using Current Procedural Terminology (CPT) codes within PearlDiver, a national, inpatient records database from 2010-2019. Outcomes were defined using the National Surgical Quality Improvement Program (NSQIP) risk calculator and identified using International Classification of Disease (ICD) diagnosis codes. Categorical variables were compared using chi-square tests and continuous variables were compared using paired t-tests. Covariate-adjusted regression models were also constructed to evaluate these associations while accounting for potential confounders.

Results: A total of 82,495 patients were assessed in this study. At 90-days, patients of the laparoscopic colectomy cohort experienced a higher rate of complications than patients who underwent robotic-assisted colectomy (9.5% vs. 6.6%, p<0.001). There were no significant differences in LOS (6 days vs. 6.5 days, p=0.08) and readmissions (6.1% vs. 6.7%, p=0.851) at 90-days.

Conclusion: Patients undergoing robotic-assisted colectomy have a lower risk for morbidity at 90-days. Neither approach is superior for LOS or 90-day readmissions. Both techniques are effective minimally invasive procedures, yet patients may gain a greater risk benefit from robotic colectomy.

colectomy

robotic

laparoscopic

minimally invasive

Prior investigations comparing perioperative outcomes among robotic-assisted and laparoscopic colectomy have generally focused on 30-day, short-term outcomes. However, 90-day perioperative comparisons have gained tremendous value in colorectal surgery and are likely to be of greater clinical utility. Private insurers and the Centers for Medicare and Medicaid Services (CMS) often scrutinize 90-day outcomes for reimbursement purposes. Additionally, academic and community hospital systems throughout the United States utilize 90-day outcomes as a quality metric. Hence, there is a need to describe outcomes of robotic-assisted colectomy at 90 days as these findings are seldom in the literature and may impact clinical practice.

The incidence of robotic-assisted colectomy in the US has expanded nearly eightfold within a single decade [1]. Subsequently, studies have compared outcomes of laparoscopic and robotic-assisted approaches as both are minimally invasive techniques that require adequate training and resource allocation. In a systematic review of 11 studies, Solaini et. al. described comparable 30-day outcomes among patients of robotic-assisted and laparoscopic right-sided colectomy [2]. Similarly, studies have also reported reduced rates of readmission and shorter length of stay (LOS) at 30 days for patients who underwent robotic colectomy versus laparoscopic [3–5]. While these reported findings enhance our understanding of short-term outcomes, data comparing laparoscopic and robotic-assisted colectomy beyond the 30-day period are lacking.

The purpose of this study is to compare the postoperative outcomes of laparoscopic and robotic-assisted colectomy at 90 days, a timeframe that is relatively unexplored and is underreported. It is hypothesized that similar outcome patterns at 30 days would be observed at 90 days postoperatively and patients who underwent a robotic-assisted colectomy would have a lower rate of postoperative morbidity compared to those undergoing laparoscopic surgery.

A retrospective review was performed using the PearlDiver dataset, a national, all-payer, inpatient database with longitudinal patient records from 2010–2019. PearlDiver contains de-identified information for 144 million patients comprising commercial, Medicare, Medicaid, government, and cash payers. All patients undergoing either a laparoscopic or robotic-assisted colectomy were identified using Current Procedural Terminology codes (CPT) yielding 82,495 total patients (Appendix A). Patients who lacked a coexisting robotic-assisted CPT code were considered laparoscopic.

Perioperative outcomes were assessed using the definitions for complications established by the National Surgical Quality Improvement Program (NSQIP) risk calculator (https://riskcalculator.facs.org/RiskCalculator/). Each outcome was then identified within the PearlDiver dataset using International Classification of Diseases 9 and 10 codes and included: postprocedural infections, deep venous thrombosis (DVT), myocardial infarction (MI), pneumonia, pulmonary embolisms (PE), respiratory failures (RF), cardiac arrests, chronic kidney disease (CKD), acute renal failure, sepsis, UTI, wound disruption, postoperative ileus, 48-hour ventilator support, and unplanned intubation. All-cause readmission was defined as the total number of patients who were readmitted by the same healthcare provider within 90-days after their index colectomy. Length of hospital stay was defined as the number of days per patient stay post index procedure within the same admission record and does not include readmissions. In accordance with the terms and conditions of the end user license agreement with PearlDiver Inc., cohorts with populations less than 11 total patients cannot be disclosed or published and are therefore listed as “***”. No ethical approval was required for this retrospective, database study.

Continuous variables, including age and Charlson Comorbidity Index (CCI), were compared via paired t-tests. Categorical variables, including demographics, comorbidities, readmissions, and perioperative outcomes, were assessed via Pearson chi-square tests. Multivariable logistic regression models were constructed to estimate risk for patients undergoing laparoscopic and robotic colectomy for each defined complication while adjusting for key covariates, including age, CCI, Tobacco Use, COPD, Chronic Kidney disease, and obesity. All statistical analyses were performed within PearlDiver using RStudio (v. 1.4.1717) with statistical significance defined as p < 0.05.

Overall, 82,495 patients were included in the analysis. As indicated in Table 1, the patients in the laparoscopic colectomy cohort had a greater prevalence of hypertension (laparoscopic: 73% vs. robotic: 70%, p=0.001), tobacco abuse (27% vs. 25%, p=0.012), COPD (33% vs. 29%, p=<0.001), chronic kidney disease (19% vs. 16%, 0.001), congestive heart failure (10% vs 6%, p<0.001), and obesity (44% vs. 37%, p<0.004) compared to patients of the robotic-assisted cohort. There were no differences in the prevalence of diabetes, coronary artery disease, and Charlson Comorbidity Index between patients in the robotic and laparoscopic cohorts (p>.09). A greater proportion of colonic procedures were performed laparoscopically (70% vs. 52%, p=<0.001) while a greater proportion of rectal procedures (31% vs. 50%, p<0.001) were performed robotically. There was no difference in the number of patients who received a stoma among both cohorts (8% vs. 8%, p=0.996).

A greater proportion of patients in the laparoscopic cohort experienced any given complication within 90-days postoperatively than those of the robotic-assisted colectomy cohort (Table 2) (9.5% vs. 6.6%, p<0.001). The laparoscopic cohort had a higher rate of blood transfusions (2.4% vs. 1.5%, p=0.013), pneumonia (1.9% vs. 0.7%, p<0.001), chronic kidney disease (2.1% vs. 0.9%, p<0.001), acute renal failure (2.4% vs. 1.2%, p<0.001), sepsis (1.4% vs. 0.6%, p=0.004), and wound disruption (1.1% vs. 0.5%, p=0.018) at 90-days than the robotic-assisted colectomy cohort. There was no difference in the number of patients who were diagnosed with postprocedural infections (3.5% vs. 3.0%, p=0.25), DVTs (0.9% vs. 1.0%, p=0.49), MIs (0.35% vs. 0.26%, p=0.66), PEs (1.4% vs. 1.6%, p=0.54), RFs (3.5% vs. 2.9%, p=0.19), cardiac arrests (0.3% vs 0.3%, p=0.99), UTIs (5.5% vs. 4.8%, p=0.16), and post-operative ileus (4.1% vs. 3.6%, p=0.25).There were no differences among patients from either cohort for 48-hour ventilator support (0.13% vs. 0.10%, p=0.999), unplanned intubation (0.07% vs. 0.10%, p=0.94), and readmissions at 90-days (6.1% vs. 6.7%, p=0.851).

Table 3 provides the results of the covariate-adjusted logistic regression modeling of any 90-day complications. Compared to the laparoscopic cohort, patients who underwent robotic-assisted colectomy had a significantly decreased risk for perioperative morbidity after adjusting for confounders (Odds Ratio [OR]: 0.85; 95% Confidence Interval [CI]: 0.75 – 0.96;p = 0.01). Risk factors which increased the risk for 90-day morbidity included CCI (OR: 1.05; 95% CI: 1.01 – 1.09; p = 0.01), tobacco use (OR: 1.53; CI: 1.15 – 2.0; p<0.05), CKD (OR: 2.07; CI: 1.50 – 2.84; p<0.001), and presence of a stoma (OR: 3.29; CI: 2.25 – 4.79; p<0.001). Age, male gender, COPD, and obesity were not associated with 90-day perioperative complications among the robotic-assisted colectomy cohort (p >0.05).

Prior investigations have compared 30-day outcomes for robotic-assisted and laparoscopic colectomy, reporting lower risk among robotic-assisted cohorts. Few studies have compared both minimally invasive approaches beyond a 30-day interval. This study is among the first to compare perioperative outcomes using data beyond a 30-day interval for patients undergoing robotic-assisted and laparoscopic colectomy. The bivariate analysis found that patients of the laparoscopic cohort experienced an associated higher rate of complications than patients of the robotic-assisted colectomy cohort. These differences between the two cohorts remained robust when results were adjusted in regression modeling, and patients who underwent robotic surgery had 15% lower odds of a complication at 90 days compared to patients who underwent laparoscopic surgery. There were no significant differences between the two groups with respect to prevalence of readmissions and mean LOS. These findings suggest robotic-assisted colectomy can achieve comparable and possibly improved outcomes compared to a laparoscopic technique.

There is a discrepancy regarding whether true differences exist for perioperative outcomes between patients of robotic-assisted and laparoscopic colectomy. Studies that report improved outcomes with robotic-assisted colectomy are contested by studies that demonstrate no significant differences among laparoscopic and robotic-assisted colectomy. In a retrospective study by Ackerman et. al, they report no significant difference in 30-day perioperative outcomes among patients of robotic rectal resections with matched recipients of laparoscopic rectal resections [6]. A systematic review comparing patients of laparoscopic and robotic-assisted right colectomy has also reported no significant differences in outcomes at 30-days among both cohorts [2]. However, in a systematic review and meta-analysis by Trastulli et. al., patients of robotic-assisted colectomy were reported to have lower postoperative complications, fewer wound infections, reduced intraoperative blood loss, and shorter hospital length of stay compared to patients who underwent a laparoscopic colectomy [7]. In a retrospective study by Moghadamyeghaneh et. al., the authors report a lower risk of conversion to an open laparotomy among patients who had undergone a robotic-assisted total colectomy when compared to a laparoscopic cohort [8]. In another systematic review by Waters et. Al, they report robotic-assisted hemicolectomy recipients had a reduced risk for anastomotic complications, better lymph node removal, reduced hospital length of stay, and a reduced risk for conversion to open laparotomy [9]. Our study found reduced rates of postoperative morbidity among the robotic-assisted colectomy cohort when compared to the laparoscopic colectomy cohort and supports the reported findings of robotic-assisted colectomy having improved outcomes.

Retrospective studies comparing 30-day outcomes have reported shorter LOS and a non-significant difference for readmissions among robotic-assisted colectomy cohorts. A propensity scored matched study by Al-Temimi et. al report a significant shorter LOS (3.89 vs. 4.75 days, p < 0.001) among patients undergoing robotic-assisted colectomy for diverticulitis compared to patients who underwent a laparoscopic colectomy [10]. Similarly, in another retrospective study of 30-day outcomes, Tagliabue et. al also reports a significantly shorter LOS (6 vs. 7 days, p = 0.028) for patients who underwent a robotic-assisted colectomy compared to those who had a laparoscopic colectomy [11]. Investigators have also reported similar findings using the NSQIP database. A study by Bhama et. al., reported no difference in 30-day readmissions (7.2% vs. 7.0%, p = 0.70) with a significantly shorter LOS for patients who underwent a robotic-assisted colorectal procedure versus laparoscopic (4.3 vs. 5.3 days, p < 0.001) [12]. A study by Miller et. al reports decreased length of stay (5.04 vs. 6.06 days, p < 0.01) with no significant difference in 30-day readmissions (9.3% vs. 8.7%, p = 0.593) among patients who underwent a robotic-assisted colectomy versus laparoscopic [13]. In another NSQIP study by Kulaylat et. al, patients undergoing an elective robotic-assisted colectomy had no difference in 30-day readmissions when compared to a matched cohort of laparoscopic colectomy recipients (8.9% vs. 8.3%, p = 0.368) [14]. In this study of over 80,000 total patients did not find significant differences in LOS and readmission rates at 90 days for either laparoscopic or robotic-assisted colectomy cohorts. Our reported rates for readmission generally agrees with the current literature; however, our reported LOS was slightly higher compared to what has been previously reported. Our reported findings may be partially explained by the duration of our study interval, which includes patients over the last decade, as it has been recently reported that LOS is continuously decreasing over time for colorectal surgery patients (Moon, Surgical Endoscopy 2022 PMID 34988738).

This study has several limitations. The retrospective design and use of administrative data have inherent risks for selection, misclassification, or even registry bias. PearlDiver is a multimillion patient longitudinal record database compiled from large insurance registries. Our specific cohorts were identified by ICD diagnosis and CPT codes, resulting in patient cohorts that may represent a small proportion of our database. Thus, our cohorts may not be entirely representative of the entire general population and maybe a source of selection bias when interpreting our final results. Furthermore, the integrity of ICD and CPT codes relies predominantly on providers to accurately enter the most appropriate CPT and ICD code. This allows for another source of bias in our study as providers may not always enter the most accurate code to reflect the true diagnosis and/or procedure performed. However, it is unlikely this limitation negatively impacts our reported findings as the coding is unlikely to have differed between the laparoscopic and robotic cohorts of this study. Various academic and community hospitals rely on chart compliance coordinators who are specialized with CPT and ICD coding systems. These coordinators continuously evaluate patient records and enable care providers to accurately utilize the most appropriate CPT and ICD codes in clinical practice. Another limitation is the lack of data for potential confounders that could not be accounted for because they are not included in the source data. These include patient-specific (degree of intra-abdominal adhesions, cognition, measures of function), surgeon specific (years of experience, training background, surgical volume), and institution-specific variables (institutional volume, type of surgical robot, presence of a designated robotic surgery program). This study also lacks mortality data when comparing outcomes among patients who had robotic and laparoscopic colectomy. Therefore, it was not possible to estimate mortality for the populations in the study, and patients with early mortality following surgery may be inadvertently classified as having no complications or readmissions within a specified time frame.

Our study demonstrates an overall improved 90-day morbidity and lower complication risks among patients who underwent a robotic-assisted colectomy compared to patients in the laparoscopic cohort. Both cohorts were comparable in regard to LOS and readmissions rate. Future studies using a stratified cost-analysis of laparoscopic and robotic-assisted colectomy will help determine the impact to the overall cost of care in light of the decreased morbidity risk.

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

The authors have no relevant financial or non-financial interests to disclose.

Author Contributions:

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by all the authors listed. The first draft of the manuscript was written by Sahir Pervaiz, MD, MS and Joshua Wolf, MD, FACS and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

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Table 1. Demographics Among Both Robotic and Laparoscopic Cohorts

	Laparoscopic N=80,590	Robotic N=1,905	P-Value
Age, mean (SD)	61 (14)	59 (12)	<0.001
Gender	F: 43,909 (54.5)^a	F: 969 (50.9%)	0.007
CCI, mean (SD)	3 (3)	3 (3)	0.999
Hypertension	58,812 (73)	1,325 (70)	0.001
Diabetes	32,221 (40)	724 (38)	0.086
Tobacco Use	21,896 (27)	468 (25)	0.012
COPD	26,747 (33)	553 (29)	<0.001
CKD	14,935 (19)	297 (16)	0.001
CHF	8,428 (10)	112 (6)	<0.001
CAD	24,379 (30)	551 (29)	0.222
Obesity^b	35,493 (44)	714 (37)	0.004
Stoma	6,279 (8)	149 (8)	0.996
Proctectomy	25,151 (31)	943 (49)	<0.001

^aUnless otherwise stated, values reflect N (%)

^bReflects a BMI >30 kg/m²

Abbreviations: CCI=Charlson Comorbidity Index, COPD=chronic obstructive pulmonary disease, CKD=chronic kidney disease, CHF=congestive heart failure

Table 2. 90 Day Outcomes for Robotic and Laparoscopic Cohorts

	Laparoscopic N=80,590	Robotic N=1,905	P-value
Overall complications	7,620 (9.5)^a	125 (6.6)	<0.001
Postoperative transfusion	1,905 (2.4)	28 (1.5)	0.013
Surgical site infection	2,826 (3.5)	57 (3.0)	0.252
Deep venous thrombosis	705 (0.9)	20 (1.0)	0.493
Myocardial infarction	281 (0.35)	5 (0.26)	0.663
Pneumoniae	1,526 (1.9)	13 (0.7)	<0.001
Pulmonary embolism	1,112 (1.4))	30 (1.6)	0.535
Respiratory failure	2,794 (3.5)	55 (2.9)	0.192
Cardiac arrest	275 (0.3)	6 (0.3)	0.999
Chronic kidney disease	1,687 (2.1)	17 (0.9)	<0.001
Acute renal failure	1,956 (2.4)	23 (1.2)	<0.001
Sepsis	1,160 (1.4)	12 (0.6)	0.004
Urinary tract infection	4,470 (5.5)	91 (4.8)	0.161
Wound disruption	906 (1.1)	10 (0.5)	0.018
Postoperative ileus	3,321 (4.1)	68 (3.6)	0.254
Prolonged ventilation	102 (0.13)	2 (0.10)	0.999
Unplanned intubation	59 (0.07)	2 (0.10)	0.938
LOS, days (SD)	6 (5.1)	6.5 (8.0)	0.080
Readmission	4,941 (6.1)	127 (6.7)	0.851

^aUnless otherwise stated, values reflect N (%)

Table 3. Multivariable regression model for 90-day complications (binary dependent variable)

Variable	Odds Ratio	95% Confidence Interval	P-value
Robotic Approach (Lap)*	0.85	0.75 - 0.96	0.01
Age	1.00	1.002 - 1.004	0.58
CCI	1.05	1.01 - 1.09	0.01
Male gender	0.92	0.72 - 1.19	0.56
Tobacco Use	1.53	1.15 - 2.02	<0.05
COPD	1.18	0.90 - 1.56	0.22
Chronic Kidney Disease	2.06	1.50 - 2.84	<0.001
Obesity	1.22	0.94 - 1.57	0.13
Presence of a Stoma	3.29	2.25 - 4.79	<0.001
Rectal Procedure	0.75	0.58 - 0.97	0.03

^*Reference categories are in parenthesis

Abbreviations: CCI=Charlson comorbidity index; COPD=Chronic obstructive pulmonary disease; BMI=Body mass index;

No competing interests reported.

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Editorial decision: Accepted
28 May, 2023
Reviewers agreed at journal
06 Mar, 2023
Reviewers invited by journal
05 Mar, 2023
Editor assigned by journal
28 Feb, 2023
Submission checks completed at journal
13 Feb, 2023
First submitted to journal
12 Feb, 2023

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A Retrospective Comparison of 90-day Outcomes, Length of Stay, & Readmissions Between Robotic-Assisted & Laparoscopic Colectomy

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