Risk Factors for Readmission Following Minimally Invasive Hysterectomy for Benign Indications in the United States—Outpatient and Inpatient Setting

Minimally invasive hysterectomy (MIH), one of the most common gynecologic surgical procedures in the United States, is associated with shorter hospital stay, faster recovery and lower morbidity compared to laparotomy [1]. Readmission after surgery is a quality metric, posing major clinical and cost burden on patients and hospitals [2]. Prior studies have reported 3%–12% readmission rates after hysterectomy, based on surgical indication and approach [3]. However, data on readmission following MIHs for benign indications, the most common indication for hysterectomy, remain relatively limited. Specifically, the impact of same day discharge, and of concomitant surgical procedures performed on readmission rates is underexplored. We aimed to study the risk factors for readmission following MIH in the outpatient (same day discharge) and the inpatient setting using The American College of Surgeons National Surgical Quality (NSQIP) database, a robust and validated database that includes surgical characteristics and postoperative diagnoses. Vaginal hysterectomies were excluded, in order to minimise heterogeneity of the study cohort [4]. This was a cohort study of prospectively collected data from the NSQIP database. We included laparoscopic and robotic hysterectomies performed for benign indications between 2012 and 2022. Non-elective cases, concurrent malignancies, cases with preoperative sepsis, vaginal and laparoscopic/robotic assisted vaginal hysterectomies were excluded (Supporting Information). We classified patients into outpatient (same day discharge) and inpatient (overnight-hospital stay) groups. Data collected included baseline, preoperative, intraoperative and 30-days postoperative characteristics. We further collected postoperative readmissions related to index surgery and readmission indications. We performed multivariable regression analyses to identify factors associated with 30-days postoperative readmission for outpatient and inpatient cases. The primary outcome was risk factors for readmission. Secondary outcomes included readmission rates, readmission indications and outpatient/inpatient proportions during the study period. The study was deemed exempt from IRB approval. A total of 219, 986 patients; 174 594 (79.4%) outpatient patients and 45 391 (20.6%) inpatient patients met inclusion criteria and comprised the study cohort. Rate of outpatient MIH increased steadily from 59.9% to 85.3% with an annual increase rate of 1.8% (p < 0.001) (Figure S1). Readmission rates were 1.9% (n = 3335) for outpatient MIH, and 3.0% (n = 1365) for inpatient MIH (p < 0.001) (Supporting Information). The most common indications for readmission were organ space surgical site infection in both groups (outpatients 29.7% and inpatients 23.4%). In a multivariable regression, the following factors were independently associated with readmission in both groups (Figure S2): younger age, Black or African American race, chronic obstructive pulmonary disease, bleeding disorders, immunosuppressive therapy, tobacco use, American Society of Anesthesiologists classification III/IV, total laparoscopic hysterectomy compared to supracervical hysterectomy, and, lysis of adhesions (Figure 1). Surgery with adnexal cystectomy was associated with readmission in the outpatient group. Same-day discharge MIH for benign indications is constantly increasing, has a low readmission rate, and is lower than in the inpatient setting. The difference in readmission rates between both groups may be the result of increased surgical complexity, intraoperative complications, and comorbidities among inpatients [5]. Black or African American race was the only race at increased risk of readmission in our study. This association likely reflects unmeasured structural and system-level factors—including differential access to high-volume surgeons, practice settings, and postoperative support, rather than intrinsic patient characteristics. The lower risk of readmission following supracervical hysterectomy is in line with prior publications, underlying lower risk of postoperative complications, specifically organ space surgical site infections [6]. With pertains to modifiable risk factors, such as smoking, these associations should be considered descriptive signals rather than evidence of modifiable risk. Given the observational design and unmeasured confounding, our findings should be interpreted cautiously. Interestingly, diabetes and hypertension were not associated with increased readmission risk. As the sample size in our analysis is solid, it is possible that in the clinical setting of MIH, these factors do not significantly increase the risk for readmission and are not associated with the common indications for readmission. However, as these risk factors are common in our cohort (hypertension approximately 25%, diabetes approximately 8%), it is possible that an even larger sample size was needed to demonstrate statistical significance. The most common indication for readmission, infections, is in line with prior studies. Efforts should be made to reduce this possible preventable postoperative sequela. Strengths of this study include the large sample size spanning 11 years, strict inclusion criteria of benign MIH only, analysis by concomitant surgical procedures, identified as independent risk factors, as well as separation into inpatient and outpatient cases. Among the limitations of the study, we can mention that data is only within 30-days postoperatively, and does not include postoperative and post-discharge care. Furthermore the database lacks surgeon-level and hospital-level variables such as surgeon volume, specialty, institutional volume or practice setting. As a result, patient-level associations cannot be disentangled from provider-level or structural contributors, and our findings should be interpreted as descriptive rather than causal. Furthermore, the database used does not record exact uterine weights, and there is no differentiation between robotic-assisted and traditional laparoscopic approaches. Lastly, approximately 6% of the study cohort underwent MIH for pelvic organ prolapse. Although this route is used for prolapse, it may also represent misclassification and information bias. In conclusion, our findings highlight risk factors that should be addressed by targeted interventions to reduce readmission risks. The study was conceived, planned and carried out by R.M. and G.L.; all authors contributed to the completion of the submission. S.L., S.S., Y.N., and M.B. contributed to the writing of the research letter. R.M. Intuitive Surgical, Claria Medical consultant. All other authors have no disclosures. The authors declare no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Data S1: bjo70123-sup-0001-Supinfo.docx. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.