COVID-19 on Elective Surgery Outcomes in a Brazilian Tertiary Hospital: A Retrospective Cohort Study

Introduction

The COVID-19 pandemic posed extraordinary challenges to healthcare systems worldwide, triggering an unprecedented reorganization of hospital operations and a dramatic redefinition of healthcare priorities. Among the most profoundly affected areas was surgical care, particularly elective procedures, which were widely suspended to reallocate resources and reduce transmission risks [1,2]. Global estimates indicate that over 28 million elective surgeries were canceled during the initial months of the pandemic, resulting in long-term consequences for patient outcomes and healthcare systems [3].

In Brazil, a country characterized by stark regional inequalities and a heavily burdened public health care system, which serves approximately 75% of the population, the disruption of surgical services had far-reaching implications [4]. Government-mandated lockdowns and institutional restructuring led to the postponement of non-essential procedures, limits on operating room availability, and delays in critical treatments [5,6]. These circumstances raised significant concerns about the potential for increased postoperative complications, reinterventions, and mortality, particularly in vulnerable populations dependent on public hospitals [7,8].

Despite the prioritization of emergency surgeries, hospitals also faced operational challenges. Many patients delayed seeking care because of limited access or fear of infection, often presenting with more advanced stages of illness [9,10]. The introduction of preoperative testing, isolation protocols, and heightened infection control measures, although necessary, added complexity and cost to the delivery of surgical care [11]. International studies from Europe and the United States reported drastic reductions, up to 80%, in emergency surgical volume during lockdown periods, alongside proportional increases in morbidity due to treatment delays [12–14].

Despite these global trends, the actual impact of the pandemic on surgical safety metrics, such as hospital mortality, day-of-surgery cancellations, and surgical reinterventions, remains debated and may vary significantly depending on local health infrastructure and public health responses [15,16]. Brazil’s response to the pandemic was marked by heterogeneity across states. Notably, the Federal District (FD), the location of this study, was the first to implement social distancing measures in March 2020, potentially mitigating the more severe disruptions observed elsewhere [4]. In this context, understanding how tertiary public hospitals navigated the crisis is crucial for shaping future strategies to enhance surgical resilience. Although many observers expected surgical quality indicators to deteriorate under pandemic strain, emerging evidence shows that targeted institutional adaptations, such as stricter patient selection, enhanced preoperative planning, and more efficient workflows, preserved and, in some cases, improved surgical outcomes [17–20].

Elective surgical outcomes are influenced by multiple interacting factors at the patient, procedural, and institutional levels. Postoperative hospital mortality is affected by patient age, comorbidities, nutritional and functional status, as well as by surgical complexity and intraoperative complications. Day-of-surgery cancellations are frequently related to administrative and structural factors, such as bed shortages, operating room delays, or emergency case prioritization, and can negatively affect hospital efficiency, costs, and patient satisfaction [21,22]. Surgical reintervention rates reflect the quality of postoperative care and are influenced by infection control practices, surgical technique, and the timeliness of recognizing and managing complications [23]. Together, these indicators serve as measures of hospital performance and surgical safety, providing a framework for assessing the institutional impact of the COVID-19 pandemic on elective surgical care.

In a previous study, we used causal impact analysis to evaluate the effect of the COVID-19 pandemic on elective and emergency surgeries, as well as postoperative mortality, in a Brazilian metropolitan area, and found no significant impact on overall postoperative mortality [13]. However, the absence of a pandemic-related effect on total postoperative deaths may have been influenced by the substantial reduction in surgical volume or by differences in case selection and access to healthcare. This finding highlighted the need for a more detailed investigation into whether institutional characteristics and patient factors affected surgical outcomes during and after the pandemic [24–26].

Although the acute phase of the COVID-19 pandemic has passed, examining its effects remains essential for understanding institutional resilience, system adaptability, and the lasting consequences of large-scale healthcare disruptions [24–26]. This aspect is particularly relevant in middle-income settings, where limited resources heighten vulnerability to service interruptions. Insights gained from pandemic-related changes in surgical care can strengthen preparedness and enhance responses to future global health crises [13,24,26]. Furthermore, despite the time elapsed since the pandemic, few studies involving surgical patients have evaluated its impact on healthcare quality outcomes, such as day-of-surgery cancellations and the need for postoperative reintervention. Therefore, in this retrospective study, we aimed to evaluate 8806 adult elective surgery procedures performed between January 2018 and December 2022 at a tertiary public hospital in the FD of Brazil, comparing postoperative hospital mortality, day-of-surgery cancellations, and surgical reintervention rates before, during, and after the COVID-19 pandemic.

Material and Methods

STUDY DESIGN AND SETTING:

This retrospective cohort study was conducted at Hospital Regional de Sobradinho (HRS), a tertiary public hospital located in Brasília, FD, Brazil. The FD has the highest Human Development Index in the country and was the first Brazilian state to implement government-enforced social distancing during the COVID-19 pandemic. HRS provides a comprehensive range of surgical specialties, including general, orthopedic, urological, vascular, gynecological, and emergency surgeries. The hospital performs approximately 350 surgeries per month, primarily serving patients who rely exclusively on the Brazilian public health system.

The study was approved by the Institutional Review Board of the Education and Research Foundation of Health Sciences, Brasília, Federal District, Brazil (number 6,092,322), with a waiver of informed consent. The study was conducted in accordance with the principles outlined in the Declaration of Helsinki. Since this study involved no specific intervention and used only anonymized medical record data, which generated results in an aggregate manner that did not allow for the identification of participants, written consent was deemed unnecessary.

STUDY POPULATION AND DATA COLLECTION:

We included all adult patients (aged 18 years or older) scheduled for surgery at HRS between January 1, 2018, and December 31, 2022. The cohort encompassed elective and emergency procedures, regardless of whether the surgery was ultimately performed. There were no exclusion criteria, ensuring a complete representation of surgical scheduling and outcomes over the period. Data were extracted from the electronic health records of the FD’s Public Health System and from HRS’s internal surgical scheduling system.

PANDEMIC PERIOD CLASSIFICATION:

To evaluate the effects of the COVID-19 pandemic, we divided the study period into 3 distinct phases based on the governmental and institutional public health measures implemented. The pre-pandemic period spanned from March 1, 2018, to February 29, 2020. The lockdown period, which extended from March 1 to August 31, 2020, was marked by strict lockdowns and social distancing policies. The post-lockdown period, spanning from September 1, 2020, to February 28, 2022, was characterized by the progressive relaxation of public health restrictions and the partial normalization of surgical services. This temporal segmentation enabled a detailed evaluation of evolving trends in surgical outcomes.

VARIABLES AND OUTCOMES:

Collected variables included demographic characteristics (age and sex), surgical parameters (elective or emergency status, specialty, and anatomical site), surgery status (performed or canceled), reintervention status (yes/no), and hospital mortality. Surgical sites were classified into 7 categories: gynecologic/mammary, orthopedic/trauma, digestive, skin/soft tissue, vascular, renal/urinary tract, and head/neck.

The 3 primary outcomes were as follows: (1) hospital mortality, (2) day-of-surgery cancellations, defined as any scheduled procedure not performed on its planned date, and (3) surgical reinterventions, defined as additional procedures performed during the same hospitalization due to complications or treatment failure.

STATISTICAL ANALYSIS:

Continuous variables are described as means with standard deviations (SD) or medians with interquartile ranges (IQR), depending on normality assessed via the Shapiro-Wilk test. Categorical variables were summarized using absolute and relative frequencies.

In the univariate analysis, comparisons of day-of-surgery cancellation, surgical reintervention, hospital mortality, sex, and surgical site between the pre-pandemic, lockdown, and post-lockdown periods were performed using the Cochran-Armitage test for trend. Age was compared among the 3 periods using ANOVA. Additionally, to evaluate factors other than the classification of the pandemic period associated with day-of-surgery cancellation and surgical reintervention, the t test or the Mann-Whitney U test was applied for continuous variables, and the Pearson chi-square test was used for categorical variables.

Multivariate logistic regression models were constructed to identify independent predictors of the 3 primary outcomes (day-of-surgery cancellation, surgical reintervention, and hospital mortality). The time period (pre-pandemic, lockdown, and post-lockdown) was included as a key independent variable in all models. Other variables with P values <0.05 in the univariate analyses, as well as clinically relevant variables with P<0.20, were also included in the multivariate models using the Enter method. We assessed multicollinearity using tolerance values >0.10 and variance inflation factors <10. Final results are presented as adjusted odds ratios (OR) with corresponding 95% confidence intervals (CI). Statistical significance was defined as P≤0.05. All analyses were performed using IBM SPSS Statistics for Mac, version 20.0, and Jamovi version 2.3.24.

Results

SURGICAL VOLUME AND PATIENT CHARACTERISTICS:

A total of 8806 surgical procedures were scheduled between March 2018 and February 2022. Of these, 5146 (58.4%) were performed during the pre-pandemic period, 2528 (28.7%) during the lockdown, and 1132 (12.9%) during the post-lockdown period (Table 1).

The mean patient age was 44.7±18.7 years, and 53.4% of the patients were female. The most frequently represented surgical sites were orthopedic/trauma (31.5%), digestive (29.7%), and gynecological/mammary (12.2%). Elective surgeries comprised 62.3% (n=5482) of all scheduled procedures.

SHIFTS IN SURGICAL PATTERNS AND HOSPITAL POSTOPERATIVE MORTALITY DURING THE COVID-19 PANDEMIC:

The proportion of elective surgeries decreased significantly during the lockdown period, from 73.1% to 42.3%, and partially recovered to 62.3% in the post-lockdown period (P<0.001). The mean patient age differed significantly between the study periods (P=0.044), increasing slightly from the pre-pandemic period to the post-lockdown period (44.8±18.9 years to 45.4±18.7 years). The proportion of female patients also changed significantly over time (P=0.022), decreasing from 54.7% before the pandemic to 50.8% during the lockdown and rising again to 53.0% in the post-lockdown period (Table 1).

Surgical site distribution also changed significantly (P<0.001), with orthopedic and trauma procedures becoming more frequent during the pandemic period, replacing the pre-pandemic predominance of digestive surgeries, while gynecologic/mammary, vascular, skin/soft-tissue, renal/urinary tract, and head/neck surgeries remained relatively stable in proportion. Hospital postoperative mortality did not differ significantly across the 3 periods (P=0.356), and no significant differences were observed when mortality was analyzed by surgical site (all P>0.05) (Table 1).

When considering only the elective surgeries (n=5482), hospital postoperative mortality also showed no significant variation across the 3 periods (P=0.356), nor when stratified by surgical site (all P>0.05). The distribution of surgical sites also differed significantly (P<0.001), with digestive procedures being the most frequent before the COVID-19 pandemic, while gynecologic/mammary surgeries became predominant during the lockdown and post-lockdown periods (Table 2).

DAY-OF-SURGERY CANCELLATION RATES IN ELECTIVE PROCEDURES:

Among the 5482 elective surgeries, the overall day-of-surgery cancellation rate was 16.4% (n=897). Compared with the pre-pandemic period, the rate decreased significantly during the lockdown period (18.2% to 10.8%) and partially increased in the post-lockdown period (15.0%) (P<0.001). Gynecologic/mammary (P=0.020) and orthopedic/trauma procedures (P<0.001) showed significant reductions in cancellations during the pandemic, while other surgical categories (digestive, vascular, skin/soft tissue, renal/urinary tract, and head/neck) remained relatively stable across periods (all P>0.05) (Table 2).

In the univariate analysis, in addition to the pandemic period and surgical site, sex was also significantly associated with day-of-surgery cancellation rates (Table 3).

In the multivariate analysis, compared with the pre-pandemic period, the lockdown period was independently associated with a decreased rate of day-of-surgery cancellation (OR: 0.556; 95% CI: 0.448–0.691; P<0.001), while the post-lockdown period did not show a significant difference (OR: 0.828; 95% CI: 0.650–1.055; P=0.126). Gynecological/mammary (OR: 0.530; 95% CI: 0.417–0.672; P<0.001), skin/soft tissue (OR: 0.468; 95% CI: 0.335–0.654; P<0.001), and head/neck (OR: 0.468; 95% CI: 0.335–0.654; P<0.001) procedures were also independently associated with a reduced risk of day-of-surgery cancellation, whereas orthopedic/trauma procedures were independently associated with an increased risk (OR: 1.492; 95% CI: 1.228–1.813; P<0.001) (Table 4).

SURGICAL REINTERVENTION RATES IN ELECTIVE PROCEDURES:

The rate of surgical reintervention in elective procedures was 11.6% (n=638). Compared with the pre-pandemic period, the reintervention rate decreased slightly during the lockdown (12.4% to 11.6%) and declined significantly in the post-lockdown period (7.3%) (P<0.001), with notable reductions in gynecologic/mammary (P=0.004) and renal/urinary tract surgeries (P=0.040) (Table 2).

In the univariate analysis, in addition to pandemic period and surgical site, age and sex were significantly associated with surgical reintervention rates (Table 3).

In the multivariate analysis, compared with the pre-pandemic period, there was no significant difference in the reintervention rate during the lockdown period (OR: 0.888; 95% CI: 0.717–1.099; P=0.274). However, the post-lockdown period showed a significant reduction in the risk of requiring a surgical reintervention (OR: 0.534; 95% CI: 0.390–0.733; P<0.001). Female sex was independently associated with a lower risk of surgical reintervention (OR: 0.803; 95% CI: 0.658–0.980; P=0.031), whereas increasing age (OR: 1.006; 95% CI: 1.001–1.011; P=0.018) and undergoing orthopedic/trauma (OR: 1.662; 95% CI: 1.287–2.145; P<0.001), gynecologic/mammary (OR: 1.429; 95% CI: 1.085–1.883; P=0.011), vascular (OR: 3.326; 95% CI: 2.449–4.517; P<0.001), or renal/urinary tract procedures (OR: 2.164; 95% CI: 1.496–3.131; P<0.001) were independently associated with an increased risk (Table 5).

Discussion

This study provides a comprehensive evaluation of the impact of the COVID-19 pandemic on elective surgical care in a Brazilian tertiary public hospital, revealing outcomes that contrast with early global concerns. As expected, elective surgery volume fell substantially during the initial pandemic phase, reflecting national restrictions and global estimates of over 28 million canceled elective procedures during the first wave of COVID-19 [3]. However, contrary to initial expectations, hospital postoperative mortality remained stable, while day-of-surgery cancellations and surgical reinterventions decreased significantly. These findings suggest that, despite intense operational pressures, surgical teams and hospital systems demonstrated the capacity to adapt rapidly, maintaining or even enhancing the quality of care and preserving surgical safety indicators [17–20]. Adaptations such as stricter triage, standardized preoperative testing pathways, and tighter operating-room scheduling may have supported the safe restoration of services [26]. In parallel, clearing the accumulated backlog has required sustained capacity increases and transparent prioritization frameworks to balance equity and clinical urgency [24,26].

The observed reduction in day-of-surgery cancellations during the early pandemic period likely reflects improvements in hospital logistics, patient triage, and operating room management. With fewer cases scheduled overall and a greater emphasis on necessity, hospitals could optimize workflow efficiency and ensure that only well-prepared patients proceeded to surgery. Similar patterns were reported in Germany and Romania [21,27], where stricter protocols and more selective admissions during the pandemic resulted in fewer last-minute cancellations. In our setting, enhanced preoperative assessment and consistent adherence to institutional guidelines during the period of most significant operational constraint likely reinforced these gains [28,29]. Consistent with previous reports, programs that paired standardized prioritization tools with process redesign, such as uniform preoperative testing, staggered list starts, and rapid rebooking of deferred cases, achieved fewer same-day cancellations and more predictable operating lists, which remain useful in the post-pandemic recovery phase [26].

Moreover, the significant decline in surgical reinterventions during the post-restriction phase may reflect changes in perioperative management. With lower procedural volume and greater attention to preoperative preparation, surgical teams may have been able to mitigate complications more effectively. Patients selected for surgery during this period may have had more stable clinical conditions, contributing to improved outcomes. Similar findings have been reported in the United Kingdom, where no increase in reoperation rates was observed across the pandemic period [30], and in the United States, where metabolic and bariatric surgery reinterventions declined in 2020 relative to prior years [31]. Our results are also consistent with studies from Romania that found no association between the pandemic and increased reintervention risk [27].

Notably, hospital mortality among elective surgeries remained unchanged across all phases of the pandemic, even when stratified by surgical site. This finding contrasts with early projections and reports from the United States, Italy, Portugal, and the southern region of Brazil, which described increased postoperative mortality even among patients without COVID-19 [7,32–36]. Conversely, our findings align with studies from Sweden, France, and Spain [27,37–39], as well as our previous study in the FD, which analyzed elective and emergency surgeries and found no increase in postoperative mortality during the pandemic [13]. While the earlier study evaluated the overall metropolitan impact using time-series methods, the present analysis focuses on patient-level outcomes and specific surgical quality indicators, such as day-of-surgery cancellations and reintervention rates, within a single tertiary hospital. Together, these complementary studies suggest that institutional adaptations, early lockdown implementation, and robust perioperative governance were associated with maintained surgical safety despite systemic strain [3]. Further supporting this pattern, a study from a Brazilian tertiary-care center focusing on high-risk abdominal surgeries reported a persistent post-onset reduction in surgical volume with no recovery by 2022 and a disproportionate decline in colorectal procedures, yet found no effect of COVID-19 on postoperative mortality, underscoring that volume shocks did not necessarily translate into excess in-hospital deaths when perioperative safeguards were maintained [20].

Nonetheless, this study has limitations. Its retrospective design, based on administrative and clinical records, is inherently subject to information bias, data incompleteness, and potential misclassification. Variables such as comorbidities, surgical risk scores, intraoperative complications, and COVID-19 test results were not evaluated, which limited the ability to adjust for clinical risk and reduced the depth of outcome interpretation. Additionally, the database did not include post-discharge mortality or complications, nor the outcomes of surgeries that were indefinitely postponed or never rescheduled. Methodologically, the use of secondary data and logistic regression analysis, although robust for identifying associations, does not permit causal inference. Moreover, aggregating data by time period may mask individual-level temporal variations. Finally, as this was a single-center study conducted in a relatively well-resourced region, the findings may not be generalizable to hospitals in more vulnerable or underserved areas. Despite these limitations, our results provide valuable insights into how public hospitals can maintain surgical quality during systemic crises. The observed reductions in day-of-surgery cancellations and reintervention rates, without a concurrent rise in mortality, may be associated with improved triage, focused perioperative care, and structured prioritization. These strategies can be especially relevant for low- and middle-income countries, where capacity constraints are routine even in non-crisis contexts. The experience of HRS may highlight the potential value of rapid institutional reorganization, early adoption of public health measures, and disciplined clinical protocols in safeguarding surgical care during global health emergencies.

Conclusions

This study, which evaluated adult elective surgeries from January 2018 to December 2022 at a tertiary public hospital in the FD of Brazil, spanning the pre-pandemic, lockdown, and post-lockdown periods, observed a substantial reduction in day-of-surgery cancellations and a decline in surgical reinterventions in the post-lockdown period, with no increase in postoperative hospital mortality. These results suggest that early, coordinated institutional responses and targeted reforms implemented during the pandemic may be associated with benefits for surgical care delivery in public health systems.