Treatment and Outcomes in Patients With COVID-19 and Competing Acute Surgical Diseases in Moscow (SurgCOVID-Mos)

Outcomes and Treatment Strategy for Patients With COVID-19 and Concurrent Acute Surgical Conditions: a Single-center Retrospective/Prospective Observational Cohort Study Based on Real-world Data (RWD)

The COVID-19 pandemic has posed a significant challenge to surgical practice. This study aims to investigate the structure of hospitalizations, treatment outcomes, and surgical tactics in patients with COVID-19 and competing different acute surgical diseases (ASD). The research is based on real-world data (RWD) from a large multidisciplinary hospital repurposed as a COVID-19 center. The study analyze the mutual impact of these two acute conditions on patient outcomes, develop prognostic models for in-hospital mortality, and evaluate changes in surgical approaches during the pandemic.

Study Overview

• Status: Completed
• Conditions: COVID-19; Abdominal Surgery; Emergency Surgery; Real-World Data
• Intervention / Treatment: Procedure: Surgical and Interventional Management of Acute Surgical Conditions

Detailed Description

This is a single-center, ambidirectional observational cohort study based on routinely collected clinical data from the Moscow Multidisciplinary Clinical Center "Kommunarka," Moscow, Russia. The study evaluates the organization and outcomes of care for patients with acute surgical conditions during two distinct periods of hospital activity: the COVID-19 pandemic period and the post-pandemic period.

The study was designed to address the methodological challenges of analyzing patients with two potentially competing acute conditions: COVID-19 and an acute surgical disease. The clinical spectrum includes acute abdominal diseases, thrombotic and hemorrhagic conditions, soft-tissue infections, thoracic complications, and other conditions requiring surgical assessment or treatment. No diagnostic, surgical, interventional, or medical treatment was assigned or modified by the study protocol. All clinical decisions were made by the treating teams as part of routine care.

Data were obtained from hospital information systems and routine electronic medical records. Source data included demographic characteristics, diagnoses, operative and interventional procedures, selected clinical severity indicators, comorbid conditions, hospitalization dates, discharge status, and other variables required for the planned analyses. The principal unit of analysis was a hospitalization episode rather than an individual data row. Repeated technical records and duplicated entries relating to the same hospitalization were identified and resolved before analysis.

A multistage data-management process was used to transform poorly structured real-world data into clinically interpretable analytical cohorts. The initial screening procedure used diagnostic codes, relevant text fields, procedure information, and predefined clinical terms to identify potentially eligible hospitalization episodes. More specific analytical datasets were subsequently created using stricter diagnostic definitions and clinical review. Certain clinically complex disease groups required manual review of medical records, reassessment of the final diagnosis, clarification of the surgical condition, or verification using imaging and procedural information.

Quality-control procedures included assessment of duplicate records, repeated hospitalizations, inconsistent diagnostic classification, incomplete variables, implausible values, and discrepancies between diagnosis and procedure fields. The process also included review of hospitalizations that may have been incorrectly included or excluded by the initial screening algorithm. Changes to cohort composition, classification rules, and derived variables were documented through versioned datasets and change records. A cohort or dataset passport was used to describe the origin of the data, unit of analysis, cohort-formation rules, level of clinical validation, data limitations, and intended analytical use.

Missing data were not automatically interpreted as absence of the corresponding clinical condition. The amount and pattern of missingness were assessed for relevant variables. Statistical analyses were conducted using the available data for each predefined analytical task. Sensitivity analyses were used where appropriate to assess whether the main findings were affected by alternative cohort definitions, stricter phenotyping rules, or differences in data completeness.

The pandemic and post-pandemic cohorts were analyzed separately and comparatively. The inter-period analysis was intended to assess whether the structure of acute surgical hospitalizations, treatment patterns, and clinical outcomes differed between the specialized pandemic hospital setting and subsequent routine hospital activity. Both broad and more specific cohort definitions were used to evaluate the robustness of the observed differences.

The study also included the development of an organizational and methodological model for conducting research based on real-world data within a medical organization. The model describes the sequence of research activities, distribution of professional roles, clinical validation procedures, data-quality controls, standard operating procedures, dataset documentation, and change management. This component represents a methodological and organizational output of the study and does not constitute an evaluation of the clinical effectiveness of an implemented institutional program.

Because this is a nonrandomized observational study, associations between patient characteristics, treatment strategies, historical periods, and outcomes are interpreted cautiously. Surgical intervention may reflect disease severity, clinical selection, and treatment necessity and is not interpreted as an independently assigned exposure or a proven cause of outcome.

• Study Type: Observational
• Enrollment (Actual): 58000

Contacts and Locations

Study Locations

• Russia
  • Moscow, Russia
    • Moscow Multidisciplinary Clinical Center Kommunarka

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

The study cohort was assembled based on data from the Kommunarka Moscow Multidisciplinary Clinical Center (Moscow)-a facility repurposed to treat patients with COVID-19 alongside concurrent acute emergencies across surgical, cardiological, neurological, trauma, and neurosurgical specialties. It comprises medical data regarding the hospitalization and treatment outcomes of patients treated as inpatients during the pandemic period (March 1, 2020, to March 1, 2022) and the post-pandemic period (January 1, 2023, to December 31, 2024). De-identified data were derived from routine medical records and the hospital's medical information system. The dataset reflects real-world clinical practice in the care of patients with COVID-19 and acute surgical conditions, including abdominal, thrombotic, hemorrhagic, infectious-inflammatory, and other surgically significant pathologies.

Description

Inclusion Criteria:

• Age 18 years or older.
• Hospitalization at the MMCC "Kommunarka".
• A confirmed diagnosis of COVID-19 (based on current clinical guidelines).
• Presence of one or more any acute surgical diseases (ASD) considered competing with COVID-19 or as a complication of COVID-19/its treatment, as per the discharge summary.
• For specific sub-studies: Patients with acute surgical diseases of the abdominal organs.
• For specific sub-studies: Patients with clinically significant spontaneous soft tissue hematomas or pneumomediastinum or other acute surgical diseases.

Exclusion Criteria:

• Patients for whom a diagnosis of COVID-19 was not established according to the discharge summary.
• Patients for whom none of the studied acute surgical diseases were established according to the discharge summary.
• Patients who underwent elective surgeries and developed COVID-19 in the postoperative period.
• Patients operated on in another hospital and transferred with suspected COVID-19 (if not confirmed).

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Pandemic-Period Acute Surgical Disease Cohort; This cohort includes hospitalizations at the Moscow Multidisciplinary Clinical Center "Kommunarka" from March 1, 2020, to March 1, 2022, in which one or more acute surgical conditions were identified from routine clinical records. The cohort includes hospitalizations with confirmed COVID-19 and hospitalizations without confirmed or probable COVID-19, allowing within-period comparisons by COVID-19 status. No intervention was assigned by the study. Surgical, interventional, or conservative treatment was provided according to routine clinical practice. The cohort was used to assess the structure of acute surgical conditions, in-hospital and postoperative mortality, surgical activity, treatment strategies, and factors associated with adverse outcomes.	Procedure: Surgical and Interventional Management of Acute Surgical Conditions; Surgical and interventional procedures performed as part of routine clinical care for acute surgical conditions, including abdominal, thrombotic, hemorrhagic, infectious, and other surgically significant conditions. Procedures included open and laparoscopic surgery, bowel resection, drainage, debridement, hemostatic procedures, angiography, endovascular embolization, and other condition-specific interventions, as clinically indicated. Treatment was not assigned, standardized, or modified by the study protocol. The type and timing of each procedure and the associated in-hospital and postoperative outcomes were obtained from routine medical records and analyzed across clinical subgroups and the pandemic and post-pandemic periods.
Post-Pandemic Acute Surgical Disease Cohort; This cohort includes emergency hospitalizations at the Moscow Multidisciplinary Clinical Center "Kommunarka" from January 1, 2023, to December 31, 2024, in which one or more acute surgical conditions were identified from routine clinical records. Elective hospitalizations were excluded from the analytical cohort. No intervention was assigned by the study. Surgical, interventional, or conservative treatment was provided according to routine clinical practice. The cohort was used to assess the structure of hospitalizations, in-hospital and postoperative mortality, and surgical activity, and to compare these outcomes with the corresponding pandemic-period cohort using broad and more specific RWD-based cohort definitions.	Procedure: Surgical and Interventional Management of Acute Surgical Conditions; Surgical and interventional procedures performed as part of routine clinical care for acute surgical conditions, including abdominal, thrombotic, hemorrhagic, infectious, and other surgically significant conditions. Procedures included open and laparoscopic surgery, bowel resection, drainage, debridement, hemostatic procedures, angiography, endovascular embolization, and other condition-specific interventions, as clinically indicated. Treatment was not assigned, standardized, or modified by the study protocol. The type and timing of each procedure and the associated in-hospital and postoperative outcomes were obtained from routine medical records and analyzed across clinical subgroups and the pandemic and post-pandemic periods.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
In-Hospital Mortality	The proportion of patients who died during their hospital stay. Assessed in patients with a primary or secondary diagnosis of COVID-19 in combination with competing acute surgical diseases.	From the moment of admission to the hospital until the date of discharge from the hospital or death (until the end of hospitalization) for the entire study period from 01 march 2020 to 01 march 2022 (from the date of discharge)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Structure of Morbidity	The proportion of patients hospitalized with COVID-19 and various groups of acute surgical diseases (e.g., acute abdominal, thrombotic, hemorrhagic).	During the entire study period (from 01 march 2020 to 01 march 2022)
Postoperative Mortality	The proportion of patients who died after undergoing a surgical intervention for an acute surgical disease.	From the moment of admission to the hospital until the date of discharge from the hospital or death (until the end of hospitalization) for the entire study period from 01 march 2020 to 01 march 2022 (from the date of discharge)
Surgical Tactics and Outcomes for Specific Conditions	Comparison of outcomes (e.g., mortality, complications) for different surgical treatment strategies (e.g., conservative vs. any surgical management) for specific COVID-19-associated conditions like spontaneous hematomas, pneumomediastinum, and diverticulitis. The number of cases using various surgical approaches in individual subcohorts of patients with various groups of acute surgical diseases, and the number of fatal outcomes depending on the surgical approach used.	From the moment of admission to the hospital until the date of discharge from the hospital or death (until the end of hospitalization) for the entire study period from 01 march 2020 to 01 march 2022 (from the date of discharge)
Surgical Activity	The proportion of hospitalizations in which a surgical intervention for an acute surgical disease was performed, assessed overall and by acute surgical disease group, COVID-19 status, and study period. Inter-Period Comparison of Hospitalization Structure and Treatment Outcomes for operated patients.	At hospital discharge for each hospitalization, with period-level summary at the end of each study period (pandemic: from 01 march 2020 to 01 march 2022 ; post-pandemic: from 01 january 2023 to 01 january 2024).

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Inter-Period Comparison of Hospitalization Structure and Treatment Outcomes	Comparison of the Rate of distribution of acute surgical disease groups, in-hospital mortality, postoperative mortality, and surgical activity between the pandemic and post-pandemic periods using broad and strict RWD-based cohort definitions.	Pandemic period (March 1, 2020 - March 1, 2022) versus post-pandemic period (January 1, 2023 - December 31, 2024)
Predictive Performance of the In-Hospital Mortality Model	Discrimination and calibration of a multivariable model for the number of participants with in-hospital mortality based on age, current clinical severity, number of participants with surgical intervention, and the number of recorded rate of comorbid conditions, including assessment of the area under the receiver operating characteristic curve.	From admission until discharge or death for hospitalizations during March 2020 - March 2022; model performance assessed during the data analysis phase through June 2026
Clinical Suitability and Robustness of RWD-Based Cohort Formation	Consistency of Major Outcomes Across Broad, Strict, and Manually Reviewed Cohorts	During the data management and analysis phase (March 2022 - June 2026)
Organizational and Methodological Model for RWD-Based Research in a Medical Organization	Completion of an Organizational and Methodological Model for Conducting RWD-Based Research in a Medical Organization	By study completion (June 1, 2026)

Collaborators and Investigators

• Sponsor: Pirogov Russian National Research Medical University
• Collaborators: Moscow Multidisciplinary Clinical Center "Kommunarka"

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2020
• Primary Completion (Actual): January 1, 2024
• Study Completion (Actual): July 1, 2026

Study Registration Dates

• First Submitted: July 15, 2026
• First Submitted That Met QC Criteria: July 17, 2026
• First Posted (Actual): July 22, 2026

Study Record Updates

• Last Update Posted (Actual): July 22, 2026
• Last Update Submitted That Met QC Criteria: July 17, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: SARS-CoV-2, COVID-19, Emergency Surgery, Abdominal Surgery, Real-World Data, Data-management, Mortality, Pandemic
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Pneumonia, Viral; Pneumonia; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; COVID-19; Surgical Procedures, Operative
• Other Study ID Numbers: SurgCOVID-Mos

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: in accordance with national requirements for the security and protection of personal data

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No