Materials and methods

Study design and setting

This is a retrospective analysis of a prospectively maintained database, evaluating perioperative mortality rates for major lower limb amputations. The research was conducted at the Hospital de Base of the FAMERP, São Paulo, Brazil, covering the period between January 2010 and December 2024.

Inclusion and exclusion criteria

Medical records of patients undergoing above-knee or below-knee non-traumatic major lower limb amputations by the vascular surgery service between January 2010 and December 2024 were considered for inclusion. Medical records of patients who underwent minor amputations (e.g., toes, transmetatarsal) and cases where the amputation indication was primarily due to orthopedic, neoplastic, or traumatic conditions were excluded.

Data collection

Data was extracted from the hospital’s electronic database and organized into a dedicated Microsoft Excel spreadsheet (Microsoft Corp., Redmond, WA, USA). The primary variables analyzed included perioperative mortality, biological sex, and age.

Statistical analysis

A descriptive statistical analysis was performed to evaluate mortality rates by year, sex, and age group (Yates-corrected chi-square: p-value = 0.5), comparing two groups: the COVID-19 and non-COVID-19 period. Statistical analyses were performed using StatsDirect software (Version 4.0.4; StatsDirect Ltd., Cheshire, UK).

Ethical considerations

The study protocol was reviewed and approved by the Research Ethics Committee of the FAMERP, Brazil (approval number: 7.346.790). Patient consent for publication was exempted by the Research Ethics Committee due to the retrospective design, the historical nature of the medical records, and the impossibility of contacting family members of deceased patients. Thus, the authors ensured the privacy and confidentiality of the data obtained, fully preserving the anonymity of the participants in accordance with the Declaration of Helsinki.