Nationwide Analysis of Intact Abdominal Aortic Aneurysm Repair in Portugal From 2000-2015

All AAA interventions performed during the period 2000 to 2015 were retrospectively identified in a National Health Service (NHS) administrative database, the hospital morbidity database, formerly designated as Diagnosis-Related Groups (DRGs) database. This database was provided by the Portuguese Central Health System Administration (ACSS) and contains a registration of all hospitalizations (retrospective consecutive case entry) occurring in public hospitals in mainland Portugal.

Each episode includes information about diagnoses (primary and secondary diagnoses) and medical or surgical procedures, both coded using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9).

All admissions considered have a primary diagnosis ICD-9 codes for ruptured and non-ruptured AAA. The primary diagnosis of an episode represents the main condition investigated or treated during that hospital stay.

The rate of the repair was calculated based on the episodes of care with the above-mentioned disease ICD-9 codes plus the ICD-9 procedure codes suitable for AAA repair. Admissions with a primary diagnose of AAA that lacked a ICD-9 procedure code suitable for AAA repair were excluded, assuming that no repair was performed during that hospital stay. General indication for iAAA repair in Portugal are a maximum transverse diameter ≥5.5cm in men and ≥5.0 cm in women, as recommended by guidelines.

The number of deaths accounted for all patients that fail to be discharged alive from the hospital admission where the repair took place, irrespective to the direct cause of death. The number of admissions for repair in which the patient died divided by the number of all admissions for repair was used as a proxy of in-hospital mortality due to iAAA. The number of resident population in each year under analysis was provided by the National Institute of Statistics (INE) from 2000 to 2015. Resident population per year was used to calculate the rate of AAA repair and the death associated with AAA repair (thereafter mentioned as mortality to distinguish from the above-mentioned in-hospital mortality).