Low Socioeconomic Status Predicts Worse Outcome in Patients with Ruptured Abdominal Aortic Aneurysm

Abstract

Introduction - Low socioeconomic status (SES) has been reported to negatively influence cardiovascular morbidity and mortality. The prognostic implication of SES on the outcome of abdominal aortic aneurysm (AAA) has never been investigated in a large population-based study. The aim of this study was to compare the SES distribution in patients with intact (iAAA) and ruptured AAA (rAAA), with the particular aim to elucidate the influence of SES on intervention rate and outcome for rAAA patients. Methods - Nationwide, population-based study on all individuals diagnosed with iAAA or rAAA during the period 2001-2015. All cases were retrieved from the National Patient Register and the Cause of Death Register. Individual-level data on indicators of SES, including annual disposable household income (in quintiles) and educational level (low = ≤9 school years, middle = 10-12 school years, high = university or higher) were obtained from Statistics Sweden. The proportion of iAAA vs rAAA at initial diagnosis in relation to SES was analysed by calculating odds ratios (OR) with 95% confidence intervals (CI) using logistic regression models, as were the treatment frequencies and 90-day mortality outcome after treatment. Results - The total number of individuals with an AAA (iAAA or rAAA) was 42,997, of whom 34,335 (79.9%) with iAAA and 8,662 (20.1%) with rAAA. The overall proportion of women was 21.6%, but was higher in the rAAA group (29.9%) than in the iAAA group (21.2%). In age- and sex-adjusted analysis, individuals with low disposable household income as well as those with low educational level were found to have a higher risk of presenting with a rAAA at the time of the first diagnosis (OR 1.61, 95% CI 1.48-1.74, p<0.001 and OR 1.36, 95% CI 1.24-1.49, p<0.001 respectively). More than one third (38.6 %) of the rAAA patients underwent repair. Low disposable household income was associated with a lower treatment frequency (OR 0.71, 95% CI 0.61-0.82, p<0.001) and was also significantly associated with increased 90-day mortality after treatment (OR 1.78 95% CI 1.39-2.27, p<0.001). Corresponding analyses of low educational level showed less clear associations (OR 0.85 95% CI 0.72-1.01, p=0.051 and OR 1.27 95% CI 0.97-1.68, p=0.091). Conclusion - Low SES is an indicator of poorer outcome and higher disease severity at initial presentation in patients with AAA. These results confirm that social inequalities can also be found in patients treated for aortic disease. In a western, modernized country where health care is regulated to be equally distributed and offered to its inhabitants, we still find discrepancies in how care is distributed through different socioeconomic strata. This should implicate the need for the development of strategic and logistical efforts to prevent rupture among individuals with low SES. Increased attention should be shown towards groups with obviously higher risks for complications postoperatively.