# Long-Term Nitrogen Dioxide Exposure as a Possible 5-Year Mortality Risk Factor in Diabetic Patients Treated Using Off-Pump Surgical Revascularization—A Retrospective Analysis

## TL;DR

Long-term exposure to nitrogen dioxide may increase 5-year mortality risk in diabetic patients who had heart surgery.

## Contribution

Identifies nitrogen dioxide as a novel risk factor for mortality in diabetic patients after off-pump revascularization.

## Key findings

- Nitrogen dioxide exposure was linked to higher 5-year mortality (HR: 3.99).
- Complete revascularization was associated with lower mortality (HR: 0.19).
- Exposure above 15 µg/m³ NO₂ increased mortality risk in diabetic patients.

## Abstract

Background: There is mounting evidence that diabetic-related cardiac metabolism abnormalities with oxidative stress and inflammatory mechanism activation align with the functional impairments that result in atherosclerotic lesion formation. Among the possible non-traditional coronary lesion risk factors, environmental exposure may be significant, especially in diabetic patients. Methods: A total of 140 diabetic patients (115 (82%) males and 25 (18%) females) with a mean age of 65 (60–71) underwent surgical revascularization due to multivessel coronary disease. The possible all-cause mortality risk factors, including demographical and clinical factors followed by chronic air pollution exposure, were identified. Results: All patients were operated on using the off-pump technique and followed for 5.6 (5–6.1) years. The multivariable model for 5-year mortality prediction presented the nitrogen dioxide chronic exposure (HR: 3.99, 95% CI: 1.16–13.71, p = 0.028) and completeness of revascularization (HR: 0.19, 95% CI: 0.04–0.86, p = 0.031) as significant all-cause mortality risk factors. Conclusions: Ambient air pollutants such as an excessive chronic nitrogen dioxide concentration (>15 µg/m3) may increase 5-year all-cause mortality in diabetic patients following surgical revascularization.