Is health-related quality of life 1-year after coronary artery bypass graft surgery associated with living in a greener environment?

Abstract

Introduction: Greenery in the residential environment and in the hospital has been associated with improved surgical outcomes and recovery. We investigated the association between the level of residential greenness of patients with coronary disease and their heart disease-related Quality of Life (HRQoL) 1-year after a coronary artery bypass grafting (CABG) surgery.

Methods: Participants in a prospective cohort study who underwent CABG surgery at seven cardiothoracic units throughout Israel during the years 2004-2007 filled in the MacNew HRQoL one day before and one year after surgery. Successful recovery was defined as ≥0.5 increase in the MacNew score between baseline and follow-up. Exposure to residential greenness in 90 m and 300 m buffers around the patient's home was assessed with Linear Spectral Unmixing analysis of Landsat 30 m imagery.

Results: The cohort comprised of 861 patients (22% female) with a mean age of 65.5 years, and 59.2% classified as low-income. In the total cohort, higher residential greenness was associated with an improvement in emotional HRQoL (OR = 1.33 (95%CI: 0.99-1.79)), adjusting for demographic and socio-economic factors, living in the periphery/center, presence of diabetes, attending cardiac rehabilitation following surgery, BMI, and change in physical fitness and depression over the 1-year follow-up. Although no association was found between greenness and change in the physical or social subscales, a positive association was specifically observed among the low-income patients for the global HRQoL score, OR = 1.42 (95%CI: 0.97-2.10), as compared to the higher-income patients, p for interaction = 0.03.

Conclusions: Residential greenness is associated with improvement in HRQoL 1-year after CABG surgery, but not the physical and social scales, only in low-income patients. Ensuring greenery in the living environment may act as a social intervention that supports human health and disease recovery.

Keywords: Cohort study; Coronary artery bypass graft surgery; Linear spectral unmixing (LSU); Normalized difference vegetation index (NDVI); Quality of life; Residential greenness.