Association between obesity and health-related quality of life in patients with coronary artery disease

BACKGROUND AND OBJECTIVE

In patients with coronary artery disease (CAD), obesity is paradoxically associated with better survival (the 'obesity paradox'). Our objective was to determine whether this counterintuitive relationship extends to health-related quality of life (HRQOL) outcomes.

DESIGN

Cross-sectional observational study.

SUBJECTS

All adults undergoing coronary angiography residing in Alberta, Canada between January 2003 and March 2006 in the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) registry.

METHODS

Patients completed self-reported questionnaires 1 year after their index cardiac catheterization, including the Seattle Angina Questionnaire (SAQ) and the EuroQol 5D (EQ-5D Index). Patients were grouped into six body mass index (BMI) categories (underweight, normal, overweight, mild obesity, moderate obesity and severe obesity). An analysis of covariance was used to create risk-adjusted scores.

RESULTS

A total of 5362 patients were included in the analysis. Obese patients were younger than normal and overweight participants, and had a higher prevalence of depression and cardiovascular risk factors. In the adjusted models, SAQ physical function scores and the EQ Index (representing overall QOL) were significantly reduced in patients with mild, moderate and severe obesity compared with patients with a normal BMI. Patients with severe obesity had both statistically and clinically significant reductions in HRQOL scores. Depressive symptoms accounted for a large proportion in variability of all HRQOL scores.

CONCLUSIONS

BMI is inversely associated with physical function and overall HRQOL in CAD patients, especially in patients with severe obesity. High body weight is a modifiable risk factor; however, given the apparent obesity paradox in patients with CAD, it is critical that future studies be conducted to fully clarify the relationships between HRQOL and body composition (body fat and lean mass), nutritional state and survival outcomes.

Cryopreservation of rat pancreatic islets: effect of ethylene glycol on islet function and cellular composition

BACKGROUND

Inasmuch as cryopreservation can facilitate clinical islet transplantation by providing a means of storing supplemental islets in order to augment marginally adequate grafts, protocols are needed to allow for a minimal loss in viable beta cells. By replacing the cryoprotectant dimethyl sulfoxide (DMSO) with ethylene glycol (EG), a more simplified cryopreservation protocol was developed, which resulted in improved survival and function of rat pancreatic islets.

METHODS

Nonfrozen islets, islets cryopreserved in DMSO, and EG-cryopreserved islets were compared for percent recovery, cellular composition, in vitro viability, and metabolic function after transplantation.

RESULTS

After cryopreservation in DMSO or EG, islet yield was similar to that of nonfrozen controls; however, islets cryopreserved in DMSO exhibited lower cellular DNA, insulin, and glucagon content, as well as an impaired insulin secretory capacity in vitro than the nonfrozen controls. When compared with controls, islets cryopreserved in DMSO contained a higher proportion of beta cells but a lower number of glucagon-positive cells, whereas cryopreservation with EG resulted in similar DNA/hormone contents, in vitro viability, and cellular composition. Transplantation of islet grafts composed of comparable numbers of beta cells (2.1-2.3 million) corrected diabetes in 100% (6/6; nonfrozen controls), 92% (10/11; DMSO), and 100% (14/14; EG) of the recipients; however, those who received DMSO-treated islets took longer to achieve euglycemia and remained glucose-intolerant.

CONCLUSIONS

These results demonstrate that EG allows for the successful cryopreservation of rat islet beta and a cells with the same yield and quality as nonfrozen islets. The observation that alpha-cell survival was better after cryopreservation with EG may explain the improved functional viability of these grafts. Further studies are needed to assess whether this protocol provides any advantage for cryopreserving large numbers of human islets.