Body Mass Index and Clinical and Health Status Outcomes in Chronic Coronary Disease and Advanced Kidney Disease in the ISCHEMIA-CKD Trial

Abstract

Objective: This study aimed to assess whether an obesity paradox (lower event rates with higher body mass index [BMI]) exists in participants with advanced chronic kidney disease (CKD) and chronic coronary disease in the International Study of Comparative Health Effectiveness of Medical and Invasive Approaches (ISCHEMIA)-CKD, and whether BMI modified the effect of initial treatment strategy.

Methods: Baseline BMI was analyzed as both a continuous and categorical variable (< 25, ≥ 25 to < 30, ≥ 30 kg/m²). Associations between BMI and the primary outcome of all-cause death or myocardial infarction (D/MI), and all-cause death, cardiovascular death, and MI individually were estimated. Associations with health status were also evaluated using the Seattle Angina Questionnaire-7, the Rose Dyspnea Scale, and the EuroQol-5D Visual Analog Scale.

Results: Body mass index ≥ 30 kg/m² vs < 25 kg/m² demonstrated increased risk for MI (hazard ratio [HR] [95% confidence interval] = 1.81 [1.12-2.92]) and for D/MI (HR 1.45 [1.06-1.96]) with a HR for MI of 1.22 (1.05-1.40) per 5 kg/m² increase in BMI in unadjusted analysis. In multivariate analyses, a BMI ≥ 30 kg/m² was marginally associated with D/MI (HR 1.43 [1.00-2.04]) and greater dyspnea throughout follow-up (P < .05 at all time points). Heterogeneity of treatment effect between baseline BMI was not evident for any outcome.

Conclusions: In the ISCHEMIA-CKD trial, an obesity paradox was not detected. Higher BMI was associated with worse dyspnea, and a trend toward increased D/MI and MI risk. Larger studies to validate these findings are warranted.

Keywords: Body Mass Index; Chronic Kidney Disease; Coronary Artery Disease; Death; Dialysis; Myocardial Infarction; Obesity; Obesity Paradox.

Main Manuscript Figure:

Health status scores based on BMI category. Panels represent the different health status measures assessed during the study follow-up (0: baseline, 1.5 months, 3 months, 6 months, then every 6 months until 24 months). EQ-5D: Euroqol 5D visual analog scale; SAQ-7: Seattle Angina Questionnaire −7.