The effects of canagliflozin compared to sitagliptin on cardiorespiratory fitness in type 2 diabetes mellitus and heart failure with reduced ejection fraction: The CANA-HF study

Background Canagliflozin reduces hospitalizations for heart failure (HF) in type 2 diabetes mellitus (T2DM). Its effect on cardiorespiratory fitness and cardiac function in patients with established HF with reduced ejection fraction (HFrEF) is unknown. Methods We conducted a double-blind randomized controlled trial of canagliflozin 100 mg or sitagliptin 100 mg daily for 12 weeks in 88 patients, and measured peak oxygen consumption (VO2 ) and minute ventilation/carbon dioxide production (VE/VCO2 ) slope (co-primary endpoints for repeated measure ANOVA time_x_group interaction), lean peak VO2 , ventilatory anaerobic threshold (VAT), cardiac function and quality of life (ie, Minnesota Living with Heart Failure Questionnaire [MLHFQ]), at baseline and 12-week follow-up. Results The study was terminated early due to the new guidelines recommending canagliflozin over sitagliptin in HF: 17 patients were assigned to canagliflozin and 19 to sitagliptin, total of 36 patients. There were no significant changes in peak VO2 and VE/VCO2 slope between the two groups (P = .083 and P = .98, respectively). Canagliflozin improved lean peak VO2 (+2.4 mL kgLM -1 min-1 , P = .036), VAT (+1.5 mL kg-1 min-1 , P = .012) and VO2 matched for respiratory exchange ratio (+2.4 mL Kg-1 min-1 , P = .002) compared to sitagliptin. Canagliflozin also reduced MLHFQ score (-12.1, P = .018). Conclusions In this small and short-term study of patients with T2DM and HFrEF, interrupted early after only 36 patients, canagliflozin did not improve the primary endpoints of peak VO2 or VE/VCO2 slope compared to sitagliptin, while showing favourable trends observed on several additional surrogate endpoints such as lean peak VO2 , VAT and quality of life.