The effect of canagliflozin on amputation risk in the CANVAS program and the CREDENCE trial.

AIM: To determine whether there was an explanation as to why the effects of the sodium-glucose co-transporter-2 (SGLT2) inhibitor canagliflozin on amputation risk vary between the CANVAS program and the CREDENCE trial. METHODS: We performed a pooled analysis of patient-level data from the CANVAS program and the CREDENCE trial. Patient characteristics associated with amputation risk were assessed in univariable and multivariable regression models and compared between studies. Effects of canagliflozin on amputation risk were determined from Cox proportional hazards models and compared between studies, subgroups and for a range of amputation outcomes. Effects over time were explored by cumulative event curves. RESULTS: In the CANVAS program (n = 10 142; median follow-up 2.4 years) and CREDENCE trial (n = 4401; median follow-up 2.5 years), 2.3% and 5.3% of participants, respectively, reported baseline amputation history. Key differences at baseline were the proportions with nephropathy (CREDENCE higher, 100% vs. 17.5%) and cardiovascular disease (CANVAS higher, 66% vs. 50%). There were 133 amputations in CREDENCE (3.0% annual event rate) and 187 amputations in CANVAS (1.8% annual event rate), with prior amputation being the strongest predictor of future amputation in both groups. Effects of canagliflozin on amputation risk were significantly different between trials (Pheterogeneity .02, I2 = 82%), but this was not explained by participant or trial differences. There was no evidence that foot disease management protocols instituted during CREDENCE ameliorated amputation risk. CONCLUSIONS: We identified no explanation for the difference in amputation risk between the CREDENCE trial and the CANVAS program. In the context of null effects of SGLT2 inhibition on amputation in CREDENCE and all other large trials, there is a possibility that the finding in CANVAS was the result of chance.

Effects of canagliflozin on amputation risk in type 2 diabetes: the CANVAS Program.

AIMS/HYPOTHESIS: The primary analysis of the Canagliflozin cardioVascular Assessment Study (CANVAS) Program showed canagliflozin to have a beneficial effect on cardiovascular and renal outcomes in people with type 2 diabetes at high cardiovascular risk, but also an unexpected increased risk of major or minor lower extremity amputation. These secondary analyses explore this finding in more detail. METHODS: The effect of canagliflozin on amputation risk in the CANVAS Program was calculated for amputations of different types and proximate aetiologies and different canagliflozin doses. Univariate and multivariate associations of baseline characteristics with amputation risk were determined and proportional and absolute effects of canagliflozin were compared across subgroups. RESULTS: There were 187 (1.8%) participants with atraumatic lower extremity amputations (minor 71%, major 29%); as previously published, rates were 6.30 vs 3.37 per 1000 participant-years with canagliflozin vs placebo (HR 1.97 [95% CI 1.41, 2.75]). Risk was similar for ischaemic and infective aetiologies and for 100 mg and 300 mg doses. Overall amputation risk was strongly associated with baseline history of prior amputation (major or minor) (HR 21.31 [95% CI 15.40, 29.49]) and other established risk factors. No interactions between randomised treatment and participant characteristics explained the effect of canagliflozin on amputation risk. For every clinical subgroup studied, numbers of amputation events projected were smaller than numbers of major adverse cardiovascular events averted. CONCLUSIONS/INTERPRETATION: The CANVAS Program demonstrated that canagliflozin increased the risk of amputation (mainly minor) in this study population. Anticipated risk factors for amputation were identified, such as prior history of amputation, peripheral vascular disease and neuropathy, but no specific aetiological mechanism or at-risk subgroup for canagliflozin was identified.