The use of evidence-based medical therapy in patients with critical limb-threatening ischaemia

Aims To describe the practice patterns of evidence-based medical therapy (EBM) and overall mortality in high-risk patients with critical limb-threatening ischaemia (CLTI), compared with patients with myocardial infarction (MI). Methods and results Using Danish registries, we identified patients 40-100 years of age with a first-time hospitalization for CLTI or MI from 2008-2018 and grouped them into CLTI, MI, and CLTI and history of MI (CLTI + MI). We examined the likelihood of filling prescriptions with EBM [i.e. antiplatelets (Aps), lipid-lowering agents (LLAs), angiotensin-converting enzyme inhibitor (ACEi), or angiotensin II-receptor blockers (ARBs)] within 3 months after discharge among survivors. Further, we assessed the adjusted 3-year mortality rates. We included 92 845 patients: 14 941 with CLTI (54.7% male), 74 830 with MI (64.6% male) and 3,074 with CLTI + MI (65.2% male). Patients with CLTI and CLTI + MI were older and had more comorbidities than patients with MI. Compared with patients with MI, the unadjusted odds ratios of filling prescriptions were 0.15 [confidence interval (CI): 0.14-0.15] for AP, 0.26 (CI: 0.25-0.27) for LLA, and 0.71 (CI: 0.69-0.74) for ARB/ACEi in patients with CLTI, and 0.22 (CI: 0.20-0.24) for AP, 0.38 (CI: 0.35-0.42) for LLA, and 1.17 (CI: 1.08-1.27) for ARB/ACEi in patients with CLTI + MI. Adjusted analyses showed similar results. Compared with patients with MI, adjusted 3-year hazard ratios for mortality were 1.69 (CI: 1.64-1.74) in patients with CLTI and 1.60 (CI: 1.51-1.69) in patients with CLTI + MI. Conclusion Patients with CLTI were undertreated with EBM and carried a more adverse prognosis, as compared with patients with MI, despite similar guidelines. Lay Summary Patients with critical limb-threatening ischaemia (CLTI) have a higher risk of cardiovascular complications and death compared with patients suffering from a heart attack. Clinicians are recommended by guidelines to prescribe drugs that can reduce the risk in both patient groups. Key findings Patients with CLTI are undertreated, compared with patients suffering from heart attacks, despite similar treatment guidelines. Patients with CLTI had an increased risk of death compared with patients suffering from a heart attack.