European multicenter study on propionyl-L-carnitine in intermittent claudication

Abstract

OBJECTIVESThis study was performed to identify a target population of claudicants for propionyl-L-carnitine treatment.BACKGROUNDPrevious studies suggest that the efficacy of propionyl-L-carnitine in intermittent claudication is greater in patients with severe functional impairment than in those with mild walking disability.METHODSAfter run-in, 485 claudicant patients were randomized to placebo or propionyl-L-carnitine (1 g bid, po) and then stratified on the basis of maximal walking distance (cutoff point 250 m) and maximal walking distance variability (cutoff point 25%). Treatment lasted 12 months. Walking capacity was assessed by treadmill and quality of life by a questionnaire exploring various aspects of daily life.RESULTSIn the target population, that is, patients who at baseline walked ≤250 m and showed a maximal walking distance variability ≤25%, per-protocol analysis showed that the effect of propinyl-L-carnitine was significantly greater than that with placebo for both maximal walking distance and initial claudication distance (ICD). In the intention-to-treat population, maximal walking distance increased by 62 ± 14% on propionyl-L-carnitine and by 46 ± 9% (p < 0.05) on placebo, while no difference between treatments was observed for ICD. The beneficial effect of propionyl-L-carnitine was confirmed when data of the target population were pooled with those of patients who at baseline walked ≤250 m and showed a >25% maximal walking distance <50% variability. Actually, maximal walking distance increased by 98 ± 16% in the propionyl-L-carnitine group and by only 54 ± 10% in the placebo group (p < 0.01). The corresponding values for ICD were 99 ± 21% and 51 ± 8% (p < 0.05). For patients with baseline maximal walking distance >250 m, no difference between treatments was observed.CONCLUSIONSClaudicants with maximal walking distance ≤250 m benefited from the use of propionyl-L-carnitine, with improvement in walking distance and quality of life. However, patients with mild functional impairment (i.e., walking distance >250 m) showed no response to propionyl-L-carnitine.