Effect of Propionyl-L-Carnitine on Quality of Life in Intermittent Claudication

Abstract

A double-blind, dose titration study was designed to assess the efficacy of propionyl-L-carnitine in intermittent claudication. The effect on walking capacity was described in a previous article. This study reports on the effect on quality of life, assessed by the McMaster Health Index Questionnaire (MHIQ). After 24 weeks of treatment, the global MHIQ score did not show any difference from baseline in patients randomized to placebo (n = 102). Conversely, it increased from 0.59 ± 0.12 to 0.64 ± 0.12 in those taking propionyl-L-carnitine (n = 85). Analysis of variance showed a significant difference between treatments (p = 0.018). Stepwise multiple regression analysis identified baseline maximal walking capacity (cutoff point 250 m) as a predictor of treatment outcome. In patients walking <250 m, propionyl-L-carnitine significantly improved physical function (p = 0.027), emotional function (p = 0.002), and global MHIQ score (p = 0.002) compared with placebo. Also, for maximal walking capacity, group difference significantly favored propionyl-L-carnitine (p = 0.009). In patients with baseline maximal walking capacity ≥250 m, propionyl-L-carnitine did not affect the MHIQ scores, nor improve walking performance. These data indicate that propionyl-L-carnitine exerts beneficial effects on quality of life and walking performance in patients with more severely limited walking capacity.The results of this double-blind, dose-titration study indicate that propionyl-L-carnitine improves quality of life and maximal walking capacity in patients with intermittent claudication. By using a clinically relevant parameter, which is a baseline maximal walking capacity <250 m, a target population was defined in whom trial results became highly significant.