Efficacy of micronized purified flavonoid fraction (Daflon®) on improving individual symptoms, signs and quality of life in patients with chronic venous disease: a systematic review and meta-analysis of randomized double-blind placebo-controlled trials.

INTRODUCTION: The use of a venoactive drug is considered an important component of medical treatment of chronic venous disease (CVD), although the efficacy of certain venoactive drugs (VADs) on one or more individual leg symptoms or signs may have not been extensively studied to justify a strong recommendation in guidelines on CVD. The aim of this systematic review and meta-analysis was to study the effectiveness of the micronized purified flavonoid fraction (MPFF, Daflon®) across the spectrum of defined venous symptoms, signs, quality of life (QoL) and treatment assessment by the physician.

EVIDENCE ACQUISITION: On September 9, 2017, a systematic review of the databases MEDLINE, Scopus and Cochrane Central was performed, supplemented by hand searching, to identify randomized double-blind placebo-controlled trials on MPFF in patients with CVD.

EVIDENCE SYNTHESIS: The main outcome measures were the individual and global symptoms, leg edema and redness, skin changes, QoL and evaluation of the overall effectiveness of the treatment by the physician. The effectiveness of MPFF compared with placebo was expressed as risk ratio (RR) or standardized mean difference (SMD) with 95% confidence interval (CI). Trial quality of evidence was graded using the GRADE system.

RESULTS: We identified 7 trials, mostly with low risk of bias, involving 1,692 patients. On qualitative analysis, MPFF significantly improved nine defined leg symptoms, including pain, heaviness, feeling of swelling, cramps, paresthesia, burning sensation, and pruritus (itching), but also functional discomfort compared with placebo, leg redness, skin changes and QoL. On quantitative analysis, MPFF compared with placebo, assessed as a categorical variable, reduced leg pain (RR 0.53, P=0.0001, NNT=4.2), heaviness (RR 0.35, P<0.00001, NNT=2.0), feeling of swelling (RR 0.39, P<0.00001, NNT=3.1), cramps (RR 0.51, P=0.02, NNT=4.8), paresthesia (RR 0.45, P=0.03, NNT=3.5), and functional discomfort (RR 0.41, P=0.0004, NNT=3.0). Similarly, MPFF compared with placebo, assessed as a continuous variable reduced pain (SMD -0.25, 95% CI -0.38 to -0.11), heaviness (SMD -0.80, 95% CI -1.05 to -0.54), feeling of swelling (SMD -0.99, 95% CI -1.25 to -0.73), burning sensation (SMD -0.46, 95% CI -0.78 to -0.14), cramps (SMD -0.46, 95% CI -0.78 to -0.14), and functional discomfort (SMD -0.87, 95% CI -1.13 to -0.61). Regarding objective assessments of leg edema, the use of MPFF compared with placebo reduced ankle circumference (SMD -0.59, 95% CI -1.15 to -0.02), and leg redness (SMD -0.32, 95% CI -0.56 to -0.07, RR 0.50, P=0.03, NNT=3.6), improved skin changes (RR 0.18, P=0.0003, NNT=1.6) and quality of life (SMD -0.21, 95% CI -0.37 to -0.04) and was associated with clinical improvement as assessed by the physician (RR 0.28, P<0.00001, NNT=2.5). Heterogeneity was mostly minimal. The existing evidence where sufficient was mostly of high quality.

CONCLUSIONS: Based on high quality evidence, MPFF is highly effective in improving leg symptoms, edema and quality of life in patients with CVD.