CRD summary

This review assessed the safety and efficacy of vardenafil, compared with placebo, for erectile dysfunction (ED). The authors concluded that vardenafil is superior to placebo in the treatment of symptoms of ED, although more research is required on its effectiveness and safety in different groups of patients. The authors' conclusions appear to be supported by the evidence presented, but the reliability of them is unclear.

Authors' objectives

To assess the efficacy and safety of vardenafil in the treatment of male erectile dysfunction (ED).

Searching

MEDLINE, EMBASE, CINAHL, Current Contents and the Cochrane Library were searched (from January 2001 to November 2003), as were the proceedings of the U.S. Food and Drug Administration and the European Agency for the Evaluation of Medical Products; the search terms were reported. In addition, the Science Citation Index was used for frequently cited papers, conference proceedings and other relevant publications were searched, the bibliographies of relevant papers were checked and experts were contacted.

Study selection

Assessment of study quality

Trials were assessed for appropriateness of randomisation and blinding, description of withdrawals and drop-outs, and the use of intent-to-treat analysis. Two reviewers independently evaluated study quality.

Data extraction

Two reviewers independently extracted the data. For continuous outcomes, the weighted mean difference (WMD) and 95% confidence interval (CI) were estimated for individual studies; the weighted relative risk and 95% CI were calculated for dichotomous outcomes. For adverse events and withdrawals, the percentage of men achieving each outcome according to treatment was calculated, along with the weighted relative risk and 95% CIs.

Methods of synthesis

Results of the review

Nine RCTs (6,809 men in total) were included.

Eight trials reported that they were randomised and double-blind, though only two reported the method of randomisation. None reported whether there was concealment of treatment allocation, and only one provided details of blinding. Six described withdrawals and drop-outs, and eight described results based on an intention-to-treat principle (although the latter was reported to be inadequately described and applied).

All doses of vardenafil led to statistically significant improvements in the EF-IIEF domain score in comparison with placebo. The WMD was 5.06 (95% CI: 3.67, 6.45) for a 5-mg dose, 6.16 (95% CI: 5.25, 7.07) for a 10-mg dose, 6.91 (95% CI: 6.11, 7.70) for a 20-mg dose, and 7.45 (95% CI: 3.97, 10.92) for a flexible dose. There was no evidence of statistically significant heterogeneity (P=0.11). The findings were similar for the other two primary outcomes, with vardenafil showing a significant improvement when compared with placebo: there was a 26% (95% CI: 22.89, 29.11) increase in the success rate for penetration and a 29.8% (95% CI: 26.47, 33.06) increase in the success rate for maintaining erection. The P-values from the tests of heterogeneity (P=0.05 and P=0.06, respectively) were above the cut-off point for significance, as defined by the authors. There was also a significant benefit with vardenafil over placebo for the secondary outcome GAQ. There was evidence of statistical heterogeneity for this outcome.

There was no statistically significant association between vardenafil and serious cardiovascular events or death. Vardenafil was associated with a higher rate of treatment-emergent adverse events, with headache, flushing, rhinitis-sinusitis and dyspepsia occurring at least twice as often. All adverse effects were more frequent at higher doses, compared with placebo, with incidence rates higher in the flexible-dose studies than in the fixed-dose studies. Discontinuations were greater with vardenafil than with placebo.

Authors' conclusions

In the broad population of men with ED, vardenafil safely and consistently improved all aspects of erectile functioning assessed after 12 weeks.

CRD commentary

The review addressed a clear research question using defined inclusion criteria. A range of databases was searched and appropriate attempts were made to identify unpublished studies. Appropriate procedures were used to minimise the possibility of error and bias in the review. Study quality was assessed and reported. Relevant participant characteristics were presented, although four of the trials were only available as abstracts and, therefore, relevant details were not available from all of the studies. It was unclear whether the trials only available as abstracts were completed trials. Statistical heterogeneity was assessed, but only for all drug doses combined. Where there was evidence of statistical heterogeneity, possible causes were not investigated or discussed. The authors' conclusions appear to follow from the evidence presented, although the reliability of them is unclear given the concerns about the lack of detail on the participants and the heterogeneity.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors highlighted several important areas for future research. In particular, the efficacy of vardenifil according to the etiology of ED, baseline severity, patient age and prior use of sildenafil; the consistency of efficacy beyond 12 weeks; and its efficacy compared with other active treatments.

Bibliographic details

Markou S, Perimenis P, Gyftopoulos K, Athanasopoulos A, Barbalias G. Vardenafil (Levitra) for erectile dysfunction: a systematic review and meta-analysis of clinical trial reports International Journal of Impotence Research 2004; 16(6): 470-478. [PubMed: 15229625]

Indexing Status

Subject indexing assigned by NLM

MeSH

3',5'-Cyclic-GMP Phosphodiesterases; Cyclic Nucleotide Phosphodiesterases, Type 5; Erectile Dysfunction /drug therapy; Humans; Imidazoles /adverse effects /therapeutic use; MEDLINE; Male; Penile Erection; Phosphodiesterase Inhibitors /therapeutic use; Phosphoric Diester Hydrolases; Piperazines /adverse effects /therapeutic use; Placebos; Randomized Controlled Trials as Topic; Sulfones; Treatment Outcome; Triazines

AccessionNumber

12005009084

Database entry date

30/11/2005

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.