Reply: ß-Blocker effects on sexual function

Giuseppe M.C Rosano, Antonello Silvestri*, Roberto Patrizi, Giuseppe Marazzi, Elena Cerquetani, Cristiana Vitale and Massimo Fini

Cardiovascular Research Unit, Department of Medical Sciences, San Raffaele – Roma, Tosinvest Sanità, via della Pisana 235, 00163 Rome, Italy

* Corresponding author. Tel.: +39-6660581; fax: +39-69636715
E-mail address: antosilv{at}hotmail.com

Received 8 December 2003; accepted 12 December 2003

Dear Sir

In their letter, Jaarsma et al. raised some methodological concerns regarding the study we conducted on the effect of ß-blockers on erectile dysfunction. These criticisms are in our view the result of a misinterpretation of the manuscript.

The first criticism is related to the small number of patients included in each group. However the number of patients required in clinical trials depends on the incidence of the events in the population studied and on the expected effect of the treatment on those events. It has been reported that ß-blockers may induce ED in 25% of cases in open studies while clinical studies failed to support any effect of ß-blockers on ED.1–3 Therefore, forecasting an incidence of ED of 5% in patients blinded on the treatment and of 25% in those knowing the side effect of the drug it becomes evident that the number of patients included in each group is more than adequate to detect a difference.

Patients were randomized into the three groups and, as stated in the manuscript they were randomized again to sildenafil or placebo once they reported ED at the follow up visit.

Jaarsma et al. suggest that there was a difference in the incidence of diabetes and hypertension between group, and although this difference was not statistically significant could have been responsible for the different incidence of ED between groups. Firstly, if read with attention, it is stated that none of the patients was suffering from ED at baseline and the incidence of risk factors for cardiovascular disease was similar amongst groups. The fact that none of the patients had ED at baseline implies that the different incidence of risk factors was not related to the presence of ED at baseline. Secondly, the sum of patients with diabetes and hypertension in the patients blinded on treatment, in those knowing they were taking a ß-blocker and in those also informed on the side effects on erectile function was 24, 20 and 27, respectively. It is stated in the manuscript that the number of patients that reported of ED at follow up was 1, 5 and 10, respectively. It becomes clear that the argument that the uneven distribution of risk factors could have been responsible of the different incidence of ED is not justified. Furthermore, the fact that there might have been one more patient with diabetes or hypertension in one group or in another is a unshared critical since it is known that is the clustering and severity or risk factors that influence endothelial function rather than the presence of the single risk factor. The severity of each risk factor has its importance in the single patient since for example in patients with diabetes the incidence of erectile dysfunction varies according to the severity, duration of the disease and the use of insulin. In any case, since none of the study patients had erectile dysfunction at baseline it is clear that the distribution of risk factors did not have had any relevance in causing a different incidence of ED between groups.

Jaarsma et al. also suggest that the difficulty to discuss ED due to embarrassment or to ignorance may make easier to `blame it to a pill' in the `atenelol-know side effects' group patients but forget to consider that all patients had already received a questionnaire at baseline when they reported no ED.

As stated in the manuscript ED was diagnosed and defined according to the validated IIEF questionnaire taking into account the score obtained from the answers on the erectile function domains. Patients were diagnosed as having ED if they had a score compatible with the international diagnosis of ED moderate or severe. None of the patients reported a score compatible with mild ED ("minimal" is not an internationally accepted definition) in the erectile function domains of the IIEF questionnaire.

Jaarsma et al. mention that a 16% incidence of ED is high compared with the general population without knowing the exact incidence of the problem in a population of normal subjects of the same age as that of our patient population is around 65%.

The comment of Jaarsma et al. on the fact that the conclusions of our article suggest that "patients might benefit if health care providers withhold information from patients about the potential sexual side effects of medications" is an over- and misinterpretation of our conclusions. Since by saying that the expectations of side effects may influence the occurrence of erectile dysfunction we never said that doctors should withhold a complete information to patients. Conversely we strongly believe that the results of our study will help doctors to give a clear explanation on the side effects of the drug thereby increasing patient compliance.

References

  1. Keene LC, Davies PH. Drug-related erectile dysfunction. Adverse Drug React. Toxicol. Rev. 1999;18(1):5–24.[Medline]
  2. Rosen RC, Kostis JB, Jekelis A et al. Sexual sequelae of antihypertensive drugs: treatment effects on self-report and physiological measures in middle-aged male hypertensives. Arch. Sex Behav. 1994;23(2):135–152.[Medline]
  3. Rosen RC, Kostis JB, Jekelis AW. ß-Blocker effects on sexual function in normal males. Arch. Sex Behav. 1988;17(3):241–255.[Medline]




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