Viagra trials in specific conditions

Several studies have assessed International Index of Erectile Function results before and after Viagra treatment in men with erectile dysfunction caused by certain specific conditions. This research is interesting because it throws more light on the IIEF and the effect of Viagra; for example, do these men show lower scores on the IIEF before treatment, and do they show a different response to treatment according to the condition from which their erectile dysfunction originates? This helps to explain the efficacy of Viagra in specific conditions, namely: diabetes, heart disease, depression and spinal cord injury.

Viagra and Diabetes

Rendell reported the very first controlled trial of Viagra in diabetic men with erectile dysfunction, in which almost 270 men with diabetes and erectile dysfunction were randomly allocated to receive three months of flexible-dose treatment with either a placebo or Viagra. The results were clear: mean scores on Question 3 increased from 1.8 at the start of the investigation to 3.2 after three months, and in response to Question 4, from 1.5 at the start of the investigation to 2.9 in the group receiving Viagra group after three months. The comparative figures in the control group were 2.0 for Question 3 and 1.6 for Question 4 after three months. These differences were very significant (P less than 0.001). Moreover, 61% of men in the Viagra treatment group reported at least one successful episode of intercourse, while only 22% of men receiving the placebo did so. There's no doubt men with diabetes have more erectile dysfunction than men who do not: this shows up in lower scores on the IIEF both before and after treatment.

Viagra and spinal cord injury

Men with spinal cord injury often have severe erectile dysfunction caused by a loss of nerve cell supply to the erectile mechanism. These men will have lower starting scores than other groups of men with ED, but their response to treatment depends on the type and level of their  injury. Giuliano conducted a study on 178 European men who had spinal-cord injury and found that men treated with Viagra relative to placebo showed significantly improved erectile function; indeed, the men recorded many more successful attempts at intercourse, with eighty per cent of men reporting improved intercourse when they took Viagra, compared with 10% who took the placebo.

Viagra and Heart disease

Conti reported on results from studies of 357 patients with ischaemic heart disease who were also mostly taking medication for hypertension, ^{diabetes or} hyperlipidemia. They reported mean scores for Question 3 of 1.8 and for Question 4 of 1.6 before treatment, while the results after treatment with Viagra were 3.3 and 3.2 respectively. Comparative results with the placebo were 2.0 and 1.8 respectively. These differences were highly significant (P < 0.0001). Erectile function scores after treatment were also increased with Viagra compared to the placebo (19.7 versus 10.9), and so were the scores for other areas of sexual function; the. International Index of Erectile Function scores matched the events that the men recorded in their logs of intercourse. All of this suggest that erectile dysfunction patients with ischaemic heart disease respond a little better to Viagra than those with diabetes, but a little less well than men with spinal cord injury.

^{Viagra and} Depression

Seidman analyzed a controlled trial of three months' treatment using flexible doses of Viagra (25-100 mg) versus placebo in 152 US men with erectile dysfunction and depression. The results clearly showed that Viagra can impact on erectile dysfunction caused by depression: before treatment, scores were 1.6 for Question 3, 1.4 for Question 4, and 9.3 for the erectile function score. After treatment with Viagra, the corresponding numbers were 3.7 for Question 3, 3.9 for Question Q4, and 23.4 for the erectile function overall score. After placebo, the comparative numbers were: 2.2 for Question Q3 and 2.0 for Question 4, and 12.4 for overall erectile function. Erectile Function scores went up - and so did the men's mood, which raises the question of whether the men were depressed because of their erectile problems or had erectile problems because they were depressed.

Summary

The International Index of Erectile Function has been important in all trials with Viagra to date, and its reliability is shown by the consistent pattern of findings which all the studies have shown - whatever condition the men had when they were assigned to the trials. Men with various causes of erectile dysfunction, such as diabetes, heart disease, depression, or ^{spinal cord injury}, have all shown a range of scores which intuitively follow what we would expect from Viagra based on what we know about its mechanism of action.

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