Summary of protocol
This was a randomised, single blind crossover study of testosterone replacement therapy versus placebo in men with hypogonadism and coronary heart disease. Men who had never had an exercise test were required to perform a run-in exercise test according to the standard Bruce protocol. Participants were randomly assigned to testosterone injections (1 ml of Sustanon 100, 100 mg testosterone/ml) every two weeks or placebo for one month. Drug order was allocated by blocks of computer generated random numbers. Before and after the month of treatment, patients were assessed in the cardiology department with questionnaires, blood tests, and a treadmill exercise test. After the initial month of treatment there was a month washout period of no treatment, after which the patient crossed over to the alternate arm of treatment. At the end of the three month study period, patients continued taking testosterone as prescribed by their own doctor.
Twelve men with coronary artery disease (> 70% stenosis of a major coronary artery at coronary angiography) or previous proven myocardial infarction with typical symptoms of angina pectoris were recruited from August 2002 to December 2002. These patients were referred from a male andrology clinic and each had a clinical need for testosterone replacement as judged by a consultant endocrinologist (THJ). All patients were naive to androgen replacement and their androgen status had never been investigated. All patients gave informed written consent and the local ethics committee approved the protocol. No changes were made to antianginal medication for four weeks before or during the trial. Inclusion criteria for patients were male sex, age greater than 18 years, and a clinical indication for testosterone therapy. Patients were excluded if they had a prostate specific antigen (PSA) concentration above the normal range or any other contraindication to androgen therapy. They were also excluded if they had left main stem (or equivalent) stenosis, a coronary or cerebrovascular event or other trial drugs within the preceding three months, severe hypertension (blood pressure > 180/114 mm Hg), significant arrhythmia, poor physical mobility, and ECG abnormalities precluding ST segment analysis on a treadmill.
Of 12 patients screened, one patient did not meet accepted ECG criteria during exercise treadmill testing and 11 were randomly assigned to treatment. One study patient underwent an elective coronary artery bypass earlier than expected and was withdrawn from the study. Complete data were available for 10 patients; table 1 presents baseline data.
We used intramuscular injection of Sustanon 100 every two weeks, which is the usual method of initiating testosterone treatment in men with hypogonadism. Testosterone (Sustanon 100, 100 mg testosterone/ml; Organon Laboratories Ltd, Cambridge, UK) or placebo (1 ml of 0.9% normal saline) in an identical syringe was given by deep intramuscular injection to the buttock every two weeks by a member of the research staff. Patients were blinded to the identity of the injection and the drug was drawn up away from the patient.
Patients were assessed at weeks 0, 4, 8, and 12 between 8 am and 9.30 am under fasting conditions and within 10–14 days of the final injection of that phase. Demographic details, hormone profiles, PSA concentration, and antianginal drug use were recorded at the beginning of the trial. Treadmill exercise testing was performed at weeks 0, 4, 8, and 12 according to the Bruce protocol (MAX-1 Marquette advanced exercise system, software version 002E). Patients continued their medication but were asked not to use glyceryl trinitrate for six hours before the test. The primary end point was defined as the time to 1 mm ST segment depression and exercise tests were terminated when this criterion was met. All treadmill tests were supervised by a cardiac technician with one investigator (CJM) present.
Electrocardiographic data were analysed by the Marquette 002E software package. This system analyses the signal averaged ECG and produces a graphical display of the level of the ST segment 80 ms after the J point against time. Time to 1 mm ST segment depression was measured from computer derived analysis effectively eliminating observer bias. All blood tests were performed at weeks 0, 4, 8, and 12; total testosterone and sex hormone binding globulin were measured by enzyme immunoassay (DRG Instruments GmbH, Marburg, Germany). Bioavailable testosterone was calculated by a modification of the method described by Tremblay and Dube.17
In this method testosterone is removed from the test serum by the addition of activated charcoal and replaced by testosterone labelled with hydrogen-3, which binds to sex hormone binding globulin and other plasma proteins in equimolar concentrations as native testosterone. Sex hormone binding globulin-bound testosterone is then precipitated out of the sample by the addition of cold ammonium sulfate. The remaining 3
H-testosterone, comprising the unbound fraction and the fraction weakly bound to albumen, is then measured by a β counter. Full blood count, glucose concentration, and lipid profiles were measured with standard hospital assays. Low density lipoprotein (LDL) cholesterol was calculated with the Friedewald equation ((LDL cholesterol
total cholesterol − (high density lipoprotein (HDL) cholesterol + triglyceride / 2.2)). Serum tumour necrosis factor α (TNFα) was assayed with high sensitivity enzyme linked immunosorbent assay (ELISA) (Quantikine R&D, Abingdon, UK). PSA was measured at the beginning and end of the trial.
Patients were asked to complete the Seattle angina questionnaire (an objective measure of quality of life in patients with angina), the Beck depression inventory (a commonly used assessment of mood and depressive symptoms), the general health screening questionnaire (a multipurpose mood and general wellbeing screening tool), and the androgen deficiency in the adult male screening questionnaire at weeks 0, 4, 8, and 12. The androgen screening questionnaire is a 10 statement true or false answer sheet. A positive screen is defined as a score of 3 or more out of 10 or a single positive response to any one of two highly specific questions: “Do you have reduced libido (sex drive)?” or “Do you have reduced ability to maintain erections?”
Statistical analysis and sample size calculation
From previous work with eugonadal men, in which we found a 37% increase in time to 1 mm ST segment depression with testosterone, we calculated that for hypogonadal men 12 participants would be needed to detect a 50% increase in a crossover study protocol, with 80% power and 5% significance.
The raw data were analysed with a statistical software package (SPSS version 11.5, SPSS Inc, Chicago, Illinois, USA). The data were tested against a normal distribution with Kolmogorov-Smirnov tests. All the biological data were found to be normally distributed and therefore were tested with paired t tests. Questionnaire scores were compared by Wilcoxon matched pair tests. The baseline results of each crossover phase were examined and tested for period or treatment period interaction. When no such interaction was found data were deemed suitable for further analysis. Unless otherwise stated, data are expressed as mean (SD). Significance was accepted when p < 0.05.