Hormone replacement therapy and cardiovascular disease: the case for a randomized controlled trial

Hormone replacement therapy for preventing cardiovascular disease in post-menopausal women

BACKGROUND

There is apparently compelling evidence, from observational studies, that hormone replacement therapy (HRT) may have benefits in reducing cardiovascular events in post-menopausal women. However, these observational data are subject to biases and confounding and require support from formally designed randomised controlled trials of the effects of HRT on cardiovascular disease risk.

OBJECTIVES

To assess the effects of HRT for the primary and secondary prevention of cardiovascular diseases in post-menopausal women.

SEARCH STRATEGY

We searched MEDLINE (1998 to December 2002)), EMBASE (1998 to December 2002), the Cochrane Controlled Trials Register (CCTR) (Issue 4 2002), the National Research Register (1998 to present), Clinical Trials.gov (1998 to present), and the database of Spanish Clinical Trials (1998 to present) and reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials comparing HRT with controls (placebo or no treatment) with a minimum follow up of 6 months for treating or preventing cardiovascular disease in postmenopausal women with or without cardiovascular disease.

DATA COLLECTION AND ANALYSIS

Three independent reviewers extracted information from the articles, solving discrepancies by consensus. All outcomes studied were dichotomous. Risk ratios and 95% confidence intervals (CI) were calculated for each study and plotted. Random effects meta-analysis was used in efficacy outcomes (cardiovascular events) and fixed-effects meta-analysis in variables regarding side effects (deep venous thrombosis).

MAIN RESULTS

No protective effect of HRT was seen for any of the cardiovascular outcomes assessed: all cause mortality, cardiovascular death, non-fatal MI, venous thromboemboli or stroke. Higher risks of venous thromboembolic events (Relative risk (RR) 2.15, 95% CI 1.61 to 2.86), pulmonary embolus (RR 2.15, 95% CI 1.41 to 3.28), and stroke (RR 1.44, 95% CI 1.10 to 1.89) was found in those randomised to HRT compared with placebo. No substantial heterogeneity (p <0.1) was detected in any of the outcomes studied.

AUTHORS' CONCLUSIONS

At present, a recommendation for initiating HRT for the reason of preventing cardiovascular events in post-menopausal women (with or without cardiovascular disease) should not be made. Women with other risk factors for venous thromboembolic events should be discouraged from using HRT if the sole goal is to prevent cardiovascular events.

American Society of Clinical Oncology technology assessment on breast cancer risk reduction strategies: tamoxifen and raloxifene

OBJECTIVE

To conduct an evidence-based technology assessment to determine whether tamoxifen and raloxifene as breast cancer risk-reduction strategies are appropriate for broad-based conventional use in clinical practice.

POTENTIAL INTERVENTION

Tamoxifen and raloxifene.

OUTCOME

Outcomes of interest include breast cancer incidence, breast cancer-specific survival, overall survival, and net health benefits.

EVIDENCE

A comprehensive, formal literature review was conducted for tamoxifen and raloxifene on the following topics: breast cancer risk reduction; tamoxifen side effects and toxicity, including endometrial cancer risk; tamoxifen influences on nonmalignant diseases, including coronary heart disease and osteoporosis; and decision making by women at risk for breast cancer. Testimony was collected from invited experts and interested parties.

VALUES

More weight was given to publications that described randomized trials. BENEFITS/HARMS/COSTS: The American Society of Clinical Oncology (ASCO) Working Group acknowledges that a woman's decision regarding breast cancer risk-reduction strategies will depend on the importance and weight attributed to the information provided regarding both cancer and non-cancer-related risks.

CONCLUSIONS

For women with a defined 5-year projected risk of breast cancer of >/= 1.66%, tamoxifen (at 20 mg/d for up to 5 years) may be offered to reduce their risk. It is premature to recommend raloxifene use to lower the risk of developing breast cancer outside of a clinical trial setting. On the basis of available information, use of raloxifene should currently be reserved for its approved indication to prevent bone loss in postmenopausal women. Conclusions are based on single-agent use of the drugs. At the present time, the effect of using tamoxifen or raloxifene with other medications (such as hormone replacement therapy), or using tamoxifen and raloxifene in combination or sequentially, has not been studied adequately. The continuing use of placebo-controlled trials in other risk-reduction trials highlights the current unanswered issues concerning the use of such interventions, especially when the influence on net health benefit remains to be determined. Breast cancer risk reduction is a rapidly evolving area. This technology assessment represents an ongoing process with existing plans to monitor and review data and to update recommendations in a timely matter. (See

VALIDATION

The conclusions of the Working Group were evaluated by the ASCO Health Services Research Committee and by the ASCO Board of Directors.

SPONSOR

American Society of Clinical Oncology.