There was some crap science reported in 2002 that encouraged older women to give up their Hormone Replacement Therapy. The science was crap because the differences between groups that it relied on were not apparently statistically significant. See my post of October 27 2003. There is also a dismissive academic re-analysis of the 2002 “findings” here.

Nonetheless, everybody hates drug companies so doctors everywhere jumped on the bandwagon and tried to get women off their pills. We now see how dangerous crap science is. It looks like the advice could have killed a lot of women. Read this report:

“Hormone replacement therapy significantly increases the life expectancy of older women, but only if they begin taking the drugs soon after the onset of the menopause, a major review of the evidence has found. A new analysis of 30 trials involving a total of 26,708 women has revealed that the benefits of the treatment substantially outweigh the risks, so long as it is started before a woman reaches the age of 60. In women who started HRT at 56, the risk of death from all causes was cut by 39 per cent”.

Some more high quality data has just emerged which scotches the risk of increased heart attacks in women on HRT but which did find a slightly increased incidence of stroke. Abstract follows:

Postmenopausal hormone therapy and risk of cardiovascular disease by age and years since menopause

By Rossouw JE et al.

CONTEXT: The timing of initiation of hormone therapy may influence its effect on cardiovascular disease.

OBJECTIVE: To explore whether the effects of hormone therapy on risk of cardiovascular disease vary by age or years since menopause began.

DESIGN, SETTING, AND PARTICIPANTS: Secondary analysis of the Women’s Health Initiative (WHI) randomized controlled trials of hormone therapy in which 10,739 postmenopausal women who had undergone a hysterectomy were randomized to conjugated equine estrogens (CEE) or placebo and 16,608 postmenopausal women who had not had a hysterectomy were randomized to CEE plus medroxyprogesterone acetate (CEE + MPA) or placebo. Women aged 50 to 79 years were recruited to the study from 40 US clinical centers between September 1993 and October 1998.

MAIN OUTCOME MEASURES: Statistical test for trend of the effect of hormone therapy on coronary heart disease (CHD) and stroke across categories of age and years since menopause in the combined trials.

RESULTS: In the combined trials, there were 396 cases of CHD and 327 cases of stroke in the hormone therapy group vs 379 cases of CHD and 239 cases of stroke in the placebo group. For women with less than 10 years since menopause began, the hazard ratio (HR) for CHD was 0.76 (95% confidence interval [CI], 0.50-1.16); 10 to 19 years, 1.10 (95% CI, 0.84-1.45); and 20 or more years, 1.28 (95% CI, 1.03-1.58) (P for trend = .02). The estimated absolute excess risk for CHD for women within 10 years of menopause was -6 per 10,000 person-years; for women 10 to 19 years since menopause began, 4 per 10,000 person-years; and for women 20 or more years from menopause onset, 17 per 10,000 person-years. For the age group of 50 to 59 years, the HR for CHD was 0.93 (95% CI, 0.65-1.33) and the absolute excess risk was -2 per 10,000 person-years; 60 to 69 years, 0.98 (95% CI, 0.79-1.21) and -1 per 10,000 person-years; and 70 to 79 years, 1.26 (95% CI, 1.00-1.59) and 19 per 10,000 person-years (P for trend = .16). Hormone therapy increased the risk of stroke (HR, 1.32; 95% CI, 1.12-1.56). Risk did not vary significantly by age or time since menopause. There was a nonsignificant tendency for the effects of hormone therapy on total mortality to be more favorable in younger than older women (HR of 0.70 for 50-59 years; 1.05 for 60-69 years, and 1.14 for 70-79 years; P for trend = .06).

CONCLUSIONS: Women who initiated hormone therapy closer to menopause tended to have reduced CHD risk compared with the increase in CHD risk among women more distant from menopause, but this trend test did not meet our criterion for statistical significance. A similar nonsignificant trend was observed for total mortality but the risk of stroke was elevated regardless of years since menopause. These data should be considered in regard to the short-term treatment of menopausal symptoms.

Putting that into plain English: 2% of women on the pills had a stroke versus 1% who were not on anything. That’s a pretty tiny risk. And all drugs and therapies have side effects. The iron rule of drug therapy is: No side effects = no main effects either. So the slightly increased risk of stroke has to be weighed against the risk of brittle bones. Any woman with either a family history of osteoporosis or some osteoporosis already visible in herself via a bone-density scan would be pretty foolish not to go onto HRT in my non-medical opinion. By going onto HRT you would be taking a tiny risk in order to avert an almost certain major problem.

There are some more reactions to the recent study here.

NHS blog doctor has a coverage of the subject but I cannot see why he is so indecisive about what to recommend in the circumstances. Maybe he can’t follow the statistics. He would not be alone in that. I used to teach social statistics in a major Australian university and I find medical statistics pretty obfuscatory. They seem uniformly designed to make mountains out of molehills.

Many times in the academic literature I have excoriated my colleagues in psychology and sociology for going ga-ga over very weak correlations but what I find in the medical literature makes the findings in the social sciences look positively muscular. In fact, medical findings are almost never reported as correlations — because to do so would exhibit how laughably trivial they generally are.

The 2002 study was the basis for a great drama, with the risk of breast cancer particularly highlighted. The study was halted when too many women on HRT were getting cancer. The women on HRT in the study were told to throw away their pills because they were too risky. And millions of women worldwide followed suit.

But what they actually found was that 3 women in a thousand in their study group who were NOT taking HRT pills got breast cancer. So how many who WERE taking HRT got breast cancer? 4. Yes. 4. 4 out of a thousand compared to 3 out of a thousand. See here. Some people have just got no sense of proportion.

So, regardless of statistical significance (statistical significance simply tell you that the result was unlikely to be an effect of small sample size), there was absolutely no real-world significance in the result. It could have been due to any number of randomly-present factors. Aren’t we lucky to have such wise medical attention-seekers researchers to guide us?


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