Postmenopausal osteoporosis: patient choices and outcomes

Ipriflavone modulates IGF-I but is unable to restore bone in rats

Previously it has been reported that ipriflavone can prevent bone loss in ovarian hormone deficient rats. The present study evaluated whether ipriflavone was able to restore bone mass in osteopenic ovariectomized rats. Seventy-two, 90 day-old Sprague-Dawley rats were divided into six groups (sham two groups; ovariectomized four groups). Thirty-five days from the date of surgery, one sham and one ovx group were killed to verify the occurrence of bone loss. The remaining four groups were sham, ovx, ovx + ipriflavone (100 mg[sol ]kg body weight per day), or ovx + 17beta-estradiol (10 microg[sol ]kg body weight daily) for a period of 65 days. Ipriflavone was ineffective in restoring bone density and unlike estrogen did not prevent bone resorption as evidenced by increased (p < 0.05) urinary excretion of hydroxyproline and serum tartrate-resistant acid phosphatase activity. Ipriflavone increased (p < 0.05) the expression of IGF-I in the femur. These observations suggest that higher doses of ipriflavone or longer-term studies may be necessary to restore bone mass.

Compliance with oral HRT in postmenopausal women in clinical trials--meta analysis

OBJECTIVE

To assess compliance with oral hormone replacement therapy (HRT) over time in postmenopausal women in clinical trials and to examine aspects of study conduct (e.g. randomized vs. nonrandomized design) that might be associated with observed compliance rates.

METHODS

Aggregation of data from the available published studies using meta-analysis. Eligible studies had to be clinical trials reporting compliance with oral HRT among postmenopausal women and have a sample size of at least 20. MEDLINE and EMBASE databases were used through January 1998 to find studies that assessed compliance with oral HRT in postmenopausal women in clinical trials. Summary estimates of compliance, and of associations between compliance and features of study conduct, were computed allowing for clustering of data within studies.

RESULTS

Thirty reports met the inclusion criteria. Overall compliance at about 1 year on average was 83.4%. In a multivariable model, one variable, whether compliance was the primary objective of the study or not, remained statistically significant, even after adjustment for clustering (odds ratio=0.47, 95% confidence interval: 0.22-1.00, P=0.05).

CONCLUSIONS

This study supports the importance of using appropriate methods for measuring compliance, if valid estimates of compliance are a serious objective of an investigation. There has been much discussion about the need for increased medication compliance, particularly for those medications used for prevention, but the means and methods to improve compliance remain elusive.

Does serum cholesterol contribute to vertebral bone loss in postmenopausal women?

Recent in vitro and animal studies suggest that cholesterol and its metabolites inhibit the functional activity of osteoblasts and thereby induce reduced bone mineralization. However, scant information is available on the clinical implication of these findings with special regard to postmenopausal bone loss. Therefore, the aim of the present study was to investigate cross-sectional and longitudinal associations between serum cholesterol, bone mineral density (BMD), and bone turnover in 340 postmenopausal women aged 50-75 years (mean 59 years), who were followed for 8.3 +/- 1.1 years. BMD in the lumbar spine, distal forearm, and total hip was measured by dual energy X-ray absorptiometry. Other study variables were physical measures, serum cholesterol, serum markers of bone turnover, and self-reported information on various risk factors for osteoporosis. At baseline, serum cholesterol showed significant negative correlation with BMD at the lumbar spine (r = -0.21, P < 0.0001) and distal forearm (r = -0.14, P = 0.013), but not at the hip. No associations of serum cholesterol with serum osteocalcin (r = 0.054, P = 0.317) and CTX (r = -0.027, P = 0.623) were, however, noted. After adjustment for age and BMI, the negative correlation remained significant at the lumbar spine (r = -0.16, P = 0.004), but not at the distal forearm (r = -0.018, P = 0.738). At the end of the 8-year follow-up, the correlation between serum cholesterol and spine BMD was not observed. Those with the largest increases in serum cholesterol, however, showed the greatest decreases in spine BMD independently of the changes in BMI (r = -0.16, P = 0.004). The correlation between the changes in serum cholesterol and the simultaneous changes in osteocalcin (r = 0.081, P = 0.140) and CTX (r = 0.042, P = 0.441) were statistically insignificant. Thus, our results suggest that the weak associations between spine BMD and serum cholesterol can be explained by the fact that both variables are simultaneously affected by estrogen deficiency rather than by a direct influence of serum cholesterol on osteoblast function.

A comparison of observational studies and randomized, controlled trials

BACKGROUND

For many years it has been claimed that observational studies find stronger treatment effects than randomized, controlled trials. We compared the results of observational studies with those of randomized, controlled trials.

METHODS

We searched the Abridged Index Medicus and Cochrane data bases to identify observational studies reported between 1985 and 1998 that compared two or more treatments or interventions for the same condition. We then searched the Medline and Cochrane data bases to identify all the randomized, controlled trials and observational studies comparing the same treatments for these conditions. For each treatment, the magnitudes of the effects in the various observational studies were combined by the Mantel-Haenszel or weighted analysis-of-variance procedure and then compared with the combined magnitude of the effects in the randomized, controlled trials that evaluated the same treatment.

RESULTS

There were 136 reports about 19 diverse treatments, such as calcium-channel-blocker therapy for coronary artery disease, appendectomy, and interventions for subfertility. In most cases, the estimates of the treatment effects from observational studies and randomized, controlled trials were similar. In only 2 of the 19 analyses of treatment effects did the combined magnitude of the effect in observational studies lie outside the 95 percent confidence interval for the combined magnitude in the randomized, controlled trials.

CONCLUSIONS

We found little evidence that estimates of treatment effects in observational studies reported after 1984 are either consistently larger than or qualitatively different from those obtained in randomized, controlled trials.