Sex Bias in Studies Selected for Clinical Guidelines

Influence of patient sex and gender on medication use, adherence, and prescribing alignment with guidelines

BACKGROUND

This study evaluates the differences between women and men in medication use, medication adherence, and prescribing alignment with clinical guidelines.

METHODS

We conducted an analysis of pharmacy and medical claims for 29.5 million adults with prescription benefits administered by a pharmacy benefits manager in the United States, age 18 and older, between January 1, 2010, and December 31, 2010. Prevalence and intensity of medication use were evaluated by sex, age group, and medication type (acute vs. chronic). Medication adherence was measured by the percentage of patients with a medication possession ratio (MPR) ≥80%. The percentage of patients receiving guideline-based treatment was measured for diabetes and select cardiovascular conditions.

RESULTS

The study population comprised 16.0 million women and 13.5 million men with continuous pharmacy benefit eligibility. Women were significantly more likely than men to use one or more medications during the analysis period (68% vs. 59%, respectively, p<0.001), and women used more unique medications, on average, than men (5.0 vs. 3.7 medications per year, respectively, p<0.001). Differences in drug utilization were observed for all age groups and medication types. For all clinical metrics evaluated, women were less likely than men to be adherent in their use of chronic medications, and they were less likely to receive the medication treatment and monitoring recommended by clinical guidelines.

CONCLUSIONS

There are significant disparities between women and men in their intensity of medication use, their adherence to medications, and their likelihood of receiving guideline-based drug therapy. These differences may indicate a need for more personalized drug selection and therapeutic management to improve clinical outcomes.

The evidence-based medicine paradigm: where are we 20 years later? Part 1

The evidence-based medicine (EBM) paradigm, introduced in 1992, has had a major and positive impact on all aspects of health care. However, widespread use has also uncovered some limitations; these are discussed from the perspectives of two clinicians in this, the first of a two part narrative review. For example, there are credible reservations about the validity of hierarchical levels of evidence, a core element of the EBM paradigm. In addition, potential and actual methodological and statistical deficiencies have been identified, not only in many published randomized controlled trials but also in systematic reviews, both rated highly for evidence in EBM classifications. Ethical violations compromise reliability of some data. Clinicians need to be conscious of potential limitations in some of the cornerstones of the EBM paradigm, and to deficiencies in the literature.

Sexual dimorphisms in the immune system of catechol-O-methyltransferase knockout mice

The enzyme catechol-O-methyltransferase (COMT) is part of the metabolic pathway of 17β-estradiol, converting 2-hydroxyestradiol to 2-methoxyestradiol. We recently showed that administration of the COMT product 2-methoxyestradiol has anti-inflammatory and anti-osteoporotic effects. We have now investigated whether COMT affects the immune system, by immunologically phenotyping COMT deficient (COMT(-/-)) mice. Immunoglobulin production, T lymphocyte proliferation, NK cell cytotoxicity and oxygen radical production were assessed. In male COMT(-/-)-mice, the total number of T-, and B-lymphocytes from spleen increased but the T-cell proliferative response decreased. The NK cell population shifted toward less mature cells, leaving cytotoxic capacity unaffected. In COMT(-/-)-females, a higher frequency of neutrophils was found but the oxygen radical production was unaltered. In conclusion, only minor changes of the immune system were seen in COMT deficient mice, and the changes were usually seen in males. This study provides clues into how COMT activity, and hence gender differences, affects the immune system.