Clinical Briefs

By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is an advisor for Endo, Kowa, Pricara, and Takeda.

Our Patients May Not be Getting the Message About Colon Cancer Screening

Source: Barton MK. CA Cancer J Clin 2012;62:1-2.

In its most recent guidance regarding colon cancer screening (CCS), the American Cancer Society iterated a new position on choice of tests, basically stating that "the best test is the test you can get done." This new orientation reflects both the philosophical and logistical realities that of the preventable cancers, CCS is the area in which we see the most missed opportunity. Currently, only about 60% of individuals are receiving any of the age-appropriate CCS available.

Barton reports on an observational study performed in 26 clinics in Michigan in which physicians volunteered to have patient visits audio-recorded, understanding that investigators were evaluating communication in general, but the study physicians were not told about any particular disease-state focus. Prior to the office visit, patients (n = 415) wrote down what information they felt they needed to understand to decide whether to participate in CCS.

Of the patients who indicated that information about test accuracy was very important, such information was imparted by the physician only 7% of the time. Even though most patients (77%-89%) rated information about pros/cons of testing and alternative testing methods as very important, communication about these components was similarly lacking (4% and 29%, respectively).

About half of patients did have questions about CCS, but clinicians invited questions in only about 5% of interviews. These well-demonstrated communication gaps provide an important opportunity for meeting patient needs, which will hopefully translate into better adherence with CCS recommendations.

BMD Testing: What's the Appropriate Interval?

Source: Gourlay ML, et al. N Engl J Med 2012;366:225-233.

Several national and international guidelines provide advice about when to consider bone mineral density (BMD) screening to identify osteoporosis (OSPS) based upon age, ethnicity, gender, and other risk factors. However, conspicuously lacking from these guidelines is an evidence-based path for when to recheck BMD, once a baseline is established.

The Study of Osteoporotic Fractures enrolled mid-life American women without OSPS at baseline (n = 4957; age ≥ 67) in an observational study. After baseline DEXA, scans were performed again at year 2, year 6, year 8, year 10, and year 16. The primary outcome of the trial was the interval after a baseline DEXA at which point 10% of participants would progress from normal BMD or osteopenia to OSPS.

As might be completely intuitive, the interval for progression to lower BMD levels was proportional to the degree of bone loss at baseline. That is, the interval before progression to OSPS for women with normal BMD or mild osteopenia at baseline was about 17 years; for those with moderate osteopenia, the interval was 4.7 years, and 1.1 years for women with advanced osteopenia (T-score = -2 to -2.49).

Based on these data, the authors suggest that for women with baseline T scores > -1.5, there is little likelihood of progression to osteoporosis (< 10%) over 15 years, and — in the absence of additional new risk factors to dictate otherwise — retesting BMD might be reasonably put off for that same interval. For women with lower levels of BMD at baseline, however, a shorter interval for re-testing would be appropriate: 5 years for those with moderate osteopenia, and only 1 year for those with advanced osteopenia.

How Common is Vitamin B12 Deficiency in Patients on Metformin?

Source: Reinstatler L, et al. Diabetes Care 2012;35:327-333.

It has been recognized since the first published metformin clinical trials that B12 levels were impacted. For instance, a recent clinical trial found a 19% reduction in B12 levels (compared with placebo) after 4 years. Perhaps because common clinical signs of B12 deficiency (e.g., anemia, neuropathy, cognitive impairment) related to metformin treatment are rarely seen, clinicians have had low levels of apprehension about the effects of metformin on vitamin B12 levels.

How common is B12 deficiency in patients on metformin? An answer can be found in the NHANES data. Comparing adults with (n = 1621) and without (n = 6867) type 2 diabetes, Reinstatler et al report that biochemical deficiency of B12 (defined as level B12 < 148 pmol/L) was seen in 5.8% of diabetics on metformin; this was more than twice as frequent as the prevalence among diabetics not on metformin (2.4%), and about more than 1.5 times as frequent as in non-diabetics (3.3%).

One curious finding from this study was that consumption of B12 supplements by diabetics did not reduce the frequency of deficiency. It might be that the amount typically found in over-the-counter multivitamin supplements (6 mcg) is insufficient, even though the amount recommended by the Institute of Medicine is only 2.4 mcg/day.