Clinical Briefs in Primary Care
Rationale for Zinc Supplementation in Older Adults with Wounds
Source: Sallit J. Ann Long-Term Care: Clin Care Aging 2012;20:39-41.
Zinc deficiency is defined as a serum zinc level < 60 mg/dL. Unfortunately, there is some question about the reliability of zinc levels to accurately reflect zinc status, since some persons with prototypic symptoms of zinc deficiency (loss of appetite, diarrhea, hair loss, delayed wound healing, and smell and taste disturbances) have normal zinc levels. Residents of long-term care facilities are at risk for zinc deficiency, both because they may be consuming diets that are lower in zinc and also because they may not absorb zinc from the diet as well as younger persons. For instance, one clinical trial of patients from nursing homes (n = 617) found that almost half had subnormal zinc levels. Some medications can compound the issue — diuretics can deplete zinc.
The roles of zinc in wound healing are diverse, including collagen and protein synthesis, cell proliferation, and immune function. The body's demands for zinc are thought to increase at the time of injury, and continue through the early inflammatory phase; hence, zinc deficiency at this time can delay wound healing.
When a long-term care facility resident sustains a wound, although it is reasonable to ascertain zinc status through serum levels and treat accordingly, it appears equally reasonable based upon a high level of suspicion of zinc deficiency to simply supplement zinc at moderate doses (15-30 mg/d), since such dosing is well tolerated. Indeed, a clinical trial at slightly higher supplementation doses (25-50 mg/d ¡Á 3 months) has been documented to have a beneficial effect on wound healing in zinc- deficient individuals. The authors suggest that 40 mg/d be the maximum dose administered to non-deficient persons, due to tolerability issues (diarrhea, nausea, vomiting, vertigo).
Occupational Stress and Hypertension
Source: Rosenthal T, Alter A. J Am Soc Hypertens 2012;6:2-22.
The consequences of job-related stress (JRS) have been the object of a great deal of research. Of course it is difficult to determine the best measurement tool for JRS, and it is equally difficult to explain how similar levels of JRS are interpreted and managed variably by different individuals. Some of the data on JRS and its relationship to blood pressure suggest that JRS need not necessarily be perceived to be associated with adverse effects. Nonetheless, several lines of evidence lead to the conclusion that identification of JRS is replicable and consequential in some settings.
For instance, a review of data from 34 studies on professional drivers (e.g., bus drivers) found a consistent increased risk of heart disease and hypertension, attributed to the wide range of psychological and physical stressors. To describe the inherent stressful conflict of bus drivers, the authors remind us that the drivers are constantly dealing with the competing agendas of staying on time and optimizing safety.
Despite the large amount of descriptive data that help us identify the negative impact of job stress on health, there is little substantive information that anyone has found highly effective methods to improve outcomes from JRS. It is likely that reducing JRS and its consequences will require interventions on a public health level.
Association of Psoriasis with CV Risk Factors
Source: Shapiro J, et al. J Am Acad Dermatol 2012;66:252-258.
In the last decade, the recognition that rheumatoid arthritis (RA) is associated with adverse cardiovascular (CV) outcomes has been increasingly highlighted, to the point that some voices suggest including the presence of RA as a formal CV risk factor of similar impact to having a low HDL. Psoriasis (PSR) and RA share some common features, especially including their responsiveness to similar disease-modifying therapies, suggesting common pathophysiology. The mechanism by which RA imparts increased CV risk is unclear, though it is commonly attributed simply to the deleterious effects of chronic inflammation. Might PSR also be associated with CV risk?
To examine this issue, Shapiro et al performed a case-control study that compared PSR inpatients (n = 1079) to age- and gender-matched inpatient controls who had other non-psoriatic dermatitis issues, such as atopic dermatitis and contact dermatitis (n = 1079).
Multivariate logistic regression found that PSR was associated with greater odds ratio (OR) for diabetes (OR = 1.43) and hypertension (OR = 1.31). Although PSR was associated with CVD, the association was no longer present when correcting for obesity and hypertension. Although the pathogenesis of increased CV risk associated with PSR is uncertain, the fact that PSR produces systemic effects on tumor necrosis factor alpha and other inflammatory markers may be critically linked.
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.
Rationale for Zinc Supplementation in Older Adults with Wounds; Occupational Stress and Hypertension; Association of Psoriasis with CV Risk Factors; Our Patients May Not be Getting the Message About Colon Cancer Screening; BMD Testing: What's the Appropriate Interval?; How Common is Vitamin B12 Deficiency in Patients on Metformin?Subscribe Now for Access
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