Clinical Briefs

By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is a consultant for GlaxoSmithKline and is on the speaker's bureau of GlaxoSmithKline, 3M, Wyeth-Ayerst, Pfizer, Novartis, Bristol-Myers Squibb, AstraZeneca, Jones Pharma, and Boehringer Ingelheim.

BNP: Not Just for Heart Failure

Elevated levels of brain natriuretic peptide (BNP) reflect cardiac ventricular wall stress, and correlate well with the presence and severity of heart failure. Similarly, BNP levels at hospital discharge for heart failure predict prognosis. Indeed, BNP levels can discriminate between heart failure and pulmonary etiologies amongst dyspneic patients presenting to an acute care setting.

The Heart and Soul Study is comprised of approximately 1000 patients with stable coronary heart disease (CHD) residing in Southern California, followed to evaluate the relationship between psychological factors and outcomes in persons with existing CHD.

Bibbins-Domingo report on data evaluating the relationship between BNP and CHD in patients with stable heart disease, without evidence of exercise intolerance (patients must be able to walk one block).

Over a 3.7 year period of observation, a linear relationship between BNP and cardiovascular events/death was noted. This relationship was not altered by the presence of an abnormal ejection fraction. Individuals in the uppermost quartile of BNP experienced 8 times the rate of cardiovascular events compared to those in the lowest BNP quartile.

BNP is a potent prognostic marker, not only in acute and recently treated heart failure, but also in ambulatory patients with stable coronary artery disease.

Bibbins-Domingo, et al. JAMA. 2007;297:169-176.

Like Everything Else, The Brain is Use It or Lose It

Cognitive Decline (CGD) has effects that spill over into impaired activities of daily living (ADL). Cognitive training has been used to remedy CGD, and has been shown to produce significant improvements in cognitive function; whether these cognitive improvements translate into favorable effects upon ADL has not been studied.

Adult senior citizens (n = 2,832) were invited to join a 5-year study investigating the impact of 3 areas of training (memory, reason, and processing speed) on both ADL and cognitive abilities. Subjects were randomized to receive either 10 sessions of training at baseline, followed by booster sessions at 1 year and 3 years, or no intervention.

The training in reasoning resulted in less decline in ADL than no cognitive training. Training for processing and memory did show prompt positive effects on each of those specific cognitive components, and these effects were quite durable, since they remained measureably different 5 years later. However, only reasoning training impacted ADL. Cognitive training favorably affects cognitive decline. Of the cognitive training interventions, this study suggests that cognitive reasoning training also reduces decline in ADL.

Willis SL, et al JAMA. 2006;296:2805-2814.

High Vitamin D Levels are Associated with Reduced Risk of MS

Although the cause of MS remains uncertain, prevailing opinion suggests that it is an autoimmune disorder. Epidemiologic data shows that geography is associated with MS: increasing distance from the equator—north or south—is associated with greater incidence of MS. One explanation for the observation that increasing latitude is associated with increased MS is that Vitamin D status at increasing latitude is progressively less optimal. For example, in Boston during the winter, little UV-B light penetrates the atmosphere, producing inadequate vitamin D generation.

To study the relationship between Vitamin D status and MS, serum samples from active duty US military (n = 7 million) were assayed for 25-hydroxyvitamin D (25HD). Persons with MS had their 25HD levels compared with persons without MS.

Using the lowest 25HD quintile for comparison, higher quintiles of 25HD were associated with 40-60% lower incidence of MS, but only in the Caucasian population. No relationship between 25HD and MS was seen in black or Hispanic subjects. There may be a relationship between MS and 25HD.

Munger KL, et al. JAMA. 2006;296:2832-2838.