Clinical Briefs-By Louis Kuritzky, MD

Cholesterol-Lowering, Dietary Treatment, and Psychological Function

The role of cholesterol lowering for prevention of cardiovascular disease went through a trying period during which there was concern expressed that pharmacologic reduction of cholesterol might have adverse psychological consequences. Some observational studies have found an association between depression, suicide, aggression and hostility and lower cholesterol levels. This study evaluated the psychological effect of implementing a cholesterol-lowering diet in 176 individuals with cholesterol levels of more than 198 mg/dL.

The group was divided into those receiving a low-fat diet, Mediterranean diet, and control diet. Diets were evaluated over a 12-week period, and in addition to physical and laboratory parameters, depression and anger were measured with the Beck Depression Inventory, Profile of Mood States. A variety of other psychometric tests were administered to assess stress, general health perceptions, and even perceptions of partners or close friends were included for analysis.

All groups had stable or improved psychological status throughout the study. Lipid changes were seen in both the participants in the low-fat diet group (5.1% cholesterol reduction) and Mediterranean diet (10% cholesterol reduction) compared with control. Wardle and colleagues conclude that their study does not demonstrate any adverse psychological effect from dietary cholesterol reduction. An adverse cognitive effect noted among the cholesterol-lowering diet groups seen during the trial was felt to be a chance event, but it is suggested that future trials seek further demonstration of the effect of cholesterol reduction on cognitive function.

Wardle J, et al. Am J Med 2000;108: 547-553.

Risk of CHD Events After Menopause

Debate about the relative risks and benefits of postmenopausal hormone replacement therapy (HRT) continues unabated. The favorable effect of HRT upon traditional lipid fractions HDL, LDL is well established. Lipoprotein(a) (Lpa) is known to be an important risk factor for coronary heart disease (CHD), but has been dominantly studied in men, and usually in those without known coronary disease. This study examined the effects of HRT on Lpa in participants of the HERS trial (Heart and Estrogen/progestin Replacement Study), and the relationship with subsequent coronary heart disease end points.

This study evaluated 2763 postmenopausal women, measuring Lpa at baseline and at the conclusion of the trial (mean = 4.1 years). At baseline, the Lpa level of African American women was almost twice as high as other women. Baseline Lpa level was linearly associated with risk of subsequent CHD events.

HRT produced a significant reduction in Lpa, which was most evident in women with the highest levels of Lpa prior to treatment at baseline. Although the reduction in Lpa achieved with HRT did not reveal a significant association with reduced CHD events, a threshold effect was suggested by the fact that the women in the highest quartile of Lpa reduction did have a significantly lower risk of CHD events than those with smaller reductions. Though modulation of Lpa is not currently a commonplace therapeutic target, it is encouraging that women with highest deviations of Lpa from normal do demonstrate benefit from HRT.

Shlipak MG, et al. JAMA 2000;283: 1845-1852.

Diagnosing OAD

The clinical diagnosis of ob- structive airway disease (OAD) has not been systematically evaluated in rigorous blinded trials. Straus and colleagues evaluated 309 patients subgrouped into those with known chronic airway disease, suspected chronic OAD, and those free of either known or suspected OAD (asthma patients were excluded, so this was essentially a group of patients with consequences of chronic smoking). Among this group, they compared sensitivity, specificity, and likelihood ratios for spirometry-defined OAD (gold standard) with nine clinical factors, including history of chronic OAD, smoking history, presence of wheezing, maximum laryngeal height, minimum laryngeal height, and laryngeal descent.

Laryngeal height was measured as the distance from the suprasternal notch and the top of the thyroid cartilage. The difference between laryngeal height at end inspiration and end expiration was considered laryngeal descent.

Of the factors measured, only self-reported smoking history, self-reported history of chronic OAD, age, and maximum laryngeal height proved useful to discriminate OAD. Though previous studies have suggested a role for laryngeal descent, it was not found helpful in this trial, nor was wheezing. Straus et al acknowledge that spirometry should remain the diagnostic tool of choice, but suggest that their four described factors may facilitate a diagnosis of OAD in the absence of availability of spirometry.

Straus SE, et al. JAMA 2000;283: 1853-1857.