This is Journal Watch, a medical-literature survey produced by the Massachusetts Medical Society. Twice a week, our physician-editors summarize important new clinical research from a group of 25 journals. Twice a month, the summaries get compiled into newsletter form and mailed to subscribers. If you'd like to subscribe to the newsletter, which costs $US79 a year, please call 800-843-6356; international orders: (49) 30 335 8006. To comment via e-mail, please contact us at jwatch@world.std.com. Contents copyright 1994, Mass. Medical Society. Journal Watch Summaries for August 23, 1994 SLEEP DISTURBANCES IN OBESE PATIENTS. Arch Intern Med 1994 Aug 8; 154:1705-11. PREVENTING HIV TRANSMISSION WITH CONDOMS. N Engl J Med 1994 Aug 11; 331:341-6. LYME DISEASE DOESN'T IMPAIR COGNITIVE FUNCTION IN KIDS. Pediatrics 1994 Aug; 94:185-9. DO CASE MANAGERS REDUCE READMISSIONS?. Arch Intern Med 1994 Aug 8; 154:1721-9. THE BENEFITS OF DIETARY CHANGE AND SMOKING CESSATION. Arch Intern Med 1994 Aug 8; 154:1697-1704. ASSESSING CARDIOLOGY'S FUTURE. J Am Coll Cardiol 1994 Aug; 24:275-328. CAN GENE THERAPY PREVENT VASCULAR RESTENOSIS?. Science 1994 Aug 5; 265:781-4. SLEEP DISTURBANCES IN OBESE PATIENTS. An increasing number of Americans are overweight and obesity is a known risk factor for sleep apnea. This study compared sleep disturbances of obese patients (50 men, 200 women) referred for weight management with 128 controls matched for age and sex. Most obese patients were severely or morbidly overweight and none had presented with sleep-related complaints. Staff, students, and friends of staff served as controls. None of the controls had sleep apneic activity during sleep testing. In contrast, 40 percent of obese men and 3 percent of obese women had sleep apnea that required intervention. Other sleep disturbances (e.g., number of awakenings) were also much more frequent among the obese patients. The severity of snoring (based on frequency and loudness), sleep attacks, and self-reported nocturnal breathing cessation were the best clinical predictors of sleep apnea in obese patients. Comment: The actual incidence of sleep disturbances and apnea cannot be determined from this study because it involved referred patients, but the large number of obese men with apnea warranting intervention illustrates the importance of considering this diagnosis in this population. --CD Mulrow. Citation: Vgontzas A; et al. Sleep apnea and sleep disruption in obese patients. Arch Intern Med 1994 Aug 8; 154:1705-11. PREVENTING HIV TRANSMISSION WITH CONDOMS. How well do condoms prevent heterosexual transmission of HIV? To find out, this European prospective study followed 256 sexually active heterosexual couples, each with one HIV-infected partner. The couples were counseled about safe sex and the HIV- negative partners were interviewed and tested for HIV every six months. None of the uninfected partners reported other HIV risk factors such as injection drug use. About two thirds of the HIV-positive partners were men and about 10 percent had AIDS. During a median follow-up of 22 months, 124 couples (48%) reported using condoms every time they had intercourse; none of the HIV-negative partners in these couples seroconverted. In contrast, there were 12 seroconversions among the 121 couples who reported that they inconsistently or never used condoms. (The remaining 11 couples refused to answer questions about sexual behavior). The risk of transmission was enhanced if the HIV-positive partner had advanced disease or the HIV-negative partner reported genital infections. Transmission risk was lower if the couple practiced withdrawal before ejaculation. The rate of transmission did not differ by the sex of the infected partner. Comment: Although it is unlikely that a larger study with longer follow-up would find the rate of HIV transmission among condom users to be zero, this report provides reassuring evidence that condoms are highly effective. The sobering news is that half the couples did not use condoms consistently despite ongoing counseling. --AS Brett. Citation: De Vincenzi I; et al. A longitudinal study of human immunodeficiency virus transmission by heterosexual partners. N Engl J Med 1994 Aug 11; 331:341-6. LYME DISEASE DOESN'T IMPAIR COGNITIVE FUNCTION IN KIDS. Nervous system involvement is common in Lyme disease (LD), and previous studies suggest that LD can eventually cause cognitive impairment. This pediatric study says "it ain't so." The authors studied 41 children (6 to 17 years old) who were treated for LD at a children's hospital in a Lyme- endemic area, and compared them with two control groups: 23 healthy siblings closest in age to the patients and 14 children with non-Lyme arthritis. The children with LD had become ill an average of two years earlier and had a range of clinical findings, including CNS involvement in 9 and arthritis in 22. Extensive neuropsychologic testing, including tests of general intelligence, information processing, and memory, found no differences among the three groups. Academic achievement was comparable before and after the onset of LD. Comment: This study is more credible than previous investigations because of its superior design: it was prospective, controlled, and blinded and used formal cognitive testing. I would have been more convinced by the findings if more of the children with LD had presented with neurologic involvement. It is also important to note that all children were adequately treated for LD, and the two- year gap between disease onset and testing may have been too short for all cognitive impairment to surface. --RA Dershewitz. Citation: Adams WV; et al. Cognitive effects of Lyme disease in children. Pediatrics 1994 Aug; 94:185-9. DO CASE MANAGERS REDUCE READMISSIONS?. Descriptive studies suggest that nearly ten percent of hospital readmissions are preventable. This trial evaluated whether nurse case managers reduce readmission rates. Researchers randomized 668 patients over age 44 years who were discharged from a Veterans Affairs general medicine inpatient service to receive usual primary care follow-up or follow-up with case managers. Using educational materials, routine telephone calls, and regularly scheduled general medicine visits, case managers educated patients about their diseases, facilitated access, identified unmet needs and alternative sources of care, and helped coordinate overall care. After one year, patients with case managers had 15 percent more clinic visits but not a significant reduction in readmissions or total readmission days when compared with controls. About 49 percent of patients in both groups were readmitted. Comment: This study found that case managers did not reduce readmissions. A reasonable approach for future studies evaluating case managers is to target high-risk patients with very high readmission rates and measure more comprehensive outcomes such as functional status and overall costs. --CD Mulrow. Citation: Fitzgerald J; et al. A case manager intervention to reduce admissions. Arch Intern Med 1994 Aug 8; 154:1721-9. THE BENEFITS OF DIETARY CHANGE AND SMOKING CESSATION. Health promotion programs that involve behavior change, such as diet modification and smoking cessation, are often recommended for reducing coronary disease, but what are the expected benefits of each strategy? This study used a computer model to estimate the impact on life expectancy of reduced-cholesterol diet or smoking cessation. The distribution of coronary risk factors such as blood pressure, glucose intolerance, cholesterol, and smoking status were derived from the Canadian Health Survey. The predicted change in cholesterol was based on a diet with cholesterol intake of 240 to 300 mg/day and 8 to 10 percent of calories from fat; the model assumed that, on average, such diets would reduce serum cholesterol 17 to 29 mg/dl in men and 5 to 21 mg/dl in women. Smoking cessation assumed that all smokers became nonsmokers. The maximal increase in life expectancy from dietary modification was 0.4 year for men and 0.16 year for women. The maximal increase in life expectancy from smoking cessation was 4.43 years for men and 3.68 years for women. The greatest dietary benefits were estimated in men who were assumed to start dieting at ages 30 to 59. The benefits of smoking cessation were fairly consistent regardless of age and sex. Comment: Although these results are based on estimates from a computer model and not the actual efficacy of specific programs, they do highlight the need to continue to focus on cigarette smoking as a public health priority. --CD Mulrow. Citation: Grover S; et al. Life expectancy following dietary modification or smoking cessation. Arch Intern Med 1994 Aug 8; 154:1697-1704. ASSESSING CARDIOLOGY'S FUTURE. Increasing financial pressures on health care have led many professional groups to attempt predictions of future personnel needs. Six task forces convened by the American College of Cardiology met last November to evaluate the outlook for cardiology. The most striking conclusion was that there seems to be "an abundance of interventional cardiologists" and that training should emphasize other aspects of cardiovascular care, including noninvasive and preventive cardiology. Other task forces concluded that, despite large numbers of cardiologists at some centers, poor and lower-class rural and urban populations are often underserved. If these populations are "brought into the mainstream of cardiac care," it's projected that the need for pediatric cardiologists will increase, as the latter are in undersupply relative to adult cardiologists. Other major challenges for cardiology include improving the training of generalists in cardiovascular medicine, decreasing the number of training positions without adversely affecting the quality of training, and integrating cardiologists more effectively into networks of care in partnership with nonphysician providers. Comment: Changes in the health care system are likely to limit and even reduce the number of cardiologists, but such is the case for many other specialties. The conclusions of these task forces are in many ways generalizable to other fields. --TH Lee. Citation: 25th Bethesda Conference. Future personnel needs for cardiovascular health care. November 15 to 16, 1993. J Am Coll Cardiol 1994 Aug; 24:275-328. CAN GENE THERAPY PREVENT VASCULAR RESTENOSIS?. A top gene-therapy team at the University of Michigan reports using gene therapy to reduce the proliferation of vascular smooth muscle cells that causes arterial narrowing. The researchers, led by Gary and Elizabeth Nabel, deliberately injured the endothelium of the ileofemoral artery in pigs (a good animal model for vascular disease) to induce smooth-muscle-cell proliferation. They then inserted a special double-balloon catheter that stopped blood flow and allowed prolonged therapeutic infusions into the space between the two balloons. First, they infused adenoviruses that contained a herpesvirus gene for thymidine kinase (tk) and infected the smooth muscle cells in the area. They then infused ganciclovir, a drug that stops proliferation of cells that contain the tk gene. Smooth-muscle-cell proliferation was indeed prevented in the animals receiving these infusions, but not in control animals. No damage to nonproliferating cells adjacent to the lesion was observed, and none was expected, since the treatment affects only dividing cells. Comment: There are several caveats to this potentially important study. A peripheral artery was used, not a coronary artery. Healthy endothelium was deliberately injured: this was not a model of atherosclerosis. Finally, the technique required blockage of blood flow for 20 minutes. The efficacy and feasibility of this approach in human coronary atherosclerosis are therefore unknown. --AL Komaroff. Citation: Ohno T; et al. Gene therapy for vascular smooth muscle cell proliferation after arterial injury. Science 1994 Aug 5; 265:781-4.