EXERCISE LOWERS DIASTOLIC BLOOD PRESSURE
According to a study published in a recent issue of Archives of Internal Medicine, improvements in body composition are linked to blood pressure (BP) reductions. These findings could link exercise training to improvements in cardiovascular health in older persons. This six-month, randomized, controlled trial compared participants (ages 55-75 years) who combined aerobic and resistance training (n = 51) with controls who followed usual care physical activity and diet advice (n = 53). The participants had untreated systolic BP (SBP) of 130-159 mm Hg or diastolic BP (DBP) of 85-99 mm Hg. Kerry J. Stewart, EdD, and coauthors found that those who exercised significantly improved aerobic and strength fitness, increased lean mass, and reduced general and abdominal obesity. Although the mean DBP reduction was greater among those who exercised, there were no significant differences in mean SBP change. Mean decreases in SBP and DBP in the exercise group were 5.3 and 3.7 mm Hg (P < 0.001), respectively; among controls, mean decreases were 4.5 and 1.5 mm Hg (P < 0.001), respectively. Improvements in body composition accounted for 8% of the SBP reduction (P = 0.006) and 17% of the DBP reduction (P < 0.001). The authors noted that aortic stiffness did not change in either group. The lack of improvement in aortic stiffness found in the exercise group suggests that older persons may be resistant to exercise-induced reductions in SBP.
CARDIOVASCULAR MORTALITY RISK RATE AND KIDNEY DISEASE
Michael G. Shlipak, MD, MPH, and colleagues found that in elderly persons with chronic kidney disease, traditional cardiovascular risk factors had larger associations with cardiovascular mortality than novel risk factors. Authors of the study, published in a recent issue of the Journal of the American Medical Association, noted that there is a need for additional research on whether aggressive lifestyle intervention reduces substantial cardiovascular risk in persons with chronic kidney disease. Traditional and novel cardiovascular risk factors as predictors of cardiovascular mortality were compared in 5808 community-dwelling persons ages 65 years or older who were participating in the Cardiovascular Health Study cohort. Traditional risk factors included systolic hypertension, diabetes, current smoking, high-density and low-density lipoprotein, triglycerides, regular alcohol use, obesity, physical inactivity, and left ventricular hypertrophy. Novel risk factors included C-reactive protein, fibrinogen, interleukin 6, factor VIIIc, lipoprotein(a), and decreased hemoglobin levels. At baseline, 1249 (22%) participants had chronic kidney disease. The cardiovascular mortality risk rate was 32 deaths/1000 person-years among persons with chronic kidney disease versus 16/1000 person-years among participants without it. Researchers found that traditional risk factors were linked to the largest absolute increases in risks for cardiovascular deaths among persons with chronic kidney disease, whereas C-reactive protein and interleukin 6 were the only novel risk factors that were linked to the outcome as linear predictors.
MRSA INFECTION COMMON IN COMMUNITY-DWELLING PERSONS
Methicillin-resistant Staphylococcus aureus (MRSA) infections have recently been reported in community-dwelling persons without established risk factors. To determine the national burden and clinical effect of this new setting for MRSA infections, authors of a recent study published in the New England Journal of Medicine evaluated participants from population-based surveillance in the cities of Baltimore and Atlanta and from hospital-laboratory–based sentinel surveillance in a dozen hospitals in Minnesota. Scott K. Fridkin, MD, and colleagues concluded that community-associated MRSA infections, which usually involve the skin and frequently lead to hospitalization, have become a common and serious problem. The authors categorized these infections as community-associated in persons with no established risk factors for MRSA infection. Established risk factors were described as isolation of MRSA two or more days after hospitalization; a history of hospitalization, surgery, dialysis, or residence in a long-term care facility within one year before the MRSA-culture date; the presence of a permanent indwelling catheter or percutaneous medical device at the time of culture; or previous isolation of MRSA. Data were collected through patient interviews and a review of their medical records. Researchers recorded 1647 cases of community-acquired MRSA disease from 2001-2002. Incidence varied in different sites, and was significantly higher among participants who were younger than two years than among those who were two years of age or older; it was also significantly higher among blacks than among whites in Atlanta. The authors determined that 6% of cases were invasive, and 77% involved skin and soft tissue. In addition, in 73% of cases the infecting strain of MRSA proved resistant to prescribed antimicrobial agents. Among those with skin or soft-tissue infections, therapy to which the infecting strain was resistant did not appear to be linked to adverse patient-reported outcomes. Hospitalization for the MRSA infection occurred in 23% of patients. The authors noted that clinicians should now consider MRSA as a potential pathogen in community-dwelling patients with suspected S. aureus infection.