Association of low heart rate variability with atherosclerotic cardiovascular disease in hemodialysis patients.

OBJECTIVE: The aim of this study was to investigate the left-ventricular (LV) mass-adjusted association between low heart rate variability (HRV) and atherosclerotic cardiovascular disease (ASCVD) among hemodialysis patients in Kuwait. SUBJECTS AND METHODS: One hundred and eight patients were enrolled in the study. HRV time domain measures were obtained by 48-hour Holter monitoring, including the standard deviation of all R-wave-to-R-wave (RR) intervals (SDNN), standard deviation of all 5-min averaged intervals (SDANN), HRV triangular index (HRV-TI), percent of adjacent RR intervals differing by >50 ms (pNN50), and root mean square of sums of squares of all differences (rMSSD). Left ventricular ejection fraction (LVEF) and LV mass index (LVMI) were measured by M-mode echocardiography. Comorbidity was assessed using medical record review. Prevalent ASCVD was defined as coronary artery, cerebrovascular, or peripheral vascular disease. RESULTS: Prevalence of ASCVD, LV hypertrophy, and LVEF <40% were 56, 59, and 10%, respectively. The SDANN was negatively associated with ASCVD (-20 ms; p = 0.003), LV systolic dysfunction (-20 ms; p = 0.001), elevated LVMI (-20 ms; p = 0.002), hypertension (-34 ms; p = 0.01), and diabetes (-20 ms; p = 0.001). After adjustment for hypertension and LVMI using logistic regression, ASCVD was associated with the lowest quartile of SDANN (OR = 4.3, p = 0.009), HRV-TI (OR = 3.3, p = 0.03), and SDNN (OR = 2.3, p = 0.10). These associations persisted after adjusting for LVEF. CONCLUSION: In dialysis patients, low HRV indices were strongly associated with prevalent ASCVD, independent of LVMI and LVEF. The interrelationships among HRV, diabetes, hypertension, and LVMI should be addressed in studies of HRV and ASCVD.

Undertreatment of hyperlipidemia in a cohort of United States kidney dialysis patients.

BACKGROUND: Application of national guidelines regarding cardiovascular disease risk reduction to kidney dialysis patients is complicated by the conflicting observations that dialysis patients have a high risk of atherosclerotic cardiovascular disease (ASCVD), but dialysis patients with higher serum cholesterol have lower mortality rates. Actual treatment patterns of hyperlipidemia are not well studied. METHODS: We assessed the prevalence, treatment and control of hyperlipidemia in this high-risk patient population from 1995 - 1998. We measured low-density lipoprotein cholesterol, treatment with a lipid-lowering agent, and prevalence of hyperlipidemia as defined by the National Cholesterol Education Program (NCEP), Adult Treatment Panel (ATP) II guidelines in 812 incident hemodialysis (HD), and peritoneal dialysis (PD) patients from dialysis clinics in 19 states throughout the United States. RESULTS: Hyperlipidemia was present in 40% of HD and 62% of PD patients. Among subjects with hyperlipidemia, 67% of HD and 63% of PD patients were untreated and only 22% of HD and 14% of PD patients were treated and controlled. Those who entered the study in 1997 or 1998, those with diabetes, males and Caucasians were more likely to be treated and controlled, whereas subjects on PD and those with ASCVD were less likely to be treated and controlled. CONCLUSION: These data suggest that high rates of undertreatment exist in the United States ESRD dialysis population. Whether improved rates of treatment will result in decreased cardiovascular disease events needs to be tested in randomized clinical trials.

Relative androgen excess and increased cardiovascular risk after menopause: a hypothesized relation.

Many studies have investigated the role of estrogen during menopause; however, less attention has been paid to the role of androgen. Given the possible opposite effects of estrogen and androgen on cardiovascular disease risk, it is suggested that relative androgen excess may better predict the increased risk of cardiovascular disease in women over the age of 50 years than estrogen levels alone. Three phases of hormonal milieu changes are hypothesized as a better way to identify the hormone-cardiovascular disease risk association. A first phase, prepause, occurs before estrogen levels decline (approximately 2 years before menopause). A second phase, interpause, occurs from the end of prepause until approximately age 55. A third phase, postpause, occurs after interpause. The duration of the interpause phase, characterized by relative androgen excess, may be an independent risk factor of cardiovascular disease. This hypothesis could provide a basis for further clinical and epidemiologic research, and it could have important implications for establishing the initiation and duration of estrogen replacement therapy use as a means to prevent cardiovascular disease.

How physicians diagnose urinary tract infections: the potential influence of laboratory regulations on test availability and use.

OBJECTIVE: Physician office laboratory regulations may decrease test availability. We examined the potential effects of regulations on test availability and whether the use of tests in diagnosing uncomplicated urinary tract infections is related to availability. STUDY DESIGN: We performed an analysis of a cross-sectional survey conducted in 1994 and 1995. Test availability and use were determined by physicians' reports. POPULATION: The survey respondents included practicing physicians in 3 specialties (family medicine, general internal medicine, and obstetrics and gynecology) from 4 states: Pennsylvania (which had longstanding office laboratory regulations), and Alabama, Minnesota, and Nebraska (states that were not regulated until the implementation of the Clinical Laboratory Improvement Amendment of 1988). OUTCOMES MEASURED: We determined whether 4 specific tests were available in the office and how the tests were used to diagnose uncomplicated urinary tract infections. RESULTS: Our analysis was based on the responses from the 1898 respondents to the survey. All tests were less commonly available in Pennsylvania; this included the dipstick, microscopic urinalysis, wet prep, and urine culture (odds ratio [OR]=0.20-0.34; all P values < .05). The availability of the microscopic urinalysis and culture increased their use (OR = 4.37 and 2.03, respectively; P=.001). The availability of microscopic urinalysis was associated with a decrease in ordering urine cultures (OR=0.42; P=.001), and the availability of the dipstick was associated with a decrease in the use of both the microscopic urinalysis (OR=0.36; P=.02) and the culture (OR=0.48; P=.05). CONCLUSIONS: We found lower test availability in the state with office laboratory regulations and a decrease in testing when availability is reduced, suggesting that laboratory regulations may influence physicians&rsquo diagnostic approach to urinary tract infections. Further study will be required to determine the level of testing that maximizes patient welfare.

Variation by specialty in the treatment of urinary tract infection in women.

To determine practicing physicians' strategies for diagnosing and managing uncomplicated urinary tract infection, we surveyed physicians in general internal medicine, family practice, obstetrics and gynecology, and emergency medicine in four states. Responses differed significantly by respondents' specialty. For example, nitrofurantoin was the antibiotic of first choice for 46% of obstetricians, while over 80% in the other specialties chose trimethoprim-sulfamethoxazole. Most surveyed said they do not usually order urine culture, but the percentage who do varied by specialty. Most use a colony count of 10(5) colony-forming units or more for diagnosis although evidence favors a lower threshold, and 70% continue antibiotic therapy even if the culture result is negative. This survey found considerable variation by specialty and also among individual physicians regarding diagnosis and treatment of urinary tract infection and also suggests that some of the new information from the literature has not been translated to clinical practice.

A decision analysis of mandatory compared with voluntary HIV testing in pregnant women.

BACKGROUND: The benefit of antiretroviral therapy in reducing maternal-fetal transmission of HIV during pregnancy has caused a public policy debate about the relative benefits of mandatory HIV screening and voluntary HIV screening in pregnant women. OBJECTIVE: To evaluate the benefits and risks of mandatory compared with voluntary HIV testing of pregnant women to help guide research and policy. DESIGN: A decision analysis that incorporated the following variables: acceptance and benefit of prenatal care, acceptance and benefit of zidovudine therapy in HIV-infected women, prevalence of HIV infection, and mandatory compared with voluntary HIV testing. MEASUREMENTS: The threshold deterrence rate (defined as the percentage of women who, if deterred from seeking prenatal care because of a mandatory HIV testing policy, would offset the benefit of zidovudine in reducing vertical HIV transmission) and the difference between a policy of mandatory testing and a policy of voluntary testing in the absolute number of HIV-infected infants or dead infants. RESULTS: Voluntary HIV testing was preferred over a broad range of values in the model. At baseline, the threshold deterrence rate was 0.4%. At a deterrence rate of 0.5%, the number of infants (n = 167) spared HIV infection annually in the United States under a mandatory HIV testing policy would be lower than the number of perinatal deaths (n = 189) caused by lack of prenatal care. CONCLUSIONS: The most important variables in the model were voluntary HIV testing, the deterrence rate associated with mandatory testing compared with voluntary testing, and the prevalence of HIV infection in women of child-bearing age. At high levels of acceptance of voluntary HIV testing, the benefits of a policy of mandatory testing are minimal and may create the potential harms of avoiding prenatal care to avoid mandatory testing.

Epidemiology of cardiovascular risk factors in chronic renal disease.

Treatment and prevention of cardiovascular disease in the general population has benefited greatly from the identification of cardiovascular disease risk factors. Given the particularly high risk of cardiovascular disease and total mortality among patients with chronic renal insufficiency (CRI) and end-stage renal disease (ESRD), it is important to assess the role of traditional and nontraditional risk factors for cardiovascular disease. This review discusses the foundations of risk factor epidemiology and briefly summarizes the evidence regarding cardiovascular risk factors in renal disease. Diabetes and hypertension have a very high prevalence in patients with CRI. Patients with CRI and ESRD also have a higher frequency of cardiac dysfunction and left ventricular hypertrophy, which further increase the risk of cardiovascular disease. Finally, patients with renal disease have a higher prevalence of less established risk factors, including low HDL, and high triglycerides, lipoprotein(a), and homocysteine, where prospective studies and clinical trials are needed to provide a scientific basis for reduction of cardiovascular risk among patients with renal disease.

The emergence of case-control studies in hypertension research: valid or misleading?

Recently published case-control studies have generated considerable controversy. Compared with prospective studies, case-control studies permit investigation of uncommon diseases or outcomes in a more cost and time efficient manner. In addition, multiple possible risk factors can be studied simultaneously. If the assumptions of the study design are met, results of case-control studies are valid. For this reason, the use of this study design has increased markedly. This review summarizes the advantages and disadvantages of this study design and criteria to evaluate the results of such studies.

Morbidity of systemic lupus erythematosus: role of race and socioeconomic status.

OBJECTIVE: To determine if differences in morbidity of systemic lupus erythematosus (SLE) as measured by (1) important renal disease, (2) number of hospitalizations, and (3) neurologic disease can be explained by race, socioeconomic status (SES), or measures of compliance. DESIGN: The interrelationship of black race, SES, and the physician's assessment of compliance as risk factors for morbidity was examined in a cohort of 198 patients with SLE (179 female, 115 black). SES was measured with Nam-Powers scores for education (years), income, and job status, and source of insurance; compliance was assessed by physician global assessment and percent of protocol visits kept. Morbidity outcomes were important renal disease (creatinine level 1.5 mg/dL or greater, renal failure, nephrotic syndrome), neurologic involvement, and number of hospitalizations. SETTING: The Johns Hopkins Rheumatology Faculty Practice, in which both private and clinic patients are seen. RESULTS: Black patients had significantly lower SES on all measures (p less than 0.0001) and were also less compliant by physician global assessment (odds ratio [OR] = 0.39, p = 0.002). Univariate analyses showed that blacks had a higher frequency of important renal disease (OR = 2.07, 95% confidence interval [CI] 1.05 to 4.11) and hypertension (OR = 1.80, 95% CI 1.01 to 3.23). Important renal disease was associated with the physician global assessment of compliance (p = 0.009) and hypertension (p less than 0.001). Multiple regression models for important renal disease, including race, physician global assessment of compliance, hypertension, SES, age, and gender, identified significant associations with only physician global assessment of compliance (OR = 0.40, 95% CI 0.17 to 0.91) and hypertension (OR = 5.37, 95% CI 2.40 to 11.98); black race was not significant (OR = 1.60, 95% CI 0.68 to 3.76). The second morbidity measure, number of hospitalizations, was associated with renal disease, neurologic disease, mouth ulcers, duration of disease, and public insurance but not with black race, in the best log-linear model. Neither race, SES variables, nor physician assessment of compliance was significantly associated with neurologic disease, the third morbidity measure. CONCLUSIONS: These data fail to support an independent association of black race with morbidity in SLE; rather, they suggest that noncompliance (as measured by physician global assessment) and type of medical insurance are important factors in morbidity. Classical epidemiologic measures of SES (education, income, occupation) do not appear to be significant confounders of the relationship of race to morbidity in SLE.