Fatigue Rating Scale May Predict Cardiovascular Events in Dialysis Patients
By Laurie Barclay, MD
Medscape Medical News
March 2, 2010 — High scores on a new fatigue rating scale predict an increased risk for myocardial infarction or other cardiovascular (CV) events in patients with end-stage renal disease (ESRD), according to the results of a study reported online in the February 25 issue of the Clinical Journal of the American Society of Nephrology.
"Despite potential significance of fatigue and its underlying components in the occurrence of cardiovascular diseases, epidemiologic data showing the link are virtually limited," write Dr. Hidenori Koyama, from Osaka City University Graduate School of Medicine in Osaka, Japan. "This study was designed to examine whether fatigue symptoms or fatigue's underlying components are a predictor for cardiovascular diseases in high-risk subjects with ESRD."
Between October and November 2005, a total of 788 patients (506 men, 282?women) undergoing hemodialysis completed a survey questionnaire of 64?questions. Eight fatigue-related factors were covered by the survey: fatigue itself, anxiety and depression, loss of attention and memory, pain, overwork, autonomic imbalance, sleep problems, and infection. During follow-up for up to 26 months, patients were monitored for occurrence of fatal or nonfatal CV events.
Fatigue scores were higher than twice the SD of the mean for healthy volunteers in 15.7% of the patients. In these patients, the risk for CV events was significantly increased (hazard ratio, 2.17; P < .01). This association was independent of age, diabetes, CV disease history, markers of inflammation and malnutrition, and other well-known risk factors.
Subgroup analysis showed that the risk for CV events associated with high fatigue score was more pronounced in well-nourished patients of younger age, with absence of past CV diseases, higher serum albumin levels, and high non–high-density lipoprotein (HDL) cholesterol levels.
"Our data highlight for the first time the pathophysiological significance of fatigue as an important bio-alarm for cardiovascular disease," Dr. Koyama said in a news release.
However, the investigators note many unanswered questions.
"Can our novel fatigue score predict cardiovascular events in the general population or other patients with disease?" they write. "Can a quantitative marker for fatigue be a good biomarker to predict cardiovascular events? Can improvement of fatigue lead to decreased morbidity? All of these steps are crucial to highlighting the significance of fatigue as an important piece of risk predictors for CVD in patients with ESRD."
The 21st Century COE Program "Base to Overcome Fatigue" from the Ministry of Education, Culture, Sports, Science and Technology of Japan supported this study. It was also partly supported by grants from the Japanese Ministry of Health, Labor and Welfare. The study authors have disclosed no relevant financial relationships.
Clin J Am Soc Nephrol. Published online February 25, 2010.
