Type of Dialysis Access May Depend on How Much the Patient Knows

Type of Dialysis Access May Depend on How Much the Patient Knows
By John Gever, Senior Editor, MedPage Today
Published: April 23, 2009
Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston.
WHEELING, W.Va., April 23 -- Patients with renal failure who demonstrated strong knowledge of dialysis care were more likely to have permanent arteriovenous access, researchers said.
Action Points

* Explain to interested patients that permanent arteriovenous access via fistulas or grafts has been found to be safer than using catheters in patients undergoing regular hemodialysis.

The likelihood of having permanent access via fistula or graft upon starting hemodialysis as well as six months later was increased by a third among patients with high scores on a test of chronic dialysis knowledge, reported Kerri L. Cavanaugh, M.D., of Vanderbilt University in Nashville, and colleagues online in the Clinical Journal of the American Society of Nephrology.

The findings are important because such access is believed to reduce mortality risk when compared with catheter-based access. But a recent study found that more than 80% of hemodialysis patients start with catheter access, Dr. Cavanaugh and colleagues said.

To see if information played a part in the decision, the researchers investigated the relationship between patient knowledge and uptake of permanent access in 490 patients.

Participants were enrolled in a comprehensive disease-management program designed for patients starting on chronic dialysis.

The researchers tested their understanding of dialysis care with the Chronic Hemodialysis Knowledge Survey, a 23-item instrument covering such topics as dialysis adequacy, nutrition, anemia, medications, and safety as well as access care. Scores are given on a 100-point scale.

Dr. Cavanaugh and colleagues said the survey was easy and quick to administer, making it a potentially valuable clinical tool.

The median score was 65 (interquartile range 52 to 78).

Older age, less formal education, and nonwhite race were associated with lower scores, although the differences were not large. For example, the mean score for nonwhite patients was 59 compared with 65 for white patients.

Patients with high scores were more likely to use catheter-based access at baseline, the researchers found.

Adjusted odds ratios for use of permanent fistula- or graft-based access associated with each 20 points on the survey were:

* At start of dialysis, 1.34 (95% CI 1.02 to 1.76)
* After three months, 1.49 (95% CI 1.16 to 1.93)
* After six months, 1.33 (95% CI 1.03 to 1.72)

The adjustments included age, sex, race, education, and diabetes status.

The multivariate analysis also found that age, sex, race, education, and diabetes were not independent predictors of use of permanent arteriovenous access. Odds ratios ranged from 0.88 to 1.24 and failed to reach statistical significance.

But education did interact with dialysis knowledge at baseline, the researchers found.

In patients with less than a high-school education, survey scores were not associated with permanent access use.

On the other hand, survey scores were a powerful predictor of permanent access at baseline in patients with more education (OR 1.60, 95% CI 1.15 to 2.24).

The effect was seen at three months but disappeared by six months, the researchers said.

"Our study . . . suggests that patients with greater knowledge about dialysis at initiation are more likely to use an arteriovenous fistula or graft," Dr. Cavanaugh and colleagues concluded.

However, they cautioned that knowledge might also be associated with other factors not measured in the study, such as income, social support, and general health literacy. How access was chosen was not directly studied.

They also noted that participants were enrolled in a special program; hence the results may not be applicable to the general population of patients going on chronic dialysis.

In addition, the study might have been limited by selection bias since not all patients took the survey and the knowledge test was not evaluated for reliability comparing first test and repeat testing.

But despite these limitations, Dr. Cavanaugh and colleagues said, the study suggested that the survey could help identify patients who would benefit from permanent access but who may not choose it without targeted educational intervention.

The study was funded by the National Kidney Foundation and the National Institute of Diabetes and Digestive and Kidney Diseases. Amgen supported the education program in which participants were enrolled but did not provide support for the analyses.

No potential conflicts of interest were reported.

Primary source: Clinical Journal of the American Society of Nephrology
Source reference:
Cavanaugh K, et al "Patient dialysis knowledge is associated with permanent arteriovenous access use in chronic hemodialysis" Clin J Am Soc Nephrol 2009; DOI: 10.2215/CJN.04580908.

http://www.medpagetoday.com/Nephrology/ESRD/13879