HCPLive Network

Hyponatremia Clinical Update, July 19, 2011

Increased 90-Day Mortality in Acute Heart Failure Patients with Elevated Copeptin and Hyponatremia
A recent study has shown a significant increase in 90-day mortality, readmissions, and emergency department visits in patients with elevated copeptin, especially in those with hyponatremia.

In heart failure (HF) patients, increased arginine vasopressin (AVP) concentrations are associated with more severe disease, making AVP an attractive target for therapy. However, AVP is difficult to measure due to its in-vitro instability and rapid clearance. Copeptin, the C-terminal segment of pre-pro-vasopressin, is a stable and reliable surrogate biomarker for serum AVP concentrations.

The BACH trial, which was headed by researchers at the VA San Diego Healthcare System and the University of California, San Diego, was a 15-center diagnostic and prognostic study of 1641 patients with acute dyspnea; 557 patients with acute HF were included in this analysis.

“Copeptin and other biomarker measurements were performed by a core laboratory at the University of Maryland. Patients were followed for up to 90 days after initial evaluation for the primary endpoint of all-cause mortality, HF related readmissions, and HF related emergency department visits,” the researchers wrote in the study abstract, which was published online ahead of print in the journal Circulation: Heart Failure.

Patients with copeptin concentrations in the highest quartile had increased 90-day mortality (P<0.001, HR=3.85). Mortality was significantly increased in patients with elevated copeptin and hyponatremia (P<0.001, HR=7.36). Combined endpoints of mortality, readmissions, and emergency department visits were significantly increased in patients with elevated copeptin. There was no correlation between copeptin and sodium (R=0.047).

“Copeptin was highly prognostic for 90-day adverse events in acute HF patients, adding prognostic value to clinical predictors, serum sodium and natriuretic peptides,” the authors concluded.

Malnutrition, Renal Function Impairment, Anemia are Associated with Hyponatremia in Elderly
Anemia, the placement of tubes, and hypouricemia were associated with hyponatremia in the institutionalized elderly, according to a recent study in the Archives of Gerontology and Geriatric Practice conducted by researchers in the Department of Family Medicine at the China Medical University Hospital in Taiwan.

Hyponatremia is the most common electrolyte abnormality among the elderly living in long-term care facilities. In the study, researchers investigated the associated factors of hyponatremia and its association with anemia in the institutionalized elderly in Taiwan.

A total of 414 participants aged 65 years and above were recruited from eight long-term care facilities in 2002-2003. Baseline characteristics, medical records, and biomarkers were obtained.

Hyponatremia was defined as a serum Na-concentration<135mmol/l. Relationships between hyponatremia and the demographic and laboratory characteristics were tested using multiple logistic and linear regression analyses, the researchers wrote.

“The prevalence of hyponatremia and anemia was 14.7% and 56.0%, respectively. Anemia, hypouricemia, and the placement of tubes (including nasogastric tube, tracheostomy tube, and Foley catheter) were significantly associated with hyponatremia after adjustment for potential confounders using multiple logistic regression analysis,” according to the study.

The adjusted odds ratios and 95% confidence interval (95%CI) for these three factors were 3.28 (1.40-7.69), 4.98 (2.18-11.36), 9.15 (3.33-25.12), respectively.
“Multiple linear regression analyses also showed that serum Na concentration was significantly associated with hemoglobin, uric acid, and number of tubes. … In those with the above conditions, serum Na concentration should be monitored,” the researchers concluded.

Sources
Increased 90-Day Mortality in Acute Heart Failure Patients with Elevated Copeptin and Hyponatremia [Circulation: Heart Failure]

Malnutrition, Renal Function Impairment, Anemia are Associated with Hyponatremia in Elderly [Archives of Gerontology and Geriatric Practice]



Further Reading
One of the key issues in the treating elderly patients with HF is assessing and managing frailty--an issue many cardiologists don't hear much about.
When it comes to treating heart failure, what works for a young male may not work for an elderly woman, according to new HFSA guidelines.
As the medical home model gains ground, are cardiologists and other specialists being left out in the cold?
Results of a randomized controlled trial demonstrate that a long-term, supervised, moderate-intensity exercise training program for chronic heart failure patients can produce improvements in hospital readmission and survival rates.
Intravenous treatment with the iron compound ferric carboxymaltose improves health-related quality of life in patients with chronic heart failure.
Dr. Cohn discusses heart failure in women, the role of a primary care physician, and the Rasmussen test series.
Assessing readiness and determining the patient's capabilities are the keys to building a successful exercise program in HF patients.
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