Creatinine, albumin levels at diagnosis tied to ALS survival

By Anne Harding

NEW YORK (Reuters Health) - Albumin and creatinine levels at diagnosis of amyotrophic lateral sclerosis (ALS) are independently associated with survival, according to a new population-based study.

"The lower the levels, the worse the prognosis," Dr. Adriano Chiò of Rita Levi Montalcini Department of Neuroscience in Turin, Italy, the study's first author, told Reuters Health in a telephone interview.

The findings were published July 21 online in JAMA Neurology.

There are currently no confirmed biological markers for ALS prognosis, although several have been proposed, Dr. Chiò and his team write in their report. In the current study, they looked at 16 hematological markers in a discovery cohort of patients newly diagnosed with ALS and included in the Piemonte and Valle d'Aosta Register for Amyotrophic Lateral Sclerosis between 2007 and 2011. They confirmed the findings in a validation cohort of 122 consecutive patients seen at an ALS tertiary center between 2007 and 2009.

Overall median survival was 1.7 years. Univariate analysis found that serum albumin, creatinine and lymphocyte count were associated with outcome. After multivariate analysis, only albumin and creatinine were linked to survival.

The hazard ratio (HR) for surviving for one year after diagnosis was 1.39 for men with serum albumin levels above 4.3 mg/dL, while it was 1.73 for women.

Men with creatinine levels above 0.82 mg/dL had a survival HR of 1.47, while for women, creatinine levels above 0.65 mg/dL were associated with a survival HR of 1.49.

Patients with lower levels of creatinine and albumin also had worse function at diagnosis, as measured by Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised score and forced vital capacity. Albumin levels were not related to nutritional status, but did correlate to markers of inflammation, and creatinine was associated with free fat mass in the validation cohort.

"Both creatinine and albumin are reliable and easily detectable blood markers of the severity of motor dysfunction in ALS and could be used in defining patients' prognosis at the time of diagnosis," Dr. Chiò and colleagues write. "Longitudinal studies on the variations of serum albumin and creatinine levels and their relationships to clinical status will help determine whether and how these hematological factors vary during the progression of the disease."

Dr. Chiò told Reuters Health that he and his colleagues have launched a prospective study in which they will check albumin and creatinine levels in ALS patients every three months. He emphasized that the biomarkers should be considered a prognostic tool, and do not serve a diagnostic purpose.

SOURCE: http://bit.ly/1lnsNH2

JAMA Neurol 2014.

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