Link between vitamin D, mortality not impacted by eGFR

(HealthDay)—Adults with low levels of 25-hydroxyvitamin D (25[OH]D) have increased mortality, regardless of the presence of estimated glomerular filtration rate (eGFR) of <60 ml/min/1.73 m², according to a study published online Oct. 24 in PLoS One.

Holly Kramer, M.D., M.P.H., from the Loyola University Medical Center in Maywood, Ill., and colleagues examined all-cause mortality rates across 25(OH)D levels over an 18-year follow-up period for adults stratified according to their eGFR. Participants included 1,097 U.S. adults with eGFR <60 ml/min/1.73 m² and 14,002 with an eGFR ≥60 ml/min/1.73 m².

The researchers found that, for adults with eGFR <60 ml/min/1.73 m², the prevalence of 25(OH)D levels <30 ng/mL was 76.5 percent and the prevalence of 25(OH)D levels <20 ng/mL was 35.4 percent. The corresponding prevalences among adults with eGFR ≥60 ml/min/1.73 m² were 70.5 and 30.3 percent. After adjustment for covariables, including comorbid conditions, individuals with 25(OH)D levels <12 ng/mL had significantly higher mortality rates compared to those with levels of 24 to <30 ng/mL, with a rate ratio of 1.41 for those with eGFR <60 ml/min/1.73 m² and 1.32 for those with eGFR ≥60 ml/min/1.73 m². After adjustment for all covariates, mortality rates were fairly similar across all 25(OH)D groups with levels above 20 ng/mL.

"In conclusion, while significantly higher mortality rates are noted with 25(OH)D levels <12 ng/mL, mortality rates are fairly similar across the range of 25(OH)D levels 20 to 40 ng/mL among adults with and without eGFR <60 ml/min/1.73 m²," the authors write.