The researchers looked at the impact of vitamin D status on the risk of hospital-acquired new-onset delirium (HANOD), a complex neuropsychiatric syndrome which can include symptoms of acute confusion, brain failure and postoperative psychosis.
The retrospective cohort study looked at 4508 adult inpatients at two teaching hospitals in Boston from 1993 to 2006, all of whom had their vitamin D blood levels tested before admission.
Patients with vitamin D levels of less than 10 nanogram per milliliter (ng/ml), 10–19.9 and 20–29.9 ng/ml had higher odds of HANOD than patients with vitamin D levels of or greater than 30 ng/ml.
The results, published in the British Journal of Nutrition, suggested pre-hospital vitamin D status may be a “modifiable risk factor” for HANOD.
Among the participants, the average vitamin D level was 22 ng/ml. About 4% of the total patients met the criteria for HANOD.
They suggested this correlation may be due to vitamin D’s effect on endogenous proteins involved in the maintenance of neuronal health, particularly in the areas of the central nervous system responsible for cognition.
“These data support the rationale for randomised, controlled trials to test the role of vitamin D supplementation in the prevention of HANOD,” they wrote.
Patients with a history of delirium or dementia upon hospitalisation were excluded from the study.
Public health implications
The researchers said HANOD was a common problem within health care settings. While the risk was greater for those with a history of delirium or other neurocognitive disorders like dementia, among otherwise ‘low-risk’ individuals the incidence of HANOD was still between 3 and 29% of hospitalised patients in the US, according to estimates. For the at-risk group this was between 11 and 56%.
On average patients who developed HANOD stayed in hospital 4-13 days longer than those who had not developed the condition. There was also a two-fold increased risk of mortality.
As a result research in this area could have massive public health and spending implications, they said.
"In the USA, annual health care expenditures attributable to HANOD are estimated to be $38–152 billion [€25.4-101.8bn]."
According to a report from the UK's National Institute for Health and Care Excellence (NICE), delirium occurs in about 15-20% of all general admissions to hospital.
Source: British Journal of Nutrition
Published online ahead of print,doi:10.1017/S0007114515001245
“Association between pre-hospital vitamin D status and hospital-acquired new-onset delirium”
Authors: S. A. Quraishi, A. A. Litonjua, K. M. Elias, F. K. Gibbons, E. Giovannucci, C. A. Camargo Jr and K. B. Christopher