Factors associated with zinc levels in hospitalized patients: An observational study using routinely collected data

Abstract

BackgroundZinc deficiency is easily treated and has been associated with worse outcomes in hospitalized patients. Zinc testing is time-consuming and relatively costly. We identified every zinc level measured at our teaching hospital and quantified how much zinc variation is explained by other hospital factors. MethodsWe linked tables from our hospital data warehouse from 1996 to 2019 to identify all patients who had at least 1 serum zinc measured during their admission. We determined the status of factors that could influence zinc levels including severity of illness, presence of bleeding or inflammation, and factors influencing zinc absorption. ResultsWe identified only 318 adult patients having zinc measurement during their hospitalization. Patients were elderly (median age 71 [IQR 56–78]) and arrived by ambulance 45% of the time. Zinc was measured a median of 5 days into the hospitalization (IQR 3–13) with 154 (51.6%) recording a low level. Almost half of patients were missing at least one covariable laboratory test. Multilinear regression models using complete case analysis returned more extreme parameter estimate values and deemed as significant only two thirds of the factors identified as significant in models using data with missing values imputed. Imputed models found significant associations between lower zinc levels and recent surgery, decreased albumin, creatinine, and sodium, earlier hospitalization day of sampling, and increased patient comorbidity. These models explained 32% of zinc variation. ConclusionsZinc testing is rare, low zinc levels are very common, and one third of its variation in hospitalized patients is explained by other covariables.