Background: Copper is an essential trace element in the human body acting as a cofactor in many enzymatic reactions. Notably copper is involved in iron metabolism, neurohormone homeostasis, production of collagen, electron transport, regulation of gene expression, immune system function and melanin production. Two diseases that have been well documented in regards to copper regulation is Menkes Disease with effects of copper deficiency and Wilson disease demonstrating the effects of excess copper. However, limited data is available on the trends of copper levels in hospitalized patients. Copper circulates largely bound to ceruloplasmin as well as freely in the serum. The normal total serum copper in healthy adults’ ranges from 0.75-0.145 mcg/ml. The purpose of this study is to evaluate the trends of serum copper levels at UMMC and the number of reported values outside of normal limits.
Methods: We performed a retrospective observational study of all inpatients aged 18 and over who received the Serum Copper level at UMMC from January 1, 2013 to December 30, 2020. Patient Cohort Explorer was used to obtain de-identified patient data from EPIC. We obtained the data for hospitalized patients on whom the serum Copper level was ordered. Microsoft Excel was used to do the calculations.
Results: Serum Copper level was ordered 537 times on 508 patients during 469 hospital encounters from January 1st 2013 to December 30th, 2020. 29, 41, 42, 84, 64, 66, 138, 67 tests were done annually from 2013 to 2020. 287 tests were done in females and 248 in males. About 251 tests were done in African Americans and 265 tests were done in Caucasians. Of the 534 tests, 99 tests (18.43%) came back with level < 0.75 mcg/ml, the lower cut off value. 97 tests (18.06%) came back over the upper limit of >1.45 mcg/ml. Most of the tests (504) are done only once in the hospital encounter. The median age of testing was 54. 287 tests were done in females, of which 59 tests (20.55%) were low and 55 (19.16%) were elevated. 248 tests were done in males, of which 40 tests (16.12%) were low and 42 (16.93%) were elevated. Of the 251 tests done in African Americans (AA) 39 (15.53%) were low and 65 (25.89%) were elevated. 265 tests were done in Caucasians. 55 tests (20.75%) came back low while only 32 (12.07%) were elevated. At the end of study period, of the 508 unique patients 380 (74.8%) are alive and 128 (25.1%) deceased. Mortality is higher in copper deficient patients with 38 (45.45%) deceased compared to only 23 (23.95%) in patients with elevated copper.
Conclusions: To our knowledge this is the largest data sample with Serum Copper levels in adult hospitalized patients. Interestingly close to one in five samples that was tested for serum copper level was lower than the minimum cut off and about the same number came elevated for copper. Low copper levels are more prevalent in males and Caucasians compared to female and African Americans. Even though copper deficiency in hospitalization may not reflect copper deficiency in general population, it is alarming to see the prevalence copper deficiency in hospitalized patients. More studies are needed to see which patients are copper deficient and if copper deficiency is responsible for increased mortality and morbidity in hospitalized patients.