Zinc deficiency: A cause of opioid-induced physical dependence and addiction in post-operative total hip arthroplasty patients.

ABSTRACT

OBJECTIVES: Recently, opioid abuse and related overdoses have increased warranting the need for research directed against the opioid epidemic. Previous studies identified that patients on opioid therapy may become zinc deficient and that zinc, in a murine model, may antagonistically affect the opioid receptor.13 Further understanding the relationship between opioid use and zinc deficiency may mitigate the opioid epidemic. METHODS: A retrospective study was conducted to identify zinc (Zn2+) deficiencies among post-operative total hip arthroplasty (THA) patients. On post-operative day one, patients had routine blood tests, including Zn2+ plasma levels. Patients were considered Zn2+-deficient if their Zn2+ plasma was < 56 µg/dL (Reference 56-134 µg/dL). Upon discharge from the hospital, the patients' inpatient opioid medication consumption per day was determined by dividing total morphine milligram equivalents (MMEs) by length of stay. A Student's t-test was performed to compare the total MMEs for Zn2+-deficient patients versus Zn2+-normal patients. A univariate analysis followed by multiple linear regression was performed to identify demographic or surgical predictors of MMEs/day. RESULTS: For Zn2+-deficient patients, the total MMEs/day was 33.62 ( ± 27.06), as compared to Zn2+-normal patients who consumed 16.22 ( ±16.01) MMEs/day (p = 0.031). The univariate analysis and multiple linear regression showed that patients' Zn2+ status had a significant contribution toward predicting MMEs/day, with p = 0.022 and p = 0.04, re-spectively. CONCLUSION: The results of this study suggest that Zn2+ deficiency may potentiate opioid consumption. Thus, Zn2+ sup-plementation may be a simple approach to reducing opioid addiction and dependence.