Zinc deficiency in diabetes: Does it occur and does therapy aid outcome in diabetic foot ulcers?
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Authors: Valayatham,V. M.;Twigg,S.
Publication: Diabetes research and clinical practice
Start Page: S237
Background: Zinc is thought to be important in wound healing, yet reviews addressing its potential role in diabetic foot ulceration, are lacking.We performed a systematic review to identify any evidence that zinc deficiency may occur in people with diabetes, and also effects of systemic zinc therapy randomised controlled trials in foot ulcers, including in people with diabetes.
Method: A systematic review using the standardised PRISMA method was undertaken, including a search of electronic databases, of PUBMED, EMBASE and Cochrane as well as manual search, addressing: (i) measurements of serum zinc in people with diabetes differ from those without diabetes, and (ii) to determine any effect of systemic zinc therapy on healing in those with, and without, diabetic foot ulcers. Titles, abstracts and articles were reviewed and only RCTs were included in the therapy question. A meta-analysis of results was performed, using Revman 5.2.
Result: Results for question (i), showed that of 2678 citations, 16 studies were identified involving in total 2251 adults with zinc levels measured that met the meta-analysis inclusion criteria. In ten studies, serum zinc was measured, plasma zinc was determined in 5, and whole blood zinc in 1 study. Circulating zinc levels were found to be an average âˆ¼12.5% (1.87 mM) lower (p < 0.001) in people with, compared without, diabetes. Significant heterogeneity in outcome existed across studies (P < 0.001). For question (ii), of 7500 citations, 6 studies were identified involving in total 200 adults with zinc treatment in RCTs for foot ulcer complete healing. The risk ratio of healing with systemic zinc therapy in RCTs was found to be 1.20 (1.01-1.42, 95% CI), without heterogeneity. These zinc therapy studies included ulcers of venous, arterial and sickle-cell ulcers. No RCTs examined the effect of systemic zinc treatment on diabetic foot ulcer healing. Overall, the study quality in each of the systematic reviews was found to be fair only.
Conclusion: In conclusion, circulating zinc levels are generally lower in people with diabetes. Zinc treatment appears to be favouring wound healing, however with an absence of good quality recent data and no data reported in diabetic foot ulcers. From this review it is suggested that well powered RCTs are required to address whether systemic zinc therapy in addition to standardised multidisciplinary care may aid healing in diabetic foot ulceration.