FPIN's Clinical Inquiries

Preoperative A1C Threshold in Patients with Diabetes


Am Fam Physician. 2021 Jun 1;103(11):693-694.

Clinical Question

In patients with diabetes mellitus who are preparing for total joint replacement, what is the preoperative A1C goal to reduce postoperative periprosthetic joint infections?

Evidence-Based Answer

The risk of infection in patients with diabetes increases as the perioperative A1C level increases, although a cutoff of 7% for A1C is not achievable for all patients with diabetes. There is no definitive evidence-based A1C goal that will reduce periprosthetic joint infections for patients with diabetes who are preparing for total joint replacement. The evidence suggests that a perioperative A1C level of less than 7.5% may reduce the risk of such infections. (Strength of Recommendation: C, based on two retrospective cohort studies.)

Evidence Summary

A 2018 systematic review and meta-analysis assessed the relationship between perioperative glycemic control and the risk of surgical site infection, mainly periprosthetic joint infection.1 Six studies were included in the meta-analysis and had stratified glycemic control using a distinct A1C cutoff. The pooled results did not demonstrate a statistically significant association between an A1C level of greater than 7% and surgical site infection or periprosthetic joint infection (pooled odds ratio = 0.87; 95% CI, 0.57 to 1.32; P = .51). Heterogeneity among the studies was statistically significant (I2 = 54.25%; P = .05).

A 2017 retrospective cohort study (7,736 patients) analyzed the link between perioperative A1C and periprosthetic joint infections, as well as a potential threshold for risk stratification.2 The risk of infection in patients with diabetes increases as perioperative A1C increases (odds ratio = 2.6; 95% CI, 1.9 to 3.4; P < .0001). Out of 877 patients with an A1C level of 7.5 mg per dL (75 mg per L) or greater, 21 were infected (2.4%). In comparison, among those with an A1C level of less than 7.5 mg per dL, 69 out of 6,859 were infected (1.0%).

A 2017 retrospective multicenter study was designed to evaluate the p

Address correspondence to Bernadette Kiraly, MD, at bernadette.kiraly@hsc.utah.edu. Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.

Copyright © Family Physicians Inquiries Network. Used with permission.


show all references

1. Shohat N, Muhsen K, Gilat R, et al. Inadequate glycemic control is associated with increased surgical site infection in total joint arthroplasty: a systematic review and meta-analysis. J Arthroplasty. 2018;33(7):2312–2321.e3....

2. Cancienne JM, Werner BC, Browne JA. Is there a threshold value of hemoglobin A1c that predicts risk of infection following primary total hip arthroplasty? J Arthroplasty. 2017;32(9S):S236–S240.

3. Tarabichi M, Shohat N, Kheir MM, et al. Determining the threshold for HbA1c as a predictor for adverse outcomes after total joint arthroplasty: a multicenter, retrospective study. J Arthroplasty. 2017;32(9S):S263–S267.e1.

4. American Diabetes Association. Standards of medical care in diabetes—2014. Diabetes Care. 2014;37(suppl 1):S14–S80.

5. Handelsman Y, Bloomgarden ZT, Grunberger G, et al. American Association of Clinical Endocrinologists and American College of Endocrinology – clinical practice guidelines for developing a diabetes mellitus comprehensive care plan – 2015. Endocr Pract. 2015;21(suppl 1):1–87.

6. Inzucchi SE, Bergenstal RM, Buse JB, et al. Management of hyperglycemia in type 2 diabetes, 2015: a patient-centered approach: update to a position statement of the American Diabetes Association and the European Association for the Study of Diabetes. Diabetes Care. 2015;38(1):140–149.

7. Tubb CC, Polkowksi GG, Krause B. Diagnosis and prevention of periprosthetic joint infections. J Am Acad Orthop Surg. 2020;28(8):e340–e348.

Clinical Inquiries provides answers to questions submitted by practicing family physicians to the Family Physicians Inquiries Network (FPIN). Members of the network select questions based on their relevance to family medicine. Answers are drawn from an approved set of evidence-based resources and undergo peer review.

The complete database of evidence-based questions and answers is copyrighted by FPIN. If interested in submitting questions or writing answers for this series, go to http://www.fpin.org or email: questions@fpin.org.

This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.

A collection of FPIN's Clinical Inquiries published in AFP is available at https://www.aafp.org/afp/fpin.



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