The criteria for exclusions were checked consecutively. ICD-9 indicates International Classification of Diseases, Ninth Revision; TJR, total joint replacement.
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MacFarlane LA, Jin Y, Franklin PD, Lii J, Katz JN, Kim SC. Assessment for Perioperative Hyperglycemia Prior to Total Joint Replacement in Patients With and Without Diabetes. JAMA Netw Open. Published online September 04, 20192(9):e1910589. doi:10.1001/jamanetworkopen.2019.10589
More than 1 000 000 total joint replacements (TJRs) are performed annually in the United States,1 most of which are for osteoarthritis.2 Diabetes is a frequent comorbidity in patients with osteoarthritis3 and suboptimal glucose control preoperatively is associated with poor TJR outcomes.4,5 Despite the concern for hyperglycemia in the period before TJR, there is a paucity of data regarding the frequency of preoperative outpatient screening. We aimed to assess how frequently hemoglobin A1c (HbA1c) was measured 90 days prior to TJR among Medicare enrollees.
We conducted a cohort study using claims data from Medicare Parts A (hospital), B (medical), and D (pharmacy) from January 2010 to December 2014; data were analyzed from May 2018 to July 2019. The index date was the date of first TJR (total hip or knee) during the study period. Patients were aged 65 years or older and were continuously enrolled in Medicare for at least 360 days prior to the index date.
This study was approved by the Brigham and Women’s Health institutional review board, which waived the requirement for obtaining patients’ consent because data were deidentified and patients incurred minimal risk. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.
International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) or Current Procedural Terminology codes were used to identify diabetes, complications of diabetes (nephropathy, neuropathy, retinopathy, or foot problems associated with diabetes), TJR, and comorbidities. Using claims from the 270 days prior to the 90-day outcome period, we created 4 mutually exclusive groups: (1) no diabetes (no ICD-9 code for diabetes or diabetes complications and no claim for insulin or other antidiabetic medications); (2) diabetes and not receiving medication (≥1 ICD-9 code for diabetes but no claim for insulin or other antidiabetic medications); (3) diabetes and receiving noninsulin medications for diabetes (≥1 ICD-9 code for diabetes and ≥1 claim for noninsulin antidiabetic medications); and (4) diabetes and receiving insulin (≥1 ICD-9 code for diabetes and ≥1 claim for insulin).
The primary outcome was the proportion of patients who had an HbA1c level tested in the 90 days prior to TJR. We also assessed the proportion of patients who had a code for serum blood glucose level tested separately or in metabolic panels in the 90 days preceding TJR.
We had access to 1 046 660 claims for TJR; of these, 465 566 patients met the inclusion criteria (Figure). Among the groups, mean age ranged from 73 to 75 years and 64% to 68% were female (Table). In the 90 days prior to TJR, 4.9% (95% CI, 4.8%-5.0%) of patients without diabetes had HbA1c testing compared with 25.8% (95% CI, 25.4%-26.2%) of those with diabetes not receiving medication, 39.0% (95% CI, 38.6%-39.4%) of those with diabetes receiving noninsulin medications, and 43.4% (95% CI, 42.8%-44.1%) of those with diabetes receiving insulin. Serum glucose testing was performed in 37.2% (95% CI, 37.0%-37.4%) of those without diabetes, 45.7% (95% CI, 45.2%-46.1%) of those with diabetes not receiving medication, 47.7% (95% CI, 47.3%-48.1%) of those with diabetes receiving noninsulin medications, and 50.2% (95% CI, 49.5%-50.9%) of those with diabetes receiving insulin. The proportion of patients with HbA1c or serum glucose level tested was 37.6% in those without diabetes, 48.6% in those with diabetes not receiving medication, 52.9% for those with diabetes receiving noninsulin medication, and 56.8% for those with diabetes receiving insulin.
In this large Medicare cohort undergoing TJR, preoperative HbA1c testing was performed in 26% to 43% of patients with diabetes and in only 5% of those without diabetes. Prior research has shown that an elevated HbA1c level is associated with postoperative complications and, furthermore, that screening and addressing risk factors such as HbA1c preoperatively may reduce complications, highlighting the importance of HbA1c screening.4-6
Limitations of our study include possible misclassification of diabetes, as we relied on ICD-9 codes, although we also used medication dispensing data to maximize accuracy. We were unable to assess for screening with fingerstick blood glucose or inpatient testing. Data were available from 2010 to 2014 and may not reflect current practice.
In a real-world clinical setting, hyperglycemia is often not screened for prior to TJR. Further study on the utility of perioperative hyperglycemia monitoring and optimization is warranted.
Accepted for Publication: July 15, 2019.
Published: September 4, 2019. doi:10.1001/jamanetworkopen.2019.10589
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2019 MacFarlane LA et al. JAMA Network Open.
Corresponding Author: Lindsey A. MacFarlane, MD, MPH, Brigham and Women's Hospital, 60 Fenwood Rd, Boston, MA 20115 (email@example.com).
Author Contributions: Drs MacFarlane and Kim had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: MacFarlane, Jin, Kim.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: MacFarlane, Jin, Lii.
Critical revision of the manuscript for important intellectual content: MacFarlane, Franklin, Katz, Kim.
Statistical analysis: MacFarlane, Jin, Lii, Kim.
Obtained funding: Kim.
Administrative, technical, or material support: MacFarlane, Katz, Kim.
Conflict of Interest Disclosures: Dr MacFarlane reported receiving personal fees from Flexion outside the submitted work. Dr Franklin reported receiving grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases during the conduct of the study; and grants from National Institutes of Health, the Patient-Centered Outcomes Research Institute, and the Agency for Healthcare Research and Quality outside the submitted work. Dr Katz reported receiving grants from Flexion Therapeutics and Samumed outside the submitted work. Dr Kim reported receiving grants from Pfizer, AbbVie, Roche, and Bristol-Myers Squibb outside the submitted work. No other disclosures were reported.
Funding/Support: This work was supported by National Institutes of Health grant R01AR069557.
Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
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