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. 2025 Feb 4;13(1):e004536.
doi: 10.1136/bmjdrc-2024-004536.

Association of glycemic control with Long COVID in patients with type 2 diabetes: findings from the National COVID Cohort Collaborative (N3C)

Samuel Soff  1 , Yun Jae Yoo  2 , Carolyn Bramante  3 , Jane E B Reusch  4 , Jared Davis Huling  5 , Margaret A Hall  2 , Daniel Brannock  6 , Til Sturmer  7 , Zachary Butzin-Dozier  8 , Rachel Wong #  9   10 , Richard Moffitt #  11 ; N3C Consortium
Collaborators, Affiliations

Association of glycemic control with Long COVID in patients with type 2 diabetes: findings from the National COVID Cohort Collaborative (N3C)

Samuel Soff et al. BMJ Open Diabetes Res Care. .

Abstract

Introduction: Elevated glycosylated hemoglobin (HbA1c) in individuals with type 2 diabetes is associated with increased risk of hospitalization and death after acute COVID-19, however the effect of HbA1c on Long COVID is unclear.

Objective: Evaluate the association of glycemic control with the development of Long COVID in patients with type 2 diabetes (T2D).

Research design and methods: We conducted a retrospective cohort study using electronic health record data from the National COVID Cohort Collaborative. Our cohort included individuals with T2D from eight sites with longitudinal natural language processing (NLP) data. The primary outcome was death or new-onset recurrent Long COVID symptoms within 30-180 days after COVID-19. Symptoms were identified as keywords from clinical notes using NLP in respiratory, brain fog, fatigue, loss of smell/taste, cough, cardiovascular and musculoskeletal symptom categories. Logistic regression was used to evaluate the risk of Long COVID by HbA1c range, adjusting for demographics, body mass index, comorbidities, and diabetes medication. A COVID-negative group was used as a control.

Results: Among 7430 COVID-positive patients, 1491 (20.1%) developed symptomatic Long COVID, and 380 (5.1%) died. The primary outcome of death or Long COVID was increased in patients with HbA1c 8% to <10% (OR 1.20, 95% CI 1.02 to 1.41) and ≥10% (OR 1.40, 95% CI 1.14 to 1.72) compared with those with HbA1c 6.5% to <8%. This association was not seen in the COVID-negative group. Higher HbA1c levels were associated with increased risk of Long COVID symptoms, especially respiratory and brain fog. There was no association between HbA1c levels and risk of death within 30-180 days following COVID-19. NLP identified more patients with Long COVID symptoms compared with diagnosis codes.

Conclusion: Poor glycemic control (HbA1c≥8%) in people with T2D was associated with higher risk of Long COVID symptoms 30-180 days following COVID-19. Notably, this risk increased as HbA1c levels rose. However, this association was not observed in patients with T2D without a history of COVID-19. An NLP-based definition of Long COVID identified more patients than diagnosis codes and should be considered in future studies.

Keywords: COVID-19; Database; Diabetes Complications; Diabetes Mellitus, Type 2.

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Conflict of interest statement

Competing interests: TS receives funding and support from the Center for Pharmacoepidemiology (current members: GlaxoSmithKline, UCB BioSciences, Takeda, AbbVie, Boehringer Ingelheim, Astellas, and Sarepta) and owns stock in Novartis, Roche, and Novo Nordisk. JEBR has affiliations with or receives funding from Springer Nature Switzerland-Exercise Book, Medtronic Diabetes, and AstraZeneca.

Figures

Figure 1
Figure 1. Cohort flow diagram. BMI, body mass index; N3C, National COVID Cohort Collaborative; NLP, natural language processing.
Figure 2
Figure 2. Forest plots showing adjusted ORs and their 95% CIs for Long COVID or death in COVID-positive and COVID-negative patients with type 2 diabetes. Multivariate analysis adjusted for age, gender, race, ethnicity, comorbidities, diabetes medication, glycosylated hemoglobin (HbA1c) range, and body mass index (BMI). *p<0.05, **p<0.01, ***p<0.001.
See this image and copyright information in PMC

References

    1. WHO COVID-19 Dashboard COVID-19 cases. 2024. https://data.who.int/dashboards/covid19/cases Available.
    1. Astin R, Banerjee A, Baker MR, et al. Long COVID: mechanisms, risk factors and recovery. Exp Physiol. 2023;108:12–27. doi: 10.1113/EP090802. - DOI - PMC - PubMed
    1. Thaweethai T, Jolley SE, Karlson EW, et al. Development of a Definition of Postacute Sequelae of SARS-CoV-2 Infection. JAMA. 2023;329:1934–46. doi: 10.1001/jama.2023.8823. - DOI - PMC - PubMed
    1. Zhang HG, Honerlaw JP, Maripuri M, et al. Characterizing the use of the icd-10 code for long covid in 3 us healthcare systems. Health Informatics. 2023 doi: 10.1101/2023.02.12.23285701. Preprint. - DOI
    1. Horberg MA, Watson E, Bhatia M, et al. Post-acute sequelae of SARS-CoV-2 with clinical condition definitions and comparison in a matched cohort. Nat Commun. 2022;13:5822. doi: 10.1038/s41467-022-33573-6. - DOI - PMC - PubMed

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