Skip to main content

Main menu

  • Home
  • Our journals
    • Clinical Medicine
    • Future Healthcare Journal
  • Subject collections
  • About the RCP
  • Contact us

Clinical Medicine Journal

  • ClinMed Home
  • Content
    • Current
    • Ahead of print
    • Archive
  • Author guidance
    • Instructions for authors
    • Submit online
  • About ClinMed
    • Scope
    • Editorial board
    • Policies
    • Information for reviewers
    • Advertising

User menu

  • Log in

Search

  • Advanced search
RCP Journals
Home
  • Log in
  • Home
  • Our journals
    • Clinical Medicine
    • Future Healthcare Journal
  • Subject collections
  • About the RCP
  • Contact us
Advanced

Clinical Medicine Journal

clinmedicine Logo
  • ClinMed Home
  • Content
    • Current
    • Ahead of print
    • Archive
  • Author guidance
    • Instructions for authors
    • Submit online
  • About ClinMed
    • Scope
    • Editorial board
    • Policies
    • Information for reviewers
    • Advertising

Sodium glucose co-transporter 2 inhibitors successfully attenuated seasonal change of glycated haemoglobin A1c

Eijiro Yamada, Tsugumichi Saito, Yawara Niijima, Shuichi Okada and Masanobu Yamada
Download PDF
DOI: https://doi.org/10.7861/clinmedicine.17-4-377
Clin Med August 2017
Eijiro Yamada
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma, Japan
Roles: Associate
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Tsugumichi Saito
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma, Japan
Roles: Associate
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Yawara Niijima
Kan-etsu Chuo Hospital, Gunma, Japan
Roles: Director
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Shuichi Okada
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma, Japan
Roles: Assistant professor
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Masanobu Yamada
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma, Japan
Roles: Professor
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
Loading

Previous studies suggested that glycated haemoglobin (HbA1c) levels are highest in winter and lowest in summer.1–4 Potential susceptibilities to seasonal change of HbA1c include inappropriate dietary calorie intake and insufficient physical activity in winter. In our hospital, the majority of diabetes patients are farmers and their physical activity is relatively lower in winter (agricultural off-season) than in summer (busy farming season). These patients face difficulties in adapting a seasonal diet modification concomitant with the variation in physical activity.

In this study, we examined the effect of sodium glucose co-transporter 2 (SGLT2) inhibitors on patients who experience seasonal change of their diabetic control. Because those patients also tend to increase body weight, SGLT2 inhibitors were considered as an addition to their current medications to minimise seasonal variation of HbA1c in winter. Our study protocol was reviewed and approved by our hospitals' review boards according to the Declaration of Helsinki. Written informed consent was obtained from each participant. This clinical study involved 30 patients with type 2 diabetes mellitus whose HbA1c showed seasonal change for the previous 3 years and got worse in the autumn of 2015. Patients were prescribed an SGLT2 inhibitor in addition to their current medications. Patients visited the hospital for follow-up examination once a month, and blood glucose levels and HbA1c levels from the same blood samples were measured. In parallel, urinary glucose levels were determined in spot urine samples at each visit. Body weight, blood pressure and estimated glomerular filtration rate (eGFR) were also measured at each visit. Plasma glucose and HbA1c concentrations were determined as previously reported.5 The median duration of type 2 diabetes mellitus was 4.7 (range 3.5–18.7) years. All patients reported that they had no infections during the observation period, including any common cold symptoms. We observed no statistically significant change in eGFR, body weight or systolic or diastolic blood pressure after SGLT2 administration.

Seasonal change of HbA1c in the previous 3 years is shown in Fig 1. Their HbA1c was lower in summer and higher in winter before the initiation of SGLT2 inhibitors. SGLT2 inhibitor administration could avoid the tendency for HbA1c to get worse towards winter season as indicated.

Fig 1.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig 1.

SGLT2 inhibitor improved seasonal change of HbA1c. Seasonal changes of HbA1c in 30 subjects are shown. The change of HbA1c from summer 2013 was obtained. For summer, we calculated the mean value of three HbA1c measurements from June through August and for winter we calculated the mean value of three HbA1c measurements from December through February. SGLT2 inhibitors were started at the beginning of autumn (mean value from October and December). Error bars represent the standard deviation. The winter HbA1c values were significantly lower in 2015 than 2013 and 2014 (*p<0.05). HbA1c = glycated haemoglobin; SGLT2 = sodium glucose co-transporter 2

Seasonal change of diabetic control triggers treatment difficulties because these variations are usually accompanied by excess calorie intake and a decrement of physical activity.1–4 If these patients are then administered excess amounts of either endogenous or exogenous insulin without correcting their excess caloric intake and/or improving their decreased physical activity, they will experience inappropriate body weight gain although their blood glucose control may be improved. In this study, we added SGLT2 inhibitors to the patients' current medication and observed whether SGLT2 inhibitor administration could attenuate the tendency for HbA1c to get worse towards winter season. We did not face any hypoglycaemic episodes and body weight gain by the addition of SGLT2 inhibitors. Furthermore, patients experienced neither dehydration nor cerebral infarction. SGLT2 inhibitors are a good option to treat seasonal change of HbA1c levels.

Conflicts of interest

The authors have no conflicts of interest to declare.

Author contributions

TS, EY, YN and SO took care of patients in this study. SO and MY analysed the data and prepared the manuscript.

  • © Royal College of Physicians 2017. All rights reserved.

References

  1. ↵
    1. Sakura H
    , Tanaka Y, Iwamoto Y. Seasonal fluctuations of glycated hemoglobin levels in Japanese diabetic patients. Diabetes Res Clin Pract 2010;88:65–70.
    OpenUrlCrossRefPubMed
  2. ↵
    1. Iwata K
    , Iwasa M, Nakatani T, et al. Seasonal variation in visceral fat and blood HbA1c in people with type 2 diabetes. Diabetes Res Clin Pract 2012;96:e53–e54.
    OpenUrlPubMed
  3. ↵
    1. Pereira MT
    , Lira D, Bacelar C, Oliveira JC, de Carvalho AC. Seasonal variation of haemoglobin A1c in a Portuguese adult population. Arch Endocrinol Metab 2015; 59:231–5.
    OpenUrl
  4. ↵
    1. Kim Y
    , Park S, Yi W, et al. Seasonal variation in hemoglobin a1c in Korean patients with type 2 diabetes mellitus. J Korean Med Sci 2014;29:550–5.
    OpenUrl
  5. ↵
    1. Osaki A
    , Okada S, Saito T, et al. Renal threshold for glucose reabsorption predicts diabetes improvement by sodium-glucose cotransporter 2 inhibitor therapy. J Diabetes Investig 2016;7:751–4.
    OpenUrl
Back to top
Previous articleNext article

Article Tools

Download PDF
Article Alerts
Sign In to Email Alerts with your Email Address
Citation Tools
Sodium glucose co-transporter 2 inhibitors successfully attenuated seasonal change of glycated haemoglobin A1c
Eijiro Yamada, Tsugumichi Saito, Yawara Niijima, Shuichi Okada, Masanobu Yamada
Clinical Medicine Aug 2017, 17 (4) 377-378; DOI: 10.7861/clinmedicine.17-4-377

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Share
Sodium glucose co-transporter 2 inhibitors successfully attenuated seasonal change of glycated haemoglobin A1c
Eijiro Yamada, Tsugumichi Saito, Yawara Niijima, Shuichi Okada, Masanobu Yamada
Clinical Medicine Aug 2017, 17 (4) 377-378; DOI: 10.7861/clinmedicine.17-4-377
del.icio.us logo Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Conflicts of interest
    • Author contributions
    • References
  • Figures & Data
  • Info & Metrics

Related Articles

  • No related articles found.
  • PubMed
  • Google Scholar

Cited By...

  • No citing articles found.
  • Google Scholar

More in this TOC Section

  • Does ultrasound-guided peripheral cannulation training for junior doctors reduce missed intravenous antibiotics doses? A teaching programme for foundation doctors in an acute medical unit
  • Unexpected deaths following discharge of medical patients from hospital
  • Promoting electric vehicle uptake, a job for the NHS?
Show more Clinical and scientific letters

Similar Articles

FAQs

  • Difficulty logging in.

There is currently no login required to access the journals. Please go to the home page and simply click on the edition that you wish to read. If you are still unable to access the content you require, please let us know through the 'Contact us' page.

  • Can't find the CME questionnaire.

The read-only self-assessment questionnaire (SAQ) can be found after the CME section in each edition of Clinical Medicine. RCP members and fellows (using their login details for the main RCP website) are able to access the full SAQ with answers and are awarded 2 CPD points upon successful (8/10) completion from:  https://cme.rcplondon.ac.uk

Navigate this Journal

  • Journal Home
  • Current Issue
  • Ahead of Print
  • Archive

Related Links

  • ClinMed - Home
  • FHJ - Home
clinmedicine Footer Logo
  • Home
  • Journals
  • Contact us
  • Advertise
HighWire Press, Inc.

Follow Us:

  • Follow HighWire Origins on Twitter
  • Visit HighWire Origins on Facebook

Copyright © 2021 by the Royal College of Physicians