{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T15:23:23Z","timestamp":1786116203198,"version":"build-2736575974"},"reference-count":25,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,7,4]],"date-time":"2026-07-04T00:00:00Z","timestamp":1783123200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T00:00:00Z","timestamp":1785974400000},"content-version":"vor","delay-in-days":33,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["BMC Endocr Disord"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Red cell distribution width-standard deviation (RDW-SD), a measure of erythrocyte volume heterogeneity, has attracted increasing interest as a hematologic marker linked to inflammation, oxidative stress, and metabolic dysfunction beyond anemia evaluation. However, evidence on the relationship between glycated hemoglobin (HbA1c) and RDW-SD in newly diagnosed, treatment-na\u00efve type 2 diabetes mellitus (T2DM) remains limited. This study investigated the association between HbA1c and RDW-SD after accounting for hematologic, nutritional, renal, and metabolic factors that are routinely available at diagnosis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In this retrospective cross-sectional study, 202 adults aged 18\u201365 years with newly diagnosed, treatment-na\u00efve T2DM were evaluated at a tertiary university hospital between September 2024 and January 2026. Patients with anemia, mean corpuscular volume abnormalities, advanced renal impairment, acute inflammation or infection, recent transfusion, prior antidiabetic therapy, active bleeding, or hematologic malignancy were excluded. Associations between HbA1c and RDW-SD were examined using correlation, partial correlation, and hierarchical linear regression analyses. Additional analyses assessed RDW-SD across HbA1c tertiles and tested the robustness of the association after inclusion of fasting glucose.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      HbA1c showed a positive correlation with RDW-SD (\n                      <jats:italic>r<\/jats:italic>\n                      \u2009=\u20090.664,\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001), which remained essentially unchanged after adjustment for age, sex, body mass index, hemoglobin, mean corpuscular volume, creatinine, ferritin, and vitamin B12 (partial\n                      <jats:italic>r<\/jats:italic>\n                      \u2009=\u20090.662,\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001). Mean RDW-SD increased stepwise across ascending HbA1c tertiles (40.40\u2009\u00b1\u20093.04, 42.96\u2009\u00b1\u20093.38, and 46.13\u2009\u00b1\u20093.85 fL; p-trend\u2009&lt;\u20090.001). In hierarchical regression, HbA1c produced the largest incremental gain in explained variance (\u0394R\u00b2 = 0.323,\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001) and remained the strongest correlate of RDW-SD in the fully adjusted model (B\u2009=\u20091.535, \u03b2\u2009=\u20090.674,\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001). In sensitivity analysis, the association persisted after additional adjustment for fasting glucose.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>In newly diagnosed, treatment-na\u00efve T2DM, higher HbA1c levels were associated with greater RDW-SD. These findings are hypothesis-generating and do not establish RDW-SD as a clinical marker of glycemic burden or dysglycemia assessment.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Clinical trial number<\/jats:title>\n                    <jats:p>Not applicable.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12902-026-02405-9","type":"journal-article","created":{"date-parts":[[2026,7,4]],"date-time":"2026-07-04T11:10:29Z","timestamp":1783163429000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Association between HbA1c and red cell distribution width-standard deviation in newly diagnosed, treatment-na\u00efve type 2 diabetes mellitus: a retrospective cross-sectional study"],"prefix":"10.1186","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3582-9663","authenticated-orcid":false,"given":"Kemal Ozan","family":"Lule","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anil","family":"Beyaz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hamit","family":"Yildiz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,7,4]]},"reference":[{"key":"2405_CR1","doi-asserted-by":"publisher","first-page":"149","DOI":"10.1016\/S2213-8587(25)00299-2","volume":"14","author":"I Genitsaridi","year":"2026","unstructured":"Genitsaridi I, Salpea P, Salim A, et al. 11th edition of the IDF Diabetes Atlas: global, regional, and national diabetes prevalence estimates for 2024 and projections for 2050. 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The study was approved by the Gaziantep University Non-Interventional Clinical Research Ethics Committee (decision no. 2026\/173; approval date: 04 March 2026). Permission for the use of retrospective hospital data was obtained from the Chief Physician\u2019s Office prior to data extraction. Because the study was based exclusively on routinely collected, non-identifiable retrospective hospital records and involved no direct patient contact or intervention, informed consent was not required in accordance with institutional procedures.","order":1,"name":"Ethics","label":"Ethics approval and consent to participate","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"Not applicable. The manuscript does not contain any individual person\u2019s identifiable data, images, or videos.","order":2,"name":"Ethics","label":"Consent for publication","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":3,"name":"Ethics","label":"Competing interests","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"226"}}