title: Effect of methotrexate use and erythrocyte methotrexate polyglutamate on glycosylated hemoglobin in rheumatoid arthritis.
abstract: OBJECTIVE
  To investigate whether methotrexate (MTX) use, as compared to other therapies, and erythrocyte methotrexate polyglutamate (MTXGlu) concentrations are associated with changes in glycosylated hemoglobin (HbA1c ) levels in rheumatoid arthritis (RA) patients.
  
  
  METHODS
  The derivation cohort consisted of patients selected from the Treatment in the Rotterdam Early Arthritis Cohort who fulfilled the 2010 American College of Rheumatology/European League Against Rheumatism classification criteria for RA. Patients were randomized to 6 treatment arms: triple disease-modifying antirheumatic drug (DMARD) therapy (consisting of MTX, sulfasalazine, and hydroxychloroquine [HCQ]) + intramuscular (IM) glucocorticoids, triple DMARD therapy + oral glucocorticoids, MTX + oral glucocorticoid therapy, MTX therapy, oral glucocorticoid therapy, and HCQ therapy. HbA1c levels were determined at baseline and at 3 months. Concentrations of erythrocyte MTXGlu1-5 were measured after 3 months of treatment. Within treatment arms, changes in the level of HbA1c were compared by paired t-test. Associations of MTXGlu concentrations with changes in the level of HbA1c were tested using multiple linear regression analysis, adjusted for age, sex, body mass index, and comedication. Significant associations were validated using data on RA patients taking MTX who were enrolled in the Methotrexate in Rotterdam cohort.
  
  
  RESULTS
  In the derivation cohort, the mean change in HbA1c level after 3 months of treatment was -1.9 mmoles/mole (-0.18%) (P = 0.001). Levels of HbA1c decreased in 4 of the individual treatment groups, as follows: for the triple DMARD therapy + IM glucocorticoids treatment arm, -5.5 mmoles/mole (-0.50%) (P < 0.001), for the triple DMARD therapy + oral glucocorticoids treatment arm, -3.7 mmoles/mole (-0.34%) (P < 0.001), for the MTX treatment arm, -0.8 mmoles/mole (-0.08%) (P = 0.018), and for the HCQ treatment arm, -2.0 mmoles/mole (-0.19%) (P = 0.175). Increased levels of MTXGlu2 (β = -0.20, P = 0.005), MTXGlu3 (β = -0.31, P < 0.001), MTXGlu4 (β = -0.33, P < 0.001) after treatment, MTXGlu5 (β = -0.39, P < 0.001), and total MTXGlu (β = -0.29, P < 0.001) were associated with decreased levels of HBA1c . In the validation cohort, levels of HbA1c were decreased by 2.6 mmoles/mole (0.23%) (P < 0.001) after treatment, and MTXGlu3 was associated with decreased levels of HbA1c (β = -0.26, P = 0.018).
  
  
  CONCLUSIONS
  MTX use and higher concentrations of erythrocyte MTXGlu are associated with decreased levels of HbA1c in RA patients. Triple DMARD therapy and HCQ treatment resulted in reduced HbA1c levels, and glucocorticoid treatment resulted in increased levels of HbA1c .
authors.affiliation: Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Maurits C F J
authors.initials: MC
authors.lastname: de Rotte
authors.forename: Pascal H P
authors.initials: PH
authors.lastname: de Jong
authors.forename: Ethan
authors.initials: E
authors.lastname: den Boer
authors.forename: Saskia M F
authors.initials: SM
authors.lastname: Pluijm
authors.forename: Behiye
authors.initials: B
authors.lastname: Özcan
authors.forename: Angelique E A M
authors.initials: AE
authors.lastname: Weel
authors.forename: Jan
authors.initials: J
authors.lastname: Lindemans
authors.forename: Johanna M W
authors.initials: JM
authors.lastname: Hazes
authors.forename: Robert
authors.initials: R
authors.lastname: de Jonge
mesh_terms: D018501:Antirheumatic Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000188:drug therapy*; D004912:Erythrocytes / Q000737:chemistry*; D005260:Female; D006442:Glycated Hemoglobin / Q000187:drug effects*; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000031:analogs & derivatives* / Q000032:analysis / Q000494:pharmacology* / Q000627:therapeutic use*; D008875:Middle Aged; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D011446:Prospective Studies
chemical_list: D018501:Antirheumatic Agents; D006442:Glycated Hemoglobin; D008727:Methotrexate; D011099:Polyglutamic Acid; C014085:methotrexate polyglutamate