title: Initiation of sulfonylureas versus metformin is associated with higher blood pressure at one year.
abstract: OBJECTIVE
  To determine if incident oral antidiabetic drug (OAD) use was associated with 12-month systolic blood pressure (BP) and if this was mediated through body mass index (BMI) changes.
  
  
  METHODS
  A retrospective cohort of veterans with hypertension who initiated metformin (n = 2057) or sulfonylurea (n = 1494) between 1 January 2000 and 31 December 2007 in the Veterans Administration Mid-South Network was assembled. Patients were included if they had complete covariates, including 12-month BP and BMI, and persisted on therapy for 12 months. Linear regression was conducted to investigate the effect of OADs on 12-month systolic BP adjusting for demographics, glycated hemoglobin, creatinine, BMI, health care utilization, and comorbidities, including cardiovascular disease (CVD). A second analysis examined if these effects were mediated by BMI change. The secondary outcome was the proportion of patients who had a controlled BP (≤ 140/90 mmHg) at 12 months adjusted for baseline BP and covariates.
  
  
  RESULTS
  Patients were white (82%) males (97%) with median age of 64 years (interquartile range [IQR] 57, 72), and 27% had history of CVD. Sulfonylurea users had a 1.33 mmHg (0.16, 2.50, p = 0.03) higher 12-month systolic BP than metformin users. The median change in BMI from OAD initiation to 12 months was -0.76 (IQR -1.78, 0.07) and 0.21 (IQR -0.57, 1.03) among metformin and sulfonylurea users, respectively. In a model adjusting for BMI change, the difference in 12-month systolic BP between sulfonylurea and metformin users became insignificant (0.23 (-1.00, 1.45), p = 0.72), while one BMI unit change was associated with an increase in 12-month systolic BP of 1.07 mmHg (0.74, 1.40, p < 0.0001). At 12 months, 68.3% of metformin patients had controlled BP versus 64.2% of sulfonylurea patients (p = 0.01).
  
  
  CONCLUSIONS
  Compared with metformin, sulfonylurea initiation was associated with increased systolic BP at 12 months, which appears to be mediated by the differential effects of these drugs on BMI.
authors.affiliation: VA Tennessee Valley Geriatric Research Education Clinical Center (GRECC), HSR&D Targeted Research, Enhancement Program for Patient Healthcare Behavior, and Clinical Research Center of Excellence, Nashville, TN 37212, USA. christianne.roumie@vanderbilt.edu
authors.forename: Christianne L
authors.initials: CL
authors.lastname: Roumie
authors.forename: Xulei
authors.initials: X
authors.lastname: Liu
authors.forename: Neesha N
authors.initials: NN
authors.lastname: Choma
authors.forename: Robert A
authors.initials: RA
authors.lastname: Greevy
authors.forename: Adriana M
authors.initials: AM
authors.lastname: Hung
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Grijalva
authors.forename: Marie R
authors.initials: MR
authors.lastname: Griffin
mesh_terms: D000284:Administration, Oral; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D015992:Body Mass Index; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D016014:Linear Models; D008297:Male; D008687:Metformin / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D008875:Middle Aged; D012189:Retrospective Studies; D013453:Sulfonylurea Compounds / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D014481:United States; D014493:United States Department of Veterans Affairs; D014728:Veterans
chemical_list: D007004:Hypoglycemic Agents; D013453:Sulfonylurea Compounds; D008687:Metformin