title: Impact of metformin-induced gastrointestinal symptoms on quality of life and adherence in patients with type 2 diabetes.
abstract: OBJECTIVE
  Gastrointestinal (GI) symptoms are common in patients with type 2 diabetes mellitus (T2DM). This study assesses the impact of 1) metformin on GI symptoms and health-related quality of life (HRQoL) and 2) metformin-associated GI symptoms on medication adherence in patients with type 2 diabetes newly beginning therapy.
  
  
  METHODS
  Patients with T2DM aged>or=18 years starting metformin from January to June 2007 who filled their prescriptions for >or=3 months were identified from a health benefits company database. Via telephone, GI symptom impact was evaluated in a 360-patient sample using the validated Bowel Symptom Questionnaire and Medical Outcomes Study 36-Item Short-Form Health (SF-36) survey. Adherence was assessed using the medication possession ratio (MPR). Logistic regression adjusting for demographic and clinical covariates was used to assess the relationship between GI symptoms and MPR<80%.
  
  
  RESULTS
  The most and least common GI symptoms reported were diarrhea (62.1%) and retching (21.1%), respectively. Most GI symptoms were associated with lower physical and mental HRQoL (P<0.05). Most changes in specific HRQoL reached the minimum important difference of 3 points. Bloating, nausea, and abdominal pain were significantly associated with MPR<80%. Adjustment for demographic, clinical, and HRQoL factors made these relationships less evident.
  
  
  CONCLUSIONS
  Metformin-associated GI symptoms in patients with T2DM lead to lower physical and mental HRQoL, which may result in patient nonadherence or physician reluctance to optimally titrate the metformin dose.
authors.affiliation: University of Miami-Humana Health Service Research Center, Miami, FL 33125, USA. hflorez@med.miami.edu
authors.forename: Hermes
authors.initials: H
authors.lastname: Florez
authors.forename: Jiacong
authors.initials: J
authors.lastname: Luo
authors.forename: Sumaya
authors.initials: S
authors.lastname: Castillo-Florez
authors.forename: Georgia
authors.initials: G
authors.lastname: Mitsi
authors.forename: John
authors.initials: J
authors.lastname: Hanna
authors.forename: Leonardo
authors.initials: L
authors.lastname: Tamariz
authors.forename: Ana
authors.initials: A
authors.lastname: Palacio
authors.forename: Sukumar
authors.initials: S
authors.lastname: Nagendran
authors.forename: Michael
authors.initials: M
authors.lastname: Hagan
mesh_terms: D000368:Aged; D016001:Confidence Intervals; D003625:Data Collection; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000523:psychology; D005260:Female; D005767:Gastrointestinal Diseases / Q000139:chemically induced* / Q000523:psychology; D006305:Health Status Indicators; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D016015:Logistic Models; D008297:Male; D055118:Medication Adherence / Q000523:psychology; D008687:Metformin / Q000009:adverse effects* / Q000627:therapeutic use; D016017:Odds Ratio; D011594:Psychometrics; D011788:Quality of Life; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States; D016903:Drug Monitoring
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin