title: A random urine test can identify patients at risk of mesalamine non-adherence: a prospective study.
abstract: OBJECTIVE
  Mesalamine non-adherence is common among patients with ulcerative colitis (UC), and can be difficult to identify in practice. We sought to determine whether a random urine test for salicylates could be used as a marker of 5-aminosalicylic acid (5-ASA) ingestion and identify patients at risk of non-adherence. Our aim is to determine whether measurement of salicylates in a random urine sample correlates with 5-ASA levels, and predicts an individual's risk of mesalamine non-adherence.
  
  
  METHODS
  Prospective observational study. Urinary salicylates (by colorimetry) and 5-ASA (by liquid chromatography and tandem-mass spectrometry) were measured in a random urine sample at baseline in patients and controls. Mesalamine adherence was quantified by patient self-reports at enrollment and pharmacy refills of mesalamine over 6 months.
  
  
  RESULTS
  A total of 93 patients with UC taking mesalamine maintenance therapy were prospectively enrolled from the clinic. Random urine salicylate levels (by colorimetry) were highly correlated with urine 5-ASA metabolite levels (by mass spectrometry; R2=0.9). A random urine salicylate level above 15 mg/dl distinguished patients who had recently taken mesalamine from controls (area under the curve value 0.9, sensitivity 95%, specificity 77%). A significant proportion of patients (27%) who self-identified as "high adherers" by an adherence questionnaire (Morisky Medication Adherence Scale-8) had random levels of urine salicylate below this threshold. These patients were at higher risk of objectively measured non-adherence to mesalamine over the subsequent 6 months (RR: 2.7, 95% CI: 1.1-7.0).
  
  
  CONCLUSIONS
  A random urine salicylate level measured in the clinic can identify patients who have not recently taken mesalamine, and who are at higher risk of longitudinal non-adherence. This test could be used to screen patients who may warrant interventions to improve adherence and prevent disease relapse.
authors.affiliation: Center for Inflammatory Bowel Disease, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Gifford
authors.forename: Anders H
authors.initials: AH
authors.lastname: Berg
authors.forename: Conor
authors.initials: C
authors.lastname: Lahiff
authors.forename: Adam S
authors.initials: AS
authors.lastname: Cheifetz
authors.forename: Gary
authors.initials: G
authors.lastname: Horowitz
authors.forename: Alan C
authors.initials: AC
authors.lastname: Moss
mesh_terms: D000328:Adult; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000652:urine; D019540:Area Under Curve; D015415:Biomarkers / Q000652:urine; D002853:Chromatography, Liquid; D003093:Colitis, Ulcerative / Q000188:drug therapy* / Q000517:prevention & control / Q000652:urine*; D003124:Colorimetry; D005260:Female; D006801:Humans; D008297:Male; D055118:Medication Adherence; D019804:Mesalamine / Q000008:administration & dosage* / Q000652:urine; D008875:Middle Aged; D011446:Prospective Studies; D020156:Salicylic Acid / Q000652:urine*; D055502:Secondary Prevention; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry; D062606:Tertiary Care Centers
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D019804:Mesalamine; D020156:Salicylic Acid