Publications

BACKGROUND

Self-reported data are widely used in substance-use research, yet few studies have assessed the validity of self-reported methamphetamine use compared to biological assays.

OBJECTIVES

We sought to assess the validity and correlates of validity of self-reported methamphetamine use compared to urine toxicology (UTOX).

METHODS

Using a sample of methamphetamine-dependent individuals enrolled in a randomized controlled pharmacotherapy trial in the United States (n = 327 visits among 90 participants), we calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the kappa coefficient of self-reported methamphetamine use in the past 3 days compared to UTOX, as well as the NPV of self-reported methamphetamine use over an extended recall period of 1 month. We used multivariable logistic regression models to assess correlates of concordance between self-reported methamphetamine use and UTOX.

RESULTS

The sensitivity of self-reported methamphetamine use in the past 3 days was 86.7% (95% confidence intervals (95%CI): 81.4%-91.4%), the specificity was 85.3% (77.7-91.3), the PPV was 91.5% (86.9-94.8), and the NPV was 78.0% (69.4-86.1), compared to UTOX (kappa = 0.71). The NPV over the extended recall period was 70.6% (48.0-85.7). In multivariable analyses, validity of self-reported methamphetamine use was higher for older participants but lower during follow-up compared to baseline and when polysubstance use or depressive symptoms were reported. Conclusions/Importance: Our sample of methamphetamine-dependent adults reported recent methamphetamine use with high validity compared to UTOX. Validity increased with age but decreased when participants reported depressive symptoms or polysubstance use as well as later in the study timeline and during longer recall periods.

Small intestinal histologic abnormalities in celiac disease include atrophy of the intestinal villi, hypertrophy of the crypts and lymphocytic infiltration of intraepithelial spaces and lamina propria. These findings are central to diagnosis and their severity and change over time are valuable to monitor disease course and response to therapy. Subjective methods to grade celiac disease histological severity include the Marsh-Oberhuber and Corazza-Villanacci systems. Quantitative histology uses villus height (Vh), crypt depth (Cd), and intra-epithelial lymphocyte count (per 100 enterocytes) to provide objective measures of histologic changes including Vh:Cd ratio. Here we examine the available literature regarding these methodologies and support the use of quantitative histology as the preferred method for accurately and reproducibly demonstrating change of relevant histologic end points over time. We also propose a Quantitative-Mucosal Algorithmic Rules for Scoring Histology (Q-MARSH) system to partially align quantitative histology results with the traditional Marsh, Marsh-Oberhuber, and Corazza-Villanacci systems. Q-MARSH can provide a standardized, objective, and quantitative histology scoring system for use as a clinical or research application.