Validity of single item responses to short message service texts to monitor depression: an mHealth sub-study of the UK ACUDep trial

Abstract

BackgroundAn increasing number of research designs are using text messaging (SMS) as a means of self-reported symptom and outcome monitoring in a variety of long-term health conditions, including severity ratings of depressed mood. The validity of such a single item SMS score to measure latent depression is not currently known and is vital if SMS data are to inform clinical evaluation in the future.MethodsA sub-set of depressed participants in the UK ACUDep trial submitted a single SMS text score (R-SMS-DS) between 1 and 9 on how depressed they felt around the same time as completing the PHQ-9 depression questionnaire on paper at 3 months follow-up of the trial. Exploratory categorical data factor analysis (EFA) was used to ascertain the alignment of R-SMS-DS scores with the factor structure of the PHQ-9. Any response bias with regard to age or gender was assessed by differential item functioning (DIF) analysis.ResultsDepression scores based on the PHQ-9 and R-SMS-DS at 3 months were available for 337 participants (74 % female; mean age: 42 years, SD = 11.1), 213 of which completed the two outcomes within 6 days of each other. R-SMS-DS scores aligned with the underlying latent depression of the PHQ-9 (factor loading of 0.656) and in particular its affective rather than somatic dimension. The R-SMS-DS score was most strongly correlated with depressed mood (r = 0.607), feeling bad about oneself (r = 0.588) and anhedonia (r = 0.573). R-SMS-DS responses were invariant with respect to gender (p = 0.302). However, there was some evidence for age related response bias (p = 0.031), with older participants being more likely to endorse lower R-SMS-DS scores than younger ones.ConclusionsThe R-SMS-DS used in the ACUDep trial was found to be a valid measure of latent affective depression with no gender related response bias. This text message item may therefore represent a useful assessment and monitoring tool meriting evaluation in further research. For future study designs we recommend the collection of outcome data by new health technologies in combination with gold standard instruments to ensure concurrent validity.

Immediate Mood Scaler: Tracking Symptoms of Depression and Anxiety Using a Novel Mobile Mood Scale

“…These findings are consistent with several recent reports that have shown good feasibility of similar ecological momentary assessment approaches in patients with mood disorder (eg, major depressive disorder) [47,49,67,68]. Other recent studies further reported good correlation between mobile monitoring tools and standard clinical measures, such as the PHQ-9 measure used in our study [16,50,51]. For example, Aguilera et al [50] found that text messages of daily mood ratings, and their weekly averages (but not their variances or 2 week averages), were highly correlated with paper-and-pencil PHQ-9 scores.…”

“…Similar results were reported by Torous et al [ 49 ], who used a mobile phone app to administer a subset of PHQ-9 questions to capture depressive symptoms in psychiatric outpatients. Others [ 16 , 50 , 51 ] have also examined the feasibility of daily or weekly short message service (SMS)–based mood ratings and found these ratings to be a valid monitoring strategy for depressed participants. Such studies provide initial promising evidence for the utility of remote momentary assessments, and additional evidence is required in order to better establish the usability of such tools.…”

Advice given by community members to pregnant women: a mixed methods study

“…Validity of data collected via text messaging may differ from traditional forms of data collection. However, studies have shown text messaging surveys to be as valid as paper surveys, and that respondents are more likely to be honest and provide higher quality data in text message surveys compared to verbal interviews [49, 50]. Finally, our research did not explore the limitations experienced by community members in speaking about weight gain during pregnancy, or the accuracy of the advice they provided.…”

The meaning of vaguely quantified frequency response options on a quality of life scale depends on respondents’ medical status and age

“…Modern (item response theory) test construction approaches have led to substantial improvements in QoL measures with category rating scales such as those developed by PROMIS [28], including the development of instruments that are calibrated based on item response functions, and the possibility to detect and recalibrate specific items that show “differential item functioning” and are not interpreted in the same way across different groups [46,47]. Additionally, techniques involving anchoring vignettes [48,49], modulus based assessments [50], and joint evaluation procedures [51], have been suggested to reduce incomparabilities in the use of response scales.…”