Abstract
BackgroundThe prevalence of depression is higher among those with diabetes than in the general population. The Patient Health Questionnaire (PHQ-9) is commonly used to assess depression in people with diabetes, but measurement invariance of the PHQ-9 across groups of people with and without diabetes has not yet been investigated. MethodsData from three independent cohorts from the USA (n=1,886 with diabetes, n=4,153 without diabetes), Quebec, Canada (n= 800 with diabetes, n= 2,411 without diabetes), and the UK (n=4,981 with diabetes, n=145,570 without diabetes), were used to examine measurement invariance between adults with and without diabetes. A series of multiple group confirmatory factor analyses were performed, with increasingly stringent model constraints applied to assess configural, equal thresholds, and equal thresholds and loadings invariance, respectively. One-factor and two-factor (somatic and cognitive-affective items) models were examined. ResultsResults demonstrated that the most stringent models, testing equal loadings and thresholds, had satisfactory model fit in the three cohorts for one-factor models (RMSEA = .063 or below and CFI = .978 or above) and two-factor models (RMSEA = .042 or below and CFI = .989 or above). LimitationsData were from Western countries only and we could not distinguish between type of diabetes. ConclusionsResults provide support for measurement invariance between groups of people with and without diabetes, using either a one-factor or a two-factor model. While the two-factor solution has a slightly better fit, the one-factor solution is more parsimonious. Depending on research or clinical needs, both factor structures can be used.
Highlights
People with diabetes have an increased risk of developing clinical and sub-clinical depression (Nouwen et al, 2010; Albertorio et al., 2017)
Studies relying on exploratory factor analysis tend to report a single factor solution (e.g. Cameron et al, 2008; Dum, et al, 2008, Hanssen et al, 2009; Huang et al, 2006), while studies using confirmatory factor analysis have found that a two-factor solution, with one factor reflecting the somatic items of the Patient Health Questionnaire-9 (PHQ-9) and the other factor the cognitive-affective items, has better model fit (Beard et al, 2016; Chil cot et al, 2013; Petersen et al, 2015)
We found that applying increasingly stringent constraints across the three levels of invariance testing did not significantly reduce model fit and model fit was acceptable for the configural, thresholds only, and loadings and thresholds models in all three cohorts
Summary
People with diabetes have an increased risk of developing clinical and sub-clinical depression (Nouwen et al, 2010; Albertorio et al., 2017). The only study examining the PHQ-9 factor structure in people with diabetes, to our knowledge, found a better fit for a two-factor solution than the one-factor solution both in people with and without diabetes (Janssen et al, 2016). The Patient Health Questionnaire (PHQ-9) is commonly used to assess depression in people with diabetes, but measurement invariance of the PHQ-9 across groups of people with and without diabetes has not yet been investigated. Conclusions: Results provide support for measurement invariance between groups of people with and without diabetes, using either a one-factor or a two-factor model. Depending on research or clinical needs, both factor structures can be used
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
