Rasch analysis suggests that health assessment questionnaire II is a generic measure of physical functioning for rheumatic diseases: a cross-sectional study

Development and Validation of a Physical Food Security Tool for Older Adults

BACKGROUND

Current measures of food insecurity focus on economic access to food, but not on the physical aspect of food insecurity that captures the inability to access food or prepare meals. This is particularly relevant among the older adult population who are at a high risk of functional impairments.

OBJECTIVES

To develop a short-form physical food security (PFS) tool among older adults using statistical methods based on the Item Response Theory (Rasch) model.

METHODS

Pooled data from adults aged ≥60 y of the NHANES (2013-2018) (n = 5892) were used. The PFS tool was derived from the physical limitation questions included in the physical functioning questionnaire of NHANES. Item severity parameters, fit and reliability statistics, and residual correlation between items were estimated using the Rasch model. The construct validity of the tool was assessed by examining associations with the Healthy Eating Index (HEI)-2015 scores, self-reported health, self-reported diet quality, and economic food insecurity, using weighted multivariable linear regression analysis, controlling for potential confounders.

RESULTS

A 6-item scale was developed, which had adequate fit statistics and high reliability (0.62). It was categorized based on raw score severity into high, marginal, low, and very low PFS. Very low PFS was associated with respondent's self-reported poor health (OR = 23.8; 95% CI: 15.3, 36.9; P < 0.0001), self-reported poor diet (OR = 3.9; 95% CI: 2.8, 5.5; P < 0.0001), low and very low economic food security (OR = 6.08; 95% CI: 4.23, 8.76; P < 0.0001), and with lower mean HEI-2015 index score, in comparison to older adults with high PFS (54.5 compared with 57.5, P = 0.022).

CONCLUSIONS

The proposed 6-item PFS scale captures a new dimension of food insecurity that can inform on how older adults experience food insecurity. The tool will require further testing and evaluation in larger and different contexts to demonstrate its external validity.

Rasch model of the child perceptions questionnaire in multi-country data

OBJECTIVE

To be fit-for-purpose, oral health-related quality of life instruments must possess a range of psychometric properties which had not been fully examined in the 16-item Short Form Child Perceptions Questionnaire for children aged 11 to 14 years (CPQ_11-14 ISF-16). We used advanced statistical approaches to determine the CPQ's measurement accuracy, precision, invariance and dimensionality and analyzed whether age range could be extended from 8 to 15 years.

METHODS

Fit to the Rasch model was examined in 6648 8-to-15-year-olds from Australia, New Zealand, Brunei, Cambodia, Hong Kong, Malaysia, Thailand, Germany, United Kingdom, Brazil and Mexico.

RESULTS

In all but two items, the initial five answer options were reduced to three or four, to increase precision of the children's selection. Items 10 (Shy/embarrassed) and 11 (Concerned what others think) showed an 'extra' dependency between item scores beyond the relationship related to the underlying latent construct represented by the instrument, and so were deleted. Without these two items, the CPQ was unidimensional. The three oral symptoms items (4 Food stuck in teeth, 3 Bad breath and 1 Pain) were required for a sufficient person-item coverage. In three out of 14 items (21 %), Europe and South America showed regional differences in the patterns of how the answer options were selected. No differential item functioning was detected for age.

CONCLUSION

Except for a few modifications, the present analysis supports the combination of items, the cross-cultural validity of the CPQ with 14 items and the extension of the age range from 8 to 15 years.

CLINICAL SIGNIFICANCE

The valid, reliable, shortened and age-extended version of the CPQ resulting from this study should be used in routine care and clinical research. Less items and a wider age range increase its usability. Symptoms items are needed to precisely differentiate between children with higher and lower quality of life.