# HADS-Anxiety: item-level investigation of the lack of

## longitudinal measurement

### invariance

## A study comparing melanoma and breast cancer patients

### Authors

Yseulys Dubuy¹

Myriam Blanchin¹

Marianne Bourdon¹,²

Bastien Perrot¹

Véronique Sébille-Rivain¹

### Affiliations

1. UMR INSERM 1246 SPHERE "methodS in Patient-Centered Outcomes and Health Research", Nantes University, University of Tours, Nantes, France
SPHERE website: https://sphere-inserm.fr/

2. Integrated Center for Oncology, Nantes, France

### Acknowledgements

The authors sincerely thank the Integrated Center for Oncology for this collaboration

### Funding

ELCCA was financially supported by the "Ligue Nationale contre le Cancer" and the "Institut pour la Recherche en Santé Publique"

### References

[1] Zigmond & Snaith (1983) in Acta psychiatrica Scandinavica

[2] Hammas et al. (2020) in Frontiers in Psychology

[3] Blanchin et al. (2022) in Methods

**Contact**: yseulys.dubuy@univ-nantes.fr

# 1 Background

## Lack of longitudinal measurement invariance?

Longitudinal self-reported questionnaire data can be challenging to analyze and interpret. Indeed, patients may give different answers to a questionnaire over time, not only because their level of the target construct (e.g., anxiety) has changed but also because their interpretation of the items aiming at measuring the construct has changed.

What we observe

<figure><img src="image_1.png" /></figure>

≠

<figure><img src="image_2.png" /></figure>

What we aimed to measure

Initiation of cancer treatments may rapidly trigger changes in the patients' internal standard of measurement (i.e., recalibration response shift), resulting in a lack of measurement invariance over time. Those changes may also differ according to the cancer site.

## Why does it matter ?

This phenomenon is crucial to investigate as it can help to better understand psychological changes after a cancer diagnosis and to make unbiased comparisons.

**Aim:** To investigate the lack of longitudinal measurement invariance within the items of the anxiety subscale of the HADS (Hospital Anxiety and depression scale) among breast cancer and melanoma patients during the 6 months following cancer diagnosis.

# 2 Materials & Methods

### Participants and data

- Data from the French cohort ELCCA (NCT02893774)

- 337 breast cancer and 110 melanoma patients

- HADS [1] completion several times after the cancer diagnosis:

<figure><img src="image_3.png" /></figure>

### Statistical analysis

Lack of longitudinal measurement invariance among the items of the anxiety subscale was investigated using the **ROSALI algorithm** [2,3] which is based on Rasch family models. ROSALI is an iterative item-by-item procedure dedicated to the detection of recalibration at the item level. For each item, ROSALI determines whether the item is affected by recalibration, that is: whether its thresholds change over time. Besides, if two patient groups are considered, ROSALI determines whether recalibration is similar in both groups or differential.

# 3 Results

Recalibration between M1 and M6 on item 3 indeed, shifts over time within this item thresholds were evidenced (identical shifts for all thresholds: +0.55, se = 0.12). Recalibration was similar for the two cancer sites:

<figure><img src="image_4.png" /><figcaption>item 3: 'I get a [...] frightened feeling as if something awful is about to happen'</figcaption></figure>

θ : Level of anxiety (the lower the better)

For a given level of anxiety (e.g., θ = 0), melanoma and breast cancer patients tended to give a **more favorable response to item 3 at M₆ than at M₁**

→ Wrongly presuming longitudinal measurement invariance (MI) would have resulted in overestimating the decrease of anxiety over time among patients:

### Change over time in anxiety among breast cancer and melanoma patients

<figure><img src="image_5.png" /></figure>

**Legend:**

— Not presuming longitudinal MI

— Presuming longitudinal MI

Time since diagnosis (months)

# 4 Conclusion

Investigating recalibration in patient-reported outcome measures is crucial to better interpret patients' responses and understand the psychological changes patients experience during the treatment period.
**Title**

Investigation of the lack of longitudinal measurement invariance within the items of the HADS-Anxiety in melanoma and breast cancer patients

**Abstract**

**Aims:** Patient-reported outcome measures (PROM) data are challenging to analyze and interpret in longitudinal settings. Indeed, patients may give different answers to a questionnaire over time, not only because their level of the target construct has changed but also because their interpretation of the items aiming at measuring the construct has changed. For instance, cancer treatment may trigger changes in the patients' internal standard of measurement (i.e., recalibration response shift), resulting in a lack of measurement invariance over time. In addition, those changes may differ according to the cancer site. This phenomenon is crucial to investigate as it can help to better understand psychological changes after a cancer diagnosis and to make unbiased comparisons.

**Methods:** We investigated longitudinal measurement invariance within the items of the HADS-A (measuring anxiety disorders) in breast cancer and melanoma patients during the 6 months following cancer diagnosis (corresponding to the treatment period). We used the data from the ELCCA cohort (NCT02893774) comprising 337 breast cancer and 110 melanoma patients. Lack of measurement invariance was investigated using the ROSALI algorithm (a method based on Rasch Measurement Theory to detect recalibration at the item level). Due to item misfit, one item was withdrawn from the analysis ('[...]have to be on the move').

**Results:** Recalibration was assumed to occur on one item: '[...] frightened feeling as if something awful is about to happen' as shifts within this item thresholds were evidenced [identical shifts for all thresholds: +0.55 (se = 0.12)]. It means that melanoma and breast cancer patients tended to give a more favorable response to the item six months post-diagnosis than in the month following diagnosis (despite assuming a constant level of anxiety over time). Wrongly presuming longitudinal measurement invariance would have resulted in overestimating the decrease of anxiety over time among breast cancer patients: -0.91 (se = 0.08) when longitudinal measurement invariance is assumed, compared to -0.79 (se = 0.08) when accounting for recalibration. Regarding melanoma patients, no significant change in anxiety was evidenced (assuming or not longitudinal measurement invariance).

**Discussion:** Investigating recalibration in PROMs is crucial to better interpret patients' responses to items and understand the psychological changes patients experience during the treatment period.