Cultural adaptation, translation and validation of Cochin Hand Function Scale and evaluation of hand dysfunction in systemic sclerosis

Clinical trajectories of hand function impairment in systemic sclerosis: an unmet clinical need across disease subsets

BACKGROUND

Hand involvement is an early manifestation of systemic sclerosis (SSc), culprit of diagnosis and classification, and recognised major driver of disability. Impairment of hand function burdens both limited and diffuse cutaneous subsets and therefore could be targeted as 'basket' endpoint in SSc. Nevertheless, its natural history in current standard of care is not well characterised, limiting the design of targeted trials. The aim of this study is to describe prevalence, natural history and clinical factors associated with hand function deterioration in a longitudinal, multicentre, observational SSc cohort.

METHODS

Hand function was captured through the validated Cochin Hand Function Scale in patients consecutively enrolled in a multicentre observational study and observed over 24 months. Minimal clinically important differences and patient acceptable symptom state were analysed as previously described.

RESULTS

Three hundred and ninety-six consecutive patients were enrolled from 10 centres; 201 with complete follow-up data were included in the analysis. Median (IQR) disease duration was 5 (2-11) years. One hundred and five (52.2%) patients reported clinically significant worsening. Accordingly, the proportion of patients reporting unacceptable hand function increased over 2 years from 27.8% to 35.8% (p<0.001). Least absolute shrinkage and selection operator analysis identified male gender, disease subset, Raynaud's Condition Score, tenosynovitis and pain, as some of the key factors associated with worsening hand involvement.

CONCLUSIONS

Hand function deteriorates over time in more than 50% of SSc patients despite available therapies. The analysis of factors associated with hand function worsening supports the involvement of both inflammation, vascular and fibrotic processes in hand involvement, making it a hallmark clinical manifestation of SSc. Our data are poised to inform the design of intervention studies to target this major driver of disability in SSc.

Differential Item Functioning on the Cochin Hand Function Scale Among People With Systemic Sclerosis by Language, Sex, and Disease Subtype: A Scleroderma Patient-Centered Intervention Network (SPIN) Cohort Study

OBJECTIVE

To evaluate the degree that the Cochin Hand Function Scale (CHFS) generates scores that are comparable across language, sex, and disease subtype.

METHODS

We included participants enrolled in the Scleroderma Patient-centered Intervention Network (SPIN) Cohort who completed the CHFS at their baseline assessment between April 2014 and September 2020. Confirmatory factor analysis (CFA) was used to test unidimensionality, and multiple indicator multiple cause (MIMIC) models were used for differential item functioning (DIF) analysis based on language, sex, and disease subtype. Both intraclass correlation coefficient (ICC) and Pearson's correlation were calculated using factor scores obtained from unadjusted and DIF-adjusted MIMIC models to evaluate agreement and correlation between scores.

RESULTS

A total of 2,155 participants were included. CFA with covarying error terms supported a good fit of the model (χ2 [127] = 1,754.671; P < 0.001; Tucker-Lewis index = 0.985; comparative fit index = 0.987; root mean square error of approximation = 0.077). Nine items displayed statistically significant DIF for language of administration, 10 items for sex, and 10 items for disease subtype. However, the overall impact of DIF was negligible when comparing factor scores that did and did not account for DIF (ICC = 0.999; r = 0.999).

CONCLUSION

The CHFS has score comparability in systemic sclerosis regardless of participants' language, sex, and disease subtype.

Expanding the Treatment Team

The optimal systemic sclerosis (SSc) care plan includes an occupational therapist and physical therapist as well as wound care experts and a registered dietitian if indicated. Screening instruments for functional and work disability, hand and mouth limitations, malnutrition, and dietary intake can identify the need for ancillary support services. Telemedicine can assist in developing effective ancillary treatment plans. Reimbursement for services may limit access for patients with SSc to expand their care team but a focus on prevention rather than management of damage is recognized as an important unmet need in SSc. In this review, the role of a comprehensive care team for SSc is discussed.

Effect of skin phototype on quantitative nailfold capillaroscopy

Objectives

To determine the impact of Fitzpatrick scale-based skin phototype on visualization of capillary density using nailfold capillaroscopy in healthy Indian adults.

Methods

In this cross-sectional study, healthy adults were examined for nailfold capillaroscopy findings utilizing a portable capillary microscope at 800× magnification. Photographs of two contiguous areas measuring 1 mm2 each of the distal row of capillaries were captured. Images were captured from the central area of all fingers except thumb in both hands. Capillary density and morphology of nailfold capillaroscopies were assessed by two blinded assessors. The nailfold capillaroscopy parameters were compared between the Standard Fitzpatrick scale-based skin phototypes.

Results

A total of 118 healthy adults were enrolled in the study. Type III, IV, V, and VI skin phototypes were seen in 27 (22.90%), 32 (27.19%), 29 (24.58%), and 30 (25.42%) participants, respectively. All participants (100%) had normal nailfold capillaroscopy morphology and architecture. Zero capillaries were visible in 11 fingers among 5 patients (4.24%) and all of them had Type VI phototype. The median capillary density per mm was 5.19 (interquartile range = 4.37-6.75) with 90 (76.27%) participants having less than seven capillaries. The median average capillary density was significantly different (p-value < 0.0001) across Type III (8.13, interquartile range = 6.44-8.88), Type IV (5.67, interquartile range = 4.41-6.98), Type V (4.94, interquartile range = 4.19-5.38), and Type VI (4.53, interquartile range = 3.72-4.91) phototypes (p < 0.05).

Conclusion

The number of capillaries visualized during nailfold capillaroscopy decreases as the skin pigmentation increases. There is a need to redefine the nailfold capillaroscopy density and avascularity by taking skin phototype as one of the determinants before labeling a nailfold capillaroscopy finding with less visualized capillaries as abnormal.