Is the six-minute walk test useful or useless in systemic sclerosis?

Reference value for the 6-min walking distance in women with systemic sclerosis considering the impact of muscle strength

BACKGROUND

Early triage, the search for new therapies, and closer monitoring of patients with systemic sclerosis before their lung function irreversibly deteriorates are urgent concerns. Because it is an independent predictor of systemic sclerosis-related mortality, the 6-min walk test is a potentially useful tool to evaluate outcomes, along with pulmonary function and computed tomography. This study aimed to establish a reference value for the 6-min walking distance in women with diffuse cutaneous systemic sclerosis-associated interstitial lung disease that takes into account the effects of muscle and lung function.

METHODS

This was a cross-sectional study in which 69 women with systemic sclerosis underwent the 6-min walk test, Health Assessment Questionnaire-Disability Index, pulmonary function, handgrip strength test, and quadriceps strength test.

FINDINGS

The mean 6-min walking distance was 447 ± 78 m, and 43.5% of the participants did not reach 80% of their predicted value. 6-min walking distance correlated positively with quadriceps strength (r = 0.418, P = 0.0004), forced vital capacity (r = 0.306, P = 0.011), pulmonary diffusion (r = 0.360, P = 0.002), maximum inspiratory pressure (r = 0.268, P = 0.029), and maximum expiratory pressure (r = 0.288, P = 0.019) and negatively with age (r = -0.378, P = 0.001), body mass index (r = -0.248, P = 0.039), and Health Assessment Questionnaire-Disability Index (r = -0.438, P = 0.0001). In the multiple linear regression analysis, quadriceps strength, body mass index, pulmonary diffusion, age, and maximum expiratory pressure explained 72% of the 6-min walking distance variability.

INTERPRETATION

Muscle function and, to a lesser extent, lung function are key contributors in determining the reference value for the 6-min walking distance in women with diffuse cutaneous systemic sclerosis-associated interstitial lung disease.

Risk factors for progression of interstitial lung disease in Sjögren's syndrome: a single-centered, retrospective study

OBJECTIVE

To identify clinical characteristics and risk factors related to the progression of interstitial lung disease (ILD) in patients with primary Sjögren's syndrome (pSS).

METHODS

In this single-centered, retrospective study, a total of 83 identified pSS-ILD patients with relatively complete clinical data were finally enrolled. Clinical symptoms, laboratory data, high-resolution computed tomography (HRCT), and pulmonary function test (PFT) results were collected. A logistic regression analysis was performed to determine the independent risk factors for ILD progression, and a nomogram was plotted to construct a predictive model.

RESULTS

The prevalence of pSS-ILD in our study was 18.89%. Among the 83 enrolled patients, 32 (38.6%) underwent ILD progression. The characteristic features associated with the progression of ILD included male sex, non-sicca onset, reticular pattern on HRCT, higher levels of baseline lactic dehydrogenase (LDH), and low baseline forced vital capacity (FVC). The results of multivariate logistic regression indicated that LDH (OR 1.008, p = 0.030) was an independent risk factor for ILD progression, while sicca onset (OR 0.254, p = 0.044) and FVC (OR 0.952, p = 0.003) were protective factors for ILD progression. A simple predictive model for ILD progression in pSS was developed and validated.

CONCLUSION

pSS patients with non-sicca onset, high baseline LDH level, and low baseline FVC were at higher risk of ILD progression.

Progress in Understanding, Diagnosing, and Managing Cardiac Complications of Systemic Sclerosis

PURPOSE OF THE REVIEW

Systemic sclerosis (scleroderma) is a complex autoimmune disease that commonly involves the cardiovascular system. Even if often subclinical, cardiac involvement is considered a poor prognostic factor as it is a leading cause of death in scleroderma patients. We review the cardiac manifestations of scleroderma, the diagnostic methods useful in detection, and current advances in therapeutic management.

RECENT FINDINGS

Beside the routine exams for the assessment of cardiac status (including EKG, standard echocardiography, provocative tests) novel techniques such as myocardial strain imaging on echocardiography, cardiac magnetic resonance imaging, invasive hemodynamic assessment, and endomyocardial biopsy have been demonstrated to be useful in understanding the cardiac alterations that typically affect scleroderma patients. Recent application of novel cardiac detection strategies is providing increased insight into the breadth and pathogenesis of cardiac complications of scleroderma. Further studies coupling exercise provocation, invasive and imaging assessment, and mechanistic studies in scleroderma cardiac tissue are needed to develop the optimal approach to early detection of cardiac disease in scleroderma and targeted therapies.