Background/Purpose:

Both the fibromyalgia impact questionnaire (FIQ) and the polysymptomatic distress scale (PSD) have been proposed as measures of FM impact and severity. It is not known how they related to each other and to what extent they relate to FM process items such as pain, depression, anxiety, and catastrophizing.

We set to compare the correlation between FIQ and PSD, and their correlates with depression, anxiety, and catastrophizing, and to determine the individual impact of FIQ and PSD on pain disability index as a measure of the extent to which fibromyalgia pain interferes with a patient’s ability to engage in essential life activities. In this study we considered pain disability index as a surrogate for FM severity.

Methods:

The PSD is the sum of two variables used in the 2010 preliminary American College of Rheumatology fibromyalgia criteria, the widespread pain index (WPI) and symptom severity scale (SS). The FiQ, captures the total spectrum of problems related to FM and has been used as a measure of fibromyalgia severity.

The pain disability index measures the impact of chronic pain on seven essential life activities, family, recreational, social, occupational, sexual, self care, and life support. and is the sum of the scores (0 – 10) of all life activities divided by the number of activities rated. We measured the patient health questionnaire (PHQ-9) for depression, the general anxiety disorder scale (GAD-7), and the pain catastrophizing scale.

Results:

Patients diagnosed clinically with FM were included:n 555, 85.5% female, 79.5% white, age 44.3 (12), 87.2% met ACR 2010 FM criteria, PHQ-9 13.7 (6.5), GAD-7 8.6 (6.6), pain catastrophizing scale 22.6 (13.4), PSD 21 (10.6), FIQ 57.9 (20.4), pain disability index 5.3 (2.3).

FIQ correlated with PSD r 0.465, GAD-7 r 0.368, PHQ-9 r 0.476, pain catastrophizing scale r 0.416, pain disability index r 0.602; PSD score correlated with GAD-7 r 0.233, PHQ-9 r 0.371, pain catastrophizing scale r 0.262, pain disability index r 0.377. All correlations were significant at p<0.001.

Linear regression was calculated to predict FIQ based on GAD-7, PHQ-9 and pain catastrophizing scale. A significant regression equation was found F(1, 120)=42.064, P<0.001, R2 0.513 of FIQ. Depression and catastrophizing scores remaining independent predictors of FIQ. A similar model significantly predicts the PSD score, F(1,130)=26.849, P<0.001, R2 0.383 of PSD; only depression measured by PHQ-9 remained an independent predictor of PSD. To measure the individual contribution of FIQ and PSD score on pain disability index we performed a linear regression model. A significant regression equation was found F(2,165)=154.619, R2 0f 0.652 of PDI. In this model, FIQ but not PSD remained independent predictor of pain disability index.

Conclusion:

Our data suggests that the FIQ and the PSD show only a moderate degree of correlation. Also, the FIQ has stronger associations with FM process measures including depression, anxiety, pain catastrophizing and pain disability index, compared to the PSD. This may explain why the FIQ, but not the PSD remains an independent predictor of pain disability score.

« Back to 2017 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/evaluating-pain-related-disability-in-fibromyalgia-a-comparison-of-the-fibromyalgia-impact-questionnaire-and-the-polysymptomatic-distress-scale/