Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


The Patient Specific Functional Scale Outperforms the Fibromyalgia Impact Questionnaire Physical Function Scale.

Boomershine1,  Chad S., Edwards2,  Kim A., Hong2,  Jennifer Y., Wallston2,  Kenneth A.

Vanderbilt University, Nashville, TN
Vanderbilt University

Background:

Fibromyalgia (FM) is a disease defined by chronic widespread pain and tenderness that causes functional impairment in many patients. The FM impact questionnaire physical function scale (FIQPFS) has been the standard used by rheumatologists to measure functional impairment in FM patients. However, its clinical utility is limited due to its length (11 questions), complex scoring, and assessment of rarely performed activities. The patient specific functional scale (PSFS) is a brief (3 question) functional impairment measure that assesses difficulty with patient-selected activities on an easily scored 0 to 10 numeric rating scale (NRS) commonly used by physical therapists. We hypothesized that the PSFS is a more clinically useful functional measure than the FIQPFS due to its brevity, ease of scoring and patient-specific nature. However, performance of the PSFS has never been compared to the FIQPFS. We compared baseline psychometric properties of the PSFS and the FIQPFS and the ability of both scales to measure global change in patients treated with physical therapy (PT).

Methods:

Patients (N=340) sent for PT treatment were assessed at baseline and after treatment for 1 month. Baseline and follow-up evaluations included demographics, a pain NRS, regional pain scale (RPS), fatigue problem scale (FPS), disease-neutral FIQPFS, PSFS, and patient global impression of change (PGIC). Baseline pain NRS scores >=4 identified pain patients. FM survey criteria (RPS >=8 and FPS >=6) at baseline identified FM patients. Spearman rank correlations were used to compare questionnaire scores. Statistical methods were performed using PASW Statistics 17.

Results:

At baseline, the PSFS had lower floor effects for all patients (n=340) compared to the FIQPFS (0.9% vs 17.3%, respectively). In patients with pain (n=249), the PSFS also had lower floor effects compared to the FIQPFS (1.2% vs 8.8%, respectively). In FM patients (N=82), the PSFS had no floor effects whereas the FIQPFS had 7.3%. Ceiling effects were negligible for both scales in all patient groups (<1%). PSFS scores were normally distributed for all patient groups, while FIQPFS scores were not normally distributed for any group. At follow-up, PGIC scores significantly correlated with change in PSFS scores for all patients (r=0.52, p<0.001), pain patients (r=0.52, p<0.001) and FM patients (r=0.91, p<0.001).

Figure 1. Patient global impression of change score correlates with change in patient specific functional scale score in fibromyalgia patients.

PGIC scores did not correlate significantly with change in FIQPFS scores for any patient group [all patients (r=0.13, p=.314), pain patients (r=0.09, p=0.548), or FM patients (r=0.272, p=.347)].

Conclusions:

The PSFS has superior psychometric properties compared to the FIQPFS and significantly correlates with PGIC scores in patients treated with PT. Our results indicate the PSFS may be a better questionnaire to evaluate functional impairment and response to therapy than the FIQPFS in many patient groups including FM patients.

To cite this abstract, please use the following information:
Boomershine, Chad S., Edwards, Kim A., Hong, Jennifer Y., Wallston, Kenneth A.; The Patient Specific Functional Scale Outperforms the Fibromyalgia Impact Questionnaire Physical Function Scale. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :115
DOI: 10.1002/art.27884

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