Rheumatoid Arthritis: Turner D

van der Leeden M, Steultjens MP, Terwee CB, Rosenbaum D, Turner D, Woodburn J, Dekker J. · Jan van Breemen Institute, Amsterdam, The Netherlands. · Arthritis Rheum. · Pubmed #18759256 No free full text.

Abstract: OBJECTIVE: To compose an inventory of instruments that have been described to measure foot function (i.e., pressure and/or gait parameters), foot pain, and foot-related disability in rheumatoid arthritis (RA), and to investigate the clinimetric quality of these measures. METHODS: A systematic search was conducted in Medline, CINAHL, EMBase, and Sportdiscus. Standardized criteria, extended with levels of evidence, were applied to assess the quality of the clinimetric studies and the properties (i.e., reliability, validity, and responsiveness) of the described instruments. RESULTS: A variety of measurement instruments were identified. Only 16 instruments have been studied for their measurement properties in RA patients: 7 for assessing foot function, 3 for measuring foot-related disability, and 6 for measuring both foot pain and foot-related disability. Thirteen instruments were rated for reliability, of which 10 were rated positively on different levels of evidence. No positive rating for absolute measurement error was applicable for any of the tests. Internal consistency was reported for 7 instruments; 3 assigned a positive rating. For 2 instruments, Rasch analysis was used to assess the methodologic quality. A positive rating was reported for goodness-of-fit only, not for item calibration. Seven instruments were rated for construct validity, and 3 assigned a positive rating. Only 2 instruments were rated positively for responsiveness. CONCLUSION: This review offers a basis for choosing the most appropriate instruments for measuring foot function, foot pain, and foot-related disability in RA patients, both for clinical practice and for research. Further research on the quality of these measures is urgently needed.

Firth J, Turner D, Smith W, Woodburn J, Helliwell P. · School of Healthcare, Postgraduate Suite, Baines Wing, University of Leeds, Leeds LS2 9JT, United Kingdom. · Clin Biomech (Bristol, Avon). · Pubmed #17374423 No free full text.

Abstract: BACKGROUND: Plantar pressure measurements are a useful screening tool to assess foot function and identify patients at risk of developing ulceration. The validity and reliability of PressureStat for measuring plantar pressures in patients with rheumatoid arthritis has not been addressed. METHODS: Bench testing placed the PressureStat under loads throughout the range reported for PressureStat (0-15.0 kg/cm(2)). The outputs were digitised to measure pixel density in comparison with the PressureStat calibration card. In clinical testing, simultaneous barefoot plantar pressure measurements were recorded from 10 rheumatoid arthritis patients using the PressureStat and EMED-ST systems. Reliability was examined by four independent examiners using kappa statistics. The absolute peak pressure values in each mask region were determined from the EMED-ST platform by masking in the same manner using a real size plantar pressure printout. FINDINGS: In all test conditions, the pixel density recorded from the PressureStat outputs exceeded the range recorded on the calibration card, with the largest difference in the lower ranges. In clinical testing, correcting the PressureStat scores for 'background noise' (not suggested by manufacturer) inverted and improved these comparisons. Inter-observer kappa values between the first and second readings ranged from 0.26 to 0.59, with some evidence of a learning effect. Intra-observer kappa values were 0.57, 0.51, 0.33 and 0.43 for observers 1-4 respectively. INTERPRETATION: Pressure data obtained with the PressureStat system in bench testing and patients with RA is inaccurate, particularly in the lower ranges. The grading of PressureStat readings taken from rheumatoid arthritis patients found fair to moderate intra and inter-observer agreement suggesting that interpretation is also imprecise.