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Morelhão P.K.1, Franco M.R.2, Oliveira C.B.2, Damato T.M.3, Hisamatsu T.M.2, Silva F.G.3, Grande G.D.3, Pinto R.Z.2
1São Paulo State University (UNESP), Physiotherapy Department, Presidente Prudente, Brazil, 2São Paulo State University (UNESP), Physiotherapy Deparment, Presidente Prudente, Brazil, 3Sao Paulo State University (UNESP), Physiotherapy Deparment, Presidente Prudente, Brazil
Background: Subjective or self-reported measures, such as the International Physical Activity Questionnaire (IPAQ-long version) and the Baecke Habitual Physical Activity Questionnaire (BPAQ), and objective measures (e.g. accelerometer) are used in clinical practice to assess physical activity (PA) levels. Nevertheless, it is unclear whether these measures are responsive in clinical population, such as those patients presenting with chronic non-specific low back pain (LBP). Responsiveness is a measurement property, which measures the ability of an instrument to detect changes over time.
Purpose: (i) To determine the responsiveness of subjective PA measures (i.e. IPAQ and BPAQ) and objective PA measures, derived from accelerometer (i.e. time spent on moderate-to-vigorous physical activity [MVPA] per day, step/day and counts/min [CPM]), in patients with chronic non-specific LBP.
Methods: Patients with chronic (i.e. reporting ≥ 3 months) non-specific LBP were considered eligible for this prospective cohort study with 2-month follow-up. At baseline, the following data were collected: anthropometric measures, pain intensity (i.e. 11-point numerical rating scale), disability (i.e. Roland Morris Disability Questionnaire), subjective and objective PA levels (i.e. IPAQ-long version, BPAQ and accelerometer). Patients were instructed to wear the accelerometer for 7 consecutive days. At the 2-month follow-up, the subjective and objective PA measures were collected again. The type of treatment was not manipulated, but the physiotherapists were instructed to follow the clinical practice guidelines for the management of chronic LBP, based on supervised and active exercises. For internal responsiveness, the effect size (ES) was calculated by dividing the mean difference (mean baseline scores minus mean follow-up scores) by the standard deviation (SD) of baseline scores with 84% confidence interval for each variable. ES was interpreted using the following thresholds: 0.20 to 0.49 considered a small effect, 0.50 to 0.79 as moderate effect and values above 0.80 as large effect.
Results: A total eighty-three patients with mean (SD) pain of 6.39 (1.73) points and mean disability of 11.77 (4.82) points were included in this study. None of the physical activity measure demonstrated good responsiveness. The effect size for total IPAQ (Met-min/week) was 0.17 (84% CI: 0.01 to 0.36), total BPAQ was 0.31 (84% CI: 0.07 to 0.59), CPM was 0.05 (84% CI: -0.07 to 0.17), step/day was 0.08 (-0.05 to 0.22) and MVPA per day was -0.09 (84% CI: -0.21-0.01).
Conclusion(s): Our findings revealed that physical activity levels, measured objectively and subjectively, had poor responsiveness in patients with chronic LBP.
Implications: Physical activity measures do not seem to be responsive in patients seeking physiotherapy care, that is, these measures are not able to detect clinical changes in physical activity levels after a period of 2 months. Future studies should aim to test strategies that could change PA levels in patients with chronic non-specific LBP.
Funding acknowledgements: Supported by the São Paulo Research Foundation (grant nos. 2015/17093-7, 2015/07704-9, 2015/02744-2 and 2014/14077-8)
Topic: Musculoskeletal: spine
Ethics approval: Approved by the Ethics Committee FCT/UNESP (CAAE:36285414.4.0000.5402), Brazil
All authors, affiliations and abstracts have been published as submitted.
