Handgrip strength is associated with, but poorly predicts, disability in older women with acute low back pain: A 12-month follow-up study.

Background: Older women with low back pain (LBP) constitute a special subpopulation at risk of severe and permanent disability. It is important to identify factors limiting functionality in this population in order to reduce costs and improve both prevention and intervention. Handgrip strength (HGS) is a biomarker of aging associated with several adverse health outcomes, but long-term associations with disability in older patients with LBP are not known.

Objective: To examine whether HGS predicts disability in older women with acute low back pain (LBP).

Methods: Longitudinal analyses were conducted with a sample of 135 older women from the international multicenter study Back Complaints in the Elders (BACE-Brazil). Women aged 60 years and over with a new episode of acute LBP were included. HGS was assessed with Jamar dynamometer, and disability was assessed using the Roland Morris questionnaire and gait speed test. Variables were assessed at baseline and at 12-month follow-up. Linear regression models explored associations between HGS and disability measures.

Results: Significant association was found between HGS at baseline and gait speed at 12-month follow-up (r=-0.24; p=0.004). A multivariable-adjusted model showed that this association was independent of age, body mass index, and pain intensity (adjusted R=0.13; p<0.001). A final prediction model showed an incremental difference of only 2.1% in gait speed after inclusion of HGS as an independent variable. No association was found between HGS and score on the Roland Morris questionnaire.

Conclusion: Caution is needed regarding the use of HGS as a predictive measure of disability in older women with acute LBP. Changes in gait speed were very small and unlikely to be of clinical relevance.