Predictors of functional improvement in people with chronic low back pain following a graded Pilates-based exercise programme.

BACKGROUND: Several studies have investigated subgroups of patients with low back pain (LBP) most likely to benefit from Pilates or movement control exercises, but none have determined prognostic factors specifically for chronic LBP. This prospective cohort study aimed to determine predictors of change in disability in people with chronic LBP following a Pilates-based exercise programme and reports summarised integrated prediction statistics to aid clinical utility for determination of subgroups likely to benefit or not benefit from treatment.

METHODS: Healthy adults (n = 55) with non-specific chronic LBP undertook a graded 6-week programme involving two 1-hour Pilates sessions/week (1 mat and 1 equipment-based) led in small groups by a trained Pilates instructor. Predictors of change in Patient-Specific Functional Scale (PSFS) were identified through regression analysis and used to develop clinical prediction statistics.

RESULTS: Clinically important improvement (n = 14 of 48 analysed) was predicted by four variables: gradual rather than sudden onset of LBP, PSFS <3.7 points, absence of aberrant motions on forward bending, and body mass index >24.5 kg/m2 . Presence of ≥3 improved probability of success from 29% to 73%. Failure to improve (n = 18) was predicted by three variables: sudden onset of low back pain, patient-specific functional score ≥3.7, and difference between left and right active straight leg raise >7°. Presence of all three increased probability of failure from 38% to 80%.

CONCLUSIONS: A combination of five, easily measured variables were able to predict disability outcome following a graded programme of Pilates-based exercises in people with chronic LBP. Two common movement deficits were inversely related to positive changes in function which may call into question the structural mechanism of improvements observed.

TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12616001588482.