Minimal Clinically Important Difference in Quality of Life for Patients With Low Back Pain.

STUDY DESIGN: Multicenter, prospective, cohort study. OBJECTIVE: To estimate the Minimal Clinically Important Difference (MCID) for the physical (PCS) and mental (MCS) component summaries of Short Form SF-12 (SF-12), in patients with low back pain (LBP). SUMMARY OF BACKGROUND DATA: Quality of life is one of the core domains recommended to be assessed in patients with LBP. SF-12 is the most widely used instrument for this purpose, but its MCID was unknown. METHODS: A total of 458 patients with subacute and chronic LBP were consecutively recruited across 21 practices. LBP, referred pain, disability, PCS, and MCS were assessed upon recruitment and 12 months later. Self-reported health status change between baseline and 12 month-assessment, was used as the external criterion. The MCID for SF-12 was estimated following four anchor-based methods; minimal detectable change (MDC); average change (AC); change difference (CD); and receiver operating characteristic curve (ROC), for which the area under the curve (AUC) was calculated. The effect on MCID values of pain duration and baseline scores was assessed. RESULTS: Values for PCS were: MDC: 0.56, AC: 2.71, CD: 3.29, and ROC: 1.14. Values for MCS were: MDC: 3.77, AC: 3.54, CD: 1.13, and ROC: 4.23. AUC values were <0.7; MCID values were smaller among chronic patients and those with better baseline quality of life. CONCLUSION: Different methods for MCID calculation lead to different results. In patients with subacute and chronic LBP, improvements >3.77 in MCS and >3.29 in PCS, can be considered clinically relevant. MCID is smaller in patients with longer pain duration and better baseline quality of life. LEVEL OF EVIDENCE: 2.

Effectiveness of the Godelieve Denys-Struyf (GDS) method in people with low back pain: cluster randomized controlled trial.

BACKGROUND: The Godelieve Denys-Struyf method (GDS) is a motor learning intervention that may be applied in group or individualized sessions. OBJECTIVE: The study objective was to compare the effectiveness of routine physical therapy, group GDS (GDS-G) sessions, and group and individualized GDS (GDS-I) sessions. DESIGN: This was a cluster randomized controlled trial. SETTING: The study took place in 21 primary care physical therapy units ("clusters") of the Spanish National Health Service (SNHS). PARTICIPANTS: The participants were 461 people with subacute and chronic low back pain (LBP). INTERVENTION: Clusters were randomized into 3 groups. All participants received medical treatment and a 15-minute group education session on active management. Additional interventions were as follows: control (fifteen 40-minute sessions of transcutaneous electrical nerve stimulation, microwave treatment, and standardized exercises), GDS-G (eleven 50-minute group GDS sessions), and GDS-I (the same 11 sessions plus four 50-minute individualized GDS sessions). MEASUREMENTS: Primary outcomes at baseline and 2, 6, and 12 months later were LBP and pain referred down the leg (separate pain intensity numeric rating scales) and disability (Roland-Morris Questionnaire [RMQ]). Secondary outcomes were use of medication and self-reported health (mental and physical component summaries of the 12-Item Short-Form Health Survey [SF-12]). Separate linear mixed models for LBP, pain referred down the leg, and disability were developed to adjust for potential confounders. Randomization, outcome assessment, and data analyses were masked. RESULTS: At 12 months, disability improved 0.7 (95% confidence interval [CI]=-0.4, 1.8) RMQ point in the control group, 1.5 (95% CI=0.4, 2.7) RMQ points in the GDS-I group, and 2.2 (95% CI=1.2, 3.2) RMQ points in the GDS-G group. There were no differences in pain. LIMITATIONS: The amount of exercise was smaller in the control group, and GDS-I sessions were provided by junior physical therapists. CONCLUSIONS: The improvement in disability was slightly higher with group GDS sessions than with the program routinely used in clusters within the SNHS. Adding individualized GDS sessions eliminated this advantage. Further studies should compare the GDS with other types of exercise.