MINIMUM CLINICALLY IMPORTANT DIFFERENCE IN LOW BACK OUTCOME SCORE IN INDIVIDUALS WITH LOW BACK PAIN

Abstract

Introduction: The ultimate aim of any treatment for low back ache is to improve the quality of life as perceived by the patients. Changes in the condition specific disability measures like the Low Back Outcome Score are used as a measure for this purpose and the results interpreted in terms of statistical significance. It is not known, however, if these changes are considered to be clinically significant by the patients. This study quantifies the Minimum Clinically Important Difference (MCID) of Low Back Outcome Score from the patient’s perspective that were treated conservatively for Mechanical Low Back Pain.

Method: In August and September 1999, a postal questionnaire was sent to a randomly selected cohort of 300 individuals who were treated in the Spinal Assessment Clinic (SAC) for low back pain.

Patient’s perception of the outcome of the rehabilitation programme was compared with the changes in LBOS from the time of initial presentation to the postal questionnaire.

Results: 186 forms (62 % response rate) were returned. Data from 170 forms were analysed, as 16 forms were incomplete. An average improvement of 17.96(p=0.001) in 75-point LBOS was noticed in those (n = 61) who reported complete recovery. Those who reported Good but incomplete recovery ( n =61) improved their LBOS by 12.37 points( p=0.001). LBOS improvement of 7.52 points ( p = 0.002) was noticed in patients reporting a minimal improvement( n= 38). Ten patients had no change in their clinical condition ( LBOS change 2.8, p =0.485).Age and gender distribution of four groups remained same ( chi square = 1.39, df = 3,p > 0.5).

Conclusion: The Minimum Clinically Important Difference for patients with Low Back Pain is a 7.5 (10%) change in the 75 point LBOS. An average change of 12 (16%) and 18(24%) can be considered to be Good and Excellent responses respectively to the treatment as perceived by the patients. This data will help to determine whether a statistically significant result is clinically meaningful.