Straford et al identified the level of change in a patient’s score from the Roland-Morris questionnaire for low back pain to detect a clinically significant clinical change. This can help the interpretation of the scores over time and to determine the effectiveness of an intervention. The authors are from McMaster University and North Georgia College.
Method 1: Figure for 90% Confidence
Minimal Detectable Change at 90% Confidence Level (Figure page 364 with initial score on X-axis and follow-up score on the Y-axis):
(1) if above upper line: deterioration
(2) if between the upper and lower line: unchanged
(3) if below the lower line: improvement
Line |
Defining Points |
Line Equation |
lower |
(0,0) – (4,0) |
y = 0 |
|
(4,0) – (11,7) |
y = x-4 |
|
(11,7) – (12,7) |
y = 7 |
|
(12,7) – (16,11) |
y = x – 5 |
|
(16,11) – (17,13) |
y = (2 * x) –21 |
|
(17,13) – (24,20) |
y = x - 4 |
upper |
(0,4) – (7, 11) |
y = x + 4 |
|
(7, 11) – (8, 13) |
y = (2 * x) -3 |
|
(8, 13) – (12, 17) |
y = x + 5 |
|
(12,17) – (13,17) |
y = 17 |
|
(13,17) – (20, 24) |
y = x + 4 |
|
(20,24) – (24,24) |
y = 24 |
Method 2: Based on Z-score (Appendix page 365)
Z =
= ((initial RMQ score) – (followup RMQ score)) / SQRT ((variance for initial RMQ score) + (variance for followup RMQ score))
If Z > 1.96, then there is a 95% chance that there has been a significant change.
RMQ Score |
Initial Visit Error Variance |
Followup Error Variance |
0 |
0.38 |
0.42 |
1 |
0.75 |
0.83 |
2 |
1.43 |
1.58 |
3 |
2.04 |
2.26 |
4 |
2.59 |
2.87 |
5 |
3.08 |
3.41 |
6 |
3.50 |
3.88 |
7 |
3.86 |
4.27 |
8 |
4.15 |
4.59 |
9 |
4.38 |
4.84 |
10 |
4.54 |
5.02 |
11 |
4.64 |
5.13 |
12 |
4.67 |
5.17 |
13 |
4.64 |
5.13 |
14 |
4.54 |
5.02 |
15 |
4.38 |
4.84 |
16 |
4.15 |
4.59 |
17 |
3.86 |
4.27 |
18 |
3.50 |
3.88 |
19 |
3.08 |
3.41 |
20 |
2.59 |
2.87 |
21 |
2.04 |
2.26 |
22 |
1.43 |
1.58 |
23 |
0.75 |
0.83 |
24 |
0.38 |
0.42 |
From Table 2, page 363
Purpose: To determine if there has been a clinically significant change in the Roland-Morris score for a patient with low back pain.
Specialty: Sports Medicine & Rehabilitation, Surgery, orthopedic, Neurology
Objective: severity, prognosis, stage, response to therapy, disability and performance
ICD-10: M54.5,