The Clinical Course of Low Back Pain
The Clinical Course of Low Back Pain
The updated search for RCTs yielded a total of 1134 citations of which papers for 70 RCTs (165 treatment arms) satisfied the inclusion criteria and provided pain intensity data useful for analysis (Figure 1). The search for observational studies yielded a total of 653 citations (Figure 2), and data for pain intensity useful for analysis were provided in 15 papers. Relevant data were obtained for further four papers by contacting authors, allowing analysis of pain intensity data from papers for a total of 19 observational studies.
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Figure 1.
Identification and inclusion of RCTs in the systematic review.
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Figure 2.
Identification and inclusion of observational cohort studies in the systematic review.
A list of the included RCTs and observational studies and their population characteristics are presented in Table 1 & Table 2. They were conducted in more than13 countries including the USA, Australia, and European countries during a period spanning two decades. They are comparable in terms of age distribution, gender composition and mean baseline pain intensity (Table 3). It appears that compared with observational studies, RCTs included a larger percentage of participants described as having chronic low back pain (57% in RCTs vs 11% in cohorts). However, these figures need to be interpreted with caution as observational studies often included a mixture of patients with acute and chronic back pain (19% in RCTs vs 63% in cohorts).
The setting of RCTs included general practice (18 RCTs), occupational health care departments (15 RCTs) and physiotherapy departments (19 RCTs). Eight trials were conducted among the general population and 10 in mixed settings. 13 RCTs (34 treatment arms) were classified by one of the authors (MA) as efficacy trials and the remaining 57 (131 treatment arms) as pragmatic trials. Eight RCTs included 'usual care' arms. The19 observational studies included consulters in general practice (11 studies) and other allied primary care services such as chiropractic clinics and physiotherapy departments, as well as cohorts sampled from the general population in two studies. All participants were described in the papers as receiving 'usual' or 'standard care'.
Pooled mean pain intensity scores at baseline and follow up for RCTs and observational studies are presented in Figure 3 and Table 4. They show a similar pattern of symptom change over time in both groups. This is represented by a substantial rapid early improvement of mean pain intensity within the first 13 weeks of follow-up followed by a smaller further improvement over the follow-up period to 52 weeks.
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Figure 3.
Pooled mean pain intensity scores (95% confidence interval) for the included RCTs and observational cohort studies from baseline to 52 week follow up.
Regarding the size of symptom change over time, pooled SMCs (Table 5) confirm the substantial improvement in pain symptoms in both groups. These range from 0.9 to 1.2 for RCTs and from 1.0 to 1.2 for observational studies.
There was a large between-study variation in the sizes of pain improvement from baseline within both observational studies and RCT treatment arms demonstrated by the high I values (99%).
Meta-regression analysis showed no statistically significant difference in the change in pain intensity (SMC) between all RCTs and observational studies at any follow up point. There was also no statistically significant difference in the change in pain intensity when considering the two types of RCTs (pragmatic and efficacy) separately compared with observational studies. Comparing cohort studies and usual care arms of RCTs also did not show any difference in the pattern or course of LBP between these groups.
Results
Included Studies
The updated search for RCTs yielded a total of 1134 citations of which papers for 70 RCTs (165 treatment arms) satisfied the inclusion criteria and provided pain intensity data useful for analysis (Figure 1). The search for observational studies yielded a total of 653 citations (Figure 2), and data for pain intensity useful for analysis were provided in 15 papers. Relevant data were obtained for further four papers by contacting authors, allowing analysis of pain intensity data from papers for a total of 19 observational studies.
(Enlarge Image)
Figure 1.
Identification and inclusion of RCTs in the systematic review.
(Enlarge Image)
Figure 2.
Identification and inclusion of observational cohort studies in the systematic review.
Characteristics of Study Setting and Population
A list of the included RCTs and observational studies and their population characteristics are presented in Table 1 & Table 2. They were conducted in more than13 countries including the USA, Australia, and European countries during a period spanning two decades. They are comparable in terms of age distribution, gender composition and mean baseline pain intensity (Table 3). It appears that compared with observational studies, RCTs included a larger percentage of participants described as having chronic low back pain (57% in RCTs vs 11% in cohorts). However, these figures need to be interpreted with caution as observational studies often included a mixture of patients with acute and chronic back pain (19% in RCTs vs 63% in cohorts).
The setting of RCTs included general practice (18 RCTs), occupational health care departments (15 RCTs) and physiotherapy departments (19 RCTs). Eight trials were conducted among the general population and 10 in mixed settings. 13 RCTs (34 treatment arms) were classified by one of the authors (MA) as efficacy trials and the remaining 57 (131 treatment arms) as pragmatic trials. Eight RCTs included 'usual care' arms. The19 observational studies included consulters in general practice (11 studies) and other allied primary care services such as chiropractic clinics and physiotherapy departments, as well as cohorts sampled from the general population in two studies. All participants were described in the papers as receiving 'usual' or 'standard care'.
The Course of Pain Intensity Scores Over Time
Pooled mean pain intensity scores at baseline and follow up for RCTs and observational studies are presented in Figure 3 and Table 4. They show a similar pattern of symptom change over time in both groups. This is represented by a substantial rapid early improvement of mean pain intensity within the first 13 weeks of follow-up followed by a smaller further improvement over the follow-up period to 52 weeks.
(Enlarge Image)
Figure 3.
Pooled mean pain intensity scores (95% confidence interval) for the included RCTs and observational cohort studies from baseline to 52 week follow up.
Regarding the size of symptom change over time, pooled SMCs (Table 5) confirm the substantial improvement in pain symptoms in both groups. These range from 0.9 to 1.2 for RCTs and from 1.0 to 1.2 for observational studies.
There was a large between-study variation in the sizes of pain improvement from baseline within both observational studies and RCT treatment arms demonstrated by the high I values (99%).
Meta-regression analysis showed no statistically significant difference in the change in pain intensity (SMC) between all RCTs and observational studies at any follow up point. There was also no statistically significant difference in the change in pain intensity when considering the two types of RCTs (pragmatic and efficacy) separately compared with observational studies. Comparing cohort studies and usual care arms of RCTs also did not show any difference in the pattern or course of LBP between these groups.
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