Systematic Reviews of Low Back Pain.

Abbreviations: LBP, low back pain; I, insufficient; P, positive; N, negative;+ = weak; ++ = moderate; +++ = strong.Items of outcomes measurement: 1 = pain; 2 = Global measure; 3 = functional status; 4 = Quality of Life; 5 = Safety; 6 = Cost effectiveness; 7 = Other outcomes.The total AMSTAR score was calculated by adding the average scores for all 11 items. We averaged item scores across guidelines. Item scores were classified such that 0–3 indicated low quality, 4–7 indicated moderate quality and 8–11 indicated high quality.