s was very high (intraclass correlation coefficient 0.996). Any disagreements were resolved through a discussion between all authors. Given the large number of potentially relevant measures identified, only those measures that were used at least 4 times in the screened abstracts were selected for this review. Consequently, this report provides reviews of 4 generic health profiles: the Medical Outcomes Study Short Form 36 and Short Form 12 Health Surveys, the Nottingham Health Profile, and the Sickness Impact Profile, and 4 health utility measures: the Medical Outcomes Study Short Form 6D, the Health Utilities Index Mark 3, Quality of Well-Being Scale (selfadministered), and the Assessment of Quality of Life Scale. Although the EuroQol 5-domain is also frequently used in rheumatology, the review of this measure is included in Measures of Disability article in this issue. MEDICAL OUTCOMES STUDY SHORT FORM 36-ITEM (SF-36) AND SHORT FORM 12-ITEM (SF-12) HEALTH SURVEYS

Adult Measures of General Health and Health-Related Quality of Life.

The aim of this systematic review is to describe the different types of anchors and statistical methods used in estimating the Minimal Clinically Important Difference (MCID) for Health-Related Quality of Life (HRQoL) instruments. PubMed and Google scholar were searched for English and French language studies published from 2010 to 2018 using selected keywords. We included original articles (reviews, meta-analysis, commentaries and research letters were not considered) that described anchors and statistical methods used to estimate the MCID in HRQoL instruments. Forty-seven papers satisfied the inclusion criteria. The MCID was estimated for 6 generic and 18 disease-specific instruments. Most studies in our review used anchor-based methods (n = 41), either alone or in combination with distribution-based methods. The most common applied anchors were non-clinical, from the viewpoint of patients. Different statistical methods for anchor-based methods were applied and the Change Difference (CD) was the most used one. Most distributional methods included 0.2 standard deviations (SD), 0.3 SD, 0.5 SD and 1 standard error of measurement (SEM). MCID values were very variable depending on methods applied, and also on clinical context of the study. Multiple anchors and methods were applied in the included studies, which lead to different estimations of MCID. Using several methods enables to assess the robustness of the results. This corresponds to a sensitivity analysis of the methods. Close collaboration between statisticians and clinicians is recommended to integrate an agreement regarding the appropriate method to determine MCID for a specific context.

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How is the minimal clinically important difference established in health-related quality of life instruments? Review of anchors and methods.

BACKGROUND
In the McKenzie system, patients are classified first into syndromes, then into subsyndromes. At present, the reliability of classification with this system is unclear. No study has included patients with cervical pain, and the studies to date have reported conflicting results.


OBJECTIVE
The aim of the study is to investigate the interexaminer reliability of the McKenzie classification system for patients with cervical or lumbar pain.


SUBJECTS
Fifty patients with spinal pain (25 with lumbar pain and 25 with cervical pain) were included in the study.


METHOD
The patients were assessed simultaneously by 2 physical therapists (14 in total) trained in the McKenzie method. Agreement was expressed using the multirater kappa coefficient and percent agreement for classification into (i) syndromes and (ii) subsyndromes.


RESULTS
The reliability for syndrome classification was kappa = 0.84 with 96% agreement for the total patient pool, kappa = 1.0 with 100% agreement for lumbar patients, and kappa = 0.63 with 92% agreement for cervical patients. The reliability for subsyndrome classification was kappa = 0.87 with 90% agreement for the total patient pool, kappa = 0.89 with 92% agreement for lumbar patients, and kappa = 0.84 with 88% agreement for the cervical patients.


CONCLUSION
The McKenzie assessment performed by persons trained in the McKenzie method may allow for reliable classification of patients with lumbar and cervical pain.

Reliability of McKenzie classification of patients with cervical or lumbar pain (2004)

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 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.

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

Objective To evaluate the effect of five years of supervised exercise training compared with recommendations for physical activity on mortality in older adults (70-77 years). Design Randomised controlled trial. Setting General population of older adults in Trondheim, Norway. Participants 1567 of 6966 individuals born between 1936 and 1942. Intervention Participants were randomised to two sessions weekly of high intensity interval training at about 90% of peak heart rate (HIIT, n=400), moderate intensity continuous training at about 70% of peak heart rate (MICT, n=387), or to follow the national guidelines for physical activity (n=780; control group); all for five years. Main outcome measure All cause mortality. An exploratory hypothesis was that HIIT lowers mortality more than MICT. Results Mean age of the 1567 participants (790 women) was 72.8 (SD 2.1) years. Overall, 87.5% of participants reported to have overall good health, with 80% reporting medium or high physical activity levels at baseline. All cause mortality did not differ between the control group and combined MICT and HIIT group. When MICT and HIIT were analysed separately, with the control group as reference (observed mortality of 4.7%), an absolute risk reduction of 1.7 percentage points was observed after HIIT (hazard ratio 0.63, 95% confidence interval 0.33 to 1.20) and an absolute increased risk of 1.2 percentage points after MICT (1.24, 0.73 to 2.10). When HIIT was compared with MICT as reference group an absolute risk reduction of 2.9 percentage points was observed (0.51, 0.25 to 1.02) for all cause mortality. Control participants chose to perform more of their physical activity as HIIT than the physical activity undertaken by participants in the MICT group. This meant that the controls achieved an exercise dose at an intensity between the MICT and HIIT groups. Conclusion This study suggests that combined MICT and HIIT has no effect on all cause mortality compared with recommended physical activity levels. However, we observed a lower all cause mortality trend after HIIT compared with controls and MICT. Trial registration ClinicalTrials.gov NCT01666340.

https://www.bmj.com/content/bmj/371/bmj.m3485.full.pdf

Effect of exercise training for five years on all cause mortality in older adults-the Generation 100 study: randomised 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.

Rosa Llorca-Palomera

Papers

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

Effectiveness of the Godelieve Denys-Struyf (GDS) Method in People With Low Back Pain: Cluster Randomized Controlled Trial