Inter-method reliability of paper surveys and computer assisted telephone interviews in a randomized controlled trial of yoga for low back pain

Yoga for chronic non-specific low back pain

BACKGROUND

Non-specific low back pain is a common, potentially disabling condition usually treated with self-care and non-prescription medication. For chronic low back pain, current guidelines recommend exercise therapy. Yoga is a mind-body exercise sometimes used for non-specific low back pain.

OBJECTIVES

To evaluate the benefits and harms of yoga for treating chronic non-specific low back pain in adults compared to sham yoga, no specific treatment, a minimal intervention (e.g. education), or another active treatment, focusing on pain, function, quality of life, and adverse events.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 31 August 2021 without language or publication status restrictions.

SELECTION CRITERIA

We included randomized controlled trials of yoga compared to sham yoga, no intervention, any other intervention and yoga added to other therapies.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. Our major outcomes were 1. back-specific function, 2. pain, 3. clinical improvement, 4. mental and physical quality of life, 5. depression, and 6.

ADVERSE EVENTS

Our minor outcome was 1. work disability. We used GRADE to assess certainty of evidence for the major outcomes.

MAIN RESULTS

We included 21 trials (2223 participants) from the USA, India, the UK, Croatia, Germany, Sweden, and Turkey. Participants were recruited from both clinical and community settings. Most were women in their 40s or 50s. Most trials used iyengar, hatha, or viniyoga yoga. Trials compared yoga to a non-exercise control including waiting list, usual care, or education (10 trials); back-focused exercise such as physical therapy (five trials); both exercise and non-exercise controls (four trials); both non-exercise and another mind-body exercise (qigong) (one trial); and yoga plus exercise to exercise alone (one trial). One trial comparing yoga to exercise was an intensive residential one-week program, and we analyzed this trial separately. All trials were at high risk of performance and detection bias because participants and providers were not blinded to treatment, and outcomes were self-assessed. We found no trials comparing yoga to sham yoga. Low-certainty evidence from 11 trials showed that there may be a small clinically unimportant improvement in back-specific function with yoga (mean difference [MD] -1.69, 95% confidence interval [CI] -2.73 to -0.65 on the 0- to 24-point Roland-Morris Disability Questionnaire [RMDQ], lower = better, minimal clinically important difference [MCID] 5 points; 1155 participants) and moderate-certainty evidence from nine trials showed a clinically unimportant improvement in pain (MD -4.53, 95% CI -6.61 to -2.46 on a 0 to 100 scale, 0 no pain, MCID 15 points; 946 participants) compared to no exercise at three months. Low-certainty evidence from four trials showed that there may be a clinical improvement with yoga (risk ratio [RR] 2.33, 95% CI 1.46 to 3.71; assessed as participant rating that back pain was improved or resolved; 353 participants). Moderate-certainty evidence from six trials showed that there is probably a small improvement in physical and mental quality of life (physical: MD 1.80, 95% CI 0.27 to 3.33 on the 36-item Short Form [SF-36] physical health scale, higher = better; mental: MD 2.38, 95% CI 0.60 to 4.17 on the SF-36 mental health scale, higher = better; both 686 participants). Low-certainty evidence from three trials showed little to no improvement in depression (MD -1.25, 95% CI -2.90 to 0.46 on the Beck Depression Inventory, lower = better; 241 participants). There was low-certainty evidence from eight trials that yoga increased the risk of adverse events, primarily increased back pain, at six to 12 months (RR 4.76, 95% CI 2.08 to 10.89; 43/1000 with yoga and 9/1000 with no exercise; 1037 participants). For yoga compared to back-focused exercise controls (8 trials, 912 participants) at three months, we found moderate-certainty evidence from four trials for little or no difference in back-specific function (MD -0.38, 95% CI -1.33 to 0.62 on the RMDQ, lower = better; 575 participants) and very low-certainty evidence from two trials for little or no difference in pain (MD 2.68, 95% CI -2.01 to 7.36 on a 0 to 100 scale, lower = better; 326 participants). We found very low-certainty evidence from three trials for no difference in clinical improvement assessed as participant rating that back pain was improved or resolved (RR 0.97, 95% CI 0.72 to 1.31; 433 participants) and very low-certainty evidence from one trial for little or no difference in physical and mental quality of life (physical: MD 1.30, 95% CI -0.95 to 3.55 on the SF-36 physical health scale, higher = better; mental: MD 1.90, 95% CI -1.17 to 4.97 on the SF-36 mental health scale, higher = better; both 237 participants). No studies reported depression. Low-certainty evidence from five trials showed that there was little or no difference between yoga and exercise in the risk of adverse events at six to 12 months (RR 0.93, 95% CI 0.56 to 1.53; 84/1000 with yoga and 91/1000 with non-yoga exercise; 640 participants).

AUTHORS' CONCLUSIONS

There is low- to moderate-certainty evidence that yoga compared to no exercise results in small and clinically unimportant improvements in back-related function and pain. There is probably little or no difference between yoga and other back-related exercise for back-related function at three months, although it remains uncertain whether there is any difference between yoga and other exercise for pain and quality of life. Yoga is associated with more adverse events than no exercise, but may have the same risk of adverse events as other exercise. In light of these results, decisions to use yoga instead of no exercise or another exercise may depend on availability, cost, and participant or provider preference. Since all studies were unblinded and at high risk of performance and detection bias, it is unlikely that blinded comparisons would find a clinically important benefit.

Learning from COVID-19 related trial adaptations to inform efficient trial design-a sequential mixed methods study

BACKGROUND

Many clinical trial procedures were often undertaken in-person prior to the COVID-19 pandemic, which has resulted in adaptations to these procedures to enable trials to continue. The aim of this study was to understand whether the adaptations made to clinical trials by UK Clinical Trials Units (CTUs) during the pandemic have the potential to improve the efficiency of trials post-pandemic.

METHODS

This was a mixed methods study, initially involving an online survey administered to all registered UK CTUs to identify studies that had made adaptations due to the pandemic. Representatives from selected studies were qualitatively interviewed to explore the adaptations made and their potential to improve the efficiency of future trials. A literature review was undertaken to locate published evidence concerning the investigated adaptations. The findings from the interviews were reviewed by a group of CTU and patient representatives within a workshop, where discussions focused on the potential of the adaptations to improve the efficiency of future trials.

RESULTS

Forty studies were identified by the survey. Fourteen studies were selected and fifteen CTU staff were interviewed about the adaptations. The workshop included 15 CTU and 3 patient representatives. Adaptations were not seen as leading to direct efficiency savings for CTUs. However, three adaptations may have the potential to directly improve efficiencies for trial sites and participants beyond the pandemic: a split remote-first eligibility assessment, recruitment outside the NHS via a charity, and remote consent. There was a lack of published evidence to support the former two adaptations, however, remote consent is widely supported in the literature. Other identified adaptations may benefit by improving flexibility for the participant. Barriers to using these adaptations include the impact on scientific validity, limitations in the role of the CTU, and participant's access to technology.

CONCLUSIONS

Three adaptations (a split remote-first eligibility assessment, recruitment outside the NHS via a charity, and remote consent) have the potential to improve clinical trials but only one (remote consent) is supported by evidence. These adaptations could be tested in future co-ordinated 'studies within a trial' (SWAT).

Comparing SF-36 Scores Collected Through Web-Based Questionnaire Self-completions and Telephone Interviews: An Ancillary Study of the SENTIPAT Multicenter Randomized Controlled Trial

Background

The 36-Item Short Form Health Survey (SF-36) is a popular questionnaire for measuring the self-perception of quality of life in a given population of interest. Processing the answers of a participant comprises the calculation of 10 scores corresponding to 8 scales measuring several aspects of perceived health and 2 summary components (physical and mental). Surprisingly, no study has compared score values issued from a telephone interview versus those from an internet-based questionnaire self-completion.

Objective

This study aims to compare the SF-36 score values issued from a telephone interview versus those from an internet-based questionnaire self-completion.

Methods

Patients with an internet connection and returning home after hospital discharge were enrolled in the SENTIPAT multicenter randomized trial on the day of discharge. They were randomized to either self-completing a set of questionnaires using a dedicated website (internet group) or providing answers to the same questionnaires administered during a telephone interview (telephone group). This ancillary study of the trial compared SF-36 data related to the posthospitalization period in these 2 groups. To anticipate the potential unbalanced characteristics of the responders in the 2 groups, the impact of the mode of administration of the questionnaire on score differences was investigated using a matched sample of individuals originating from the internet and telephone groups (1:1 ratio), in which the matching procedure was based on a propensity score approach. SF-36 scores observed in the internet and telephone groups were compared using the Wilcoxon-Mann-Whitney test, and the score differences between the 2 groups were also examined according to Cohen effect size.

Results

Overall, 29.2% (245/840) and 75% (630/840) of SF-36 questionnaires were completed in the internet and telephone groups, respectively (P<.001). Globally, the score differences between groups before matching were similar to those observed in the matched sample. Mean scores observed in the telephone group were all above the corresponding values observed in the internet group. After matching, score differences in 6 out of the 8 SF-36 scales were statistically significant, with a mean difference greater than 5 for 4 scales and an associated mild effect size ranging from 0.22 to 0.29, and with a mean difference near this threshold for 2 other scales (4.57 and 4.56) and a low corresponding effect size (0.18 and 0.16, respectively).

Conclusions

The telephone mode of administration of SF-36 involved an interviewer effect, increasing SF-36 scores. Questionnaire self-completion via the internet should be preferred, and surveys combining various administration methods should be avoided.

Trial Registration

ClinicalTrials.gov NCT01769261; https://www.clinicaltrials.gov/ct2/show/record/NCT01769261

Yoga compared to non-exercise or physical therapy exercise on pain, disability, and quality of life for patients with chronic low back pain: A systematic review and meta-analysis of randomized controlled trials

Background

Chronic low back pain (CLBP) is a common and often disabling musculoskeletal condition. Yoga has been proven to be an effective therapy for chronic low back pain. However, there are still controversies about the effects of yoga at different follow-up periods and compared with other physical therapy exercises.

Objective

To critically compare the effects of yoga for patients with chronic low back pain on pain, disability, quality of life with non-exercise (e.g. usual care, education), physical therapy exercise.

Methods

This study was registered in PROSPERO, and the registration number was CRD42020159865. Randomized controlled trials (RCTs) of online databases included PubMed, Web of Science, Cochrane Central Register of Controlled Trials, Embase which evaluated effects of yoga for patients with chronic low back pain on pain, disability, and quality of life were searched from inception time to November 1, 2019. Studies were eligible if they assessed at least one important outcome, namely pain, back-specific disability, quality of life. The Cochrane risk of bias tool was used to assess the methodological quality of included randomized controlled trials. The continuous outcomes were analyzed by calculating the mean difference (MD) or standardized mean difference (SMD) with 95% confidence intervals (CI) according to whether combining outcomes measured on different scales or not.

Results

A total of 18 randomized controlled trials were included in this meta-analysis. Yoga could significantly reduce pain at 4 to 8 weeks (MD = -0.83, 95% CI = -1.19 to -0.48, p<0.00001, I² = 0%), 3 months (MD = -0.43, 95% CI = -0.64 to -0.23, p<0.0001, I² = 0%), 6 to 7 months (MD = -0.56, 95% CI = -1.02 to -0.11, p = 0.02, I² = 50%), and was not significant in 12 months (MD = -0.52, 95% CI = -1.64 to 0.59, p = 0.36, I² = 87%) compared with non-exercise. Yoga was better than non-exercise on disability at 4 to 8 weeks (SMD = -0.30, 95% CI = -0.51 to -0.10, p = 0.003, I² = 0%), 3 months (SMD = -0.31, 95% CI = -0.45 to -0.18, p<0.00001, I² = 30%), 6 months (SMD = -0.38, 95% CI = -0.53 to -0.23, p<0.00001, I² = 0%), 12 months (SMD = -0.33, 95% CI = -0.54 to -0.12, p = 0.002, I² = 9%). There was no significant difference on pain, disability compared with physical therapy exercise group. Furthermore, it suggested that there was a non-significant difference on physical and mental quality of life between yoga and any other interventions.

Conclusion

This meta-analysis provided evidence from very low to moderate investigating the effectiveness of yoga for chronic low back pain patients at different time points. Yoga might decrease pain from short term to intermediate term and improve functional disability status from short term to long term compared with non-exercise (e.g. usual care, education). Yoga had the same effect on pain and disability as any other exercise or physical therapy. Yoga might not improve the physical and mental quality of life based on the result of a merging.

A Reliability Check of Walkability Indices in Seoul, Korea

The purpose of this study is to evaluate walkability levels using popular indices and check the measurement reliability between those indices. This study evaluates the city of Seoul, using 100 × 100 m grid points (N = 44,000) as spatial units of analysis. In this study, four types of indices were used to measure walkability levels: Walkability index (WI), Walk score (WS), Pedshed (Ps), and Movability index (MI). This study utilizes Pearson’s R, Brand–Altman plot with limit of agreement (LOA), and intraclass correlation coefficient (ICC) as reliability check methods. The measurement reliability among the four indices was found to be relatively high. The Pearson’s R values were between 0.308 and 0.645, and the range of inside LOA of Brand–Altman plots was 94.5% to 95.5%. The ICC value of the four indices was 0.544, indicating moderate reliability. The results reveal a relatively high level of measurement reliability between the four indices. On the basis of this study’s results, the level of walkability in other cities in Korea can be ascertained. The study may provide future direction for walkability index development that considers urban environmental characteristics. From the results, we expect that future urban planning and policies will aim to improve walkability.

Quadriceps Strength Deficit at 6 Months After ACL Reconstruction Does Not Predict Return to Preinjury Sports Level

Background:

There is a lack of literature-based objective criteria for return to sport after anterior cruciate ligament (ACL) injury. Establishing such objective criteria is crucial to improving return to sport after ACL reconstruction (ACLR).

Hypotheses:

Patients who return to their preinjury level of sport will have higher isokinetic, postural stability, and drop vertical jump test scores 6 months after surgery and greater patient satisfaction compared with those who did not. Additionally, quadriceps strength deficit cutoff values of 80% and 90% would differentiate patients who returned to preinjury sports level from those who did not.

Study Design:

Cohort study.

Level of Evidence:

Level 3.

Methods:

A retrospective search was conducted to identify all patients who underwent ACLR and completed isokinetic evaluation, postural stability analysis, and drop vertical jump testing at 6 months postoperatively. Patients were asked to complete 3 questionnaires at a minimum 1 year after surgery. Chi-square and logistic regression analyses were used for categorical dependent variables, while the Student t test, Pearson correlation, or analyses of variance with Bonferroni post hoc testing were used for continuous dependent variables. A post hoc power analysis was completed. Based on the results regarding correlations between return to preinjury level and all other variables, effect sizes from 0.24 to 3.03 were calculated. With these effect sizes, an alpha of 0.05 and sample size of 58, a power ranging from 0.15 to 0.94 was calculated.

Results:

The rates of return to preinjury level and to any sports activity were 53.4% and 84.4%. Those who were able to return to their preinjury level of sport (n = 33) showed significantly higher Lysholm (91.6 ± 9.7 vs 76.7 ± 15.4) and International Knee Documentation Committee (IKDC) (83.6 ± 10.6 vs 69.8 ± 14.6) values compared with those who were unable to return to their preinjury level of sport (n = 25) (P < 0.001). No significant differences were found for the clinical evaluations between those who were and those who were not able to return at the same level for the clinical evaluations (isokinetic evaluation, postural stability, drop vertical jump test) (P > 0.05). No significant differences were found when comparing quadriceps strength deficit with cutoff values of 80% and 90% for return to preinjury activity level (Tegner), Lysholm, and IKDC scores.

Conclusion:

Quadriceps strength deficit, regardless of cutoff value (80% or 90%), at 6 months after ACLR does not predict return to preinjury level of sport. Patients who returned to sport at their preinjury level were more satisfied with their reconstruction compared with those who did not.

Clinical Relevance:

Quadriceps strength deficit is not a reliable predictor of return to sports, and therefore it should not be used as the single criterion in such evaluations.

Yoga treatment for chronic non-specific low back pain

BACKGROUND

Non-specific low back pain is a common, potentially disabling condition usually treated with self-care and non-prescription medication. For chronic low back pain, current guidelines state that exercise therapy may be beneficial. Yoga is a mind-body exercise sometimes used for non-specific low back pain.

OBJECTIVES

To assess the effects of yoga for treating chronic non-specific low back pain, compared to no specific treatment, a minimal intervention (e.g. education), or another active treatment, with a focus on pain, function, and adverse events.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, five other databases and four trials registers to 11 March 2016 without restriction of language or publication status. We screened reference lists and contacted experts in the field to identify additional studies.

SELECTION CRITERIA

We included randomized controlled trials of yoga treatment in people with chronic non-specific low back pain. We included studies comparing yoga to any other intervention or to no intervention. We also included studies comparing yoga as an adjunct to other therapies, versus those other therapies alone.

DATA COLLECTION AND ANALYSIS

Two authors independently screened and selected studies, extracted outcome data, and assessed risk of bias. We contacted study authors to obtain missing or unclear information. We evaluated the overall certainty of evidence using the GRADE approach.

MAIN RESULTS

We included 12 trials (1080 participants) carried out in the USA (seven trials), India (three trials), and the UK (two trials). Studies were unfunded (one trial), funded by a yoga institution (one trial), funded by non-profit or government sources (seven trials), or did not report on funding (three trials). Most trials used Iyengar, Hatha, or Viniyoga forms of yoga. The trials compared yoga to no intervention or a non-exercise intervention such as education (seven trials), an exercise intervention (three trials), or both exercise and non-exercise interventions (two trials). All trials were at high risk of performance and detection bias because participants and providers were not blinded to treatment assignment, and outcomes were self-assessed. Therefore, we downgraded all outcomes to 'moderate' certainty evidence because of risk of bias, and when there was additional serious risk of bias, unexplained heterogeneity between studies, or the analyses were imprecise, we downgraded the certainty of the evidence further.For yoga compared to non-exercise controls (9 trials; 810 participants), there was low-certainty evidence that yoga produced small to moderate improvements in back-related function at three to four months (standardized mean difference (SMD) -0.40, 95% confidence interval (CI) -0.66 to -0.14; corresponding to a change in the Roland-Morris Disability Questionnaire of mean difference (MD) -2.18, 95% -3.60 to -0.76), moderate-certainty evidence for small to moderate improvements at six months (SMD -0.44, 95% CI -0.66 to -0.22; corresponding to a change in the Roland-Morris Disability Questionnaire of MD -2.15, 95% -3.23 to -1.08), and low-certainty evidence for small improvements at 12 months (SMD -0.26, 95% CI -0.46 to -0.05; corresponding to a change in the Roland-Morris Disability Questionnaire of MD -1.36, 95% -2.41 to -0.26). On a 0-100 scale there was very low- to moderate-certainty evidence that yoga was slightly better for pain at three to four months (MD -4.55, 95% CI -7.04 to -2.06), six months (MD -7.81, 95% CI -13.37 to -2.25), and 12 months (MD -5.40, 95% CI -14.50 to -3.70), however we pre-defined clinically significant changes in pain as 15 points or greater and this threshold was not met. Based on information from six trials, there was moderate-certainty evidence that the risk of adverse events, primarily increased back pain, was higher in yoga than in non-exercise controls (risk difference (RD) 5%, 95% CI 2% to 8%).For yoga compared to non-yoga exercise controls (4 trials; 394 participants), there was very-low-certainty evidence for little or no difference in back-related function at three months (SMD -0.22, 95% CI -0.65 to 0.20; corresponding to a change in the Roland-Morris Disability Questionnaire of MD -0.99, 95% -2.87 to 0.90) and six months (SMD -0.20, 95% CI -0.59 to 0.19; corresponding to a change in the Roland-Morris Disability Questionnaire of MD -0.90, 95% -2.61 to 0.81), and no information on back-related function after six months. There was very low-certainty evidence for lower pain on a 0-100 scale at seven months (MD -20.40, 95% CI -25.48 to -15.32), and no information on pain at three months or after seven months. Based on information from three trials, there was low-certainty evidence for no difference in the risk of adverse events between yoga and non-yoga exercise controls (RD 1%, 95% CI -4% to 6%).For yoga added to exercise compared to exercise alone (1 trial; 24 participants), there was very-low-certainty evidence for little or no difference at 10 weeks in back-related function (SMD -0.60, 95% CI -1.42 to 0.22; corresponding to a change in the Oswestry Disability Index of MD -17.05, 95% -22.96 to 11.14) or pain on a 0-100 scale (MD -3.20, 95% CI -13.76 to 7.36). There was no information on outcomes at other time points. There was no information on adverse events.Studies provided limited evidence on risk of clinical improvement, measures of quality of life, and depression. There was no evidence on work-related disability.

AUTHORS' CONCLUSIONS

There is low- to moderate-certainty evidence that yoga compared to non-exercise controls results in small to moderate improvements in back-related function at three and six months. Yoga may also be slightly more effective for pain at three and six months, however the effect size did not meet predefined levels of minimum clinical importance. It is uncertain whether there is any difference between yoga and other exercise for back-related function or pain, or whether yoga added to exercise is more effective than exercise alone. Yoga is associated with more adverse events than non-exercise controls, but may have the same risk of adverse events as other back-focused exercise. Yoga is not associated with serious adverse events. There is a need for additional high-quality research to improve confidence in estimates of effect, to evaluate long-term outcomes, and to provide additional information on comparisons between yoga and other exercise for chronic non-specific low back pain.

Mode of administration does not cause bias in patient-reported outcome results: a meta-analysis

PURPOSE

Technological advances in recent decades have led to the availability of new modes to administer patient-reported outcomes (PROs). To aid selecting optimal modes of administration (MOA), we undertook a systematic review to determine whether differences in bias (both size and direction) exist among modes.

METHODS

We searched five electronic databases from 2004 (date of last comprehensive review on this topic) to April 2014, cross-referenced and searched reference lists. Studies that compared two or more MOA for a health-related PRO measure in adult samples were included. Two reviewers independently applied inclusion and quality criteria and extracted findings. Meta-analyses and meta-regressions were conducted using random-effects models.

RESULTS

Of 5100 papers screened, 222 were considered potentially relevant and 56 met eligibility criteria. No evidence of bias was found for: (1) paper versus electronic self-complete; and (2) self-complete versus assisted MOA. Heterogeneity for paper versus electronic comparison was explained by type of construct (i.e. physical vs. psychological). Heterogeneity for self-completion versus assisted modes was in part explained by setting (clinic vs. home); the largest bias was introduced when assisted completion occurred in the clinic and follow-up was by self-completion (either electronic or paper) in the home.

CONCLUSIONS

Self-complete paper and electronic MOA can be used interchangeably for research in clinic and home settings. Self-completion and assisted completion produce equivalent scores overall, although heterogeneity may be induced by setting. These results support the use of mixed MOAs within a research study, which may be a useful strategy for reducing missing PRO data.

A call centre and extended checklist for pre-screening elective surgical patients – a pilot study

Background

Novel approaches to preoperative assessment and management before elective surgery are warranted to ensure that a sustainable high quality service is provided. The benefits of a call centre incorporating an extended preoperative electronic checklist and phone follow-up as an alternative to a clinic attendance were examined.

Methods

This was a pilot study of a new method of patient assessment in patients scheduled for elective non-cardiac surgery and who attended a conventional preoperative clinic. A call centre assessment, using a Computer-assisted Health Assessment by Telephone (CHAT), paper review by an anaesthetist, and a follow-up phone call if the anaesthetist wished more information, preceded the conventional preoperative clinic. Summaries from the call centre and clinic assessments were independently produced.

The times spent by call centre staff were recorded. The ‘procedural anaesthetist’ (who provided anaesthesia for each patient’s actual surgery/procedure) documented an opinion on whether the call centre assessment alone would have been sufficient to bypass the preoperative clinic if the patient were hypothetically undergoing laparoscopic cholecystectomy. This opinion was also sought from a panel of four senior anaesthetists, based on patient summaries from both the call centre and preoperative clinic, but expanded to three hypothetical operations of different complexity – cataract removal, laparoscopic cholecystectomy, and total hip replacement.

Results

Call centre assessment followed by clinic attendance was studied in 193 patients. The mean time for CHAT was 19.8 (SD 7.5) minutes and, after review of CHAT summaries, anaesthetists telephoned 45.6 % of cases for follow-up information. The mean time spent by anaesthetists on summary review and phone calls was 3.8 (SD 3.9) minutes. Procedural anaesthetists considered 89 % of the patients under their care suitable to have bypassed the preoperative clinic if they were to have undergone cholecystectomy. The panel of senior anaesthetists judged 95-97 % of patients suitable to have bypassed preoperative clinic for cataract surgery, 81-85 % for cholecystectomy and 79-82 % for hip replacement.

Conclusions

A call centre to pre-screen elective surgical patients might substantially reduce patient numbers attending preoperative anaesthetic assessment clinics. Further studies to assess the quality of such an approach are indicated.

Trial registration

ANZCTRACTRN12614000199617.