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Clinically Important Difference in Quality of Recovery Scores


doi: 10.1213/ANE.0000000000001060
Editorials: Editorial

From the Department of Anaesthesia and Perioperative Medicine, Alfred Hospital and Monash University, Melbourne, Victoria, Australia.

Accepted for publication September 18, 2015.

Funding: None.

The author declares no conflicts of interest.

Reprints will not be available from the author.

Address correspondence to Paul S. Myles, MBBS, MPH, MD, FCAI, FANZCA, FRCA, FAHMS, Department of Anaesthesia and Perioperative Medicine, Alfred Hospital, Commercial Rd., Melbourne, Victoria 3004, Australia. Address e-mail to

Perioperative interventions that improve the quality of recovery after anesthesia and surgery are needed. Fortunately, serious complications are rare, but minor, even transient complications, discomfort, and psychological distress have a significant effect on a patient’s overall quality of recovery. A narrow focus on any single aspect of a patient’s postoperative recovery, for example, wound pain or vomiting, can lead to tunnel vision, a type of attentional bias in which other sources of patient discomfort or impairment, such as dyspnea, confusion, or thirst, are not considered. Some treatments may improve one symptom, for example, pain, but create others, such as nausea, excessive sedation, or delirium.

Clinical trials are required to nominate study end points that may or may not truly represent the interests of the patient, and yet, the sample size estimation and resultant statistical power are mostly based on the nominated primary end point. Trials are rarely powered to detect treatment side effects or evaluate overall cost-effectiveness, despite these aspects often being of more importance to patients and society. Composite end points and/or health status scales can be used to measure a broader range of outcome events and typically provide more statistical power so that useful treatment effects can be identified. Quality of recovery scales offer particular value in this regard.1,2

Overall quality of recovery after surgery and anesthesia should be defined from the patient’s perspective.3,4 An extensive literature review, clinician and patient surveys, and psychometric development and validation led to a series of quality-of-recovery scores to measure a patient’s global health status after surgery,4–9 with the most extensively validated being the 40-item quality-of-recovery scale (the QoR-40).10 Other instruments have also been developed.11,12

The QoR-40 has 5 dimensions of recovery: (1) emotional state, (2) physical comfort, (3) psychological support, (4) physical independence, and (5) pain control, with each item rated on a 5-point Likert scale. Global QoR-40 scores range from 40 to 200, representing, respectively, very poor to excellent quality of recovery. The QoR-40 is a simple, valid, reliable, and responsive instrument.5,10

In this issue of Anesthesia & Analgesia, Alves et al.13 report on a clinical trial evaluating the outcome benefits of duloxetine, an antidepressant frequently used to treat fibromyalgia and other chronic pain conditions, in patients undergoing abdominal hysterectomy with spinal anesthesia. The primary outcome metric was the QoR-40 score at 24 hours. They found that duloxetine given before and at 24 hours after surgery increased the median (95% confidence interval) QoR-40 score by 9 (95% confidence interval, 4–20) points, which was statistically significant at P < 0.001. The actual median QoR-40 scores for the duloxetine and control groups at 24 hours after surgery were 196 and 187, respectively. This might seem impressive, but the key question readers will want to answer is whether this change in scores is clinically important? That is, does a 9-point change in QoR-40 scores mean that patients actually recover better overall? Of relevance, the authors also identified a reduction in pain scores and opioid consumption at 24 hours after surgery in those receiving duloxetine compared with control.

Clinicians sometimes need to be reminded that a statistically significant change in a health status scale (or pain) score may not represent a clinically important change in health status (or pain). There is a subtle but important difference.14,15

To help interpret the trial by Alves et al.,13 we know from previous work that patients undergoing minor, intermediate, and major surgery have mean ± SD postoperative QoR-40 scores of 178 ± 17, 173 ± 17, and 166 ± 15, respectively.6 Furthermore, in patients recovering from cardiac surgery, the day 3 QoR-40 scores in those without and with complications were 176 ± 16 and 170 ± 15, respectively.8 Thus, it can be inferred that a change in QoR-40 of 5 to 7 points would signify a clinically important difference. It should be noted that differences in QoR-40 scores across studies of similar surgical populations may relate to differences in timing of assessment (better over time) and use of adjunctive analgesics. It is therefore questionable whether across-study comparisons can be made, but the relative differences within a randomized trial are valid. We can conclude, however, that a difference of say 180 vs 175 reflects the extent of difference in quality of recovery when comparing minor versus intermediate surgery or patients with or without postoperative complications.

On the basis of the findings presented by Alves et al.,13 it seems that duloxetine is a useful adjunct to improve quality of recovery in women undergoing abdominal hysterectomy.

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Contribution: This author wrote the manuscript.

Attestation: Paul S. Myles approved the final version of the manuscript.

This manuscript was handled by: Ken B. Johnson, MD.

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