Methods to Explain the Clinical Significance of Health Status Measures

Guyatt, Gordon; Osoba, David; Wu, Albert W.; Wyrwich, Kathleen W.; Norman, Geoffrey R.

doi:10.4065/77.4.371

Cited by 1,323 publications

(1,164 citation statements)

References 57 publications

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“…Distribution‐based approaches, although easy to perform, are purely statistical, assuming that the MID is related to the distribution of observed scores in a relevant sample. This approach has been criticised for its arbitrariness, and because it is so heavily influenced by the heterogeneity of the population being studied 30. Furthermore, while, for example, a magnitude of change of 0.5 SD of a sample will probably be meaningful, it provides no direct information about the minimal difference that is important to patients.…”

Section: Discussionmentioning

confidence: 99%

“…Different researchers have suggested that specific multiplications of the standard deviation, or the standard error of the mean (SEM) may approximate the MID for patient‐reported outcome instruments 28, 30. We used the SEM approach, which calculates the MID as SD base × √(1 – r xx’ ), where SD base is the baseline standard deviation of the sample and r xx’ is the reliability coefficient, and two standard deviation approaches: 0.5 × SD base and 0.2 × SD base .…”

Section: Methodsmentioning

confidence: 99%

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ThePAC‐SYMquestionnaire for chronic constipation: defining the minimal important difference

Yiannakou

Tack

Piessevaux

et al. 2017

Aliment Pharmacol Ther

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SummaryBackgroundThe Patient Assessment of Constipation‐Symptoms (PAC‐SYM) questionnaire is frequently used in clinical trials of constipation. However, the threshold for reduction in total PAC‐SYM score used to define a clinical response on this 0‐4 point scale has not undergone formal appraisal, and its relationship with clinical benefit as perceived by patients has not been defined.AimTo determine the minimal important difference in PAC‐SYM score, and the optimum cut‐off value for defining responders.MethodsThe minimal important difference was estimated using data from six international phase 3/4, double‐blind, randomised controlled trials of prucalopride in patients with chronic constipation (NCT01147926, NCT01424228, NCT01116206, NCT00485940, NCT00483886, NCT00488137), with anchor‐ and distribution‐based approaches. Five appropriate patient‐reported outcomes were selected as anchors. In addition, receiver operating characteristics (ROC) curve analyses were used to investigate responder discrimination for each anchor.ResultsData from 2884 patients were included. Minimal important difference estimates ranged from –0.52 to –0.63 across the five anchors. Estimates were not affected by study location but were consistently lower for rectal symptoms than for abdominal and stool symptoms. Distribution‐based estimates were considerably lower than anchor‐based estimates. ROC curve analyses showed optimum cut‐off scores for discriminating responders to be similar to anchor‐based minimal important difference estimates.ConclusionsAnchor‐based methods gave consistent results for the minimal important difference, at approximately –0.6, and this value was close to the ROC‐determined optimal cut‐off scores for responder discrimination. This value could be considered in clinical practice. A slightly more conservative threshold (eg –0.75) could be used in clinical trials to reduce the placebo response rate.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

ThePAC‐SYMquestionnaire for chronic constipation: defining the minimal important difference

Yiannakou

Tack

Piessevaux

et al. 2017

Aliment Pharmacol Ther

View full text Add to dashboard Cite

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“…We will illustrate the difference in the methodology by using MID(a) for the anchor‐based approach or MID(d) for the distribution‐based approach. No single approach is perfect, and multiple strategies are likely to enhance the interpretability of changes in HRQOL scales 11, 27. An anchor‐based method was used as the primary approach (as preferred by the FDA) 2, based on the average change in LupusQoL or SF‐36 scores for the subset of patients who were considered to have a small but discernible change in that particular HRQOL domain.…”

Section: Methodsmentioning

confidence: 99%

“…As with many HRQOL measures, the interpretation of the data may be problematic and should not be based solely on P values, especially if HRQOL is a secondary outcome when a trial tends not to be powered for HRQOL. To aid the interpretation of the LupusQoL, evaluation is required to assess its sensitivity to change (the ability to detect an improvement or deterioration when patients deem themselves to have improved or deteriorated) 10 as advocated by the regulatory bodies 2, and to estimate the minimal important difference (MID), the smallest difference that patients perceive as beneficial or harmful 11.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity to Change and Minimal Important Differences of the LupusQoL in Patients With Systemic Lupus Erythematosus

McElhone

Abbott

Sutton

et al. 2016

Arthritis Care & Research

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ObjectiveAs a health‐related quality of life (HRQOL) measure, the LupusQoL is a reliable and valid measure for adults with systemic lupus erythematosus (SLE). This study evaluates the responsiveness and minimal important differences (MIDs) for the 8 LupusQoL domains.MethodsPatients experiencing a flare were recruited from 9 UK centers. At each of the 10 monthly visits, HRQOL (LupusQoL, Short Form 36 health survey [SF‐36]), global rating of change (GRC), and disease activity using the British Isles Lupus Assessment Group 2004 index were assessed. The responsiveness of the LupusQoL and the SF‐36 was evaluated primarily when patients reported an improvement or deterioration on the GRC scale and additionally with changes in physician‐reported disease activity. MIDs were estimated as mean changes when minimal change was reported on the GRC scale.ResultsA total of 101 patients were recruited. For all LupusQoL domains, mean HRQOL worsened when patients reported deterioration and improved when patients reported an improvement in GRC; SF‐36 domains showed comparable responsiveness. Improvement in some domains of the LupusQoL/SF‐36 was observed with a decrease in disease activity, but when disease activity worsened, there was no significant change. LupusQoL MID estimates for deterioration ranged from −2.4 to −8.7, and for improvement from 3.5 to 7.3; for the SF‐36, the same MID estimates were −2.0 to −11.1 and 2.8 to 10.9, respectively.ConclusionAll LupusQoL domains are sensitive to change with patient‐reported deterioration or improvement in health status. For disease activity, some LupusQoL domains showed responsiveness when there was improvement but none for deterioration. LupusQoL items were derived from SLE patients and provide the advantage of disease‐specific domains, important to the patients, not captured by the SF‐36.

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“…Finally, the sample size was not adequate to detect differences between the groups that corresponded to effect sizes below d = 0.63. While there is no consensus on the cutoff for clinical significance, differences between groups exceeding 1/3 or 1/2 of the standard deviation (effect sizes exceeding 0.33 or 0.5) are often deemed clinically significant 36, 37. In the present study, only one of the effect sizes (0.42 for visual‐spatial processing) was in this range, but statistical significance was not reached with the available sample size.…”

Section: Discussionmentioning

confidence: 52%

Absence of neurocognitive disadvantage associated with paediatric HIV subtype A infection in children on antiretroviral therapy

et al. 2017

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IntroductionInfection with HIV subtype A has been associated with poorer neurocognitive outcomes compared to HIV subtype D in Ugandan children not eligible for antiretroviral therapy (ART). In this study, we sought to determine whether subtype‐specific differences are also observed among children receiving ART.Materials and MethodsChildren were recruited from a clinical trial in which they were randomized to receive either lopinavir (LPV)‐ or non‐nucleoside reverse transcriptase inhibitor (NNRTI)‐ based ART (NCT00978068). Age at initiation of ART ranged from six months to six years. HIV subtype was determined by PCR amplification and population sequencing of the pol region derived from peripheral blood mononuclear cell DNA, followed by application of the REGA and Recombinant Identification Programme algorithms. General cognition was assessed using the Kaufman Assessment Battery for Children (Second Edition), attention using the Test of Variables of Attention, and motor skills using the Bruininks‐Oseretsky Test of Motor Proficiency (Second Edition). Home environment was assessed using the Home Observation for the Measurement of the Environment (HOME). Age‐adjusted test z‐scores were entered into a regression model that adjusted for sex, socio‐economic status score, HOME score, years of schooling, and ART treatment type.ResultsOne hundred and five children were tested; median (interquartile range) age was 7.05 years (6.30 to 8.44), CD4 count was 867.7 cells/mm3 (416.0 to 1203.5), and duration on ART was 4.03 years (3.55 to 4.23). Seventy‐eight children had HIV subtype A and 27 had subtype D; the groups had comparable home and socio‐economic status, except that there were more males among children infected with subtype A than D (64.7% vs. 35.3%, p = 0.02). There were no differences between the subtypes in general cognition (estimated mean difference: 0.20; 95% CI: −0.11 to 0.50); p = 0.21), attention (−0.18, 95% CI: −0.60 to 0.24, p = 0.41) and motor skills (1.60, 95% CI: −0.84 to 4.04, p = 0.20).ConclusionsOur results imply that ART may diminish the neurocognitive disadvantage seen in treatment‐naïve HIV‐infected children with subtype A.

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Methods to Explain the Clinical Significance of Health Status Measures

Cited by 1,323 publications

References 57 publications

ThePAC‐SYMquestionnaire for chronic constipation: defining the minimal important difference

ThePAC‐SYMquestionnaire for chronic constipation: defining the minimal important difference

Sensitivity to Change and Minimal Important Differences of the LupusQoL in Patients With Systemic Lupus Erythematosus

Absence of neurocognitive disadvantage associated with paediatric HIV subtype A infection in children on antiretroviral therapy

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