Graeme Hawthorne

A comparison of the Assessment of Quality of Life (AQoL) with four other generic utility instruments

As part of the validation of the Assessment of Quality of Life (AQoL) instrument comparisons were made between five multiattribute utility (MAU) instruments, each purporting to measure health-related quality of life (HRQoL). These were the AQoL, the Canadian Health Utilities Index (HUI) 3, the Finnish 15D, the EQ-5D (formerly the EuroQoL) and the SF6D (derived from the SF-36). The paper compares absolute utility scores, instrument sensitivity, and incremental differences in measured utility between different instruments predicted by different individuals. The AQoL predicted utilities are similar to those from the HUI3 and EQ-5D. By contrast the 15D and SF6D predict systematically higher utilities, and the differences between individuals are significantly smaller. There is some evidence that the AQoL has greater sensitivity to health states than other instruments. It is concluded that at present no single MAU instrument can claim to be the ‘gold standard’, and that researchers should select an instrument sensitive to the health states they are investigating. Caution should be exercised in treating any of the instrument scores as representing a trade-off between length of life and HRQoL.

The SF36 Version 2: critical analyses of population weights, scoring algorithms and population norms

BackgroundThe SF36 Version 2 (SF36V2) is a revision of the SF36 Version 1, and is a widely used health status measure. It is important that guidelines for interpreting scores are available.MethodA population sample of Australians (n = 3015) weighted to achieve representativeness was administered the SF36V2. Comparisons between published US weights and sample derived weights were made, and Australian population norms computed and presented.Major findingsSignificant differences were observed on 7/8 scales and on the mental health summary scale. Possible causes of these findings may include different sampling and data collection procedures, demographic characteristics, differences in data collection time (1998 vs. 2004), differences in health status or differences in cultural perception of the meaning of health. Australian population norms by age cohort, gender and health status are reported by T-score as recommended by the instrument developers. Additionally, the proportions of cases within T-score deciles are presented and show there are important data distribution issues.Principal conclusionsThe procedures reported here may be used by other researchers where local effects are suspected. The population norms presented may be of interest. There are statistical artefacts associated with T-scores that have implications for how SF36V2 data are analysed and interpreted.

Population norms and meaningful differences for the Assessment of Quality of Life (AQoL) measure

Objective: The Assessment of Quality of Life (AQoL) instrument is widely used in Australian health research. To assist researchers interpret and report their work, this paper reports population and health status norms, general minimal important differences (MIDs) and effect sizes.

Imputing cross-sectional missing data: comparison of common techniques

OBJECTIVE Increasing awareness of how missing data affects the analysis of clinical and public health interventions has led to increasing numbers of missing data procedures. There is little advice regarding which procedures should be selected under different circumstances. This paper compares six popular procedures: listwise deletion, item mean substitution, person mean substitution at two levels, regression imputation and hot deck imputation. METHOD Using a complete dataset, each was examined under a variety of sample sizes and differing levels of missing data. The criteria were the true t-values for the entire sample. RESULTS The results suggest important differences. If missing data are from a scale where about half the items are present, hot deck imputation or person mean substitution are best. Because person mean substitution is computationally simpler, similar in its efficiency, advocated by other researchers and more likely to be an option on statistical software packages, it is the method of choice. If the missing data are from a scale where more than half the items are missing, or with single-item measures, then hot deck imputation is recommended. The findings also showed that listwise deletion and item mean substitution performed poorly. CONCLUSIONS Person mean and hot deck imputation are preferred. Since listwise deletion and item mean substitution performed poorly, yet are the most widely reported methods, the findings have broad implications.

Exercise rehabilitation for patients with critical illness: a randomized controlled trial with 12 months of follow-up

IntroductionThe purpose of this trial was to investigate the effectiveness of an exercise rehabilitation program commencing during ICU admission and continuing into the outpatient setting compared with usual care on physical function and health-related quality of life in ICU survivors.MethodsWe conducted a single-center, assessor-blinded, randomized controlled trial. One hundred and fifty participants were stratified and randomized to receive usual care or intervention if they were in the ICU for 5 days or more and had no permanent neurological insult. The intervention group received intensive exercises in the ICU and the ward and as outpatients. Participants were assessed at recruitment, ICU admission, hospital discharge and at 3-, 6- and 12-month follow-up. Physical function was evaluated using the Six-Minute Walk Test (6MWT) (primary outcome), the Timed Up and Go Test and the Physical Function in ICU Test. Patient-reported outcomes were measured using the Short Form 36 Health Survey, version 2 (SF-36v2) and Assessment of Quality of Life (AQoL) Instrument. Data were analyzed using mixed models.ResultsThe a priori enrollment goal was not reached. There were no between-group differences in demographic and hospital data, including acuity and length of acute hospital stay (LOS) (Acute Physiology and Chronic Health Evaluation II score: 21 vs 19; hospital LOS: 20 vs 24 days). No significant differences were found for the primary outcome of 6MWT or any other outcomes at 12 months after ICU discharge. However, exploratory analyses showed the rate of change over time and mean between-group differences in 6MWT from first assessment were greater in the intervention group.ConclusionsFurther research examining the trajectory of improvement with rehabilitation is warranted in this population.Trial registrationThe trial was registered with the Australian New Zealand Clinical Trials Registry ACTRN12605000776606.

Quality of life assessment in the community-dwelling elderly: Validation of the Assessment of Quality of Life (AQoL) Instrument and comparison with the SF-36

Measurement of Health-Related Quality of Life (HRQoL) of the elderly requires instruments with demonstrated sensitivity, reliability, and validity, particularly with the increasing proportion of older people entering the health care system. This article reports the psychometric properties of the 12-item Assessment of Quality of Life (AQoL) instrument in chronically ill community-dwelling elderly people with an 18-month follow-up. Comparator instruments included the SF-36 and the OARS. Construct validity of the AQoL was strong when examined via factor analysis and convergent and divergent validity against other scales. Receiver Operator Characteristic (ROC) curve analyses and relative efficiency estimates indicated the AQoL is sensitive, responsive, and had the strongest predicative validity for nursing home entry. It was also sensitive to economic prediction over the follow-up. Given these robust psychometric properties and the brevity of the scale, AQoL appears to be a suitable instrument for epidemiologic studies where HRQoL and utility data are required from elderly populations.

Comorbidity As A Predictor Of Symptom Change After Treatment In Combat-related Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a difficult condition to treat, and existing studies show considerable variability in outcome. Investigations of factors that influence outcome have the potential to inform alternate treatment approaches to maximize benefits gained from interventions for the disorder. Because PTSD is commonly associated with comorbidity, it is important to investigate the influence of comorbidity on symptom change after treatment. This article examines pretreatment and 9-month follow-up data for 134 Australian Vietnam veterans who attended a treatment program for combat-related PTSD. A series of analyses were conducted to investigate the influence of the comorbid factors of anxiety, depression, anger, and alcohol use on PTSD symptom change after treatment. Analyses identified anger, alcohol, and depression as significant predictors of symptom change over time, independent of the effect of initial PTSD severity. Further analyses indicated that anger at intake was the most potent predictor of symptom change. Further investigations of anger as an influence on symptom change after treatment of combat-related PTSD is recommended.

Quality of Life after Brain Injury (QOLIBRI): Scale Validity and Correlates of Quality of Life

The QOLIBRI (Quality of Life after Brain Injury) is a novel health-related quality-of-life (HRQoL) instrument specifically developed for traumatic brain injury (TBI). It provides a profile of HRQoL in six domains together with an overall score. Scale validity and factors associated with HRQoL were investigated in a multi-center international study. A total of 795 adults with brain injury were studied from 3 months to 15 years post-injury. The majority of participants (58%) had severe injuries as assessed by 24-h worst Glasgow Coma Scale (GCS) score. Systematic relationships were observed between the QOLIBRI and the Glasgow Outcome Scale-Extended (GOSE), Hospital Anxiety and Depression Scale (HADS), and SF-36. Within each scale patients with disability reported having low HRQoL in two to three times as many areas as those who had made a good recovery. The main correlates of the total QOLIBRI score were emotional state (HADS depression and anxiety), functional status (amount of help needed and outcome on the GOSE), and comorbid health conditions. Together these five variables accounted for 58% of the variance in total QOLIBRI scores. The QOLIBRI is the first tool developed to assess disease-specific HRQoL in brain injury, and it contains novel information not given by other currently available assessments.

Quality of life after traumatic brain injury: The clinical use of the QOLIBRI, a novel disease-specific instrument

Objective: To report the clinical use of the QOLIBRI, a disease-specific measure of health-related quality-of-life (HRQoL) after traumatic brain injury (TBI). Methods: The QOLIBRI, with 37 items in six scales (cognition, self, daily life and autonomy, social relationships, emotions and physical problems) was completed by 795 patients in six languages (Finnish, German, Italian, French, English and Dutch). QOLIBRI scores were examined by variables likely to be influenced by rehabilitation interventions and included socio-demographic, functional outcome, health status and mental health variables. Results: The QOLIBRI was self-completed by 73% of participants and 27% completed it in interview. It was sensitive to areas of life amenable to intervention, such as accommodation, work participation, health status (including mental health) and functional outcome. Conclusion: The QOLIBRI provides information about patients subjective perception of his/her HRQoL which supplements clinical measures and measures of functional outcome. It can be applied across different populations and cultures. It allows the identification of personal needs, the prioritization of therapeutic goals and the evaluation of individual progress. It may also be useful in clinical trials and in longitudinal studies of TBI recovery.

Changes in the prevalence of major depression in an Australian community sample between 1998 and 2008

Objective: To identify changes in the prevalence of major depression between 1998, 2004 and 2008 in South Australia. Methods: Face-to-face Health Omnibus surveys were conducted in 1998, 2004 and 2008 with approximately 3000 participants aged 15 years and over, who were random and representative samples of the South Australian population. Each survey used the same methodology. Outcome measures were: major depression as detected by the Mood module of the Primary Care Evaluation of Mental Disorders instrument; mental health literacy by recognition and exposure to classical symptoms of depression; and health status using the SF-36 Physical and Mental Component summaries. Results: There was a significant increase in the prevalence of major depression from 6.8% (95%CI: 5.9%–7.7%) to 10.3% (95%CI: 9.2%–11.4%; χ2 24.59, p < 0.001) between 1998 and 2008. Significant increases were observed in males aged 15–29 and females aged 30–49 years. There was no significant increase in any other sub-group. The strongest predictor of major depression was health status. Participants with poor/fair mental health literacy were 37% less likely to be classified with major depression. Conclusions: The prevalence of major depression increased significantly in South Australia over the last decade and there was a reduction in mental health status and an increase in persons reporting poor health. Unexpectedly, having poor or fair mental health literacy was significantly protective for major depression. Ideally, public health initiatives should result in an improvement in health, but this did not appear to have occurred here.