Sarah Dummett

The development and validation of a quality of life measure for the carers of people with Parkinson's disease (the PDQ-Carer)

BACKGROUND Parkinsons disease (PD) can have substantial effects not only on the quality of life of those diagnosed with the condition but also upon the informal carers who provide support and assistance to them. However, to date no well-validated carer specific quality of life measure has been developed for carers of people with PD. OBJECTIVE This paper documents the development and validation of a PD specific carer quality of life scale. METHODS In depth interviews were undertaken with carers of people with PD. The interviews were transcribed and analysed thematically to derive a pool of potential items for the questionnaire. A pilot survey was used to refine the initial version of the questionnaire. A developmental survey was undertaken and the results analysed to produce the final 29-item measure. A validation survey was then undertaken to assess the construct validity and reliability of the measure. RESULTS Survey results suggest a 29-item questionnaire tapping four dimensions of quality of life (Social and Personal Activities, Anxiety and Depression, Self care, and Strain). Internal consistency reliability was found to be high for all domains. Data completeness was high. Construct validity (assessed by correlations with a generic measure of quality of life) confirmed prior hypotheses. CONCLUSION The 29-item Parkinson Disease Questionnaire for Carers (PDQ-Carer) is a short, meaningful quality of life instrument, which taps areas of specific salience and concern to PD carers.

Factors Influencing Quality of Life in Caregivers of People with Parkinson's Disease and Implications for Clinical Guidelines

The quality of life (QoL) of informal caregivers can be adversely affected by a number of factors. This issue, however, has not been well explored for carers of people with Parkinsons (PwP), with research largely restricted to the assessment of caregiver burden and caregiver strain. This study aims to determine the main influences on carer QoL in this population and consider results in the context of current clinical guidelines for the management of Parkinsons disease (PD). Carers completed the newly validated PDQ-Carer, and PwP completed the PDQ-39. The sample comprised 238 carers (mean age 68.20 years) and 238 PwP (mean age 71.64). Results suggest multiple influences on caregiver QoL. These include carer age, gender, health status, and duration of the caregiving role. PwP levels of mobility and cognitive impairment are also significant influences on carer QoL. Not only should practitioners and service providers be particularly aware of the heightened impact of PD on carers over time and as PwP symptoms deteriorate, but this should also be reflected in clinical guidelines for the management of PD.

Change in health status in long-term conditions over a one year period: a cohort survey using patient-reported outcome measures

BackgroundEnhancing quality of life for people with long-term conditions by monitoring patient-reported outcome measure scores is a key domain of health care policy. This study investigated the responsiveness of patient-reported outcome measures for long-term conditions.MethodsA cohort survey was conducted in 33 primary care practices and 4485 patients (1334 asthma, 567 chronic obstructive pulmonary disease, 1121 diabetes, 525 epilepsy, 520 heart failure and 418 stroke) were sent a baseline survey containing a generic (EQ-5D) and a disease-specific measure. Baseline respondents were sent a follow-up after 1 year. Differences in scores for each long-term condition were assessed by paired t-tests. The relationship between scores and self-reported ‘change in health’ was assessed by analysis of variance.ResultsThe baseline achieved a 38.4% response rate and the follow-up 71.5%. The only significant difference for the EQ-5D was found for the Visual Analogue Scale in heart failure between baseline and follow-up, and for change in health. Significant differences between baseline and follow-up scores were found on the disease-specific measures for 1 asthma dimension and 1 stroke dimension. No significant differences were found for other conditions. Significant differences between self-reported change in health and the disease-specific measures were found for 4 asthma dimensions and 2 stroke dimensions.ConclusionsFew significant differences were found between the baseline and follow up or between ‘change in health’ and PROMs scores. This could be explained by the time frame of one year being too short for change to occur or by the PROMs not being responsive enough to change in a primary care sample. The latter is unlikely as the PROMs were in part chosen for their responsiveness to change. The baseline response rates may mean that the sample is not representative, and stable patients may have been more likely to participate. If PROMs are to be used routinely to monitor outcomes in LTCs, further research is needed to maximize response rates, to ensure that the PROMs used are reliable, valid and sensitive enough to detect change and that the time frame for data collection is appropriate.

Evaluating the psychometric properties of an e-based version of the 39-item Parkinson’s Disease Questionnaire

BackgroundThe 39-item Parkinson’s Disease Questionnaire (PDQ-39) is the most thoroughly validated and extensively used self-report measure for the assessment of health-related quality of life in people with Parkinson’s (PwP). Given the extent of its use and increasing emphasis on electronic data capture, an e-based version of the PDQ-39, the ePDQ, has recently been developed. The aim of this short report is to present some key reliability and validity data that confirm the psychometric quality of the ePDQ.FindingsParticipants were emailed a unique link to an online survey incorporating the ePDQ and demographic questions. A total of 118 PwP fully completed the survey. Floor and ceiling effects were calculated to ensure responses were not biased to extreme values. Consequently, score reliability was assessed by item-total correlations with a range from 0.34 to 0.90. Cronbach’s alpha was calculated at between 0.64 and 0.95 for the eight domains of the ePDQ. Construct validity was assessed by comparing domain scores in relation to disease duration and gender, with hypothesised differences being largely confirmed. Construct validity was further assessed following a higher order factor analysis which confirmed the appropriateness of calculating a summary index score. Subsequently, significant, but moderate correlations were calculated between the ePDQ summary index score and disease duration and age at diagnosis.ConclusionsResults indicate that the ePDQ largely mirrors the properties of its parent instrument, the PDQ-39, in terms of reliability and validity. Potential users can therefore incorporate the ePDQ into computer-based data capture systems with confidence.

The Oxford Participation and Activities Questionnaire: study protocol.

Background With an ageing population and increasing demands on health and social care services, there is growing importance attached to the management of long-term conditions, including maximizing the cost-effectiveness of treatments. In line with this, there is increasing emphasis on the need to keep people both active and participating in daily life. Consequently, it is essential that well developed and validated instruments that can meaningfully assess levels of participation and activity are widely available. Current measures, however, are largely focused on disability and rehabilitation, and there is no measure of activity or participation for generic use that fully meets the standards set by regulatory bodies such as the US Food and Drug Administration. Here we detail a protocol for the development and validation of a new patient-reported outcome measure (PROM) for assessment of participation and activity in people experiencing a variety of health conditions, ie, the Oxford Participation and Activities Questionnaire (Ox-PAQ). The stages incorporated in its development are entirely in line with current regulations and represent best practice in the development of PROMs. Methods Development of the Ox-PAQ is theoretically grounded in the World Health Organization International Classification of Functioning, Disability, and Health. The project incorporates a new strategy of engaging with stakeholders from the outset in an attempt to identify those characteristics of PROMs considered most important to a range of potential users. Items will be generated through interviews with patients from a range of conditions. Pretesting of the instrument will be via cognitive interviews and focus groups. A postal survey will be conducted, with data subject to factor and Rasch analysis in order to identify appropriate dimensions and redundant items. Reliability will be assessed by Cronbach’s alpha and item-total correlations. A second, large-scale postal survey will follow, with the Ox-PAQ being administered in conjunction with generic measures of health status to further test the validity of the measure. The Ox-PAQ will again be administered at 2 weeks to assess test-retest reliability and at 3 months to assess responsiveness. Conclusion The development of the Ox-PAQ is a timely one. With increasing emphasis being placed on the importance of keeping people active and participating in daily life, the instrument has the potential for significant uptake. Its primary use is intended to be in clinical trials and for evaluation of interventions targeted at maintaining activity and participation.

The PDQ-Carer: Development and validation of a summary index score

INTRODUCTION The PDQ-Carer is a 29 item measure of health related quality of life for use with carers of people with Parkinsons disease. The original development of the instrument identified four domains. This study examined the possibility that the four domains could reasonably be summed to provide a single summary index score. METHODS The PDQ-Carer was administered in a postal survey of patients and carers registered with local branches of Parkinsons UK. Data from the four domains of the PDQ-Carer was subjected to higher order factor analysis. Reliability and validity of the summary index were assessed. RESULTS A total of 236 carer questionnaires were returned, a response rate of 61%. The mean age of the sample was 68.2 years (SD 9.49; range 25-89 years); 63.5% females, 21.3% males. Higher order principle components factor analysis produced one factor, accounting for 85.5% of the variance. The newly derived single index was found to be both internally reliable (alpha = 0.94) and valid through correlations with the eight domains of the SF-36 (all p < 0.001). DISCUSSION The analyses undertaken here indicate that data from the PDQ-Carer can be presented in summary form. The index will provide an overall indication of the impact of caring. Furthermore, the single index reduces the number of statistical comparisons, and hence the role of chance, when exploring data from the PDQ-Carer.

Development of the Oxford Participation and activities Questionnaire: constructing an item pool

Purpose The Oxford Participation and Activities Questionnaire is a patient-reported outcome measure in development that is grounded on the World Health Organization International Classification of Functioning, Disability, and Health (ICF). The study reported here aimed to inform and generate an item pool for the new measure, which is specifically designed for the assessment of participation and activity in patients experiencing a range of health conditions. Methods Items were informed through in-depth interviews conducted with 37 participants spanning a range of conditions. Interviews aimed to identify how their condition impacted their ability to participate in meaningful activities. Conditions included arthritis, cancer, chronic back pain, diabetes, motor neuron disease, multiple sclerosis, Parkinson’s disease, and spinal cord injury. Transcripts were analyzed using the framework method. Statements relating to ICF themes were recast as questionnaire items and shown for review to an expert panel. Cognitive debrief interviews (n=13) were used to assess items for face and content validity. Results ICF themes relevant to activities and participation in everyday life were explored, and a total of 222 items formed the initial item pool. This item pool was refined by the research team and 28 generic items were mapped onto all nine chapters of the ICF construct, detailing activity and participation. Cognitive interviewing confirmed the questionnaire instructions, items, and response options were acceptable to participants. Conclusion Using a clear conceptual basis to inform item generation, 28 items have been identified as suitable to undergo further psychometric testing. A large-scale postal survey will follow in order to refine the instrument further and to assess its psychometric properties. The final instrument is intended for use in clinical trials and interventions targeted at maintaining or improving activity and participation.

An Electronic Version of the PDQ-39: Acceptability to Respondents and Assessment of Alternative Response Formats

BACKGROUND The PDQ-39 is the most thoroughly validated and widely used self-report instrument for the assessment of health-related quality of life in people with Parkinsons (PwP). Given the breadth of its use and increasing emphasis on electronic data capture, there may be significant benefit in validating an electronic version of the PDQ-39. OBJECTIVE Firstly, to migrate the paper-based version of the PDQ-39 to a computer based platform and assess its usability and acceptability to respondents. Secondly, to investigate the impact of implementing non-response options on response rates and data completeness. METHODS Six PwP participated in cognitive interviews in order to assess the usability and acceptability of the electronic version of the PDQ-39, the ePDQ. This was followed by an online survey of 129 PwP, randomly assigned to one of two groups; one required to provide a response to every item and one with the option to skip any item they did not wish to answer. RESULTS Cognitive interviews indicated that the ePDQ is acceptable to PwP, with positive feedback regarding layout, features and functionality. 125 PwP fully completed the ePDQ. Following randomization 60 participants completed the forced response ePDQ and 65 completed the non-forced version. Response rates of 98.4% were achieved for the forced response ePDQ and 95.6% for the non-forced. Missing value analyses calculated levels of missing data at below 5% in the non-forced sample. CONCLUSIONS The ePDQ is user-friendly and acceptable to respondents. Additionally, there appears little difference when implementing non-response options on response rates and data completeness.

Validation of the Oxford Participation and Activities Questionnaire.

Purpose There is growing interest in the management of long-term conditions and in keeping people active and participating in the community. Testing the effectiveness of interventions that aim to affect activities and participation can be challenging without a well-developed, valid, and reliable instrument. This study therefore aims to develop a patient-reported outcome measure, the Oxford Participation and Activities Questionnaire (Ox-PAQ), which is theoretically grounded in the World Health Organization’s International Classification of Functioning, Disability, and Health (ICF) and fully compliant with current best practice guidelines. Methods Questionnaire items generated from patient interviews and based on the nine chapters of the ICF were administered by postal survey to 386 people with three neurological conditions: motor neuron disease, multiple sclerosis, and Parkinson’s disease. Participants also completed the Medical Outcomes Study (MOS) 36-Item Short Form Health Survey (SF-36) and EQ-5D-5L. Results Thus, 334 participants completed the survey, a response rate of 86.5%. Factor analysis techniques identified three Ox-PAQ domains, consisting of 23 items, accounting for 72.8% of variance. Internal reliability for the three domains was high (Cronbach’s α: 0.81–0.96), as was test–retest reliability (intraclass correlation: 0.83–0.92). Concurrent validity was demonstrated through highly significant relationships with relevant domains of the MOS SF-36 and the EQ- 5D-5L. Assessment of known-groups validity identified significant differences in Ox-PAQ scores among the three conditions included in the survey. Conclusion Results suggest that the Ox-PAQ is a valid and reliable measure of participation and activity. The measure will now be validated in a range of further conditions, and additional properties, such as responsiveness, will also be assessed in the next phase of the instrument’s development.

Predictors of activity and participation across neurodegenerative conditions: a comparison of people with motor neurone disease, multiple sclerosis and Parkinson’s disease

BackgroundComparisons between neurological conditions have the potential to inform service providers by identifying particular areas of difficulty experienced by affected individuals. This study aimed to identify predictors of activity and participation in people with motor neurone disease (MND), people with multiple sclerosis (MS) and people with Parkinson’s Disease (PD).MethodsThe Oxford Participation and Activities Questionnaire (Ox-PAQ) and Medical Outcomes Study 36-Item Short Form Survey (MOS SF-36) were administered by postal survey to 386 people with a confirmed diagnosis of MND, MS or PD. Data analyses focused on stepwise regression analyses in order to identify predictors of activity and participation in the three conditions assessed.ResultsThree hundred and thirty four participants completed the survey, a response rate of 86.5%. Regression analyses identified multiple predictors of activity and participation dependent on Ox-PAQ domain and disease group, the most prominent being social and physical functioning as measured by the MOS SF-36.ConclusionsResults indicate that the physical and social consequences of neurological illness are of greatest relevance to people experiencing the conditions assessed. Whilst the largely inevitable physical implications of disease take hold, emphasis should be placed on the avoidance of social withdrawal and isolation, and the maintenance of social engagement should become a significant priority.