"Like fighting a fire with a water pistol": A qualitative study of the work experiences of critical care nurses during the COVID-19 pandemic

AIM

To understand the experience of critical care nurses during the COVID-19 pandemic, through the application of the Job-Demand-Resource model of occupational stress.

DESIGN

Qualitative interview study.

METHODS

Twenty-eight critical care nurses (CCN) working in ICU in the UK NHS during the COVID-19 pandemic took part in semi-structured interviews between May 2021 and May 2022. Interviews were guided by the constructs of the Job-Demand Resource model. Data were analysed using framework analysis.

RESULTS

The most difficult job demands were the pace and amount, complexity, physical and emotional effort of their work. Prolonged high demands led to CCN experiencing emotional and physical exhaustion, burnout, post-traumatic stress symptoms and impaired sleep. Support from colleagues and supervisors was a core job resource. Sustained demands and impaired physical and psychological well-being had negative organizational consequences with CCN expressing increased intention to leave their role.

CONCLUSIONS

The combination of high demands and reduced resources had negative impacts on the psychological well-being of nurses which is translating into increased consideration of leaving their profession.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

The full impacts of the pandemic on the mental health of CCN are unlikely to resolve without appropriate interventions.

IMPACT

Managers of healthcare systems should use these findings to inform: (i) the structure and organization of critical care workplaces so that they support staff to be well, and (ii) supportive interventions for staff who are carrying significant psychological distress as a result of working during and after the pandemic. These changes are required to improve staff recruitment and retention.

REPORTING METHOD

We used the COREQ guidelines for reporting qualitative studies.

PATIENT AND PUBLIC CONTRIBUTION

Six CCN provided input to survey content and interview schedule. Two authors and members of the study team (T.S. and S.C.) worked in critical care during the pandemic.

Securing access to personnel and materials in transboundary animal disease responses

A lack of human and material resources can limit effective responses to animal disease emergencies. Drawing upon examples from Australia and New Zealand, this paper proposes a framework for identifying human and material resources and securing the necessary personnel and materials before or during an animal disease emergency. This staged process involves: a) assessing the nature of the risks to be managed, b) identifying the types of resources required, c) assessing available resources and identifying gaps and d) developing arrangements to ensure availability of resources. It discusses the advantages and disadvantages of different strategies to secure access to human and material resources, including whole-of-government arrangements to access other government resources, national and international reserve models for responders, just-in-time employment and purchase of materials, and purchase of stockpiles.

What do Demand-Control and Effort-Reward work stress questionnaires really measure? A discriminant content validity study of relevance and representativeness of measures

OBJECTIVES

The Demand-Control (DC) and Effort-Reward Imbalance (ERI) models predict health in a work context. Self-report measures of the four key constructs (demand, control, effort, and reward) have been developed and it is important that these measures have good content validity uncontaminated by content from other constructs. We assessed relevance (whether items reflect the constructs) and representativeness (whether all aspects of the construct are assessed, and all items contribute to that assessment) across the instruments and items.

METHODS

Two studies examined fourteen demand/control items from the Job Content Questionnaire and seventeen effort/reward items from the Effort-Reward Imbalance measure using discriminant content validation and a third study developed new methods to assess instrument representativeness. Both methods use judges' ratings and construct definitions to get transparent quantitative estimates of construct validity. Study 1 used dictionary definitions while studies 2 and 3 used published phrases to define constructs.

RESULTS

Overall, 3/5 demand items, 4/9 control items, 1/6 effort items, and 7/11 reward items were uniquely classified to the appropriate theoretical construct and were therefore 'pure' items with discriminant content validity (DCV). All pure items measured a defining phrase. However, both the DC and ERI assessment instruments failed to assess all defining aspects.

CONCLUSIONS

Finding good discriminant content validity for demand and reward measures means these measures are usable and our quantitative results can guide item selection. By contrast, effort and control measures had limitations (in relevance and representativeness) presenting a challenge to the implementation of the theories. Statement of contribution What is already known on this subject? While the reliability and construct validity of Demand-Control and Effort-Reward-Imbalance (DC and ERI) work stress measures are routinely reported, there has not been adequate investigation of their content validity. This paper investigates their content validity in terms of both relevance and representativeness and provides a model for the investigation of content validity of measures in health psychology more generally. What does this study add? A new application of an existing method, discriminant content validity, and a new method of assessing instrument representativeness. 'Pure' DC and ERI items are identified, as are constructs that are not fully represented by their assessment instruments. The findings are important for studies attempting to distinguish between the main DC and ERI work stress constructs. The quantitative results can be used to guide item selection for future studies.

Discriminant content validity: a quantitative methodology for assessing content of theory-based measures, with illustrative applications

OBJECTIVES

In studies involving theoretical constructs, it is important that measures have good content validity and that there is not contamination of measures by content from other constructs. While reliability and construct validity are routinely reported, to date, there has not been a satisfactory, transparent, and systematic method of assessing and reporting content validity. In this paper, we describe a methodology of discriminant content validity (DCV) and illustrate its application in three studies.

METHODS

Discriminant content validity involves six steps: construct definition, item selection, judge identification, judgement format, single-sample test of content validity, and assessment of discriminant items. In three studies, these steps were applied to a measure of illness perceptions (IPQ-R) and control cognitions.

RESULTS

The IPQ-R performed well with most items being purely related to their target construct, although timeline and consequences had small problems. By contrast, the study of control cognitions identified problems in measuring constructs independently. In the final study, direct estimation response formats for theory of planned behaviour constructs were found to have as good DCV as Likert format.

CONCLUSIONS

The DCV method allowed quantitative assessment of each item and can therefore inform the content validity of the measures assessed. The methods can be applied to assess content validity before or after collecting data to select the appropriate items to measure theoretical constructs. Further, the data reported for each item in Appendix S1 can be used in item or measure selection. Statement of contribution What is already known on this subject? There are agreed methods of assessing and reporting construct validity of measures of theoretical constructs, but not their content validity. Content validity is rarely reported in a systematic and transparent manner. What does this study add? The paper proposes discriminant content validity (DCV), a systematic and transparent method of assessing and reporting whether items assess the intended theoretical construct and only that construct. In three studies, DCV was applied to measures of illness perceptions, control cognitions, and theory of planned behaviour response formats. Appendix S1 gives content validity indices for each item of each questionnaire investigated. Discriminant content validity is ideally applied while the measure is being developed, before using to measure the construct(s), but can also be applied after using a measure.

Exploring differential item functioning in the SF-36 by demographic, clinical, psychological and social factors in an osteoarthritis population

Background

The SF-36 is a very commonly used generic measure of health outcome in osteoarthritis (OA). An important, but frequently overlooked, aspect of validating health outcome measures is to establish if items work in the same way across subgroup of a population. That is, if respondents have the same ‘true’ level of outcome, does the item give the same score in different subgroups or is it biased towards one subgroup or another. Differential item functioning (DIF) can identify items that may be biased for one group or another and has been applied to measuring patient reported outcomes. Items may show DIF for different conditions and between cultures, however the SF-36 has not been specifically examined in an osteoarthritis population nor in a UK population. Hence, the aim of the study was to apply the DIF method to the SF-36 for a UK OA population.

Methods

The sample comprised a community sample of 763 people with OA who participated in the Somerset and Avon Survey of Health. The SF-36 was explored for DIF with respect to demographic, social, clinical and psychological factors. Well developed ordinal regression models were used to identify DIF items.

Results

DIF items were found by age (6 items), employment status (6 items), social class (2 items), mood (2 items), hip v knee (2 items), social deprivation (1 item) and body mass index (1 item). Although the impact of the DIF items rarely had a significant effect on the conclusions of group comparisons, in most cases there was a significant change in effect size.

Conclusions

Overall, the SF-36 performed well with only a small number of DIF items identified, a reassuring finding in view of the frequent use of the SF-36 in OA. Nevertheless, where DIF items were identified it would be advisable to analyse data taking account of DIF items, especially when age effects are the focus of interest.

Does the impact of osteoarthritis vary by age, gender and social deprivation? A community study using the International Classification of Functioning, Disability and Health

Abstract Purpose: The aim of the study was to explore if the impact of osteoarthritis varies with respect to age, gender and social deprivation. Impact was defined as impairment, activity limitations and participation restriction (International Classification of Functioning, Disability and Health (ICF)). Investigating the functioning of the ICF model for subgroups is important both practically and theoretically.

METHOD

The sample comprised a community sample of 763 people diagnosed with osteoarthritis. Uncontaminated measures of the ICF constructs were developed using discriminant content validity from a pool of 134 items, including the WOMAC and SF-36. Multigroup Structural Equation Modelling was used to explore if the same pathways exist for subgroups of gender, age and social deprivation.

RESULTS

Different significant paths were found for gender and social deprivation: impairment did not predict participation restriction for women and those most deprived, whereas these paths were significant for men and those less deprived. No difference in the paths was found for age.

CONCLUSIONS

The impact of osteoarthritis appears to vary with respect to gender and social deprivation but not age. This suggests both that osteoarthritis per se does not adequately explain the health outcomes observed and that different clinical approaches may be appropriate for people of different gender and levels of deprivation. Implications of Rehabilitation The ICF model appears to vary with respect to gender and social deprivation for people with osteoarthritis. The ICF model did not appear to vary with respect to age for people with osteoarthritis. Different treatments and interventions for osteoarthritis may need to be targeted for specific gender and social deprivation groups.

Exploring differential item functioning in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)

Background

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) is a widely used patient reported outcome in osteoarthritis. An important, but frequently overlooked, aspect of validating health outcome measures is to establish if items exhibit differential item functioning (DIF). That is, if respondents have the same underlying level of an attribute, does the item give the same score in different subgroups or is it biased towards one subgroup or another. The aim of the study was to explore DIF in the Likert format WOMAC for the first time in a UK osteoarthritis population with respect to demographic, social, clinical and psychological factors.

Methods

The sample comprised a community sample of 763 people with osteoarthritis who participated in the Somerset and Avon Survey of Health. The WOMAC was explored for DIF by gender, age, social deprivation, social class, employment status, distress, body mass index and clinical factors. Ordinal regression models were used to identify DIF items.

Results

After adjusting for age, two items were identified for the physical functioning subscale as having DIF with age identified as the DIF factor for 2 items, gender for 1 item and body mass index for 1 item. For the WOMAC pain subscale, for people with hip osteoarthritis one item was identified with age-related DIF. The impact of the DIF items rarely had a significant effect on the conclusions of group comparisons.

Conclusions

Overall, the WOMAC performed well with only a small number of DIF items identified. However, as DIF items were identified in for the WOMAC physical functioning subscale it would be advisable to analyse data taking into account the possible impact of the DIF items when weight, gender or especially age effects, are the focus of interest in UK-based osteoarthritis studies. Similarly for the WOMAC pain subscale in people with hip osteoarthritis it would be worthwhile to analyse data taking into account the possible impact of the DIF item when age comparisons are of primary interest.

Are the mental representations of people with osteoarthritis consistent with the International Classification of Functioning Disability and Health?

PURPOSE

This study examined whether the mental representations of people with osteoarthritis (OA) were consistent with the International Classification of Functioning Disability and Health (ICF) model.

METHODS

A geographical cohort of 202 people with OA about to have joint replacement surgery completed postal questionnaires. Mental representations were measured by asking participants what they were hoping for from their joint replacement. Two expert judges classified these illness representations to the main ICF constructs of Impairment (I), Activity Limitation (A) and Participation Restriction (P).

RESULTS

There was strong agreement between the expert judges. There were a similar number of illness representations for each of the ICF constructs. The primary biomedical route of the ICF model was suggested by the ordering of the participants' illness representations i.e. I to A to P.

CONCLUSIONS

The mental representations of people with OA were consistent with the ICF theoretical framework with all three ICF constructs of importance. It appeared that people with OA implicitly apply a biomedical causal model of disability, suggesting that treatments and interventions aimed at reducing impairment may only affect P indirectly, through A. Additionally, the methods provide a novel way of exploring the potential causal relationships between constructs of the ICF model.

Neurosteroid binding to the amino terminal and glutamate binding domains of ionotropic glutamate receptors

The endogenous neurosteroids, pregnenolone sulfate (PS) and 3α-hydroxy-5β-pregnan-20-one sulfate (PREGAS), have been shown to differentially regulate the ionotropic glutamate receptor (iGluR) family of ligand-gated ion channels. Upon binding to these receptors, PREGAS decreases current flow through the channels. Upon binding to non-NMDA or NMDA receptors containing an GluN2C or GluN2D subunit, PS also decreases current flow through the channels, however, upon binding to NMDA receptors containing an GluN2A or GluN2B subunit, flow through the channels increases. To begin to understand this differential regulation, we have cloned the S1S2 and amino terminal domains (ATD) of the NMDA GluN2B and GluN2D and AMPA GluA2 subunits. Here we present results that show that PS and PREGAS bind to different sites in the ATD of the GluA2 subunit, which when combined with previous results from our lab, now identifies two binding domains for each neurosteroid. We also show both neurosteroids bind only to the ATD of the GluN2D subunit, suggesting that this binding is distinct from that of the AMPA GluA2 subunit, with both leading to iGluR inhibition. Finally, we provide evidence that both PS and PREGAS bind to the S1S2 domain of the NMDA GluN2B subunit. Neurosteroid binding to the S1S2 domain of NMDA subunits responsible for potentiation of iGluRs and to the ATD of NMDA subunits responsible for inhibition of iGluRs, provides an interesting option for therapeutic design.

Exploring the relationships between International Classification of Functioning, Disability and Health (ICF) constructs of Impairment, Activity Limitation and Participation Restriction in people with osteoarthritis prior to joint replacement

Background

The International Classification of Functioning, Disability and Health (ICF) proposes three main constructs, impairment (I), activity limitation (A) and participation restriction (P). The ICF model allows for all paths between the constructs to be explored, with significant paths likely to vary for different conditions. The relationships between I, A and P have been explored in some conditions but not previously in people with osteoarthritis prior to joint replacement. The aim of this paper is to examine these relationships using separate measures of each construct and structural equation modelling.

Methods

A geographical cohort of 413 patients with osteoarthritis about to undergo hip and knee joint replacement completed the Aberdeen measures of Impairment, Activity Limitation and Participation Restriction (Ab-IAP). Confirmatory factor analysis was used to test the three factor (I, A, P) measurement model. Structural equation modelling was used to explore the I, A and P pathways in the ICF model.

Results

There was support from confirmatory factor analysis for the three factor I, A, P measurement model. The structural equation model had good fit [S-B Chi-square = 439.45, df = 149, CFI robust = 0.91, RMSEA robust = 0.07] and indicated significant pathways between I and A (standardised coefficient = 0.76 p < 0.0001) and between A and P (standardised coefficient = 0.75 p < 0.0001). However, the path between I and P was not significant (standardised coefficient = 0.01).

Conclusion

The significant pathways suggest that treatments and interventions aimed at reducing impairment, such as joint replacement, may only affect P indirectly, through A, however, longitudinal data would be needed to establish this.

Applying the impairment, activity limitation, and participation restriction constructs of the ICF model to osteoarthritis and low back pain trials: a reanalysis

OBJECTIVE

To test the hypothesis that interventions targeting the relief of pain and disability in musculoskeletal diseases may have differential effects on activity limitation and participation restriction as defined in the International Classification of Functioning, Disability and Health (ICF).

METHODS

Full data were obtained for 3 randomized controlled trials that used the Western Ontario and McMaster Universities Osteoarthritis Measure (WOMAC), the Medical Outcomes Study Short-form 36 (SF-36), or the Oswestry Disability Questionnaire as their primary outcome measures. The trial outcomes were reanalyzed using items previously designated as assessing pure activity limitation (A) or participation restriction (P), or a mixture of the 2 (A/P) only, and the results compared with the outcomes found using the full scales, which assess a mixture of outcome domains.

RESULTS

The results did not refute the hypothesis. An exercise-based intervention and injection therapies both appeared to have more effect on participation restriction (P) than on activity limitation (A), while a drug-based intervention had more effect on A than on P.

CONCLUSION

Different interventions used to treat musculoskeletal disorders may have differential effects on impairment, activity limitation, and restricted participation. The use of outcome measures that do not differentiate these 3 domains may obscure the true value of an intervention.

Listening to patients: using verbal data in the validation of the Aberdeen Measures of Impairment, Activity Limitation and Participation Restriction (Ab-IAP)

BACKGROUND

The purpose of the study was to evaluate the validity of the self-administered Aberdeen Measures of Impairment, Activity Limitation and Participation Restriction (Ab-IAP): by investigating how participants interpret and respond to questions using the cognitive interviewing technique.

METHODS

Twenty patients with osteoarthritis of the knee or hip participated in a cognitive interview whilst completing the Ab-IAP. Interviews were conducted using the concurrent 'think aloud' design. All interviews were audio recorded and transcribed verbatim and analysed (i) using a standardised classification scheme to identify four types of response problems and (ii) thematically using the constant comparative technique.

RESULTS

Participants used various response strategies when answering questions about impairment, activity limitations and participation restriction. Problems were judged to be present in 3.1% of participants' responses for the item Ab-IAP. Thematic analysis provided insight into the type and nature of problems people experienced when completing the Ab-IAP measures. The problems identified were mainly comprehension and response problems.

CONCLUSIONS

Participants had minimal difficulties completing the Ab-IAP; however those difficulties identified have prompted suggestions for improving the measures. The cognitive interviews produced results that were compatible with statistical analysis of the measures.. Cognitive interviewing was beneficial for testing the validity and acceptability of new Ab-IAP measures. The results demonstrates that the Ab-IAP, in addition to being theoretically-based and having good psychometric properties, elicits appropriate responses.

Application of the ICF to referral delay in total joint arthroplasty

BACKGROUND

The factors that affect referral for total joint arthroplasty (TJA) have been widely studied. Implicit in this work is the assumption that patient health status should determine priority for surgery. However, specification of patient health status lacks a strong theoretical framework. This study employs the WHO model of health outcomes, the International Classification of Functioning, Disability and Health (ICF), to examine patient health factors in the referral process for TJA.

METHODS

Within 8&emsp14;weeks prior to TJA, 260 patients electing for primary TJA completed a questionnaire which measured the ICF (impairment, activity limitations and participation restrictions) and four types of delay in their journey from initial consultation with their primary care physician to surgery.

RESULTS

Impairment did not affect any stage of the referral process. In contrast, patients who had experienced a delay of 26 weeks or less between referral to a surgeon and being placed on the waiting list for surgery reported greater activity limitations and participation restrictions than patients who had waited more than 26 weeks. Further, patients who reported having wanted surgery for more than 52 weeks reported greater participation restrictions than patients who had wanted surgery for less than 52 weeks.

CONCLUSIONS

The ICF identifies three health outcomes, two of which (activity limitations and participation restrictions) are related to delay in the referral process for TJA. The ICF is a useful theoretical framework for the study of factors that influence prioritisation for surgery. The level of functional and social disability appears to inform prioritisation for TJA by consultant orthopaedic surgeons.

Measuring the ICF components of impairment, activity limitation and participation restriction: an item analysis using classical test theory and item response theory

BACKGROUND

The International Classification of Functioning, Disability and Health (ICF) proposes three main health outcomes, Impairment (I), Activity Limitation (A) and Participation Restriction (P), but good measures of these constructs are needed The aim of this study was to use both Classical Test Theory (CTT) and Item Response Theory (IRT) methods to carry out an item analysis to improve measurement of these three components in patients having joint replacement surgery mainly for osteoarthritis (OA).

METHODS

A geographical cohort of patients about to undergo lower limb joint replacement was invited to participate. Five hundred and twenty four patients completed ICF items that had been previously identified as measuring only a single ICF construct in patients with osteoarthritis. There were 13 I, 26 A and 20 P items. The SF-36 was used to explore the construct validity of the resultant I, A and P measures. The CTT and IRT analyses were run separately to identify items for inclusion or exclusion in the measurement of each construct. The results from both analyses were compared and contrasted.

RESULTS

Overall, the item analysis resulted in the removal of 4 I items, 9 A items and 11 P items. CTT and IRT identified the same 14 items for removal, with CTT additionally excluding 3 items, and IRT a further 7 items. In a preliminary exploration of reliability and validity, the new measures appeared acceptable.

CONCLUSION

New measures were developed that reflect the ICF components of Impairment, Activity Limitation and Participation Restriction for patients with advanced arthritis. The resulting Aberdeen IAP measures (Ab-IAP) comprising I (Ab-I, 9 items), A (Ab-A, 17 items), and P (Ab-P, 9 items) met the criteria of conventional psychometric (CTT) analyses and the additional criteria (information and discrimination) of IRT. The use of both methods was more informative than the use of only one of these methods. Thus combining CTT and IRT appears to be a valuable tool in the development of measures.

MOBILE and the provision of total joint replacement

Modern joint replacements have been available for 45 years, but we still do not have clear indications for these interventions, and we do not know how to optimize the outcome for patients who agree to have them done. The MOBILE programme has been investigating these issues in relation to primary total hip and knee joint replacements, using mixed methods research.

There have been five main strands: (1) Epidemiological investigations to find out who is receiving total hip and knee replacements in the National Health Service (NHS). This has shown that there are extensive variations in different regions of the UK, with inequalities and probable inequities in the provision of these operations; (2) Epidemiological work to ascertain the population-based needs for the operations, showing under-provision of knee joint replacements, and a relative reluctance of both patients and GPs to consider knee surgery; (3) Quantitative and qualitative research into the views of patients, health care professionals and the public on the indications for, and prioritization of, total hip and knee joint replacements. This has shown lack of agreement within or between professional groups, as well as a mismatch between the views of patients and the public, and those of professionals; (4) Theoretical and experimental work on patient-related outcome measures, and the development of new instruments to assess both pain and function in people with osteoarthritis, based on the International Classification of Function, as well as a new integrated model of function; (5) Cohort studies of patients undergoing hip or knee joint replacements to find out what the determinants of good and bad outcomes are. These studies have emphasized the huge variation in disease severity at the time of surgery.

The challenge now is to use and implement our findings for maximum patient benefit.

Recovery from disability after stroke as a target for a behavioural intervention: results of a randomized controlled trial

PURPOSE

Disability following stroke is highly prevalent and is predicted by psychological variables such as control cognitions and emotions, in addition to clinical variables. This study evaluated the effectiveness of a workbook-based intervention, designed to change cognitions about control, in improving outcomes for patients and their carers.

METHOD

At discharge, stroke patients were randomly allocated (with their carers) to a 5-week intervention (n = 103) or control (normal care: n = 100). The main outcome (at 6 months) was recovery from disability using a performance measure, with distress and satisfaction as additional outcomes.

RESULTS

The intervention group showed significantly better disability recovery, allowing for initial levels of disability, than those in the control group, F(1,201) = 5.61, p = 0.019. Groups did not differ in distress or satisfaction with care for patients or carers. The only psychological process variable improved by the intervention was Confidence in Recovery but this did not mediate the effects on recovery.

CONCLUSIONS

A large proportion of intervention participants did not complete the workbook tasks. This was perhaps associated with the fairly low level of personal contact with workbook providers. The modest success of this intervention suggests that it may be possible to develop effective behavioural interventions to enhance recovery from disability in stroke patients.

Theoretical framework and methodological development of common subjective health outcome measures in osteoarthritis: a critical review

Subjective measures involving clinician ratings or patient self-assessments have become recognised as an important tool for the assessment of health outcome. The value of a health outcome measure is usually assessed by a psychometric evaluation of its reliability, validity and responsiveness. However, psychometric testing involves an accumulation of evidence and has recognised limitations. It has been suggested that an evaluation of how well a measure has been developed would be a useful additional criteria in assessing the value of a measure. This paper explored the theoretical background and methodological development of subjective health status measures commonly used in osteoarthritis research. Fourteen subjective health outcome measures commonly used in osteoarthritis research were examined. Each measure was explored on the basis of their i) theoretical framework (was there a definition of what was being assessed and was it part of a theoretical model?) and ii) methodological development (what was the scaling strategy, how were the items generated and reduced, what was the response format and what was the scoring method?). Only the AIMS, SF-36 and WHOQOL defined what they were assessing (i.e. the construct of interest) and no measure assessed was part of a theoretical model. None of the clinician report measures appeared to have implemented a scaling procedure or described the rationale for the items selected or scoring system. Of the patient self-report measures, the AIMS, MPQ, OXFORD, SF-36, WHOQOL and WOMAC appeared to follow a standard psychometric scaling method. The DRP and EuroQol used alternative scaling methods. The review highlighted the general lack of theoretical framework for both clinician report and patient self-report measures. This review also drew attention to the wide variation in the methodological development of commonly used measures in OA. While, in general the patient self-report measures had good methodological development, the clinician report measures appeared less well developed. It would be of value if new measures defined the construct of interest and, that the construct, be part of theoretical model. By ensuring measures are both theoretically and empirically valid then improvements in subjective health outcome measures should be possible.

What does the chronic pain grade questionnaire measure?

This study explored the ability of the Chronic Pain Grade Questionnaire (CPG) to operationalise the WHO's model of health outcomes, namely the International Classification of Functioning, Disability and Health (ICF). Twelve expert judges used the method of discriminant content validation to allocate the seven items of the CPG to one or more ICF outcome, namely, impairment, activity limitations and participation restrictions. One-sample t-tests classified each item as measuring impairment, activity limitations or participation restrictions, or a combination thereof. The results indicated that the CPG contains items able to measure each of the three ICF outcomes. However, the pain grade classification system used in the CPG conflates the ICF outcomes. The implication of this conflation of outcome for the assessment of interventions is discussed.

The assessment of disability associated with osteoarthritis

PURPOSE OF REVIEW

Disability (activity limitation) is an important and common health outcome for patients with osteoarthritis, making accurate measures essential. This paper explores self-report measures of activity limitation associated with osteoarthritis and reports on recent conceptual advances that impact on the measurement of activity limitation.

RECENT FINDINGS

The Western Ontario and McMaster Universities Osteoarthritis Index and the Short Form-36, the most commonly used measures to assess activity limitation, continue to be validated in osteoarthritis. There has been little consensus, however, about which measure to use across different types of osteoarthritis. While new measures have been developed to assess activity limitation, it remains unclear whether or not these are an improvement over existing measures. The International Classification of Functioning, Disability and Health is becoming an important consideration. Commonly used measures do not map directly onto individual constructs of this classification, however a new measure for Japanese people with knee osteoarthritis was developed based on these constructs.

SUMMARY

There have been significant developments in the conceptual approach to measuring activity limitation. Measures are needed that operationalize activity limitation as defined by the International Classification of Functioning, Disability and Health (within or ideally across cultures), providing a common underlying construct for measures and hence facilitating comparability across studies.

Clinical efficacy and tolerance of an extract of green-lipped mussel (Perna canaliculus) in dogs presumptively diagnosed with degenerative joint disease

AIM

To evaluate the efficacy and tolerance of an extract of green-lipped mussel (GLME) in the management of mild-to-moderate degenerative joint disease (DJD) in dogs.

METHODS

Eighty-one dogs presumptively diagnosed with DJD were treated orally daily with either GLME or a placebo for 56 days, in a double-blind, placebo-controlled study. In an uncontrolled open-label extension to the study, all dogs were treated with GLME for an additional 56 days (from Days 57-112). Clinical signs were subjectively scored by the owners, and findings of detailed musculoskeletal examinations were scored by one veterinarian. Efficacy was assessed from a qualitative comparison of the proportion of dogs with improved clinical signs, and a quantitative comparison of the scores of the musculoskeletal examinations, between groups. Haematological and biochemical analyses and reports by owners of possible adverse drug reactions were used to screen for evidence of toxicity.

RESULTS

There was close agreement between assessments by the veterinarian and owners. The clinical signs of DJD in both GLME-treated and placebo groups improved significantly over baseline by Day 28; this improvement continued over the entire course of the study. There were no significant differences between groups on Day 28. On Day 56, a higher proportion of dogs in the GLME-treated group had improved clinical signs (p=0.018), and GLME-treated dogs had marginally better (p=0.053) musculoskeletal scores than dogs in the placebo group. The differences between the groups were no longer apparent by Day 112, by which time the former placebo group had been receiving GLME for 56 days in the open-label phase of the study. The proportion of dogs in the former placebo group that had improved by Day 112 (29/32; 91%) was significantly greater (p=0.012) than the proportion improved at Day 56 (15/37; 41%). No signs of toxicity were apparent.

CONCLUSIONS AND CLINICAL RELEVANCE

GLME had a beneficial effect on the clinical signs of dogs presumptively diagnosed with mild-to-moderate DJD. Long-term therapy may be required before improvement is apparent.

What do osteoarthritis health outcome instruments measure? Impairment, activity limitation, or participation restriction?

OBJECTIVE

To explore whether commonly used osteoarthritis (OA) health outcome instruments (and items) are measuring single or multiple health outcomes using the International Classification of Functioning, Disability and Health (ICF) definitions.

METHODS

Ten expert judges allocated 342 items from 13 instruments to one or more ICF construct, i.e., Impairment (I), Activity Limitation (A), and Participation Restriction (P). One-sample t tests were used to classify each item as measuring uniquely I, A, or P or some combination (i.e., IA, IP, AP, or IAP).

RESULTS

Overall, 12 of the 13 instruments had items that measured a combination of outcome domains (i.e., IA, IP, AP, or IAP). Only the American Knee Society Score (AKS) had all items uniquely measuring either I or A. The instrument with the best representation of items for Impairment was the AKS, for Activity Limitation the WOMAC and Lequesne knee index, and for Participation Restriction the Disease Repercussion Profile.

CONCLUSION

All the existing OA outcome instruments, except one, had some items that were assessing more than one health outcome. Use of these instruments may either mask true treatment effects or make an effect difficult to attribute if the content is unclear. We determined which instruments were the best for measuring each health outcome. To improve the assessment of health outcomes in OA, new instruments that uniquely measure the 3 ICF constructs should be developed and all 3 should be included in relevant studies.

Anxiety and depression 3 years following stroke: demographic, clinical, and psychological predictors

OBJECTIVES

Our earlier work had established that moderate depression significantly decreased over the first 6 months after stroke, whereas anxiety levels remained moderate but stable. This study examines the factors predictive of anxiety and depression to 3 years.

METHODS

Patients were assessed on six occasions: on hospital admission, 10-20 days following admission, 1 and 6 months following discharge, and 1 and 3 years poststroke, with 38 of the original sample of 101 taking part at Year 3. Demographic and clinical variables, disability, handicap, and psychological measures were used to predict 3-year anxiety and depression, controlling for earlier levels of anxiety or depression.

RESULTS

Multiple regression analyses of anxiety at 3 years, controlling for gender and previous anxiety, demonstrated that neither of the significant partial correlates of 6-month depression or satisfaction with treatment persisted. Gender effects persisted when controlling for previous anxiety. Multiple regression analyses of depression at 3 years, controlling for early depression, found that exercise, treatment satisfaction, anxiety, and handicap added significantly to the prediction of lower depression.

CONCLUSIONS

Anxiety remains stable over 3 years poststroke and is best explained by prior, early, anxiety, and female gender. Depression reduces over time and was explained by modifiable cognitions and behaviours, which replicates previous findings.

Extending the demand-control model to informal caregiving

OBJECTIVE

Karasek's demand-control model of job strain was used in an attempt to extend previous work examining the psychological impact of informal caregiving in stroke.

METHOD

Data were gathered from 138 informal caregivers/patient dyads at two time points. The dependent variables were the caregiver's anxiety and depression [Hospital Anxiety and Depression Scale (HADS)]. The predictor variables were caregiver demand (stroke survivor's assessment of their physical and psychosocial functional limitations) and control (caregiver's perceived control over stroke survivor's recovery).

RESULTS

In a cross-sectional analysis of Times 1 and 2 data, main effects for demand and/or control were detected for anxiety and depression. Contrary to prediction, in longitudinal analysis of change, it was found that decreasing control, along with increasing demand, was associated with reduced distress.

CONCLUSION

The model was moderately successful in predicting emotional distress. The relative importance of caregiver demand and control in predicting outcomes changed over time in these data. Attempts to replicate these findings are recommended.

Functional limitations and survival following stroke: Psychological and clinical predictors of 3-year outcome

Previous studies predicting functional outcomes of stroke have mainly used clinical and demographic measures. This study examines the additional predictive value of psychological predictors. A cohort of patients were assessed on 6 occasions between admission to hospital and 3 years post-stroke, with 40 of the original sample of 101 being available at the final assessment. Demographic variables, clinical indexes, and psychological measures were used to predict survival to 3 years and 3-year functional recovery was assessed using measures derived from the Barthel Index which took account of initial levels of performance. For functional recovery, multiple regression analyses showed that fixed clinical and demographic indexes explained 16% to 40% of the variance in recovery. Perceptions of control 6 months after discharge added significantly to the predictive equations. Because these cognitions are modifiable, they offer opportunities for intervention to improve patient outcomes. Multiple regression showed that no psychological variables predicted survival.

Motivation Is Not Enough: Prediction of Risk Behavior Following Diagnosis of Coronary Heart Disease From the Theory of Planned Behavior

Perceived behavioral control (PBC) and intention, the proximal predictors from the theory of planned behavior (TPB), were used to predict cardiovascular risk behaviors in 597 patients 1 year after diagnosis with coronary heart disease. The outcome measures were self-report measures of exercise plus objective measures of fitness (distance walked in 6 min) and cotinine-confirmed smoking cessation. In multivariate analyses incorporating both PBC and intention, PBC predicted exercise, distance walked, and smoking cessation, but intention was not a reliable independent predictor of any health behavior measured. Thus, the effective theoretical component of the TPB was PBC. Similar predictions could derive from social-cognitive theory. In coronary patients, behavioral change needs to address issues of action implementation rather than motivational factors alone.

Consequences of disease: testing the WHO International Classification of Impairments, Disabilities and Handicaps (ICIDH) model

The International Classification of Impairments, Disabilities and Handicaps (ICIDH) model proposes that there are three consequences of disease, impairment (I), disability (D) and handicap (H) and that they are sequentially related. This paper examines first, whether I, D and H can be measured independently and second, whether there is support for the sequential or causal relationship between the three constructs. Cross-sectional data from a representative sample of 101 disabled adults and longitudinal data from 108 myocardial infarction (MI) and 68 Stroke patients were used. Standard measures of I were used for each clinical condition. Measures of D and H were derived from the British version of the Sickness Impact Profile (SIP) and additional measures of D were available for the Stroke group. Judges classified SIP items according to ICIDH definitions of D and H. Correlation, Confirmatory Factor Analyses and Path Analyses were used to examine the main hypotheses. Valid measures of D and H were derived and there was evidence of separation of the three constructs for the Stroke patients but not for the other groups. For both Stroke and MI, I was not predictive of D and H. For Stroke, the best path model included a path from D to H, but not from H to D and this was found for self-report and performance measures of D. Using these measures, the ICIDH model was supported in that D predicted H for stroke, but there was no support for a path between I and D or between I and H. Further it was not always possible to distinguish the three constructs. Possible limitations in the measures and in the ICIDH model as a testable scientific model are discussed.

Problems with the sickness impact profile: a theoretically based analysis and a proposal for a new method of implementation and scoring

The Sickness Impact Profile (SIP) is one of the most widely used health status measures, but there are problems with the measure that lead to inconsistent and illogical scores. There are many desirable features to the SIP development methodology in that it is based on a good range of items and the item weightings are valuable. The current method of scoring the SIP is the use of a summated total and was selected based on limited empirical evidence. However, in this paper we argue that there are problems with the SIP because the current empirically derived method of scoring is incompatible with both the underlying theoretical scaling framework (Thurstone scaling) and the nature of the items in the SIP. In addition, the items do not have properties consistent with the scaling methodology. We suggest that it is crucial to take both a theoretical and empirical approach to selecting a scoring method. To examine problems associated with the SIP we explored the underlying scaling methodology and identified the types of items in the SIP. A new method of scoring is proposed that is consistent with the items and scaling in the SIP, namely using the maximum individual weighting from the items that were checked as a category score. This new method of scoring resolves many of the previously observed problems in the SIP. The new method of scoring also presented the opportunity for a new implementation of the SIP that reduces the number of items that most respondents, especially those with severe limitations, would be asked. Without taking a theoretical approach to scoring we suggest that subsequent, empirically based, scale amendments are unlikely to solve the problems. It is proposed that this new method of scoring justifies a thorough empirical investigation.

Construct validation of the hospital anxiety and depression scale with clinical populations

OBJECTIVE

the hospital anxiety and depression scale (HADS) attempts to measure anxiety and depression without confounding by somatic symptoms of physical disorder, and is widely used for this purpose. This paper addresses three questions about the validity of the HADS concerning its independence of physical symptoms, the extent to which its items robustly measure the identified constructs with varying clinical populations and situations, and its capacity to differentiate anxiety and depression.

METHODS

data from patients with breast disease, myocardial infarction (MI), and stroke were examined using factor analytic and psychometric analyses.

RESULTS

using exploratory factor analysis in patients with breast disease, 13 of the 14 HADS items fell on a psychological factor and loadings on the psychological factor were higher than loadings on the somatic factor for all items. The HADS showed high levels of internal consistency and there was little evidence that removing items would improve it. Confirmatory factor analyses (CFA) in MI and stroke groups confirmed the separation of anxiety and depression. Analyses indicated items, which were performing poorly for these clinical groups.

CONCLUSIONS

there was support for the validity of the HADS for all three questions. However, there were some evidences of individual items performing poorly. Given the ease of administration and the acceptability of this measure to ill or weak respondents, the HADS continues to perform satisfactorily.

Use of single-frequency bioimpedance at 50 kHz to estimate total body water in patients with multiple organ failure and fluid overload

OBJECTIVE

To investigate the relationship between single-frequency bioimpedance at 50 kHz (both total body impedance and segmental impedance) and total body water, measured using tritiated water in the presence of the severe fluid retention seen in multiple organ failure.

DESIGN

Prospective, controlled study.

SETTING

General intensive care unit.

SUBJECTS

Twenty patients with multiple organ failure and 30 normal volunteers, of whom a subgroup of ten had total body water measured.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Total body water and total and segmental bioimpedance values at 50 kHz were measured using tritiated water and a Holtain body composition analyzer in 20 patients with multiple organ failure and in ten normal volunteers. An additional 20 normal volunteers also had segmental and total body impedance measured. There was no difference in the linear regression lines constructed for the patients and the volunteers, but the SEM in the patients (7.6 L) was four times that seen in the normal subjects (1.9 L). In a further seven patients, the impedance technique overestimated the change in total body water, deduced from acute changes in weight, by between 0% and 46% (median, 12%). In the patients, who were supine, the knee-ankle segment contributed significantly more to total body impedance than it did in the normal volunteers (42.5% vs. 34.4%; p < .001), who were upright and mobile immediately before the measurement.

CONCLUSIONS

Although single-frequency bioimpedance does give an indication of total body water and change in total body water, it is neither precise nor accurate enough to be the sole guide to fluid therapy. The proportion of total impedance contributed by the knee-ankle segment, which contains relatively little water, was significantly greater in the patients than in the controls, probably reflecting better drainage of fluid from the lower limb in the supine position.

Impact on patients and partners of inpatient and extended cardiac counseling and rehabilitation: a controlled trial

OBJECTIVES

This study evaluated the effectiveness of cardiac counseling and rehabilitation programs led by a nurse counselor, compared with normal care on outcomes for myocardial infarction (MI) patients and their partners.

METHODS

A randomized controlled trial with follow-up to 1 year was conducted with 100 patients recruited within 72 hours of a first MI and their partners: a Control group received normal care; an Inpatient group received cardiac rehabilitation from a nurse counselor while in hospital; and an Extended group received the same cardiac rehabilitation as the Inpatient group, but with additional sessions continuing up to 6 weeks after discharge from hospital. The scales for main outcome measures were 1) knowledge of heart disease and treatment (correct, misconceptions, and uncertainty); 2) mood (Hospital Anxiety and Depression Scale); 3) satisfaction; 4) disability (Functional Limitations Profile).

RESULTS

Inpatient cardiac counseling and rehabilitation resulted in more knowledge, less anxiety, less depression, and greater satisfaction with care in both patients and partners and in less disability in patients, with effects enduring to 1 year. There was some evidence of additional benefit from the Extended program. Both nurse counselors achieved benefits on all outcome variables.

CONCLUSIONS

This Inpatient cardiac counseling and rehabilitation program resulted in significant and enduring benefits of clinical value. It is likely that it would be acceptable to most post-MI patients, many of whom are not offered or are unable to accept outpatient cardiac rehabilitation.

Adolescent immunization: focus on implementation

On March 11-12, 1996, a workshop on how to implement new adolescent immunization (AI) recommendations was held in Atlanta, Ga. Sponsored by the Centers for Disease Control and Prevention, it was a collaborative effort of the National Immunization Program, the Division of Adolescent and School Health/National Center for Chronic Disease Prevention and Health Promotion, and the Hepatitis Branch/National Center for Infectious Diseases. The workshop brought together organizations and individuals interested in adolescent health and immunizations so they could address how new AI recommendations can be implemented most effectively. This article offers an overview of their discussions and suggestions, including issues of cooperation, education, legislation, and AI program development among health provider organizations, health department, schools, community groups and various other agencies relating to adolescent health services.

Bears, academia, and anaesthesia: a controlled study

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