Donna L. Lamping

Determinants and Time Course of the Postthrombotic Syndrome after Acute Deep Venous Thrombosis

BACKGROUND The reason some patients with deep venous thrombosis (DVT) develop the postthrombotic syndrome is not well understood. OBJECTIVE To determine the frequency, time course, and predictors of the postthrombotic syndrome after acute DVT. DESIGN Prospective, multicenter cohort study. SETTING 8 Canadian hospital centers. PATIENTS 387 outpatients and inpatients who received an objective diagnosis of acute symptomatic DVT were recruited from 2001 to 2004. MEASUREMENTS Standardized assessments for the postthrombotic syndrome using the Villalta scale at 1, 4, 8, 12, and 24 months after enrollment. Mean postthrombotic score and severity category at each interval was calculated. Predictors of postthrombotic score profiles over time since diagnosis of DVT were identified by using linear mixed modeling. RESULTS At all study intervals, about 30% of patients had mild (score, 5 to 9), 10% had moderate (score, 10 to 14), and 3% had severe (score >14 or ulcer) postthrombotic syndrome. Greater postthrombotic severity category at the 1-month visit strongly predicted higher mean postthrombotic scores throughout 24 months of follow-up (1.97, 5.03, and 7.00 increase in Villalta score for mild, moderate, and severe 1-month severity categories, respectively, vs. none; P < 0.001). Additional predictors of higher scores over time were venous thrombosis of the common femoral or iliac vein (2.23 increase in score vs. distal [calf] venous thrombosis; P < 0.001), higher body mass index (0.14 increase in score per kg/m(2); P < 0.001), previous ipsilateral venous thrombosis (1.78 increase in score; P = 0.001), older age (0.30 increase in score per 10-year age increase; P = 0.011), and female sex (0.79 increase in score; P = 0.020). LIMITATIONS Decisions to prescribe compression stockings were left to treating physicians rather than by protocol. Because international normalized ratio data were unavailable, the relationship between anticoagulation quality and Villalta scores could not be assessed. CONCLUSION The postthrombotic syndrome occurs frequently after DVT. Patients with extensive DVT and those with more severe postthrombotic manifestations 1 month after DVT have poorer long-term outcomes.

Measuring the impact of MS on walking ability The 12-Item MS Walking Scale (MSWS-12)

Objective: To develop a patient-based measure of walking ability in MS. Methods: Twelve items describing the impact of MS on walking (12-Item MS Walking Scale [MSWS-12]) were generated from 30 patient interviews, expert opinion, and literature review. Preliminary psychometric evaluation (data quality, scaling assumptions, acceptability, reliability, validity) was undertaken in the data generated by 602 people from the MS Society membership database. Further psychometric evaluation (including comprehensive validity assessment, responsiveness, and relative efficiency) was conducted in two hospital-based samples: people with primary progressive MS (PPMS; n = 78) and people with relapses admitted for IV steroid treatment (n = 54). Results: In all samples, missing data were low (≤3.8%), item test–retest reproducibility was high (≥0.78), scaling assumptions were satisfied, and reliability was high (≥0.94). Correlations between the MSWS-12 and other scales were consistent with a priori hypotheses. The MSWS-12 (relative efficiency = 1.0) was more responsive than the Functional Assessment of Multiple Sclerosis mobility scale (0.72), the 36-Item Short Form Health Survey physical functioning scale (0.33), the Expanded Disability Status Scale (0.03), the 25-ft Timed Walk Test (0.44), and Guy’s Neurologic Disability Scale lower limb disability item (0.10). Conclusions: The MSWS-12 satisfies standard criteria as a reliable and valid patient-based measure of the impact of MS on walking. In these samples, the MSWS-12 was more responsive than other walking-based scales.

Clinical outcomes, quality of life, and costs in the North Thames Dialysis Study of elderly people on dialysis: a prospective cohort study

BACKGROUND Evidence-based health policy is urgently needed to meet the increasing demand for health services among elderly people, particularly for expensive technologies such as renal-replacement therapy. Age has been used to ration dialysis, although not always explicitly, despite the lack of rigorous empirical evidence about how elderly people fare on dialysis. We undertook a comprehensive assessment of outcomes in patients 70 years or over. METHODS We did a 12-month prospective cohort study of outcomes in 221 patients with end-stage renal failure aged 70 years or over recruited from four hospital-based renal units. We assessed 1-year survival in 125 incident patients (70-86 years) and disease burden (hospital admissions, quality of life, costs) in 174 prevalent patients (70-93 years). FINDINGS 1-year survival rates were: 71% overall; 80%, 69%, and 54% in patients 70-74 years, 75-79 years, and 80 years and older, respectively (p=0.008); and 88%, 71%, and 64% in patients with no, one, or two or more comorbid conditions, respectively (p=0.056). Cox regression analyses showed that mortality was significantly associated with age 80 years and older (relative risk 2.79 [95% CI 1.28-6.93]) and peripheral vascular disease (2.83 [1.29-6.17]), but not with diabetes, ischaemic heart disease, cerebrovascular disease, chronic obstructive airways disease, sex, or treatment method. In terms of disease burden, hospital admissions represent a low proportion of costs and was not required by a third of patients, mental quality of life in elderly dialysis patients was similar to that of elderly people in the general population, and the average annual cost per patient of 20802 (US

Determinants of health-related quality of life during the 2 years following deep vein thrombosis.

31200) (68% dialysis treatment, 1% transport, 19% inpatient hospital admissions, 12% medications) was within the range of other life-extending interventions. INTERPRETATION Our results suggest that age alone should not be used as a barrier to referral and treatment and emphasise the need to consider the benefits of dialysis in elderly people. Indicators of the ability to benefit from treatment, rather than chronological age, should be used to develop policies that ensure equal access to care for all.

Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39): Evaluation of Acceptability, Reliability, and Validity

Summary.  Background/objectives: We prospectively measured change in quality of life (QOL) during the 2 years after a diagnosis of deep vein thrombosis (DVT) and evaluated determinants of QOL, including development of the post‐thrombotic syndrome (PTS). Patients/methods: Consecutive patients with acute DVT were recruited from 2001 to 2004 at eight hospitals in Canada. At study visits at baseline, and 1, 4, 8, 12 and 24 months, clinical data were collected, standardized PTS assessments were performed, and QOL questionnaires were self‐completed. Generic QOL was measured using the Short‐Form Health Survey‐36 (SF‐36) questionnaire. Venous disease‐specific QOL was measured using the Venous Insufficiency Epidemiological and Economic Study (VEINES)‐QOL/Sym questionnaire. The change in QOL scores over a 2‐year follow‐up was assessed. The influence of PTS and other characteristics on QOL at 2 years was evaluated using multivariable regression analyses. Results: Among the 387 patients recruited, the average age was 56 years, two‐thirds were outpatients, and 60% had proximal DVT. The cumulative incidence of PTS was 47%. On average, QOL scores improved during follow‐up. However, patients who developed PTS had lower scores at all visits and significantly less improvement in QOL over time (P‐values for PTS*time interaction were 0.001, 0.012, 0.014 and 0.006 for PCS, MCS, VEINES‐QOL and VEINES‐Sym). Multivariable regression analyses showed that PTS (P < 0.0001), age (P = 0.0009), proximal DVT (P = 0.01) and inpatient status (P = 0.04) independently predicted 2‐year SF‐36 PCS scores. PTS alone independently predicted 2‐year VEINES‐QOL (P < 0.0001) and VEINES‐Sym (P < 0.0001) scores. Conclusions: Development of PTS is the principal determinant of health‐related QOL 2 years after DVT. Our study provides prognostic information on patient‐reported outcomes after DVT and emphasizes the need for effective prevention and treatment of the PTS.

Consensus Development Methods: A Review of Best Practice in Creating Clinical Guidelines

Background and Purpose— Health-related quality of life (HRQL) is a key outcome in stroke clinical trials. Stroke-specific HRQL scales (eg, SS-QOL, SIS) have generally been developed with samples of stroke survivors that exclude people with aphasia. We adapted the SS-QOL for use with people with aphasia to produce the Stroke and Aphasia Quality of Life Scale (SAQOL). We report results from the psychometric evaluation of the initial 53-item SAQOL and the item-reduced SAQOL-39. Methods— We studied 95 people with long-term aphasia to evaluate the acceptability, reliability, and validity of the SAQOL and SAQOL-39 using standard psychometric methods. Results— A total of 83 of 95 (87%) were able to complete the SAQOL by self-report; their results are reported here. Results supported the reliability and validity of the overall score on the 53-item SAQOL, but there was little support for hypothesized subdomains. Using factor analysis, we derived a shorter version (SAQOL-39) that identified 4 subdomains (physical, psychosocial, communication, and energy). The SAQOL-39 demonstrated good acceptability, internal consistency (Cronbach’s &agr;=0.74 to 0.94), test-retest reliability (intraclass correlation coefficient=0.89 to 0.98), and construct validity (corrected domain–total correlations, r =0.38 to 0.58; convergent, r =0.55 to 0.67; discriminant, r =0.02 to 0.27 validity). Conclusions— The SAQOL-39 is an acceptable, reliable, and valid measure of HRQL in people with long-term aphasia. Further testing is needed to evaluate the responsiveness of the SAQOL-39 and to investigate its usefulness in evaluative research and routine clinical practice.

The Quebec Back Pain Disability Scale: Conceptualization and development

Background: Although there is debate about the appropriate place of guidelines in clinical practice, guidelines can be seen as one way of assisting clinicians in decision-making. Given the likely diversity of opinion that any group of people may display when considering a topic, methods are needed for organising subjective judgements. Three principal methods (Delphi, nominal group technique, consensus development conference) exist which share the common objective of synthesising judgements when a state of uncertainty exists. Objectives: To identify the factors that shape and influence the clinical guidelines that emerge from consensus development methods and to make recommendations about best practice in the use of such methods. Methods: Five electronic databases were searched: Medline (1966-1996), PsychLIT (1974-1996), Social Science Citation Index (1990-1996), ABI Inform and Sociofile. From the searches and reference lists of articles a total of 177 empirical and review articles were selected for review. Results: The output from consensus development methods may be affected by: the way the task is set (choice of cues, recognition of contextual cues, the focus of the task, the comprehensiveness of the scenarios); the selection of participants (choice of individuals, degree of homogeneity of the group, their background, their number); the selection and presentation of scientific information (format, extent to which its quality and content is assessed); the way any interaction is structured (number of rating rounds, ensuring equitable participation, physical environment for meetings); and the method of synthesising individual judgements (definition of agreement, rules governing outliers, method of mathematical aggregation). Conclusions: Although a considerable amount of research has been carried out, many aspects have not been investigated sufficiently. For the time being at least, advice on those aspects has, therefore, to be based on the users own commonsense and the experience of those who have used or participated in these methods. Even in the long term, some aspects will not be amenable to scientific study. Meanwhile, adherence to best practice will enhance the validity, reliability and impact of the clinical guidelines produced.

Quality of life in dementia: more than just cognition. An analysis of associations with quality of life in dementia

The Quebec Back Pain Disability Scale is a new measure of functional disability for patients with back pain. Functional disability was operationalized in terms of perceived difficulty associated with simple physical activities. The content of the scale was developed in several stages, including a literature review, two studies seeking the opinions of patients and experts, pilot testing, and a large, longitudinal study of back pain patients. Forty-eight disability items were extensively studied using standard methods such as test-retest reliability, item-total correlations, and factor analysis, as well as modern techniques based on item response theory. Items that were highly effective in discriminating between different levels of disability were selected for the final, reduced scale. The scale has 20 items, representing six empirically derived categories of activities affected by back pain. Measurement properties of this instrument have been previously discussed.

Evidence-based measurement Which disability scale for neurologic rehabilitation?

Objectives: To explore the extent to which commonly used measures of specific outcomes in dementia are an appropriate proxy for quality of life in dementia. Methods: This was a cross sectional study set in communities in London and Nottingham, comprising 101 people with dementia and their 99 main family caregivers. The main outcome measures were health related quality of life in dementia (measured by the DEMQOL-Proxy), cognition (Mini Mental State Examination), functional impairment (Barthel Index), behavioural and psychological symptoms in dementia (Neuropsychiatric Inventory; NPI), and carer mental health (General Health Questionnaire). Results: On univariate analysis, decreased quality of life was statistically significantly correlated with higher levels of behavioural and psychological disturbance (NPI total score and its agitation, depression, anxiety, disinhibition, and irritability subscales); younger age of the person with dementia; and poorer mental health of the carer. Quality of life was not statistically significantly associated with cognition or carer age. In a multivariate model, psychological and behavioural disturbance and patient age remained statistically significantly associated with quality of life. Carer mental health was no longer statistically significantly associated, and cognition and functional limitation remained statistically insignificant. Conclusions: These data suggest that quality of life in dementia is complex, and that simple proxy substitutions of discrete measures such as cognition or function are likely to miss important factors.

Development of a new measure of health-related quality of life for people with dementia: DEMQOL.

Objective: To compare the 10-item Barthel Index (BI), 18-item Functional Independence Measure (FIM), and 30-item Functional Independence Measure + Functional Assessment Measure (FIM+FAM) as measures of disability outcomes for neurologic rehabilitation. Methods: A total of 149 inpatients from two rehabilitation units in South England specializing in neurologic disorders were studied. Traditional psychometric methods were used to evaluate and compare acceptability (score distributions), reliability (internal consistency, intrarater reproducibility), validity (concurrent, convergent and discriminant construct), and responsiveness (standardized response mean). Results: All three rating scales satisfied recommended criteria for reliable and valid measurement of disability, and are acceptable and responsive in this study sample. The FIM and FIM+FAM total scales are psychometrically similar measures of global disability. The BI, FIM, and FIM+FAM motor scales are psychometrically similar measures of physical disability. The FIM and FIM+FAM cognitive scales are psychometrically similar measures of physical disability. Conclusions: In the sample studied, the BI, FIM, FIM+FAM have similar measurement properties, when examined using traditional psychometric analyses. Although instruments with more items and item response categories generate more qualitative information about an outcome, they may not improve its measurement. Results highlight the importance of using recognized techniques of scale construction to develop health outcome measures.