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Vernon T Farewell

Publications and source records attributed to Vernon T Farewell.

10 recordsLinked to original sources
PubMed2006

Predictors for radiological damage in psoriatic arthritis: results from a single centre.

BACKGROUND: The predictors for the development of clinical damage in psoriatic arthritis (PsA) have been reported previously. AIM: To identify predictors for radiological damage in PsA. METHODS: Patients followed-up prospectively according to a standard protocol at The University of Toronto between 1978 and 2004 were included. The principal outcome was the change in the number of damaged joints between visits, both clinically and radiologically. Explanatory variables considered included: sex, age, duration of arthritis at first visit, time in clinic, number of tender swollen joints, functional class, erythrocyte sedimentation rate (ESR), concentration of drugs and, to adjust for within-patient correlation, the number of clinically damaged joints at the first of the two visits over which change was observed. RESULTS: At the time of this analysis, 625 patients were recorded in the database. Multivariate analyses of predictors for both clinical and radiological damage show that age, time in clinic, initial ESR, number of tender and swollen joints at previous visit, and number of deformed joints at previous visit were related to both clinical and radiological damage. CONCLUSIONS: The number of actively inflamed joints, particularly the number of swollen joints, was associated with the progression of radiological damage. The higher the number of previously damaged joints, the higher the risk for progression of damage. Thus, patients with PsA need to be treated, even in the presence of damage as long as there is evidence of inflammation, to prevent the progression of damage.

Adolescent↗
PubMed2006

A note on robust inference from a conditional Poisson model.

A randomised controlled trial to evaluate a training programme for physician-patient communication required the analysis of paired count data. The impact of departures from the Poisson assumption when paired count data are analysed through use of a conditional likelihood is illustrated. A simple approach to providing robust inference is outlined and illustrated.

Algorithms↗
PubMed2005

Description and prediction of physical functional disability in psoriatic arthritis: a longitudinal analysis using a Markov model approach.

OBJECTIVE: To describe the longitudinal course of physical functioning in patients with psoriatic arthritis. METHODS: Between June 1993 and June 2003, 341 patients attending the University of Toronto Psoriatic Arthritis Clinic completed 2 or more Health Assessment Questionnaires (HAQs). At the time of administration of each HAQ, patients were assigned to 1 of 3 physical functional disability states, based on their HAQ score. A Markov model that allowed for transitions to and from these 3 disability states was used to characterize the longitudinal course of physical functioning, as well as to identify factors for both progression and regression of disability. RESULTS: Despite patient variability in the course of physical functioning, the following 3 longitudinal patterns were observed: 1) a stable state of disability throughout the entire study period, with 28%, 12%, and 6% of patients experiencing no, moderate, or severe disability, respectively; 2) a steady improvement or deterioration in disability over time (this pattern was observed in 27% of patients); and 3) a fluctuating state of disability, occurring in 27% of the patients. Sex, age, disease duration, number of actively inflamed joints, and number of deformed joints predicted transitions between disability states. CONCLUSION: Although 28% of patients appeared resistant to becoming disabled over the duration of this study, the remaining patients were observed either to experience enduring disability or to move between disability states.

Arthritis, Psoriatic↗
PubMed2005

Longitudinal cohort studies.

Rheumatological disorders are complex conditions characterized by a variety of clinical manifestations and courses in different patients with the same condition. The best way to understand the course and prognosis of these patients is through longitudinal observational cohort studies. Such studies have been facilitated by computer technology that allows tracking of large numbers of patients and visits and analysis of a large amount of data. There are requirements for such datasets to be informative: internal and external consistency; clearly defined methods of observation and measurement; complete followup; consideration of potential confounders. We describe the usefulness of an observational cohort analysis using the University of Toronto Psoriatic Arthritis Clinic Database as a model. Analysis issues are highlighted and proposed mechanisms offered for keeping patients involved to ensure complete followup is maintained.

Adult↗
PubMed2005

HLA markers for susceptibility and expression in scleroderma.

OBJECTIVE: Reported associations between HLA alleles and both susceptibility to and features of scleroderma have been conflicting. Our objective was (1) to determine the role of HLA alleles in the susceptibility to scleroderma; and (2) to determine the role of HLA alleles in various aspects of disease expression. METHODS: Consecutive patients were followed in the scleroderma clinic between 1996 and 1998. Clinical data were obtained through chart review. Healthy volunteers as well as cadaveric donors served as controls. Molecular HLA typing was performed (polymerase chain reaction/sequence-specific oligonucleotides). Statistical analysis included Fisher's exact test and multivariate analyses, using logistic and linear regression models. RESULTS: Ninety-five Caucasian patients (75 women, 20 men, age 43.9 yrs, disease duration 11.9 yrs) with scleroderma and 416 controls were studied. HLA-DRB1*01 and HLA-DRB1*11 were associated with susceptibility to scleroderma, whereas HLA-DRB1*07 was protective. HLA-A*30 and HLA-A*32 were also associated with susceptibility to scleroderma, while HLA-B*57 and HLA-Cw*14 were protective. HLA-B*62 and HLA-DRB1*07 had a significant correlation with the presence of diffuse skin involvement in both univariate and multivariate analyses. HLA-DRB1*11 was associated with high skin score values, while lower values were related to the presence of HLA-Cw*14 and HLA-DQB1*06. Both alleles retained significance in a linear regression model. High skin score values were related to the absence of anticentromere antibodies. Pulmonary fibrosis was associated with HLA-B*62 and HLA-Cw*0602, whereas pulmonary hypertension was associated with HLA-B*13 and HLA-B*65. CONCLUSION: HLA alleles play a role in susceptibility to scleroderma and its disease expression.

Adult↗
PubMed2005

Reporting of mortality in a psoriatic arthritis clinic is primarily a function of the number of clinic contacts and not disease severity.

OBJECTIVE: To identify processes that influence data collection, particularly in the reporting of deaths in mortality studies, using patient registry data. METHODS: The University of Toronto Psoriatic Arthritis Clinic has mechanisms for patient followup and identification of deaths. Logistic regression was used to identify patient characteristics that discriminate between 2 populations of deaths, those reported under regular followup and those reported in the context of special studies. Factors examined were based on information available at the patients' last clinic visit and the pattern of patients' clinic visits. RESULTS: A clear relationship was found between the number of contacts with the clinic and rapid death reporting. However, no particular link between severity of disease and the reporting of death was apparent in this study. CONCLUSION: It is recommended that research databases routinely record the time between death and reporting of death and the method of ascertaining and reporting death. More detailed information on the scheduling of clinic visits may also be helpful.

Adult↗
PubMed2004

Defining response in systemic lupus erythematosus: a study by the Systemic Lupus International Collaborating Clinics group.

OBJECTIVE: In a preliminary attempt to develop a drug responder index for patients with systemic lupus erythematosus (SLE), 2 validated disease activity instruments were studied for their responsiveness and compared to a physician visual analog scale (VAS) assessment of disease activity. We attempted to determine whether these validated instruments were useful components in characterizing response in the setting of a clinical trial. METHODS: Eighty paper patients were assessed using the British Isles Lupus Assessment Group (BILAG) and Systemic Lupus Disease Activity Index (SLEDAI) and by physician's assessment of global activity. The cases were arranged in random order and divided into groups of 20 patients and each group was assessed by 20 lupus experts; change in disease activity was recorded at 3 and 6 months compared to baseline using a physician VAS. RESULTS: Four different lupus experts assessed disease activity in all 80 patients at baseline and 3 and 6 months after initiation of therapy using the BILAG and SLEDAI instruments. BILAG and SLEDAI scores correlated well over time; however, in a regression analysis where average physician VAS were chosen as the outcome variable, a significant amount of variation in the average physician VAS not related to the SLEDAI and BILAG scores was noted. CONCLUSION: The physician VAS may be too blunt to assess response in SLE, because even among experienced lupus assessors, there were considerable differences in what influenced scoring decisions.

Adult↗
PubMed2003

HLA is a candidate region for psoriatic arthritis. evidence for excessive HLA sharing in sibling pairs.

Psoriatic arthritis (PsA) is an inflammatory arthritis that may affect as many as 30% of patients with psoriasis (Ps). Genetic factors play an important role in the susceptibility to and the expression of PsA. The objective of this study was to identify whether haplotype sharing among affected sibling pairs of individuals with PsA is increased compared with unaffected sibling pairs. We collected 182 sibling pairs of probands affected with PsA. Extracted genomic DNA was amplified in polymerase chain reactions using locus specific primers homologous to nucleotide sequences for each of the HLA-A, -B, -C, -DR, and -DQ loci. Polymerase chain reaction amplicons were identified by reverse line blot assay using sequence-specific oligonucleotide probes. Evidence for excessive haplotype sharing was examined through Green and Woodrow's test. Results indicate that of the 182 sibling pairs, 46 were affected by PsA, 48 by Ps, and 88 were unaffected. The sharing of 2, 1, and 0 haplotypes for the PsA affected sibling pairs was 14, 27, and 5, respectively (p = 0.04); whereas the haplotype sharing for the Ps affected sibling pairs was 12, 26, and 10, respectively (p = 0.38). In conclusion, the human leukocyte antigen region on chromosome 6p is implicated as one of the candidate regions in PsA.

Arthritis, Psoriatic↗