Julian Thumboo

The impact of diabetes mellitus and other chronic medical conditions on health-related Quality of Life: Is the whole greater than the sum of its parts?

BackgroundDiabetes mellitus (DM) is an important public health concern, the impact of which is increased by the high prevalence of co-existing chronic medical conditions among subjects with DM. The aims of this study were therefore to (1) evaluate the impact of DM and co-existing chronic medical conditions on health-related quality of life (HRQoL) (which could be additive, synergistic or subtractive); (2) to determine the extent to which the SF-6D (a single-index preference measure) captures the multidimensional information provided by the SF-36 (a profile measure).MethodsUsing data from a cross-sectional, population-based survey of Chinese, Malay and Indians in Singapore, we developed 9 separate multiple linear regression models, with each SF-36 scale or SF-6D index score being the dependent variable for one model. The influence of DM and a second chronic medical condition (hypertension (HTN), heart disease (HD), musculoskeletal illnesses (MS)) and their interactions were studied after adjusting for the influence of potential confounding variables.ResultsAmong 5,224 subjects, the prevalence of DM, HTN, HD and MS were 5.9%, 10.7%, 2.4% and 26.6% respectively. DM lowered SF-36 scores by more than 2 points on 3 SF-36 scales and lowered SF-6D scores by 0.03 points. Subjects with DM and HTN, DM and HD or DM and MS experienced further lowering of SF-36 scores exceeding 2 points on at least 6 scales and further lowering of SF-6D scores by 0.05, 0.08 and 0.10 points respectively. Generally, DM and co-existing medical conditions exerted additive effects on HRQoL, with the exception of DM and heart disease, where a subtractive effect was noted. SF-6D index scores generally reflected the patterns of influence of DM and chronic medical conditions on SF-36 scores.ConclusionDM and chronic medical conditions generally reduced HRQoL in this multiethnic general population in an additive, rather than synergistic or subtractive fashion. In this study, the SF-6D was a reasonably good summary measure for the SF-36.

Validity and reliability of the EQ-5D self-report questionnaire in Chinese-speaking patients with rheumatic diseases in Singapore

Validity and reliability of a Singaporean English EQ-5D self-report questionnaire (EQ-5D) were evaluated among consecutive outpatients with rheumatic diseases attending a tertiary referral hospital in Singapore (a multi-ethnic, urban Asian country). Subjects were interviewed twice within a 2-week period using a standardized questionnaire containing the EQ-5D, Short Form 36 Health Survey (SF-36) and assessing demographic and psychosocial characteristics. To assess validity of the EQ-5D, 13 hypotheses relating responses to EQ-5D dimension/Visual Analogue Scale (EQ-VAS) to SF-36 scores or other variables were examined using the Mann–Whitney test, Kruskal–Wallis test, or Spearmans correlation coefficient. Test–retest reliability was assessed using Cohens κ. Sixty-six subjects were studied (osteoarthritis: 9, rheumatoid arthritis: 26, systemic lupus erythematosus: 23, spondyloarthropathy: 8; female: 72.7%; mean age: 44.3 years). Ten of 13 a-priori hypotheses relating EQ-5D responses to external variables were fulfilled, supporting the validity of the EQ-5D. Cohens κ for test–retest reliability (n = 52) ranged from 0.29 to 0.61. The Singaporean English EQ-5D appears to be valid in measuring quality of life in Singaporeans with rheumatic diseases; however, its reliability requires further investigation. These data provide a basis for further studies assessing the validity of the EQ-5D in Singapore.

Does the 12-item General Health Questionnaire contain multiple factors and do we need them?

BackgroundThe 12-item General Health Questionnaire (GHQ-12) is widely used as a unidimensional instrument, but factor analyses tended to suggest that it contains two or three factors. Not much is known about the usefulness of the GHQ-12 factors, if they exist, in revealing between-patient differences in clinical states and health-related quality of life.MethodsWe addressed this issue in a cross-sectional survey of out-patients with psychological disorders in Singapore. The participants (n = 120) completed the GHQ-12, the Beck Anxiety Inventory, and the Short-Form 36 Health Survey. Confirmatory factor analysis was used to compare six previously proposed factor structures for the GHQ-12. Factor scores of the best-fitting model, as well as the overall GHQ-12 score, were assessed in relation to clinical and health-related quality of life variables.ResultsThe 3-factor model proposed by Graetz fitted the data better than a unidimensional model, two 2-factor models, and two other 3-factor models. However, the three factors were strongly correlated. Their values varied in a similar fashion in relation to clinical and health-related quality of life variables.ConclusionsThe 12-item General Health Questionnaire contains three factors, namely Anxiety and Depression, Social Dysfunction, and Loss of Confidence. Nevertheless, using them separately does not offer many practical advantages in differentiating clinical groups or identifying association with clinical or health-related quality of life variables.

Health-Related Quality of Life in Thyroid Cancer Survivors†

Objective: The study objective was to study the impact of the diagnosis, treatment, and follow‐up of differentiated thyroid cancer (DTC) on the quality of life and related issues in an urban multi‐ethnic Asian population.

Refractory immune thrombocytopenia in systemic lupus erythematosus: response to mycophenolate mofetil.

Immune thrombocytopenia(IT) is a common manifestation of systemic lupus erythematosus (SLE). Although severe IT (< 20 ×10 9/L) occurs in about 5-10% of patients, usually in the context of active disease, the absence of randomized controlled trials has not allowed the development of evidence-basedguidelinesfor managing this condition.Conventionally, high-doseglucocorticoidsare consideredfirst-line therapy. Adjunctivemedical and surgical treatments for patients with an absent or partial response to glucocorticoids have met with varying degrees of success. We describe an SLE patient with IT refractory to high-dose corticosteroids, pulse methylprednisolone and intravenous immunoglobulin therapy, whose platelet counts normalized during therapy with mycophenolate mofetil (MMF). Pending further controlled studies to confirm this observation, we suggest that MMF may be considered as a therapeutic option in the treatment of glucocorticoid-refractory immune thrombocytopenia in SLE.

Variability and Sample Size Requirements of Quality-of-Life Measures: A Randomized Study of Three Major Questionnaires

PURPOSE To compare the variability and sample size requirements of the global quality-of-life (QOL) scores of the following three major QOL instruments: the Functional Assessment of Cancer Therapy-General (FACT-G), Functional Living Index-Cancer (FLIC), and European Organisation for Research and Treatment of Cancer Core Quality of Life Questionnaire C30 (EORTC QLQ-C30). PATIENTS AND METHODS Cancer patients were randomly assigned to answer two of the three instruments using an incomplete block design (n = 1,268). The instruments were compared in terms of coefficient of variation, effect size in detecting a difference between patients with different performance status, and correlation coefficient between scores at baseline and follow-up. RESULTS The FACT-G and FLIC had significantly smaller coefficients of variation than the EORTC QLQ-C30 (both P < .05). The FLIC also had significantly larger correlation coefficients between scores at baseline and follow-up than the EORTC QLQ-C30 (P < .05). The FACT-G and the FLIC had a larger effect size in a cross-sectional and longitudinal setting, respectively, than the EORTC QLQ-C30 in differentiating patients with different performance status (both P < .05). CONCLUSION In some aspects, the FACT-G and FLIC global QOL scores had smaller variability and larger discriminative ability than the EORTC QLQ-C30. Further research using other criteria to compare the three instruments is recommended.

An Evaluation of the Reliability and Validity of the Visual Functioning Questionnaire (VF-11) Using Rasch Analysis in an Asian Population

PURPOSE To determine whether the VF-11 is a valid scale to measure visual functioning in an Asian population with vision impairment. METHODS Participants from the Singapore Malay Eye Study (SiMES) took part. Visual functioning was assessed by using the VF-11 (a modified version of VF-14 for an Asian population). Rasch analysis was performed on 618 participants with presenting visual acuity < 6/12 in the better eye. RESULTS Disordered thresholds were initially evident, indicating that the categories were difficult to discriminate and required category collapsing (from 5 to 4) for nine items. The removal of two misfit items related to driving resulted in a fit of the VF-9 data to the Rasch model (chi(2) = 50.5, df = 27, P = 0.005). There were no more misfit items. The person separation reliability value was 0.82 which demonstrates that the VF-9 has sufficient ability to discriminate between at least two groups of participants with different levels of visual functioning. The VF-9 significantly differentiated patients stratified by visual acuity demonstrating adequate criterion validity. All items were free of differential item functioning, and there was no evidence of multidimensionality. Targeting of person ability and item difficulty was suboptimal, although this is inevitable in a population-based survey where most people would not be disabled. CONCLUSIONS Although the Rasch-modified VF-9 scale achieved fit to the Rasch model, its suboptimal targeting suggests that the instrument does not have the range of items to assess the impact of vision impairment across the severity spectrum of vision loss in this population.

The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-c30): validation of English version in Singapore.

Objective: This study aimed to validate the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30, English version 3.0) in Singaporean cancer patients. Methods: In a cross-sectional study, a heterogeneous sample of cancer patients (n = 57) self-administered a questionnaire containing the QLQ-C30, the Short Form 36 Health Survey (SF-36) and assessing health and sociodemographic status. Construct validity was assessed by testing a priori hypotheses that QLQ-C30 scales would be moderately or strongly correlated with SF-36 scales measuring similar dimensions of health-related quality of life (HRQoL) and that subjects reporting mild symptoms would have better HRQoL scores than those reporting severe symptoms. Internal consistency reliability was assessed using Cronbach’s α. Results: Strength of Spearman’s correlations between the QLQ-C30 and SF-36 scales assessing similar dimensions of HRQoL ranged from 0.35 to 0.67. Subjects with mild symptoms had better scores than those with severe symptoms for all six QLQ-C30 HRQoL scales (p < 0.05 for five scales, Mann–Whitney U tests). Cronbach’s α ranged from 0.19 for the cognitive functioning scale to 0.91 for the global QoL scale. Conclusion: This study provides preliminary evidence for the validity and reliability of the EORTC QLQ-C30 in English-speaking Singaporean cancer patients.

PULMONARY HAEMORRHAGE IN ORIENTAL PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

We reviewed the case records of 10 Oriental patients with systemic lupus erythematosus (SLE) who developed pulmonary haemorrhage (PH) between 1987 and 1996 to determine their clinical presentation and outcome. All the patients had clinical evidence of PH including a sudden onset of dyspnoea, tachycardia, fall in haemoglobin (at least 1.5 gm%) and bilateral diffuse alveolar infiltrates on chest radiographs. At the time of PH, nine patients had a disease duration of 2 years or less and all the patients had clinical and/or laboratory evidence of active lupus disease. Fever and lung crepitations were present in 90% of patients while haemoptysis and chest pain occurred in only three and two patients, respectively. All the patients were treated with high dose intravenous corticosteroids and in addition seven had a combination of pulse methylprednisolone and cyclophosphamide, and four had received plasmapheresis. Four patients died as a result of PH. One patient died of pneumonia three years after recovering from PH while the remaining five had no recurrence of PH after a median follow-up of 22 months. Our study suggests that PH in Oriental lupus patients often occurs early in the disease, rarely presents with haemoptysis and has a high mortality despite aggressive immunosuppresive therapy.

A comparison of thrombotic thrombocytopenic purpura in an inception cohort of patients with and without systemic lupus erythematosus

OBJECTIVES To compare the clinical presentation, response to therapy and outcome of thrombotic thrombocytopenic purpura (TTP) in an inception cohort of patients with and without SLE. METHODS Medical records of patients diagnosed with TTP at Singapore General Hospital between January 2003 and December 2007 were reviewed. RESULTS Ten idiopathic TTP (iTTP) and eight SLE-associated TTP (sTTP) patients were identified, with iTTP patients being older (mean 50.4 vs 34.5 yrs). Five iTTP patients were ANA positive but did not have any features of SLE. All sTTP patients had active SLE at TTP diagnosis and had more renal involvement than iTTP (87.5% vs 50%). The mean duration from the first symptom suggestive of TTP to diagnosis was 7.7 days and 19.5 days in iTTP and sTTP patients. All patients received high-dose corticosteroids. Cytotoxic and immunosuppressive drugs were used more commonly (87.5% vs 50%) and earlier (Day 2/3 vs after Day 7) in sTTP patients. Vincristine was the drug of choice in iTTP and cyclophosphamide in sTTP. Three SLE patients received rituximab. Mortality for iTTP and sTTP was 50% (95% CI 19%, 81%) and 62.5% (95% CI 29%, 96%), respectively. The mean (s.d.) time to complete remission was 31.3 (+/- 26.4) days in sTTP (n = 3) and 16.8 (+/- 6.1) days in iTTP (n = 5). CONCLUSION Despite early and more aggressive therapy in sTTP, mortality was higher and the time to complete remission were longer, suggesting that sTTP is more severe. The tempo of development of TTP in SLE patients was slower.