Estimating the lifetime economic burden of Parkinson's disease in Singapore.

BACKGROUND AND PURPOSE: We aimed to estimate the lifetime cost of Parkinson's disease (PD) from the societal perspective. METHODS: A convenience sample of English or Chinese-speaking patients with PD was recruited from a PD and Movement Disorders Centre in Singapore to complete a financial burden questionnaire. Sociodemographic and clinical data were retrieved from hospital databases. Markov cohort model analysis was performed (cycle length, 1-year; duration, death or reached 100 years old). Patients were assumed to progress from one Markov state to the next state or death without skipping states or regressing. All model parameters were based on published local data. RESULTS: In 195 patients with PD (median age: 68.9, male: 51.8%), the simulated lifetime cost of PD was Singapore Dollar (SGD) 60,487 (EUR purchasing power parity 56,253) per patient. Direct medical, non-medical and indirect cost accounted for 18.8%, 12.8% and 68.4% of total lifetime cost, respectively. The top three components of total lifetime cost were productivity losses (67.6%), pharmacotherapy (11.4%) and home care (8.7%). One-way sensitivity analysis and probabilistic sensitivity analyses revealed that estimates were sensitive to cost at H&Y stage 1, 2 and 2.5 and productivity losses. CONCLUSIONS: The lifetime cost of PD is evaluated for the first time. This cost is substantial and comparable to the lifetime cost of intracerebral haemorrhage in at least one study. Our study identified several priority areas for research and policy formulation: reducing productivity losses, reducing cost of pharmacotherapy, avoiding hospitalization and reducing home care cost.

Management of inpatients exposed to an outbreak of severe acute respiratory syndrome (SARS).

This is a prospective observational study of a cohort of inpatients exposed to a severe acute respiratory syndrome (SARS) outbreak. Strict infection control policies were instituted. The 70 patients exposed to the SARS outbreak were isolated from the rest of the hospital. They were triaged, quarantined and cohorted in three open plan wards. Selective isolation was carried out immediately when symptoms and signs suspicious of SARS manifested clinically. The patients' ages ranged from 21 to 90 years and 56% had surgery before the quarantine. Sixteen patients with unexplained fever during the period of quarantine were isolated, seven of whom were eventually diagnosed with probable SARS. The crude incidence of SARS in our cohort was 10%. The SARS case fatality was 14%. No secondary transmission of the SARS virus within the cohort was observed. Strict infection control, together with appropriate triaging, cohorting and selective isolation, is an effective and practical model of intervention in cohorts exposed to a SARS outbreak. Such a management strategy eases the logistic constraints imposed by demands for large numbers of isolation facilities in the face of a massive outbreak.

Design of a prognostic index score for metastatic nasopharyngeal carcinoma.

The survival outcome of patients with systemic cancer differs significantly between individuals even within the same tumour type. We set out to illustrate this by analysing the factors determining survival in patients with metastatic disease from nasopharyngeal carcinoma (NPC) and to design a scoring system based on these prognostic factors. Patients referred between January 1994 and December 1999 were retrospectively analysed. Factors analysed included patient (age group, gender, performance status (BS) at diagnosis of metastases), disease (number of metastatic sites, specific metastatic sites, disease-free interval (DFI), metastases at presentation, presence of locoregional recurrence), and laboratory factors (leucocyte count, haemoglobin level, albumin level). Univariate and multivariable analyses were performed using the Cox proportion hazards model. A numerical score was derived from the regression coefficients of each independent prognostic variable. The prognostic index score (PIS) of each patient was calculated by totalling up the scores of each independent variable. Independently significant, negative prognostic factors were liver metastasis, lung metastasis, anaemia, poor PS, distant metastasis at initial diagnosis, and a DFI of <6 months. Three prognostic groups based on the PIS were obtained: (i) good risk (PIS=0-6); (ii) intermediate risk (7-10); (iii) poor risk (>or=11). The median survivals for these groups were 19.5, 10, and 5.8, months, respectively, (log rank test: P<0.0001). The variable prognosis of patients with disseminated NPC can be assessed by using easily available clinical information (patient, disease and laboratory factors). The PIS system will need to be validated on prospectively collected data of another cohort of patients.

A rational alternative for the diagnosis of diabetes mellitus in high risk individuals.

INTRODUCTIONS: To facilitate early, accurate diagnosis, tests should be easy, cheap and reproducible. We studied volunteers with an increased risk of developing diabetes mellitus (DM) to see if HbA1c levels could replace the oral glucose tolerance test (OGTT) in diagnosing DM. MATERIALS AND METHOD: One hundred and eleven individuals were studied, using the standard oral glucose tolerance test, and simultaneous measurement of HbA1c levels. Receiver operator characteristic (ROC) analysis was performed to assess the sensitivity and specificity of various HbA1c cut-off levels for diagnosing DM. The relationship between fasting plasma glucose (FPG) and DM diagnosis was also investigated. RESULTS: The majority of DM and impaired glucose tolerance (IGT) cases were diagnosed on the basis of two-hour OGTT glucose values. If FPG alone had been used, 29% of the study population with DM or IGT would have been missed. HbA1c cut-off of 6.2% or 6.3% gives the optimal sensitivity and specificity. In linear regression analysis, FPG was found to be a significant predictor of 2-hour OGTT, but only accounted for 45% of the variability of 2-hour OGTT glucose value. CONCLUSIONS: Our data support the view that although HbA1c alone cannot replace the OGTT in the diagnosis of DM, it can still provide a useful guide to rational, cost-effective screening for diabetes mellitus.

Incidence of ischaemic heart disease and stroke in Chinese, Malays and Indians in Singapore: Singapore Cardiovascular Cohort Study.

INTRODUCTION: This is the first prospective cohort study in Singapore to describe the incidence of ischaemic heart disease (IHD) and stroke among Chinese, Malays and Asian Indians. MATERIALS AND METHODS: The Singapore Cardiovascular Cohort Study is a longitudinal follow-up study on a general population cohort of 5920 persons drawn from 3 previous cross-sectional surveys. Morbidity and mortality from IHD and stroke were ascertained by record linkage using a unique identification number with the death registry, Singapore Myocardial Infarct Registry and in-patient discharge databases. RESULTS: There were 193 first IHD events and 97 first strokes during 52,806 person-years of observation. The overall incidence of IHD was 3.8/1000 person-years and that of stroke was 1.8/1000 person-years. In both males and females, Indians had the highest IHD incidence, followed by Malays and then Chinese. For males after adjusting for age, Indians were 2.78 times (95% CI 1.86, 4.17; P < 0.0001) and 2.28 times (95% CI 1.34, 3.88; P = 0.002) more likely to get IHD than Chinese and Malays respectively. For females after adjusting for age, Indians were 1.97 times (95% CI 1.07, 3.63; P = 0.03) and 1.37 times (95% CI 0.67, 2.80; P = 0.39) more likely to get IHD than Chinese and Malays respectively. For stroke, male Chinese and Indians had higher incidence than Malays (though not statistically significant). However, in females, Malays had the highest incidence of stroke, being 2.57 times (95% CI 1.31, 5.05; P = 0.008) more likely to get stroke than Chinese after adjustment for age. CONCLUSIONS: This prospective study of both mortality and morbidity has confirmed the higher risk of IHD in Indians. It has also found that Malay females have a higher incidence of stroke, which deserves further study because of its potential public health importance.

Prognostic factors in 677 patients in Singapore with nondisseminated nasopharyngeal carcinoma.

BACKGROUND: The objective of the current study was to describe the survival of nasopharyngeal carcinoma (NPC) patients in Singapore, verify the prognostic value of the revised 1997 TNM staging system, and develop a multivariate prognostic model for NPC. In addition, the authors also examined the prognostic value of characteristics of lymph node spread and parapharyngeal involvement. METHODS: A prospectively maintained database containing clinical and computed tomography scan data was used to reclassify 677 NPC patients treated between 1992 and 1994 according to the new staging system. Records were linked with the death registry to ascertain the patient's vital status and date of death. Overall and stage specific survival were analyzed using the Kaplan-Meier method and the log rank test. Univariate and multivariate Cox proportional hazards regression analysis were used to obtain prognostic models. RESULTS: Two hundred seventy-four deaths (40.5%) occurred. The 5-year survival rate was 56.6% (95% confidence interval [95% CI], 52.3%, 60.7%). The stage specific 5-year survival rates were: Stage I, 88%; Stage IIA, 75%; Stage IIB, 74%; Stage III, 60%; Stage IVA, 35%; and Stage IVB, 28%. TNM stage was found to be a statistically significant prognostic factor (P < 0.0001). Cranial nerve (hazard ratio [HR]: 2.77), orbit (HR: 5.71), and intracranial involvement (HR: 2.46) conferred a particularly bad prognosis in univariate analysis. Independently significant prognostic factors were age; lymph node status; and paraoropharyngeal, cranial nerve, orbit, and nasal involvement. Among lymph node positive patients, independently significant prognostic lymph node characteristics were Ho level and laterality. Although parapharyngeal involvement appeared to be prognostically unimportant, paraoropharyngeal involvement distinguished a subgroup with a poorer prognosis (HR: 1.84; 95% CI, 1.45, 2.34; P < 0.0001). Lateral spread to the medial infratemporal fossa and beyond also was found to confer a poorer prognosis. CONCLUSIONS: The results of the current study show that the revised 1997 TNM staging system is prognostically useful. Subdivision into paraoropharyngeal involvement and using the medial infratemporal fossa to delineate prognostically significant lateral spread should be considered in future revisions.

Ethnicity, obstructive sleep apnoea and ischaemic heart disease.

We studied the relationship between different ethnic groups, obstructive sleep apnoea (OSA) and ischaemic heart disease. Four hundred and thirty-two inpatients from the medical wards were interviewed. Limited overnight sleep studies were done in 129 of those who had habitual snoring, daytime sleepiness based on an Epworth sleepiness scale of 8 or more, or a large neck size of 40 cm or more. There were 315 Chinese (72.9%), 67 Malays (15.5%), 43 Indians (10%) and 3 from other races (1.4%). The prevalence of OSA was 19.7%, 30% and 12% among the Chinese, Malays and Indians, respectively. The prevalence ratio for OSA was 1.52 in Malays using Chinese patients as the baseline (P = 0.07). The median neck circumference was 37 cm in both racial groups. The median body mass index was 22.7 kg/m2 in Chinese compared to 23.6 kg/m2 in Malays. The median apnoea-hypopnoea index was 22.7, 19.0 and 26.9 events/hour among the Chinese, Malays and Indians, respectively. OSA was independently associated with the prevalence of IHD (adjusted prevalence ratio 1.68; 95% CI: 1.15, 2.46; P = 0.009). The prevalence of ischaemic heart disease (IHD) was 31%, 24% and 28% in Chinese, Malays and Indians, respectively. The prevalence ratio for IHD in Malays compared to Chinese was 0.77. After adjusting for OSA, there was an even greater reduction in the risk of IHD (adjusted prevalence ratio 0.70). This suggests that OSA is a confounder in the relationship between race and ischaemic heart disease.