Displaying publications 41 - 60 of 94 in total

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  1. Ng SC, Lee MK, Teh A
    Postgrad Med J, 1989 Nov;65(769):843-4.
    PMID: 2616421
    A 72 year old man developed acute organic brain syndrome associated with marked eosinophilia following self medication with a variety of drugs. Investigations revealed no other known causes of eosinophilia. Withdrawal of drugs resulted in dramatic drop in eosinophil count paralleled by clinical resolution of neurological problems. To our knowledge drug-induced eosinophilia has not previously been associated with acute organic brain syndrome.
  2. Ng SC, Wong TK, Lin HP
    Ann Acad Med Singap, 1989 Nov;18(6):721-3.
    PMID: 2624424
    The simultaneous expression of both lymphoid and myeloid phenotypic features in acute leukaemia is rare. We report 3 cases of biphenotypic hybrid acute leukaemia seen in our institution. All 3 patients achieved remission with treatment for acute lymphoblastic leukaemia but two subsequently relapsed while on treatment. The hybrid acute leukaemias are important areas for further research both for delineation of basic biology and choice of optimal treatment.
  3. Ng SC, Tang W, Ching JY, Wong M, Chow CM, Hui AJ, et al.
    Gastroenterology, 2013 Jul;145(1):158-165.e2.
    PMID: 23583432 DOI: 10.1053/j.gastro.2013.04.007
    BACKGROUND & AIMS: Inflammatory bowel diseases (IBD) are becoming more common in Asia, but epidemiologic data are lacking. The Asia-Pacific Crohn's and Colitis Epidemiology Study aimed to determine the incidence and phenotype of IBD in 8 countries across Asia and in Australia.

    METHODS: We performed a prospective, population-based study of IBD incidence in predefined catchment areas, collecting data for 1 year, starting on April 1, 2011. New cases were ascertained from multiple overlapping sources and entered into a Web-based database. Cases were confirmed using standard criteria. Local endoscopy, pathology, and pharmacy records were searched to ensure completeness of case capture.

    RESULTS: We identified 419 new cases of IBD (232 of ulcerative colitis [UC], 166 of Crohn's disease [CD], and 21 IBD-undetermined). The crude annual overall incidence values per 100,000 individuals were 1.37 for IBD in Asia (95% confidence interval: 1.25-1.51; 0.76 for UC, 0.54 for CD, and 0.07 for IBD-undetermined) and 23.67 in Australia (95% confidence interval: 18.46-29.85; 7.33 for UC, 14.00 for CD, and 2.33 for IBD-undetermined). China had the highest incidence of IBD in Asia (3.44 per 100,000 individuals). The ratios of UC to CD were 2.0 in Asia and 0.5 in Australia. Median time from symptom onset to diagnosis was 5.5 months (interquartile range, 1.4-15 months). Complicated CD (stricturing, penetrating, or perianal disease) was more common in Asia than Australia (52% vs 24%; P = .001), and a family history of IBD was less common in Asia (3% vs 17%; P < .001).

    CONCLUSIONS: We performed a large-scale population-based study and found that although the incidence of IBD varies throughout Asia, it is still lower than in the West. IBD can be as severe or more severe in Asia than in the West. The emergence of IBD in Asia will result in the need for specific health care resources, and offers a unique opportunity to study etiologic factors in developing nations.

  4. Ng SC, Tsoi KK, Kamm MA, Xia B, Wu J, Chan FK, et al.
    Inflamm Bowel Dis, 2012 Jun;18(6):1164-76.
    PMID: 21887729 DOI: 10.1002/ibd.21845
    BACKGROUND: Inflammatory bowel diseases (IBD) result from an interaction between genetic and environmental factors. Preliminary findings suggest that susceptibility genes differ between IBD patients in Asia and the West. We aimed to evaluate disease-predisposing genes in Asian IBD patients.

    METHODS: A systematic review and meta-analysis were performed of published studies from 1950 to 2010 using keyword searches in MEDLINE, EMBASE, EBM Reviews, and BIOSIS Previews.

    RESULTS: In all, 477 abstracts were identified and data extracted from 93 studies, comprising 17,976 IBD patients and 27,350 age- and sex-matched controls. Major nucleotide oligomerization domain (NOD)-2 variants in Western Crohn's disease (CD) patients were not associated with CD in Han Chinese, Japanese, South Korean, Indian, and Malaysian populations. New NOD2 mutations were, however, associated with CD in Malaysians (JW1), Han Chinese, and Indians (P268S). Autophagy-related protein 16-linked 1 (ATG16L1) was not associated with CD in East Asians (odds ratio [OR] 0.97; 95% confidence interval [CI] 0.84-1.13). Interleukin (IL)-23R was associated with CD in South Koreans (OR 1.8; 95% CI 1.16-2.82) and a single nucleotide polymorphism in IL-23R (Gly149Arg) was protective of CD in Han Chinese (OR 0.3; 95% CI 0.15-0.60). Tumor necrosis factor (TNF) superfamily gene-15 (SF15) polymorphisms were associated with CD (OR 2.68; 95% CI 1.86-3.86), while TNF-308 polymorphisms (OR 1.82; 95% CI 1.15-2.9), cytotoxic T lymphocyte antigen (CTLA)-4 (OR 2.75; 95% CI 1.22-6.22) and MICA allele (OR 2.41; 95% CI 1.89-3.07) were associated with ulcerative colitis in Asians.

    CONCLUSIONS: Genetic mutations of IBD in Asians differ from Caucasians. New mutations and susceptibility genes identified in Asian IBD patients provide an opportunity to explore new disease-associated mechanisms in this population of rising incidence.

  5. Ng SC, Kaplan GG, Tang W, Banerjee R, Adigopula B, Underwood FE, et al.
    Am J Gastroenterol, 2019 01;114(1):107-115.
    PMID: 30177785 DOI: 10.1038/s41395-018-0233-2
    INTRODUCTION: Living in an urban environment may increase the risk of developing inflammatory bowel disease (IBD). It is unclear if this observation is seen globally. We conducted a population-based study to assess the relationship between urbanization and incidence of IBD in the Asia-Pacific region.

    METHODS: Newly diagnosed IBD cases between 2011 and 2013 from 13 countries or regions in Asia-Pacific were included. Incidence was calculated with 95% confidence interval (CI) and pooled using random-effects model. Meta-regression analysis was used to assess incidence rates and their association with population density, latitude, and longitude.

    RESULTS: We identified 1175 ulcerative colitis (UC), 656 Crohn's disease (CD), and 37 IBD undetermined (IBD-U). Mean annual IBD incidence per 100 000 was 1.50 (95% CI: 1.43-1.57). India (9.31; 95% CI: 8.38-10.31) and China (3.64; 95% CI, 2.97-4.42) had the highest IBD incidence in Asia. Incidence of overall IBD (incidence rate ratio [IRR]: 2.19; 95% CI: 1.01-4.76]) and CD (IRR: 3.28; 95% CI: 1.83-9.12) was higher across 19 areas of Asia with a higher population density. In China, incidence of IBD (IRR: 2.37; 95% CI: 1.10-5.16) and UC (IRR: 2.63; 95% CI: 1.2-5.8) was positively associated with gross domestic product. A south-to-north disease gradient (IRR: 0.94; 95% CI: 0.91-0.98) was observed for IBD incidence and a west-to-east gradient (IRR: 1.14; 95% CI: 1.05-1.24) was observed for CD incidence in China. This study received IRB approval.

    CONCLUSIONS: Regions in Asia with a high population density had a higher CD and UC incidence. Coastal areas within China had higher IBD incidence. With increasing urbanization and a shift from rural areas to cities, disease incidence may continue to climb in Asia.

  6. Ng SC, Abu Samah F, Helmy K, Sia KK
    Med J Malaysia, 2017 10;72(5):286-290.
    PMID: 29197884 MyJurnal
    OBJECTIVE: To compare FEV1/FEV6 to the standard spirometry (FEV1/FVC) as a screening tool for COPD.

    METHODS: This cross-sectional study was conducted at Hospital Tuanku Fauziah, Perlis, Malaysia from August 2015 to April 2016. FEV1/FEV6 and FEV1/FVC results of 117 subjects were analysed. Demographic data and spirometric variables were tabulated. A scatter plot graph with Spearman's correlation was constructed for the correlation between FEV1/FEV6 and FEV1/FVC. The sensitivity, specificity, positive and negative predictive values of FEV1/FEV6 were determined with reference to the gold standard of FEV1/FVC ratio <0.70. Receiver-operator characteristic (ROC) curve analysis and Kappa statistics were used to determine the FEV1/FEV6 ratio in predicting an FEV1/FVC ratio <0.70.

    RESULTS: Spearman's correlation with r = 0.636 (P<0.001) was demonstrated. The area under the ROC curve was 0.862 (95% confidence interval [CI]: 0.779 - 0.944, P<0.001). The FEV1/FEV6 cut-off with the greatest sum of sensitivity and specificity was 0.75. FEV1/FEV6 sensitivity, specificity, positive and negative predictive values were 93.02%, 67.74%, 88.89% and 77.78% respectively. There was substantial agreement between the two diagnostic cut-offs (κ = 0.634; 95% CI: 0.471 - 0.797, P<0.001) CONCLUSIONS: The FEV1/FEV6 ratio can be considered to be a good alternative to the FEV1/FVC ratio for screening of COPD. Larger multicentre study and better education on spirometric techniques can validate similar study outcome and establish reference values appropriate to the population being studied.

  7. Ng SC, Kuperan P, Bosco J, Menaka N
    Singapore Med J, 1990 Apr;31(2):153-8.
    PMID: 2196685
    Twenty patients with Myelodysplastic Syndrome (MDS) were diagnosed in University Hospital, Kuala Lumpur over a 5 year period. They were subclassified using the French American British (FAB) criteria. 90% of the patients were above 40 years old and the sex ratio was about equal. The predominant presenting symptom was anaemia and there was paucity of physical signs at presentation. Patients with 'aggressive' subtypes of MDS i.e. refractory anaemia with excess blasts (RAEB), refractory anaemia with excess blasts in transformation (RAEB(-)+) and chronic myelomonocytic leukaemia (CMML) had more frequent thrombocytopenia and neutropenia and their marrow pictures frequently had dysmegakaryopoiesis and dysgranulopoiesis as compared to more the "benign" subtypes i.e. refractory anaemia (RA) and refractory leukaemic anaemia with ringed sideroblasts (RARS). Four patients had leukaemic transformation and all of them came from the 'aggressive' subtypes. The current views on treatment of MDS are discussed.
  8. Ng SC, Kuperan P, Jayalakshmi P, Chua CT
    Singapore Med J, 1990 Feb;31(1):80-2.
    PMID: 2185555
    A 47-year old man had hypersplenism from massive splenomegaly, the cause of which was undetermined for 2 years. He was initially asymptomatic though there was mild pancytopenia. However, 18 months after presentation he manifested both clinical and haematological deterioration, almost succumbing to sepsis. Splenectomy finally provided a definite diagnosis of follicular lymphoma and also restored his blood counts to within normal range.
  9. Ng SC, Hilmi IN, Blake A, Bhayat F, Adsul S, Khan QR, et al.
    Inflamm Bowel Dis, 2018 Oct 12;24(11):2431-2441.
    PMID: 30312414 DOI: 10.1093/ibd/izy153
    BACKGROUND: Vedolizumab (ENTYVIO) is a humanized α4β7 integrin antagonist approved for the treatment of inflammatory bowel disease, which selectively blocks gut-specific lymphocyte trafficking. We evaluated the risk of opportunistic infections of interest in patients treated with vedolizumab.

    METHODS: We determined the frequency of opportunistic infections and tuberculosis in patients receiving vedolizumab in phase 3 clinical trials and post-marketing settings. We also evaluated adverse events reported in the post-marketing setting in patients with a history of or concurrent hepatitis B/C virus infection.

    RESULTS: The incidence of opportunistic infections in patients receiving vedolizumab was 0.7 (GEMINI 1 and 2 clinical trials) and 1.0 (long-term safety study) per 100 patient-years, with 217 events reported in approximately 114,071 patient-years of exposure (post-marketing setting). Most opportunistic infections were nonserious and the majority of patients continued treatment with vedolizumab. Clostridium difficile was the most commonly reported infection, with an incidence rate of 0.5 per 100 patient-years (clinical trials). Tuberculosis was reported at 0.1 per 100 patient-years (clinical trials), with 7 events in the post-marketing setting. No tuberculosis-related deaths were reported in either setting. No cases of progressive multifocal leukoencephalopathy were reported. In 29 patients with a history of or concurrent hepatitis B/C infection in the post-marketing setting, no viral reactivation was observed.

    CONCLUSIONS: Clinical trials and post-marketing data showed that the rate of serious opportunistic infections in patients receiving vedolizumab was low and most patients could continue vedolizumab treatment. The frequency of tuberculosis infection was also low and no hepatitis B/C viral reactivation was reported.

  10. Ng SC, Hitam O, Sawat
    Med J Malaysia, 1991 Mar;46(1):59-65.
    PMID: 1836039
    This paper reviews our first 100 consecutive PTCAs done between December 1988 and May 1990. There were 31 females and 69 males and their ages ranged from 37 years to 80 years. The mean age was 57.7 years. We achieved a follow-up rate of 66%. The restenosis rate was 22% of those that we could follow-up. There were 35 simple and 65 complex PTCAs. An average of 1.39 arteries were entered per PTCA. Of the 100 PTCAs done there was a primary success rate of 83%. On closer examination most of the failures were in the total occlusion group. There were 30 total occlusions done and 17 were successfully dilated. The primary success rate for acute total occlusions was 77% and the primary success rate for chronic total occlusions was 41%. Of the 100 PTCAs there were two deaths and only one patient had to go for emergency bypass surgery. The other complications were relatively minor including hypotension, groin bleeding, chills and rigors. This paper documents our initial 100 cases of PTCAs. It shows that our figures are compatible with other centres in this region and those around the world.
  11. Md Yusof M, Abdullah MM, Yap BK, Ng SC, Low JSH, Lam KS, et al.
    Asia Pac J Clin Oncol, 2021 Nov 23.
    PMID: 34811924 DOI: 10.1111/ajco.13667
    AIM: A large proportion of cancer patients are at high risk for chemotherapy-induced nausea and vomiting (CINV), but the choice of anti-emetics for CINV in Malaysia is limited.

    METHODS: This was a real-world study of a fixed-dose combination of netupitant and palonosetron (NEPA) to inhibit CINV in adult patients receiving moderately (MEC) or highly emetogenic chemotherapy (HEC) for solid/hematological malignancies at eight Malaysian centers. Each HEC/MEC cycle received one dose of NEPA + dexamethasone for CINV prevention. Complete response (no emesis, no rescue medication) (CR), no more than mild nausea (severity score ≤ 2.5), and complete control (CR) (no more than mild nausea) during the acute (0-24 h), delayed (25-120 h), and overall (0-120 h) phases post-chemotherapy were measured. Treatment-related adverse events (AEs) were recorded.

    RESULTS: During March 2016-April 2018 (NMRR-17-3286-38282), NEPA + dexamethasone was administered to 54 patients (77.8% solid, 22.2% hematological malignancies). Note that 59.3% received HEC, while 40.7% received MEC regimen. During the overall phase of the first cycle, the majority had CR (77.8%), no more than mild nausea (74.1%), and complete control (61.1%). Seventeen patients received two consecutive cycles at any point of chemotherapy cycles. During the overall phases across two consecutive cycles, all patients achieved CR, and the majority reported no more than mild nausea and complete control. No grades 3-4 AEs were reported.

    CONCLUSIONS: NEPA had sustained efficacy and tolerability at first administration and across two cycles of MEC/HEC for CINV prevention.

  12. Mak WY, Mak OS, Lee CK, Tang W, Leung WK, Wong MTL, et al.
    J Crohns Colitis, 2018 Nov 28;12(12):1392-1398.
    PMID: 30165543 DOI: 10.1093/ecco-jcc/jjy120
    Background: The presence of perianal fistulas in Crohn's disease [CD] denotes increased disease aggressiveness. We studied the epidemiology and clinical outcomes of perianal CD [PCD] using the Hong Kong territory-wide IBD Registry [HKIBDR].

    Methods: Consecutive patients with PCD were identified from the HKIBDR, and disease characteristics, treatments, and outcomes were analysed. The risks for medical and surgical therapies were assessed using Kaplan-Meier analysis.

    Results: Among 981 patients with CD with 10530 patient-years of follow-up, 283 [28.8%] had perianal involvement, of which 120 [42.4%] were as first presentation. The mean age at diagnosis of PCD was 29.1 years, and 78.8% were male. The median follow-up duration was 106 months (interquartile range [IQR]: 65-161 months]. Perianal fistula [84.8%] and perianal abscess [52.7%] were the two commonest forms. Male, younger age at diagnosis of CD, and penetrating phenotypes were associated with development of PCD in multivariate analysis. Of 242 patients with fistulizing PCD, 70 [29.2%] required ≥5 courses of antibiotics, and 98 [40.5%] had ≥2 surgical procedures. Nine patients required defunctioning surgery and 4 required proctectomy. Eighty-four patients [34.7%] received biologics. Cumulative probabilities for use of biologics were 4.7%, 5.8%, and 8.6% at 12 months, 36 months, and 96 months, respectively, while the probabilities for surgery were 67.2%, 71.6%, and 77.7%, respectively. Five mortalities were recorded, including 2 cases of anal cancer, 2 CD-related complications, and one case of pneumonia.

    Conclusion: Over 40% of CD patients presented with perianal disease at diagnosis. Patients with PCD had poor outcome, with young age of onset, multiple antibiotic use, and repeated surgery.

  13. Mak JWY, Tang W, Yip TCF, Ran ZH, Wei SC, Ahuja V, et al.
    Aliment Pharmacol Ther, 2019 12;50(11-12):1195-1203.
    PMID: 31638274 DOI: 10.1111/apt.15547
    BACKGROUND: Little is known of the outcome of patients with perianal Crohn's disease after stopping anti-tumour necrosis factor (TNF) therapy.

    AIM: To evaluate the rate of relapse in perianal Crohn's disease (CD) after stopping anti-TNF therapy.

    METHODS: Consecutive perianal CD patients treated with anti-TNF therapy with subsequent discontinuation were retrieved from prospective inflammatory bowel disease database of institutes in Hong Kong, Shanghai, Taiwan, Malaysia, Thailand and Singapore from 1997 to June 2019. Cumulative probability of perianal CD relapse was estimated using Kaplan-Meier method.

    RESULTS: After a median follow-up of 89 months (interquartile range [IQR]: 65-173 months), 44 of the 78 perianal CD patients (56.4%) relapsed after stopping anti-TNF, defined as increased fistula drainage or recurrence of previously healed fistula, after stopping anti-TNF therapy. Cumulative probabilities of perianal CD relapse were 50.8%, 72.6% and 78.0% at 12, 36 and 60 months, respectively. Younger age at diagnosis of CD [adjusted hazard ratio (HR): 1.04; 95% CI 1.01-1.09; P = .04] was associated with a higher chance of perianal CD relapse. Among those with perianal CD relapse (n = 44), retreatment with anti-TNF induced remission in 24 of 29 patients (82.8%). Twelve (27.3%) patients required defunctioning surgery and one (2.3%) required proctectomy. Maintenance with thiopurine was not associated with a reduced likelihood of relapse [HR = 1.10; 95% CI: 0.58-2.12; P = .77]. Among the 17 patients who achieved radiological remission of perianal CD, five (35.3%) developed relapse after stopping anti-TNF therapy after a median of 6 months.

    CONCLUSIONS: More than half of the perianal CD patients developed relapse after stopping anti-TNF therapy. Most regained response after resuming anti-TNF. However, more than one-fourth of the perianal CD patients with relapse required defunctioning surgery. Radiological assessment before stopping anti-TNF is crucial in perianal CD.

  14. Mak JWY, Sun Y, Limsrivilai J, Abdullah M, Kaibullayeva J, Balderramo D, et al.
    BMC Med Res Methodol, 2023 May 25;23(1):129.
    PMID: 37231405 DOI: 10.1186/s12874-023-01944-2
    BACKGROUND: There is a rapid increase in the incidence of inflammatory bowel diseases (IBD) in newly industrialized countries, yet epidemiological data is incomplete. We herein report the methodology adopted to study the incidence of IBD in newly industrialized countries and to evaluate the effect of environmental factors including diet on IBD development.

    METHODS: Global IBD Visualization of Epidemiology Studies in the 21st Century (GIVES-21) is a population-based cohort of newly diagnosed persons with Crohn's disease and ulcerative colitis in Asia, Africa, and Latin America to be followed prospectively for 12 months. New cases were ascertained from multiple sources and were entered into a secured online system. Cases were confirmed using standard diagnostic criteria. In addition, endoscopy, pathology and pharmacy records from each local site were searched to ensure completeness of case capture. Validated environmental and dietary questionnaires were used to determine exposure in incident cases prior to diagnosis.

    RESULTS: Through November 2022, 106 hospitals from 24 regions (16 Asia; 6 Latin America; 2 Africa) have joined the GIVES-21 Consortium. To date, over 290 incident cases have been reported. All patients have demographic data, clinical disease characteristics, and disease course data including healthcare utilization, medication history and environmental and dietary exposures data collected. We have established a comprehensive platform and infrastructure required to examine disease incidence, risk factors and disease course of IBD in the real-world setting.

    CONCLUSIONS: The GIVES-21 consortium offers a unique opportunity to investigate the epidemiology of IBD and explores new clinical research questions on the association between environmental and dietary factors and IBD development in newly industrialized countries.

  15. Long F, Zhao S, Wei X, Ng SC, Ni X, Chi A, et al.
    Front Behav Neurosci, 2021;15:720451.
    PMID: 34512288 DOI: 10.3389/fnbeh.2021.720451
    The EEG features of different emotions were extracted based on multi-channel and forehead channels in this study. The EEG signals of 26 subjects were collected by the emotional video evoked method. The results show that the energy ratio and differential entropy of the frequency band can be used to classify positive and negative emotions effectively, and the best effect can be achieved by using an SVM classifier. When only the forehead and forehead signals are used, the highest classification accuracy can reach 66%. When the data of all channels are used, the highest accuracy of the model can reach 82%. After channel selection, the best model of this study can be obtained. The accuracy is more than 86%.
  16. Ling KL, Hilmi I, Raja Ali RA, Leong RWL, Leung WK, Ng SC, et al.
    JGH Open, 2020 Jun;4(3):320-323.
    PMID: 32514431 DOI: 10.1002/jgh3.12362
    The COVID-19 pandemic, secondary to SARS-CoV-2, has resulted in high mortality and morbidity worldwide. As inflammatory bowel disease (IBD) is a chronic disease, and most patients are on long-term immunosuppressive agents, there is understandable concern, particularly in terms of therapy. In view of this, experts in IBD across the Asia Pacific region were invited to put together recommendations based on their experience and the currently available data. In general, most IBD therapies (with a few exceptions) can be continued safely, and the general consensus is that maintaining disease control should remain the main principle of management. In addition, social distancing measures and the appropriate use of personal protective equipment should be strictly adhered to. During the current pandemic, face-to-face clinic follow ups and non-urgent procedures should be kept to a minimum.
  17. Lim PK, Ng SC, Lovell NH, Yu YP, Tan MP, McCombie D, et al.
    Physiol Meas, 2018 10 11;39(10):105005.
    PMID: 30183675 DOI: 10.1088/1361-6579/aadf1e
    OBJECTIVE: The photoplethysmography (PPG) signal, commonly used in the healthcare settings, is easily affected by movement artefact leading to errors in the extracted heart rate and SpO2 estimates. This study aims to develop an online artefact detection system based on adaptive (dynamic) template matching, suitable for continuous PPG monitoring during daily living activities or in the intensive care units (ICUs).

    APPROACH: Several master templates are initially generated by applying principal component analysis to data obtained from the PhysioNet MIMIC II database. The master template is then updated with each incoming clean PPG pulse. The correlation coefficient is used to classify the PPG pulse into either good or bad quality categories. The performance of our algorithm was evaluated using data obtained from two different sources: (i) our own data collected from 19 healthy subjects using the wearable Sotera Visi Mobile system (Sotera Wireless Inc.) as they performed various movement types; and (ii) ICU data provided by the PhysioNet MIMIC II database. The developed algorithm was evaluated against a manually annotated 'gold standard' (GS).

    MAIN RESULTS: Our algorithm achieved an overall accuracy of 91.5%  ±  2.9%, with a sensitivity of 94.1%  ±  2.7% and a specificity of 89.7%  ±  5.1%, when tested on our own data. When applying the algorithm to data from the PhysioNet MIMIC II database, it achieved an accuracy of 98.0%, with a sensitivity and specificity of 99.0% and 96.1%, respectively.

    SIGNIFICANCE: The proposed method is simple and robust against individual variations in the PPG characteristics, thus making it suitable for a diverse range of datasets. Integration of the proposed artefact detection technique into remote monitoring devices could enhance reliability of the PPG-derived physiological parameters.

  18. Lim PK, Ng SC, Jassim WA, Redmond SJ, Zilany M, Avolio A, et al.
    Sensors (Basel), 2015 Jun 16;15(6):14142-61.
    PMID: 26087370 DOI: 10.3390/s150614142
    We present a novel approach to improve the estimation of systolic (SBP) and diastolic blood pressure (DBP) from oscillometric waveform data using variable characteristic ratios between SBP and DBP with mean arterial pressure (MAP). This was verified in 25 healthy subjects, aged 28 ± 5 years. The multiple linear regression (MLR) and support vector regression (SVR) models were used to examine the relationship between the SBP and the DBP ratio with ten features extracted from the oscillometric waveform envelope (OWE). An automatic algorithm based on relative changes in the cuff pressure and neighbouring oscillometric pulses was proposed to remove outlier points caused by movement artifacts. Substantial reduction in the mean and standard deviation of the blood pressure estimation errors were obtained upon artifact removal. Using the sequential forward floating selection (SFFS) approach, we were able to achieve a significant reduction in the mean and standard deviation of differences between the estimated SBP values and the reference scoring (MLR: mean ± SD = -0.3 ± 5.8 mmHg; SVR and -0.6 ± 5.4 mmHg) with only two features, i.e., Ratio2 and Area3, as compared to the conventional maximum amplitude algorithm (MAA) method (mean ± SD = -1.6 ± 8.6 mmHg). Comparing the performance of both MLR and SVR models, our results showed that the MLR model was able to achieve comparable performance to that of the SVR model despite its simplicity.
  19. Lim MC, Hatah E, Lai KC, Buang A, Koay TJ, Sim WJY, et al.
    Patient Prefer Adherence, 2022;16:3133-3142.
    PMID: 36471869 DOI: 10.2147/PPA.S382341
    PURPOSE: Previous studies show that customer loyalty and purchase intentions were influenced by perceived product value, but little is known about the factors that influence patients' perceptions of the value of their subsidized prescriptions, when purchasing of medications were not required, and how these factors influence their medication adherence. Hence, this study aims to investigate perceptions of patients receiving subsidized medications regarding the value of their medication.

    PATIENTS AND METHODS: This qualitative study involved semi-structured, face-to-face interviews with patients diagnosed with type 2 diabetes mellitus at a government district hospital in Selangor state, Malaysia between June to September 2019. Using purposive sampling, patients were identified at an out-patient pharmacy during prescription refill. They were asked how they perceived the value of their medication. Interviews were audio recorded and then transcribed verbatim for thematic analysis.

    RESULTS: A total of thirty patients were interviewed. Patients' perceptions on the value of medications were influenced by several factors such as trust, how the medications impact on their physical and social well-beings, and the perceived sacrificed made when the medications were procured and used. Perceptions on medication values were influenced by the recommendation received from someone they trust such as their doctors or significant others. It was also influenced by their perceptions of how the medication helps to improve their disease symptoms and affect their religious and social activities. Other factors include the perceived worth of the sacrifices made to access and use the medication.

    CONCLUSION: Identifying factors that may influence patients' perceived value of the medication may help improve healthcare practices.

  20. Lim E, Chan GS, Dokos S, Ng SC, Latif LA, Vandenberghe S, et al.
    PLoS One, 2013;8(10):e77357.
    PMID: 24204817 DOI: 10.1371/journal.pone.0077357
    A lumped parameter model of the cardiovascular system has been developed and optimized using experimental data obtained from 13 healthy subjects during graded head-up tilt (HUT) from the supine position to [Formula: see text]. The model includes descriptions of the left and right heart, direct ventricular interaction through the septum and pericardium, the systemic and pulmonary circulations, nonlinear pressure volume relationship of the lower body compartment, arterial and cardiopulmonary baroreceptors, as well as autoregulatory mechanisms. A number of important features, including the separate effects of arterial and cardiopulmonary baroreflexes, and autoregulation in the lower body, as well as diastolic ventricular interaction through the pericardium have been included and tested for their significance. Furthermore, the individual effect of parameter associated with heart failure, including LV and RV contractility, baseline systemic vascular resistance, pulmonary vascular resistance, total blood volume, LV diastolic stiffness and reflex gain on HUT response have also been investigated. Our fitted model compares favorably with our experimental measurements and published literature at a range of tilt angles, in terms of both global and regional hemodynamic variables. Compared to the normal condition, a simulated congestive heart failure condition produced a blunted response to HUT with regards to the percentage changes in cardiac output, stroke volume, end diastolic volume and effector response (i.e., heart contractility, venous unstressed volume, systemic vascular resistance and heart rate) with progressive tilting.
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