Displaying publications 1 - 20 of 177 in total

  1. Fang YY, Suraiya Kassim
    Sains Malaysiana, 2013;42:673-683.
    In competing risks analysis, the primary interest of researchers is the estimation of the net survival probability (NSP) if a cause of failure could be eliminated from a population. The Kaplan-Meier product-limit estimator under the assumption that the eliminated risk is non-informative to the other remaining risks, has been widely used in the estimation of the NSP. The assumption implies that the hazard of the remaining risks before and after the elimination are equal and it could be biased. This paper addressed this possible bias by proposing a non-parametric multistate approach that accounts for an informative eliminated risk in the estimation procedure, whereby the hazard probabilities of the remaining risks before and after the elimination of a risk are not assumed to be equal. When a non-informative eliminated risk was assumed, it was shown that the proposed multistate estimator reduces to the Kaplan-Meier estimator. For illustration purposes, the proposed procedure was implemented on a published dataset and the change in hazard after elimination of a cause is investigated. Comparing the results to those obtained from using the Kaplan-Meier method, it was found that in the presence of (both constant and non-constant) informative eliminated risk, the proposed multistate approach was more sensitive and flexible.
    Matched MeSH terms: Survival Analysis
  2. Bader Ahmad Aljawadi, Mohd Rizam Abu Bakar, Noor Akma
    This study deals with the analysis of the cure rate estimation based on the Bounded Cumulative Hazard (BCH) model using interval censored data, given that the exact distribution of the data set is unknown. Thus, the non-parametric estimation methods are employed by means of the EM algorithm. The Turnbull and Kaplan Meier estimators were proposed to estimate the survival function, even though the Kaplan Meier estimator faces some restrictions in term of interval survival data. A comparison of the cure rate estimation based on the two estimators was done through a simulation study.
    Matched MeSH terms: Survival Analysis
  3. Kiani K, Arasan J, Habshah Midi
    Sains Malaysiana, 2012;41:471-480.
    There are numerous parametric models for analyzing survival data such as exponential, Weibull, log-normal and gamma. One of such models is the Gompertz model which is widely used in biology and demography. Most of these models are extended to new forms for accommodating different types of censoring mechanisms and different types of covariates. In this paper the performance of the Gompertz model with time-dependent covariate in the presence of right censored data was studied. Moreover, the performance of the model was compared at different censoring proportions (CP) and sample sizes. Also, the model was compared with fixed covariate model. In addition, the effect of fitting a fixed covariate model wrongly to a data with time-dependent covariate was studied. Finally, two confidence interval estimation techniques, Wald and jackknife, were applied to the parameters of this model and the performance of the methods was compared.
    Matched MeSH terms: Survival Analysis
  4. Abdullah MM, Foo YC, Yap BK, Lee CML, Hoo LP, Lim TO
    Asian Pac. J. Cancer Prev., 2019 06 01;20(6):1701-1708.
    PMID: 31244290 DOI: 10.31557/APJCP.2019.20.6.1701
    Objective: This report focuses on a private medical centre cancer care performance as measured by patient survival
    outcome for up to 5 years. Methods: All patients with nasopharyngeal cancer treated at SJMC between 2008 and 2012
    were enrolled for this observational cohort study. Mortality outcome was ascertained through record linkage with
    national death register, linkage with hospital registration system and finally through direct contact by phone. Result:
    266 patients treated between 2008 and 2012 were included for survival analysis. 31% of patients were diagnosed with
    Early NPC Cancer (Stage I or II), another 44% with Locally Advanced Cancer (Stage III) and 25% with late stage IV
    metastatic cancer. 2%, 27% and 67% had WHO Class I, II and III NPC respectively. The overall survival at 5 years
    was 100% for patients with Stage I disease, 91% for Stage II disease, 72% for Stage III disease, and decreasing to
    44% for Stage IV disease. Overall survival at 5 years for all stages was 73%. Conclusion: SJMC is among the first
    hospitals in Malaysia to embark on routine measurement of the performance of its cancer care services and its results
    are comparable to any leading centers in developed countries.
    Matched MeSH terms: Survival Analysis
  5. Phang KC, Hussin NH, Abdul Rahman F, Tizen NMS, Mansoor A, Masir N
    Malays J Pathol, 2019 Aug;41(2):101-124.
    PMID: 31427546
    INTRODUCTION: Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive type of non-Hodgkin lymphoma with variable clinical outcomes. The immunogenotypic features of this heterogeneous disease in Malaysia were not well characterized.

    MATERIALS & METHODS: In total 141 local series of DLBCL cases from UKM Medical Centre were retrospectively studied.

    RESULTS: Of these cases, we classified our patients into two subtypes: 32.7% (37/113) GCB and non-GCB 67.3% (76/113) by Hans algorithm and the results showed strong agreement with the results by Choi algorithm (κ = 0.828, P<0.001). Survival analysis indicated significant difference in between GCB and non-GCB subtypes (P=0.01), elevated serum LDH (P=0.016), age more than 60-year-old (P=0.021) and the presence of B symptoms (P=0.04). We observed 12% DLBCL cases were CD5 positive and 81.8% of them died of the disease (P=0.076). Analysis on the dual expression of MYC/BCL2 revealed that there is no significant difference in DE and non-DE groups (P=0.916). FISH study reported there were 9.22% (13/141) rearranged cases observed in our population at which highest frequency of BCL6 gene rearrangement (76.9%), followed by MYC (15.4%) and BCL2 (7.7%); no BCL10 and MALT-1 gene rearrangement found regardless of using TMAs or whole tissue samples. More cases of MYC protein overexpression observed compared to MYC translocation.

    CONCLUSION: Relatively lower frequency of GCB tumours and low gene rearrangement rates were observed in Malaysian population. A national study is therefore warranted to know better the immunogenotypic characteristics of DLBCL in Malaysia and their implications on the survival.

    Matched MeSH terms: Survival Analysis
  6. Go KW, Teo SM
    Transplant. Proc., 2004 Sep;36(7):2046-7.
    PMID: 15518740
    To compare patient graft survival between various subgroups among renal transplant patients.
    Matched MeSH terms: Survival Analysis*
  7. Guure CB, Ibrahim NA, Adam MB
    Comput Math Methods Med, 2013;2013:849520.
    PMID: 23476718 DOI: 10.1155/2013/849520
    Interval-censored data consist of adjacent inspection times that surround an unknown failure time. We have in this paper reviewed the classical approach which is maximum likelihood in estimating the Weibull parameters with interval-censored data. We have also considered the Bayesian approach in estimating the Weibull parameters with interval-censored data under three loss functions. This study became necessary because of the limited discussion in the literature, if at all, with regard to estimating the Weibull parameters with interval-censored data using Bayesian. A simulation study is carried out to compare the performances of the methods. A real data application is also illustrated. It has been observed from the study that the Bayesian estimator is preferred to the classical maximum likelihood estimator for both the scale and shape parameters.
    Matched MeSH terms: Survival Analysis*
  8. Kong YC, Bhoo-Pathy N, Subramaniam S, Bhoo-Pathy N, Taib NA, Jamaris S, et al.
    PMID: 28420149 DOI: 10.3390/ijerph14040427
    Background: Survival disparities in cancer are known to occur between public and private hospitals. We compared breast cancer presentation, treatment and survival between a public academic hospital and a private hospital in a middle-income country. Methods: The demographics, clinical characteristics, treatment and overall survival (OS) of 2767 patients with invasive breast carcinoma diagnosed between 2001 and 2011 in the public hospital were compared with 1199 patients from the private hospital. Results: Compared to patients in the private hospital, patients from the public hospital were older at presentation, and had more advanced cancer stages. They were also more likely to receive mastectomy and chemotherapy but less radiotherapy. The five-year OS in public patients was significantly lower than in private patients (71.6% vs. 86.8%). This difference was largely attributed to discrepancies in stage at diagnosis and, although to a much smaller extent, to demographic differences and treatment disparities. Even following adjustment for these factors, patients in the public hospital remained at increased risk of mortality compared to their counterparts in the private hospital (Hazard Ratio: 1.59; 95% Confidence Interval: 1.36-1.85). Conclusion: Late stage at diagnosis appears to be a major contributing factor explaining the breast cancer survival disparity between public and private patients in this middle-income setting.
    Matched MeSH terms: Survival Analysis*
  9. Szulkin R, Karlsson R, Whitington T, Aly M, Gronberg H, Eeles RA, et al.
    Cancer Epidemiol. Biomarkers Prev., 2015 Nov;24(11):1796-800.
    PMID: 26307654 DOI: 10.1158/1055-9965.EPI-15-0543
    BACKGROUND: Unnecessary intervention and overtreatment of indolent disease are common challenges in clinical management of prostate cancer. Improved tools to distinguish lethal from indolent disease are critical.

    METHODS: We performed a genome-wide survival analysis of cause-specific death in 24,023 prostate cancer patients (3,513 disease-specific deaths) from the PRACTICAL and BPC3 consortia. Top findings were assessed for replication in a Norwegian cohort (CONOR).

    RESULTS: We observed no significant association between genetic variants and prostate cancer survival.

    CONCLUSIONS: Common genetic variants with large impact on prostate cancer survival were not observed in this study.

    IMPACT: Future studies should be designed for identification of rare variants with large effect sizes or common variants with small effect sizes.

    Matched MeSH terms: Survival Analysis
  10. Leong PK, Sim SM, Fung SY, Sumana K, Sitprija V, Tan NH
    PLoS Negl Trop Dis, 2012;6(6):e1672.
    PMID: 22679522 DOI: 10.1371/journal.pntd.0001672
    Snake envenomation is a serious public health threat in the rural areas of Asian and African countries. To date, the only proven treatment for snake envenomation is antivenom therapy. Cross-neutralization of heterologous venoms by antivenom raised against venoms of closely related species has been reported. The present study examined the cross neutralizing potential of a newly developed polyvalent antivenom, termed Neuro Polyvalent Snake Antivenom (NPAV). NPAV was produced by immunization against 4 Thai elapid venoms.
    Matched MeSH terms: Survival Analysis
  11. Kuze N, Sipangkui S, Malim TP, Bernard H, Ambu LN, Kohshima S
    Primates, 2008 Apr;49(2):126-34.
    PMID: 18297473 DOI: 10.1007/s10329-008-0080-7
    We analysed the reproductive parameters of free-ranging female orangutans at Sepilok Orangutan Rehabilitation Centre (SORC) on Borneo Island, Sabah, Malaysia. Fourteen adult females produced 28 offspring in total between 1967 and 2004. The average censored interbirth interval (IBI) (i.e. offspring was still alive when mother produced a next offspring) was 6 years. This was shorter than censored IBIs reported in the wild but similar to IBIs reported for those in captivity. The nonparametric survival analysis (Kaplan-Meier method) revealed a significantly shorter IBI at SORC compared with wild orangutans in Tanjung Putting. The infant (0-3 years) mortality rate at SORC of 57% was much higher than rates reported both in the wild and captivity. The birth sex-ratio was significantly biassed toward females: 24 of the 27 sex-identified infants were females. The average age at first reproduction was 11.6 years, which is younger than the age in the wild and in captivity. The high infant mortality rate might be caused by human rearing and increased transmission of disease due to frequent proximal encounters with conspecifics around the feeding platforms (FPs). This young age of first reproduction could be because of the uncertainty regarding estimated ages of the female orangutans at SORC. It may also be affected by association with other conspecifics around FPs, which increased the number of encounters of the females with males compared with the number of encounters that would take place in the wild. Provision of FPs, which improves the nutritional condition of the females, caused the shorter IBI. The female-biassed birth sex-ratio can be explained by the Trivers and Willard hypothesis. The female-biassed sex ratio could be caused by the mothers being in poor health, parasite prevalence and/or high social stress (but not food scarcity) due to the frequent encounters with conspecifics around FPs.
    Matched MeSH terms: Survival Analysis
  12. Mohd Suan MA, Tan WL, Soelar SA, Ismail I, Abu Hassan MR
    Epidemiol Health, 2015;37:e2015017.
    PMID: 25868638 DOI: 10.4178/epih/e2015017
    OBJECTIVES: The goal of this study was to assess the relationship between intestinal obstruction and the prognosis of colorectal carcinoma.

    METHODS: Data pertaining to 4,501 colorectal carcinoma patients were extracted from the national colorectal registry and analysed. Survival analysis was performed using the Kaplan-Meier method. The log-rank test was used to compare the survival rate between patients with intestinal obstruction and those without intestinal obstruction. The p-values<0.05 were considered to indicate statistical significance. Simple Cox proportional hazards regression analysis was used to estimate the crude hazard ratio of mortality from colorectal cancer.

    RESULTS: Intestinal obstruction was reported in more than 13% of patients. The 3-year survival rate after treatment was 48.3% (95% confidence interval [CI], 43.9 to 52.8) for patients with intestinal obstruction (n=593) and 54.9% (95% CI, 53.1 to 56.6) for patients without intestinal obstruction (n=3,908). The 5-year survival rate for patients with intestinal obstruction was 37.3% (95% CI, 31.9 to 42.8), which was lower than that of patients without intestinal obstruction (45.6%; 95% CI, 43.5 to 47.7). After adjusting the hazard ratio for other prognostic variables, intestinal obstruction had a statistically significant negative correlation with the survival rate of colorectal cancer patients, with an adjusted hazard ratio of 1.22 (p=0.008).

    CONCLUSIONS: The presence of intestinal obstruction is associated with a lower survival rate among colorectal cancer patients.

    Matched MeSH terms: Survival Analysis
  13. Loke SR, Sing KW, Teoh GN, Lee HL
    Trop Biomed, 2015 Mar;32(1):76-83.
    PMID: 25801256 MyJurnal
    Space spraying of chemical insecticides is still an important mean of controlling Aedes mosquitoes and dengue transmission. For this purpose, the bioefficacy of space-sprayed chemical insecticide should be evaluated from time to time. A simulation field trial was conducted outdoor in an open field and indoor in unoccupied flat units in Kuala Lumpur, to evaluate the adulticidal and larvicidal effects of Sumithion L-40, a ULV formulation of fenitrothion. A thermal fogger with a discharge rate of 240 ml/min was used to disperse Sumithion L-40 at 3 different dosages (350 ml/ha, 500 ml/ha, 750 ml/ha) against lab-bred larvae and adult female Aedes aegypti and Aedes albopictus. An average of more than 80% adult mortality was achieved for outdoor space spray, and 100% adult mortality for indoor space spray, in all tested dosages. Outdoor larvicidal effect was noted up to 14 days and 7 days at a dosage of 500 and 750 ml/ha for Ae. aegypti and Ae. albopictus, respectively. Indoor larvicidal effect was up to 21 days (500 ml/ha) and 14 days (750 ml/ha), respectively, after spraying with larval mortality > 50% against Ae. aegypti. This study concluded that the effective dosage of Sumithion L-40 thermally applied against adult Ae. aegypti and Ae. albopictus indoor and outdoor is 500 and 750 ml/ha. Based on these dosages, effective indoor spray volume is 0.4 - 0.6 ml/m³. Additional indoor and outdoor larvicidal effect will be observed at these application dosages, in addition to adult mortality.
    Matched MeSH terms: Survival Analysis
  14. Tay JW, Lee CY
    Trop Biomed, 2015 Sep;32(3):453-62.
    PMID: 26695205 MyJurnal
    To evaluate the effects of the juvenile hormone analogue pyriproxyfen on colonies of the Pharaoh ant Monomorium pharaonis (L.), peanut oil containing different concentrations (0.3, 0.6, or 0.9%) of pyriproxyfen was fed to monogynous (1 queen, 500 workers, and 0.1 g of brood) and polygynous (8 queens, 50 workers, and 0.1 g of brood) laboratory colonies of M. pharaonis. Due to its delayed activity, pyriproxyfen at all concentrations resulted in colony elimination. Significant reductions in brood volume were recorded at weeks 3 - 6, and complete brood mortality was observed at week 8 in all treated colonies. Brood mortality was attributed to the disruption of brood development and cessation of egg production by queens. All polygynous colonies exhibited significant reduction in the number of queens present at week 10 compared to week 1. Number of workers was significantly lower in all treated colonies compared to control colonies at week 8 due to old-age attrition of the workers without replacement. At least 98.67 ± 1.33% of workers were dead at week 10 in all treated colonies. Thus, treatment with slow acting pyriproxyfen at concentrations of 0.3 - 0.9% is an effective strategy for eliminating Pharaoh ant colonies.
    Matched MeSH terms: Survival Analysis
  15. Dieng H, Rajasaygar S, Ahmad AH, Ahmad H, Rawi CS, Zuharah WF, et al.
    Acta Trop., 2013 Dec;128(3):584-90.
    PMID: 23999373 DOI: 10.1016/j.actatropica.2013.08.013
    Annually, 4.5 trillion cigarette butts (CBs) are flicked into our environment. Evidence exists that CB waste is deadly to aquatic life, but their lethality to the aquatic life of the main dengue vector is unknown. CBs are full of toxicants that occur naturally, during planting and manufacturing, which may act as larvicidal agents. We assessed Aedes aegypti vulnerability to Marlboro butts during its development. Overall, CBs showed insecticidal activities against larvae. At early phases of development, mortality rates were much higher in two CBs solution (2CBSol) and 3CBSol microcosms (MICRs). Larval survival gradually decreased with development in 1CBSol-MICRs. However, in great presence of CBs, mortality was high even for the late developmental stages. These results suggest that A. aegypti larvae are vulnerable to CB presence in their habitats, but this effect was seen most during the early developmental phases and in the presence of increased amounts of cigarette remnants. CB filters are being used as raw material in many sectors, i.e., brick, art, fashion, plastic industries, as a practical solution to the pollution problem, the observed butt waste toxicity to mosquito larvae open new avenues for the identification of novel insecticide products.
    Matched MeSH terms: Survival Analysis
  16. Thomas R, Hamat RA, Neela V
    J. Med. Microbiol., 2013 Nov;62(Pt 11):1777-9.
    PMID: 23988629 DOI: 10.1099/jmm.0.063230-0
    Matched MeSH terms: Survival Analysis
  17. Shepard DS, Undurraga EA, Halasa YA
    PLoS Negl Trop Dis, 2013;7(2):e2055.
    PMID: 23437406 DOI: 10.1371/journal.pntd.0002055
    BACKGROUND: Dengue poses a substantial economic and disease burden in Southeast Asia (SEA). Quantifying this burden is critical to set policy priorities and disease-control strategies.

    METHODS AND FINDINGS: We estimated the economic and disease burden of dengue in 12 countries in SEA: Bhutan, Brunei, Cambodia, East-Timor, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Viet Nam. We obtained reported cases from multiple sources--surveillance data, World Health Organization (WHO), and published studies--and adjusted for underreporting using expansion factors from previous literature. We obtained unit costs per episode through a systematic literature review, and completed missing data using linear regressions. We excluded costs such as prevention and vector control, and long-term sequelae of dengue. Over the decade of 2001-2010, we obtained an annual average of 2.9 million (m) dengue episodes and 5,906 deaths. The annual economic burden (with 95% certainty levels) was US$950m (US$610m-US$1,384m) or about US$1.65 (US$1.06-US$2.41) per capita. The annual number of disability-adjusted life years (DALYs), based on the original 1994 definition, was 214,000 (120,000-299,000), which is equivalent to 372 (210-520) DALYs per million inhabitants.

    CONCLUSION: Dengue poses a substantial economic and disease burden in SEA with a DALY burden per million inhabitants in the region. This burden is higher than that of 17 other conditions, including Japanese encephalitis, upper respiratory infections, and hepatitis B.

    Matched MeSH terms: Survival Analysis
  18. Ebau W, Rawi CS, Din Z, Al-Shami SA
    Asian Pac J Trop Biomed, 2012 Aug;2(8):631-4.
    PMID: 23569984 DOI: 10.1016/S2221-1691(12)60110-5
    To investigate the acute toxicity of cadmium and lead on larvae of two tropical Chironomid species, Chironomus kiiensis (C. kiiensis) Tokunaga and Chironomus javanus (C. javanus) Kieffer.
    Matched MeSH terms: Survival Analysis
  19. Mohammed R, Goh KL, Wong NW
    Med. J. Malaysia, 1996 Mar;51(1):99-102.
    PMID: 10967987
    Primary biliary cirrhosis is an uncommon disease amongst Malaysians. Over a 12-year period, between 1979 and 1991, only seven patients with clinical, biochemical and histologic evidence of primary biliary cirrhosis were identified in University Hospital Kuala Lumpur. All were Chinese females between the ages of 30 to 55 years. The presenting complaint was pruritus in 5 patients. All except one patient was jaundiced when the diagnosis was made. These patients were followed up from 1 to 11 years. Three deaths were reported, one from massive hemetemesis and two from liver failure.
    Matched MeSH terms: Survival Analysis
  20. Choudhury A, Jindal A, Maiwall R, Sharma MK, Sharma BC, Pamecha V, et al.
    Hepatol Int, 2017 Sep;11(5):461-471.
    PMID: 28856540 DOI: 10.1007/s12072-017-9816-z
    BACKGROUND AND AIMS: Acute-on-chronic liver failure (ACLF) is a progressive disease associated with rapid clinical worsening and high mortality. Early prediction of mortality and intervention can improve patient outcomes. We aimed to develop a dynamic prognostic model and compare it with the existing models.

    METHODS: A total of 1402 ACLF patients, enrolled in the APASL-ACLF Research Consortium (AARC) with 90-day follow-up, were analyzed. An ACLF score was developed in a derivation cohort (n = 480) and was validated (n = 922).

    RESULTS: The overall survival of ACLF patients at 28 days was 51.7%, with a median of 26.3 days. Five baseline variables, total bilirubin, creatinine, serum lactate, INR and hepatic encephalopathy, were found to be independent predictors of mortality, with AUROC in derivation and validation cohorts being 0.80 and 0.78, respectively. AARC-ACLF score (range 5-15) was found to be superior to MELD and CLIF SOFA scores in predicting mortality with an AUROC of 0.80. The point scores were categorized into grades of liver failure (Gr I: 5-7; II: 8-10; and III: 11-15 points) with 28-day cumulative mortalities of 12.7, 44.5 and 85.9%, respectively. The mortality risk could be dynamically calculated as, with each unit increase in AARC-ACLF score above 10, the risk increased by 20%. A score of ≥11 at baseline or persisting in the first week was often seen among nonsurvivors (p = 0.001).

    CONCLUSIONS: The AARC-ACLF score is easy to use, dynamic and reliable, and superior to the existing prediction models. It can reliably predict the need for interventions, such as liver transplant, within the first week.

    Matched MeSH terms: Survival Analysis
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