1. Comparison of Cox proportional hazards model, Cox proportional hazards with time-varying coefficients model, and lognormal accelerated failure time model: Application in time to event analysis of melioidosis patients
Kamaruddin MARDHIAH ; Kamaruddin MARDHIAH ; Nadiah WAN-ARFAH ; Nyi NAING ; Muhammad HASSAN ; Huan-Keat CHAN
Asian Pacific Journal of Tropical Medicine 2022;15(3):128-134
Objective: To compare the prognostic factors of mortality among melioidosis patients between lognormal accelerated failure time (AFT), Cox proportional hazards (PH), and Cox PH with timevarying coefficient (TVC) models. Methods: A retrospective study was conducted from 2014 to 2019 among 453 patients who were admitted to Hospital Sultanah Bahiyah, Kedah and Hospital Tuanku Fauziah, Perlis in Northern Malaysia due to confirmed-cultured melioidosis. The prognostic factors of mortality from melioidosis were obtained from AFT survival analysis, and Cox s models and the findings were compared by using the goodness of fit methods. The analyses were done by using Stata SE version 14.0. Results: A total of 242 patients (53.4%) survived. In this study, the median survival time of melioidosis patients was 30.0 days (95% CI 0.0-60.9). Six significant prognostic factors were identified in the Cox PH model and Cox PH-TVC model. In AFT survival analysis, a total of seven significant prognostic factors were identified. The results were found to be only a slight difference between the identified prognostic factors among the models. AFT survival showed better results compared to Cox's models, with the lowest Akaike information criteria and best fitted Cox-snell residuals. Conclusions: AFT survival analysis provides more reliable results and can be used as an alternative statistical analysis for determining the prognostic factors of mortality in melioidosis patients in certain situations.
2. Predictors of in-hospital mortality by logistic regression analysis among melioidosis patients in Northern Malaysia: A retrospective study
Kamaruddin MARDHIAH ; Kamaruddin MARDHIAH ; Nadiah WAN-ARFAH ; Nyi Nyi NAING ; Muhammad Radzi Abu HASSAN ; Huan-Keat CHAN
Asian Pacific Journal of Tropical Medicine 2021;14(8):356-363
Objective: To identify the predictors of mortality among in-hospital melioidosis patients. Methods: A total of 453 patients in Hospital Sultanah Bahiyah, Kedah, and Hospital Tuanku Fauziah, Perlis with culture-confirmed melioidosis were retrospectively included in the study. Advanced multiple logistic regression was used to obtain the final model of predictors of mortality from melioidosis. The analysis was performed using STATA/SE 14.0. Results: A total of 50.11% (227/453) of the patients died at the hospital, and a majority (86.75%, 393/453) of cases were bacteremic. The logistic regression estimated that the bacteremic type of melioidosis, low platelet count, abnormal white blood cell counts, and increased urea value were predictors of mortality. The results showed that bacteremic melioidosis increased the risk of death by 4.39 times (OR 4.39, 95% CI 1.83-10.55, P=0.001) compared to non-bacteremic melioidosis. Based on laboratory test, the adjusted ORs from the final model showed that all three blood investigations were included as the associated factors of mortality for the disease [high white blood cell (>10×109/L): OR 2.43, 95% CI 1.41-4.17, P<0.001; low white blood cell (<4×109/L): OR 3.82, 95% CI 1.09-13.34, P=0.036; low platelet (<100×109/L): OR 4.19, 95% CI 1.89-9.30, P<0.001; high urea (>7 800 μmol/L): OR 5.53, 95% CI 2.50-12.30, P<0.001; and low level of urea (<2 500 μmol/L): OR 3.52, 95% CI 1.71-7.23, P=0.001). Conclusions: Routine blood investigations during a hospital admission can early identify predictors of mortality in melioidosis patients.
3.Gene isolation and prediction of the corresponding three-dimensional structure of subtilisin from the psychrophilic yeast, Glaciozyma antarctica PI12
Siti Mardhiah Mustafha ; Shazilah Kamaruddin ; Nor Muhammad Mahadi ; Abdul Munir Abdul Murad ; Farah Diba Abu Bakar
Malaysian Journal of Microbiology 2018;14(6):452-461
Aims:
Subtilisin, a serine protease, is a key player in many industrial applications especially in the detergent industry. Most reported subtilisins originate from mesophilic and thermophilic microorganisms. Only scarce information about cold-active subtilisins from psychrophilic microbes is available. Here we describe the isolation, cloning and in silico characterisation of a gene encoding subtilisin in the obligate psychrophilic yeast, Glaciozyma antarctica PI12.
Methodology and results:
A full-length cDNA from Glaciozyma antarctica encoding subtilisin (GaSUB) was isolated through Reverse-Transcription-Polymerase Chain Reaction (RT-PCR) techniques. The open reading frame of GaSUB comprised 1,125 nucleotides encoding 375 amino acids. The GaSUB amino acid sequence had 49% sequence identity with a subtilisin from the yeast, Puccinia striiformis. Bioinformatic analyses revealed that the GaSUB protein contains a domain that represents the S8 domain of the largest protease family. The predicted model of GaSUB protein using MODELLER and Pymol software revealed that this enzyme has longer loops and less intramolecular interactions between amino acid residues as compared to its mesophilic and thermophilic counterparts. These characteristics are known to help in protein flexibility and stability in cold-active enzymes.
Conclusion, significance and impact of study
Bioinformatics characterisations suggested that this enzyme is uniquely adapted to cold environments. Further work using amplified cDNA will be conducted to confirm the catalytic function of this enzyme.
4.Morbidly adherent placenta: One-year case series in a tertiary hospital
Roziana Ramli ; Kamarul Azhar Kamaruddin ; Lau Jia Him ; Aina Mardhiah Abdul Aziz ; Nadia Ramli ; Siti Nordiana Ayub ; Mohd Zulkifli Kassim
The Medical Journal of Malaysia 2019;74(2):128-132
Objective: To analyse the clinical characteristics of patients
with morbidly adherent placenta (MAP). Findings of this
study will be used to identify patients at risk of MAP and to
outline the best management strategy to deal with this
devastating condition.
Methods: Delivery records in Hospital Sultanah Nur Zahirah,
Terengganu from 1st. January 2016 until 31st. December
2016 were reviewed and analysed.
Results: Out of the 15,837 deliveries, eight cases of MAP
were identified. Six out of eight patients had previous
caesarean scar with concomitant placenta praevia, the other
two patients had previous caesarean scar with history of
placenta praevia in previous pregnancies. Seven out of eight
cases were suspected to have MAP based on risk factors.
Correct diagnosis was made by ultrasound in five patients,
all with histologically confirmed moderate/severe degree of
abnormal placentation. The other two cases of ‘unlikely
MAP’, demonstrated segmental MAP intra-operatively with
histologically confirmed milder degree of abnormal
placentation. Total intraoperative blood loss ranged from 0.8
to 20 litres. Prophylactic internal iliac artery balloon
occlusion was associated with significantly less blood loss.
Conclusion: Antenatal diagnosis is essential in outlining the
best management strategy in patients with MAP. Ultrasound
may not be accurate in ruling out lower degree of MAP. Apart
from having a scarred uterus with concomitant placenta
praevia, history of having placenta praevia in previous
pregnancy is also a risk factor for MAP. Prophylactic internal
iliac artery balloon occlusion is associated with significantly
less blood loss and should be considered in cases
suspected with MAP.