1.Cost-effectiveness analysis of various Coronavirus Disease (COVID-19) vaccines against emerging variants of concern in the Philippines.
Haidee A. VALVERDE ; Clarence C. YACAPIN ; Paul Matthew D. PASCO ; Joana Ophelia M. REAL ; Jaifred Christian F. LOPEZ ; Hannah Eleanor CLAPHAM ; Yi Zhen CHEW ; Chris Erwin G. MERCADO ; Siobhan BOTWRIGHT ; Madison SILZLE ; Hilton Y. LAM
Acta Medica Philippina 2025;59(14):37-48
OBJECTIVES
During the early COVID-19 pandemic (2020 to mid-2021), the Philippine government relied on nonpharmaceutical interventions such as lockdowns and Enhanced Community Quarantine (ECQ). With the emergency use authorization of vaccines, assessing their potential impact became essential. This study develops a Philippine model to evaluate the epidemiologic and economic effects of COVID-19 vaccination, estimating its impact on mortality, hospitalization, and mild/asymptomatic cases under various prioritization strategies, including booster doses and the presence of variants of concern.
METHODSA dynamic transmission model (DTM) with an SEIR (Susceptible-Exposed-Infected-Recovered) structure was calibrated using local data, including case numbers, deaths, seroprevalence, vaccination coverage, and intervention costs. The model’s outputs informed a cost-effectiveness analysis (CEA) from health system and societal perspectives over a two-year horizon. Incremental Cost-Effectiveness Ratios (ICERs) were calculated, with costs adjusted to 2020 prices and discount rates of 3%-10% applied. Sensitivity analyses, including one-way and probabilistic approaches, assessed robustness, while a budget impact analysis (BIA) estimated government expenditures in 2020 and 2021.
RESULTSWithout vaccination, daily cases could have peaked at 400,000 between February and May 2021. A vaccination campaign was projected to reduce cases to around 20,000, significantly lowering mortality.
From the health system perspective, the estimated cost without vaccination was PhP 14.46 trillion, with 93.83 million QALYs. With vaccination, costs dropped to PhP 2.36 trillion, while QALYs increased to 101.79 million. From the societal perspective, costs were PhP 14.68 trillion without vaccination and PhP 2.38 trillion with vaccination, with the same QALY outcomes.
CEA results confirmed that vaccination was cost-saving, with ICERs of -PhP 1,520,727.28 per QALY (health system) and -PhP 1,546,171.63 per QALY (societal). Sensitivity analyses supported these findings, with oneway sensitivity analysis showing minimal impact from parameter changes and probabilistic sensitivity analysis confirming cost-saving outcomes. The BIA estimated government expenditures of PhP 983.45 billion in 2020 and PhP 1.47 trillion in 2021 for the vaccine scenario, lower than the no-vaccine scenario.
CONCLUSIONIndeed, our modeling has shown that COVID-19 vaccines could mitigate the spread of COVID-19 and provide good value for money.
Human ; Covid-19 ; Cost-effectiveness Analysis ; Vaccines ; Philippines
2.2021 Asian Pacific Society of Cardiology Consensus Recommendations on the use of P2Y12 receptor antagonists in the Asia-Pacific Region: Special populations.
W E I C H I E H T A N TAN ; P C H E W CHEW ; L A M T S U I TSUI ; T A N TAN ; D U P L Y A K O V DUPLYAKOV ; H A M M O U D E H HAMMOUDEH ; Bo ZHANG ; Yi LI ; Kai XU ; J O N G ONG ; Doni FIRMAN ; G A M R A GAMRA ; A L M A H M E E D ALMAHMEED ; D A L A L DALAL ; T A N TAN ; S T E G STEG ; N N G U Y E N NGUYEN ; A K O AKO ; A L S U W A I D I SUWAIDI ; C H A N CHAN ; S O B H Y SOBHY ; S H E H A B SHEHAB ; B U D D H A R I BUDDHARI ; Zu Lv WANG ; Y E A N Y I P F O N G FONG ; K A R A D A G KARADAG ; K I M KIM ; B A B E R BABER ; T A N G C H I N CHIN ; Ya Ling HAN
Chinese Journal of Cardiology 2023;51(1):19-31
3.Evaluating the Revised American Society for Gastrointestinal Endoscopy Guidelines for Common Bile Duct Stone Diagnosis
Jake S. JACOB ; Michelle E. LEE ; Erin Y. CHEW ; Aaron P. THRIFT ; Robert J. SEALOCK
Clinical Endoscopy 2021;54(2):269-274
Background/Aims:
The American Society for Gastrointestinal Endoscopy (ASGE) revised its guidelines for risk stratification of patients with suspected choledocholithiasis. This study aimed to assess the diagnostic performance of the revision and to compare it to the previous guidelines.
Methods:
We conducted a retrospective cohort study of 267 patients with suspected choledocholithiasis. We identified high-risk patients according to the original and revised guidelines and examined the diagnostic accuracy of both guidelines. We measured the association between individual criteria and choledocholithiasis.
Results:
Under the original guidelines, 165 (62%) patients met the criteria for high risk, of whom 79% had confirmed choledocholithiasis. The categorization had a sensitivity and specificity of 68% and 55%, respectively, for the detection of choledocholithiasis. Under the revised guidelines, 86 (32%) patients met the criteria for high risk, of whom 83% had choledocholithiasis. The revised categorization had a lower sensitivity and higher specificity of 37% and 80%, respectively. The positive predictive value of the high-risk categorization increased with the revision, reflecting a potential decrease in diagnostic endoscopic retrograde cholangiopancreatograpies (ERCPs). Stone visualized on imaging had the greatest specificity for choledocholithiasis. Gallstone pancreatitis was not associated with the risk for choledocholithiasis.
Conclusions
The 2019 revision of the ASGE guidelines decreases the utilization of ERCP as a diagnostic modality and offers an improved risk stratification tool.
4.Evaluating the Revised American Society for Gastrointestinal Endoscopy Guidelines for Common Bile Duct Stone Diagnosis
Jake S. JACOB ; Michelle E. LEE ; Erin Y. CHEW ; Aaron P. THRIFT ; Robert J. SEALOCK
Clinical Endoscopy 2021;54(2):269-274
Background/Aims:
The American Society for Gastrointestinal Endoscopy (ASGE) revised its guidelines for risk stratification of patients with suspected choledocholithiasis. This study aimed to assess the diagnostic performance of the revision and to compare it to the previous guidelines.
Methods:
We conducted a retrospective cohort study of 267 patients with suspected choledocholithiasis. We identified high-risk patients according to the original and revised guidelines and examined the diagnostic accuracy of both guidelines. We measured the association between individual criteria and choledocholithiasis.
Results:
Under the original guidelines, 165 (62%) patients met the criteria for high risk, of whom 79% had confirmed choledocholithiasis. The categorization had a sensitivity and specificity of 68% and 55%, respectively, for the detection of choledocholithiasis. Under the revised guidelines, 86 (32%) patients met the criteria for high risk, of whom 83% had choledocholithiasis. The revised categorization had a lower sensitivity and higher specificity of 37% and 80%, respectively. The positive predictive value of the high-risk categorization increased with the revision, reflecting a potential decrease in diagnostic endoscopic retrograde cholangiopancreatograpies (ERCPs). Stone visualized on imaging had the greatest specificity for choledocholithiasis. Gallstone pancreatitis was not associated with the risk for choledocholithiasis.
Conclusions
The 2019 revision of the ASGE guidelines decreases the utilization of ERCP as a diagnostic modality and offers an improved risk stratification tool.
5.Choroidal thickness in Malaysian eyes with full-thickness macular holes
Tan Y CHEW ; Vengadasalam R SELVA ; Samsudin AMIR ; Khaliddin NURLIZA
International Eye Science 2018;18(3):401-405
·AIM: To compare choroidal thickness at the macula in eyes with unilateral idiopathic full - thickness macular holes (FTMH) with that of unaffected fellow eyes, and eyes of normal control patients. ·METHODS: Cross-sectional study. Thirty patients with unilateral idiopathic FTMH and thirty age, sex, and race-matched controls were recruited. Axial lengths were measured using laser interferometry. Enhanced depth imaging optical coherence tomography images were obtained using Heidelberg spectral - domain optical coherence tomography. Choroidal thickness was measured at the fovea, and at 1 mm and 2 mm nasally, temporally, superiorly and inferiorly from the center of the fovea. Statistical analysis was performed using independent and paired t-tests, chi-square tests, and Pearson correlation tests (P<0.05). ·RESULTS:The mean subfoveal choroidal thickness was 201.0±44.0 μ m in the FTMH group,225.3± 51.4 μ m in the fellow eye group and 262.3±70.3 μ m in the control group. The choroid was thinner in FTMH eyes at all locations when compared to control eyes(P<0.05). The fellow eye group also had thinner choroids than the control group at all locations except at 1 mm and 2 mm nasal to the fovea (P<0.05). Choroidal thickness in the FTMH group was lower than in the fellow eye group, but the differences were not statistically significant (P > 0.05). Choroidal thickness was generally highest subfoveally and lowest nasally. Subfoveal choroidal thickness was negatively correlated with age (r = -0.278, P = 0.032), and axial length (r=-0.328,P=0.011). ·CONCLUSION:Choroidal thickness is lower in both eyes of patients with unilateral FTMH compared to healthy control eyes.
6.Ministry of Health Clinical Practice Guidelines: Hypertension.
Jam Chin TAY ; Ashish Anil SULE ; E K CHEW ; Jeannie S TEY ; Titus LAU ; Simon LEE ; Sze Haur LEE ; Choon Kit LEONG ; Soo Teik LIM ; Lip Ping LOW ; Vernon Min Sen OH ; K Y PHOON ; Kian Wee Kenneth TAN ; Akira WU ; Loo See YEO
Singapore medical journal 2018;59(1):17-27
The Ministry of Health (MOH) has updated the clinical practice guidelines on hypertension to provide doctors and patients in Singapore with evidence-based treatment for hypertension. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on hypertension, for the information of SMJ readers. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov.sg/content/moh_web/healthprofessionalsportal/doctors/guidelines/cpg_medical.html. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.
Antihypertensive Agents
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therapeutic use
;
Blood Pressure
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Evidence-Based Medicine
;
Health Promotion
;
Humans
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Hypertension
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diagnosis
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therapy
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Life Style
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Risk Factors
;
Singapore
7.High Intensity Interval Training Increases Natural Killer Cell Number and Function in Obese Breast Cancer-challenged Mice and Obese Women.
Nicole G BARRA ; Isabella Y FAN ; Jenna B GILLEN ; Marianne CHEW ; Katarina MARCINKO ; Gregory R STEINBERG ; Martin J GIBALA ; Ali A ASHKAR
Journal of Cancer Prevention 2017;22(4):260-266
High intensity interval training (HIIT) boosts natural killer (NK) cell number and activity in normal weight breast cancer patients; however, whether this occurs in obese individuals is not well established. The goal of this study was to determine whether HIIT effectively boosts NK cells as a therapeutic strategy against breast cancer in an obese mouse model and in overweight/obese women. Diet induced female C57Bl/6 obese mice were assigned to undergo HIIT for four weeks or remain sedentary. Female participants were subjected to a six weeks HIIT protocol. HIIT mice acclimatized to treadmill running were subsequently injected with 5 × 105 polyoma middle T (MT) breast cancer cells intravenously. NK cell number and activation were monitored using flow cytometry, and tumor burden or lipid content evaluated from histological lung and liver tissues, respectively. In both mice and humans, circulating NK cell number and activation (CD3−NK1.1+CD27+ and CD3−CD56+, respectively) markedly increased immediately after HIIT. HIIT obese mice had reduced lung tumor burden compared to controls following MT challenge, and had diminished hepatic lipid deposition despite minimal body weight loss. Our findings demonstrate that HIIT can benefit obese individuals by enhancing NK cell number and activity, reducing tumor burden, and enhancing metabolic health.
Animals
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Body Weight
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Breast Neoplasms
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Breast*
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Cell Count
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Diet
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Female
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Flow Cytometry
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Humans
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Killer Cells, Natural*
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Liver
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Lung
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Mice*
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Mice, Obese
;
Obesity
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Running
;
Tumor Burden
8.Use of the Sole Flap to Convert an Above Knee Amputation to a Below Knee Amputation in Trauma.
Faisal JOHANDI ; Zhihao TANG ; Sandeep Jacob SEBASTIN ; Winston Y C CHEW
Annals of the Academy of Medicine, Singapore 2015;44(5):191-193
Adult
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Amputation
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methods
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Female
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Humans
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Knee Joint
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Leg Injuries
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surgery
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Male
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Surgical Flaps
9.Singapore Chapter of Rheumatologists Consensus Statement on the Eligibility for Government Subsidy of Biologic Disease Modifying Antirheumatic Agents for Treatment of Rheumatoid Arthritis (RA).
Gim Gee TENG ; Peter P CHEUNG ; Manjari LAHIRI ; Jane A CLAYTON ; Li Ching CHEW ; Ee Tzun KOH ; Wei Howe KOH ; Tang Ching LAU ; Swee Cheng NG ; Bernard Y THONG ; Archana R VASUDEVAN ; Jon K C YOONG ; Keng Hong LEONG
Annals of the Academy of Medicine, Singapore 2014;43(8):400-411
INTRODUCTIONUp to 30% of patients with rheumatoid arthritis (RA) respond inadequately to conventional non-biologic disease modifying antirheumatic drugs (nbDMARDs), and may benefit from therapy with biologic DMARDs (bDMARDs). However, the high cost of bDMARDs limits their widespread use. The Chapter of Rheumatologists, College of Physicians, Academy of Medicine, Singapore aims to define clinical eligibility for government-assisted funding of bDMARDs for local RA patients.
MATERIALS AND METHODSEvidence synthesis was performed by reviewing 7 published guidelines on use of biologics for RA. Using the modified RAND/UCLA Appropriateness Method (RAM), rheumatologists rated indications for therapies for different clinical scenarios. Points reflecting the output from the formal group consensus were used to formulate the practice recommendations.
RESULTSTen recommendations including diagnosis of RA, choice of disease activity measure, initiation and continuation of bDMARD and option of first and second-line therapies were formulated. The panellists agreed that a bDMARD is indicated if a patient has (1) active RA with a Disease Activity Score in 28 joints (DAS28) score of ≥3.2, (2) a minimum of 6 swollen and tender joints, and (3) has failed a minimum of 2 nbDMARD combinations of adequate dose regimen for at least 3 months each. To qualify for continued biologic therapy, a patient must have (1) documentation of DAS28 every 3 months and (2) at least a European League Against Rheumatism (EULAR) moderate response by 6 months after commencement of therapy.
CONCLUSIONThe recommendations developed by a formal group consensus method may be useful for clinical practice and guiding funding decisions by relevant authorities in making bDMARDs usage accessible and equitable to eligible patients in Singapore.
Antirheumatic Agents ; economics ; therapeutic use ; Arthritis, Rheumatoid ; drug therapy ; Financing, Government ; Humans ; Practice Guidelines as Topic ; Singapore
10.Use of the Fix and Flap Approach to Complex Open Elbow Injury: The Role of the Free Anterolateral Thigh Flap.
Christopher Hoe Kong CHUI ; Chin Ho WONG ; Winston Y CHEW ; Mun Hon LOW ; Bien Keem TAN
Archives of Plastic Surgery 2012;39(2):130-136
BACKGROUND: Complex elbow injuries with associated nerve, muscle, or joint injury commonly develop post-inury stiffness. In order to preserve function, joint congruency, elbow stability and durable wound coverage must be achieved in a timely manner. METHODS: A retrospective review of patients who underwent orthopaedic fixation followed by free anterolateral thigh (ALT) flap soft tissue coverage was performed. Five patients were identified and included in this study. RESULTS: We present a series of 5 cases managed with this principle. Soft tissue defects ranged in size from 4x9 cm (36 cm2) to 15x30 cm (450 cm2) and were located either posteriorly (n=4) or anteriorly (n=1). Associated injuries included open fractures (n=3) and motor nerve transection (n=2). Wound coverage was achieved in a mean duration of 18.8 days (range, 11 to 42 day). There were no flap failures and no major complications. The mean postoperative active elbow motion was 102degrees (range, 45degrees to 140degrees). CONCLUSIONS: In our small series we have highlighted the safety and utility of using the free ALT flap in complex elbow injuries. The ALT flap has many advantages which include abundant skin and subcutaneous tissue; vascularised vastus lateralis muscle that was used in our series to obliterate dead space, provide a vascular bed for nerve grafts and combat infection; and, access to fascia lata grafts for reconstruction of the triceps tendon.
Elbow
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Elbow Joint
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Fascia Lata
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Fractures, Open
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Free Tissue Flaps
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Humans
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Joints
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Muscles
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Quadriceps Muscle
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Reconstructive Surgical Procedures
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Retrospective Studies
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Skin
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Tendons
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Thigh
;
Transplants


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